11-23-2006, 08:18 AM
Wise, maybe my phrasing of the title of the thread caused a misconception. I realize after reading your post that "self-aware" is a broad term that can be used to describe many different kinds of behavior.
But how many species can recognize themselves in a mirror? Distinguish themselves as being an individual, and not mistake the image as another member of one's species? This is the form of self-awareness the article addresses.
Do you believe it is it true only dolphins, great apes, humans and now elephants can do this?
Early studies by Hauser, et al. in 1995 (Hauser, et al., 1995) suggested that chimpanzees and gorillas cannot distinguish between images of self compared to video images of others. However, other studies suggest that this ability is age-dependent (Eddy, et al., 1996, Povinelli, et al., 1994, Povinelli, et al., 1993) and that older chimpanzees do recognize themselves in mirror images (Kojima, et al., 2003, de Veer, et al., 2003). Likewise, orangutans (Tobach, et al., 1997) and gorillas can learn to understand mirror reflections of their body. Note that rhesus monkeys prefer video images of themselves rather than their roommates (Washburn, et al., 1997). Marmoset monkeys, on the other hand, even after extensive training with mirror-related tasks, often failed to find markers on their body that they can only see in mirrors (Heschl and Burkart, 2006). Capuchin monkeys will look more at non-distorted mirrored images of themselves but they show no evidence of self-directed responses (Paukner, et al., 2004). Tamarin monkeys show more interest to real-time images in mirrors than non-moving digitized photographs of themselves (Neiworth, et al., 2001). Note that most of these monkeys are able to use a mirror instrumentally to grasp at hidden objects, while failing the marker test.
An early study by Marten & Psarakos in 1995 (Marten and Psarakos, 1995) suggested that dolphins can recognize self in video images but this conclusion was controversial (Anderson, 1995, Loveland, 1995, Mitchell, 1995, Hart and Whitlow, 1995). Later studies suggest that dolphins apparently not only show interest in mirrored reflections of themselves but can use the mirrors to investigate marked parts of their bodies (Reiss and Marino, 2001). Likewise, killer whales and false killer whales (pseudorca crassidens) are able to recognize themselves and pass marker tests whereas California sea lions cannot (Delfour and Marten, 2001).
There have been many studies of visual self-recognition phenomenon in adult humans. For example, self recognition depends on the angle of visualization (Jokisch, et al., 2006). Different parts (Sugiura, et al., 2006, Platek, et al., 2006) and both sides (Uddin, et al., 2005) of the brain are involved in self-recognition of the face and different parts of the body. The right hemisphere is involved in self-recognition (Turk, et al., 2002) or morphed self-faces (Kircher, et al., 2001) whereas the prefrontal cortex is involved in self-awareness (Keenan, et al., 1999). Recognition of one’s own face (Sugiura, et al., 2005) and hands involve different mechanisms and information. The latter, for example, is facilitated by memory of voluntary movement of the hand (Tsakiris, et al., 2005, van den Bos and Jeannerod, 2002) while facial self-recognition is facilitated by body odor and auditory cues (Platek, et al., 2004).
Visual self-recognition can be impaired in various psychological and neurological conditions (Zeman, 2001), such as autism (Mitchell, 1997), infants cared for by depressed mothers (Cicchetti, et al., 1997), and schizophrenia (Jeannerod, 2003). Failure to recognize oneself in a mirror is called the “mirror sign” and is considered evidence of profound neurological impairment (Phillips, 1996). Studies of human toddlers (18-24 months old) suggest that visual self-recognition emerges around the age of 3-4. Three-year old children will touch stickers placed on their bodies that they can see only in a mirror (Nielsen, et al., 2006) and their performance improves with age (Zelazo, et al., 1999). Most 4 year olds will reach for their heads if they see an image of themselves with the sticker on the head but 2-year olds are less likely to do so (Povinelli, et al., 1996). While 2.5 year old children can use delayed video information to locate objects in space that cannot be seen by the unaided eye, they cannot use this type of information to locate objects on their bodies, such a sticker in their hair (Skouteris, et al., 2006).
Babies are self-aware long before they develop mirror self-recognition (Rochat, 1998). Five-month old infants, for example, show a significant preference for images of their own faces compared to images of peers and dolls (Legerstee, et al., 1998). In 1986, Priel & Schonen (Priel and de Schonen, 1986) compared the response of children who had been exposed to mirrors and those who had not seen mirrors before, finding that self-recognition does not depend on experience whereas experience with mirrors strongly influences their capacity to relate mirror images with real spaces. Severely autistic children (Spiker and Ricks, 1984, Dawson and McKissick, 1984), maltreated infants (Schneider-Rosen and Cicchetti, 1984), children with Down’s syndrome (Mans, et al., 1978), and mentally retarded adolescents (Fryrear, et al., 1981) show less capacity for visual self-recognition.
The recent demonstration (Plotnik, et al., 2006) that elephants not only recognize themselves in mirrors but engage in investigative behaviors that show awareness of what a mirror image represents extends the range of animals that exhibit visual self-recognition, an ability that was thought to be limited to anthropoid and cetaceans (Marino, 2002). It is important to note that elephants have significant individual variations in ability to do visual discrimination tasks (Nissani, et al., 2005). Elephants have the largest brains amongst land mammals (Cozzi, et al., 2001). Amongst marine mammals, the cetaceans have the largest brains but close examination of the cetacean brains suggest that large volumetric sizes do not necessarily mean more neurons. The cetacean brain has unusually high numbers of glial cells. Manger (Manger, 2006) has recently proposed that the large size of the cetacean brain may have evolved in part to withstand heat loss in water.
I wonder what other animals with large brains can recognize themselves in mirrors. For example, the octopus is one of the most intelligent non-vertebrate creatures with exceptional visual capabilities. I also wonder about self-recognition based on other senses. Kojima, et al. (Kojima, et al., 2003) studied the ability of chimpanzees to recognize their own vocalizations and they seem not to show vocal self-identification. I have observed rats showing greater interest in sniffing feces of other rats than their own, suggesting that they distinguish self from others. There are also differences amongst different strains of rats and their ability to recognize each other and humans. For example, Long-Evan’s hooded rats appear to recognize people familiar to them whereas Sprague-Dawley rats do so to a lesser extent. Some evidence suggests that olfaction and audition may play an important role in human self-recognition (Platek, et al., 2004). However, olfactory self-recognition depends on gender. Platek, et al. (Platek, et al., 2001), for example, found that 59% of women can recognize their own body odor whereas only 6% of males do so.
Hauser MD, Kralik J, Botto-Mahan C, Garrett M and Oser J (1995). Self-recognition in primates: phylogeny and the salience of species-typical features. Proc Natl Acad Sci U S A 92: 10811-14. Self-recognition has been explored in nonlinguistic organisms by recording whether individuals touch a dye-marked area on visually inaccessible parts of their face while looking in a mirror or inspect parts of their body while using the mirror's reflection. Only chimpanzees, gorillas, orangutans, and humans over the age of approximately 2 years consistently evidence self-directed mirror-guided behavior without experimenter training. To evaluate the inferred phylogenetic gap between hominoids and other animals, a modified dye-mark test was conducted with cotton-top tamarins (Saguinus oedipus), a New World monkey species. The white hair on the tamarins' head was color-dyed, thereby significantly altering a visually distinctive species-typical feature. Only individuals with dyed hair and prior mirror exposure touched their head while looking in the mirror. They looked longer in the mirror than controls, and some individuals used the mirror to observe visually inaccessible body parts. Prior failures to pass the mirror test may have been due to methodological problems, rather than to phylogenetic differences in the capacity for self-recognition. Specifically, an individual's sensitivity to experimentally modified parts of its body may depend crucially on the relative saliency of the modified part (e.g., face versus hair). Moreover, and in contrast to previous claims, we suggest that the mirror test may not be sufficient for assessing the concept of self or mental state attribution in nonlinguistic organisms. Department of Anthropology, Harvard University, Cambridge, MA 02138, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7479889
Eddy TJ, Gallup GG, Jr. and Povinelli DJ (1996). Age differences in the ability of chimpanzees to distinguish mirror-images of self from video images of others. J Comp Psychol 110: 38-44. To evaluate Heyes's (1994) claim that chimpanzees are incapable of using mirrored information to obtain otherwise unavailable information about the self, we exposed two different age groups of chimpanzees (3-year-olds and 7- to 10-year-olds) to mirrors and video images of conspecifics. Their reactions to these stimuli were videotaped and were later scored for behavioral indices of self-recognition by a trained observer who was blind to the purpose and conditions of the study. Some types of behavior (contingent facial and body movements) were clearly influenced by the type of stimulus that the chimpanzees were viewing but not by age; however, other behaviors (self-exploration) were affected by age in conjunction with the type of stimulus the animals were viewing. The results suggest that, unlike self-exploratory behavior, contingent facial and body movements may not, by themselves, be reliable indicators of self-recognition. New Iberia Research Center, University of Southwestern Louisiana 70560, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8851551
Povinelli DJ, Rulf AB and Bierschwale DT (1994). Absence of knowledge attribution and self-recognition in young chimpanzees (Pan troglodytes). J Comp Psychol 108: 74-80. Mirror self-recognition in chimpanzees (Pan troglodytes) is typically delayed until 4 1/2-8 years of age. Also, species capable of mirror self-recognition may be capable of some forms of mental state attribution related to intentions and knowledge. Previous investigations of knowledge attribution by chimpanzees used adolescents and adults but did not explicitly test for self-recognition. We report an investigation of knowledge attribution in 6 young chimpanzees previously tested for self-recognition. Subjects were required to discriminate between a person who had seen where food was hidden and another person who had not. The results are consistent with the proposition that most chimpanzees younger than 4 1/2 years of age show neither mirror self-recognition nor knowledge attribution. The results are also consistent with the idea that, just as in humans, development of self-recognition in chimpanzees may precede development of knowledge attribution. Laboratory of Comparative Behavioral Biology, New Iberia Research Center, University of Southwestern, Louisiana 70560. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8174347
Povinelli DJ, Rulf AB, Landau KR and Bierschwale DT (1993). Self-recognition in chimpanzees (Pan troglodytes): distribution, ontogeny, and patterns of emergence. J Comp Psychol 107: 347-72. Investigations of mirror self-recognition (SR) in chimpanzees (Pan troglodytes) have had small samples and divergent methods. In Experiment 1, 105 chimpanzees (10 months to 40 years of age) were observed for signs of SR across 5 days of continuous mirror exposure. In Experiments 2 and 3, negative SR adult and adolescent chimpanzees were saturated with mirror exposure in efforts to facilitate SR and a longitudinal study was conducted with a number of young subjects. In Experiment 4, mark tests were administered to groups of positive SR, negative SR, and ambiguous SR subjects. In Experiment 5, we explored whether previous positive SR reports in young chimpanzees were artifacts of increased arousal during mirror exposure. Results suggest that SR typically emerges at 4.5-8 years of age, at the population level the capacity declines in adulthood, and in group settings SR typically occurs within minutes of a subject's exposure to a mirror. Laboratory of Comparative Behavioral Biology, New Iberia Research Center, University of Southwestern Louisiana 70560. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8112048
Kojima S, Izumi A and Ceugniet M (2003). Identification of vocalizers by pant hoots, pant grunts and screams in a chimpanzee. Primates 44: 225-30. Identification of vocalizers was examined using an auditory-visual matching-to-sample task with a female chimpanzee. She succeeded in selecting the picture of the vocalizer in response to various types of vocalizations: pant hoots, pant grunts, and screams. When pant hoots by two chimpanzees were presented as a "duet", she could identify both of the vocalizers. These results suggest that researchers have underestimated the capability of vocalizer identification in chimpanzees. The chimpanzee correctly chose her own pictures in response to her vocalizations only by exclusion, and she did not show vocal self-recognition. The effect of acoustical modification (pitch shift and filtration) on the performance suggested that pitch is an important cue for the vocalizer identification. Department of Behavioral and Brain Sciences, Primate Research Institute, Kyoto University, Kanrin, Inuyama, Aichi 484-8506, Japan. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12884113
de Veer MW, Gallup GG, Jr., Theall LA, van den Bos R and Povinelli DJ (2003). An 8-year longitudinal study of mirror self-recognition in chimpanzees (Pan troglodytes). Neuropsychologia 41: 229-34. In a previous cross-sectional study of mirror self-recognition involving 92 chimpanzees, Povinelli et al. [Journal of Comparative Psychology 107 (1993) 347] reported a peak in the proportion of animals exhibiting self-recognition in the adolescent/young adult sample (8-15 years), with 75% being classified as positive. In contrast, only 26% of the older animals (16-39 years) were classified as positive, suggesting a marked decline in self-recognition in middle to late adulthood. In the present study, all of the chimpanzees from the 8-15-year-old group in the Povinelli et al. study (n=12) were again tested for self-recognition, 8 years later. Using the same criteria, 67% of the animals were classified the same. Although a higher proportion of the adult animals in this study (50%) exhibited self-recognition than would be inferred on the basis of the previous study (25%), all changes in self-recognition status were in the negative direction. These results show that mirror self-recognition is a highly stable trait in many chimpanzees, but may be subject to decline with age. Connections with human research are briefly discussed. Animal Welfare Centre, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12459221
Tobach E, Skolnick AJ, Klein I and Greenberg G (1997). Viewing of self and nonself images in a group of captive orangutans (Pongo pygmaeus Abellii). Percept Mot Skills 84: 355-70. Reports on self-recognition in great apes have been mostly derived from experimental studies of mirror behavior (mark test) requiring anesthetization of the animals. We investigated a relatively noninvasive technique to study this behavior. In two experiments with a group of captive orangutans (1 adult male, 3 adult females, 1 juvenile male, and 1 juvenile female), we presented combinations of blank posters, life-size portraits of each individual in the group, a mirror, and videos. Durations of viewing and patterns of viewing were recorded. The prominent features of the viewing were the differences among the individuals in frequency, duration, and pattern of viewing. Some evidence of mirror-based self-referent behavior (behavior in which the activity of the animal with its body was related to the activity of the image in the mirror) was seen in the juvenile female, but more was seen in one adult female. This adult female spent the most time viewing the mirror and was the only animal to view her own portrait more than the other portraits in one session. In addition, she moved from one portrait to another, and back to the first, and to her own portrait and the mirror in a pattern resembling comparison of the two portraits as well as of her portrait and her mirror image. It is suggested that data based on self-referent behavior of the same animal during self-viewing in a mirror and during viewing of its self-portrait and on behavior observed in the mark test are worth further investigation. American Museum of Natural History, New York, NY 10024, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9106821
Washburn DA, Gulledge JP and Rumbaugh DM (1997). The heuristic and motivational value of video reinforcement. Learn Motiv 28: 510-20. Four rhesus monkeys (Macaca mulatta) were tested on joystick-based computer tasks in which they could choose to be reinforced either with pellets-only or with pellets + video. A variety of videotapes were used to reinforce task performance. The monkeys significantly preferred to be rewarded with a pellet and 10 s of a blank screen than a pellet plus 10 s of videotape. When they did choose to see videotaped images, however, they were significantly more likely to view video of themselves than video of their roommate or of unfamiliar conspecifics. These data support earlier findings of individual differences in preference for video reinforcement, and have clear implications for the study of face-recognition and self-recognition by nonhuman primates. Sonny Carter Life Sciences Laboratory, Georgia State University, USA. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11543307
Heschl A and Burkart J (2006). A new mark test for mirror self-recognition in non-human primates. Primates 47: 187-98. For 30 years Gallup's (Science 167:86-87, 1970) mark test, which consists of confronting a mirror-experienced test animal with its own previously altered mirror image, usually a color mark on forehead, eyebrow or ear, has delivered valuable results about the distribution of visual self-recognition in non-human primates. Chimpanzees, bonobos, orangutans and, less frequently, gorillas can learn to correctly understand the reflection of their body in a mirror. However, the standard version of the mark test is good only for positively proving the existence of self-recognition. Conclusive statements about the lack of self-recognition are more difficult because of the methodological constraints of the test. This situation has led to a persistent controversy about the power of Gallup's original technique. We devised a new variant of the test which permits more unequivocal decisions about both the presence and absence of self-recognition. This new procedure was tested with marmoset monkeys (Callithrix jacchus), following extensive training with mirror-related tasks to facilitate performance in the standard mark test. The results show that a slightly altered mark test with a new marking substance (chocolate cream) can help to reliably discriminate between true negative results, indicating a real lack of ability to recognize oneself in a mirror, from false negative results that are due to methodological particularities of the standard test. Finally, an evolutionary hypothesis is put forward as to why many primates can use a mirror instrumentally - i.e. know how to use it for grasping at hidden objects - while failing in the decisive mark test. Konrad Lorenz Institute for Evolution and Cognition Research, Adolf Lorenz Gasse 2, 3422, Altenberg, Austria. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16432640
Paukner A, Anderson JR and Fujita K (2004). Reactions of capuchin monkeys (Cebus apella) to multiple mirrors. Behav Processes 66: 1-6. This study attempted a new manipulation to prompt mirror self-recognition in a monkey species through simultaneous exposure to two mirrors. Four capuchin monkeys (Cebus apella) were exposed to one large and one small mirror object with different reflective or configurational properties, which was thought to deepen their understanding of mirrors. The monkeys predominantly engaged in looking behaviours towards the large mirror, which decreased over sessions. There was also an increase in looking behaviours towards the small mirror object when it reflected an undistorted image compared to the control condition. No instances of self-directed responses, oblique looks or manipulations of both mirror objects in combination were observed. The results confirm and expand on previous reports of failure to find evidence of mirror self-recognition in monkeys. Department of Psychology, University of Stirling, Stirling FK9 4LA, UK. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15062965
Neiworth JJ, Anders SL and Parsons RR (2001). Tracking responses related to self-recognition: a frequency comparison of responses to mirrors, photographs, and videotapes by cotton top tamanins (Saguinus oedipus). J Comp Psychol 115: 432-8. The frequency of responses cotton top tamarins (Saguinus oedipus) emitted indicative of self-recognition to a mirror was compared with the frequencies of responses emitted to digitized photographs of tamarins (Experiment 1) and to videotapes of real-time or prior tamarin action (Experiment 2). Results indicated more attentional responses toward the mirror in both studies, but behavioral indices of self-recognition were not consistently generated by the mirror. The 2 experiments confirmed that real-time self-reflection is a condition that generates heightened attention and rare examples of particular mirror-specific behaviors in tamarins. Department of Psychology, Carleton College Northfield, Minnesota 55057, USA. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11824907
Marten K and Psarakos S (1995). Using self-view television to distinguish between self-examination and social behavior in the bottlenose dolphin (Tursiops truncatus). Conscious Cogn 4: 205-24. In mirror mark tests dolphins twist, posture, and engage in open-mouth and head movements, often repetitive. Because postures and an open mouth are also dolphin social behaviors, we used self-view television as a manipulatable mirror to distinguish between self-examination and social behavior. Two dolphins were exposed to alternating real-time self-view ("mirror mode") and playback of the same to determine if they distinguished between them. The adult male engaged in elaborate open-mouth behaviors in mirror mode, but usually just watched when played back the same material. Mirror mode behavior was also compared to interacting with real dolphins (controls). Mark tests were conducted, as well as switches from front to side self-views to see if the dolphins turned. They presented marked areas to the self-view television and turned. The results suggest self-examination over social behavior. Earthtrust, Kailua, Hawaii 96734, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8521259
Anderson JR (1995). Self-recognition in dolphins: credible cetaceans; compromised criteria, controls, and conclusions. Conscious Cogn 4: 239-43. Laboratoire de Psychophysiologie, CNRS URA 1295, Universite Louis Pasteur, Strasbourg, France. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8521263
Loveland KA (1995). Self-recognition in the bottlenose dolphin: ecological considerations. Conscious Cogn 4: 254-7. Department of Psychiatry and Behavioral Sciences, University of Texas Medical School, Houston 77025, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8521267
Mitchell RW (1995). Evidence of dolphin self-recognition and the difficulties of interpretation. Conscious Cogn 4: 229-34. Department of Psychology, Eastern Kentucky University, Richmond 40508, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8521261
Hart D and Whitlow JW, Jr. (1995). The experience of self in the bottlenose dolphin. Conscious Cogn 4: 244-7. Marten and Psarakos have presented some evidence which suggests that objective self-awareness and possibly representations of self may characterize the dolphins' experience of self. Their research demonstrates the possibility of similarities in the sense of self between primate species and dolphins, although whether dolphins have subjective self-awareness, personal memories, and theories of self--all important facets of the sense of self in humans--was not examined. Clearly, even this limited evidence was difficult to achieve; the difficulties in adapting methods and coding behavior are quite apparent in their report. Future progress, however, may depend upon clarification of what are the necessary components for a sense of self and an explication of how these might be reflected in dolphin behavior. We are mindful of the authors' point (pp. 219 and 220) that the dolphin lives more in an acoustic than a visual environment. Thus, while tasks relying upon vision may reveal the presence or absence of the sense of self in primates, it might well be the case that in dolphins self-related experiences might be better revealed in auditory tasks. But then, what is the nature of human self-awareness in terms of audition? While both conceptual and methodological hurdles remain, Marten and Psarakos have demonstrated that important questions can be asked about the minds and phenomenal worlds of nonanthropoid species. Department of Psychology, Rutgers University, Camden, New Jersey 08102, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8521264
Reiss D and Marino L (2001). Mirror self-recognition in the bottlenose dolphin: a case of cognitive convergence. Proc Natl Acad Sci U S A 98: 5937-42. The ability to recognize oneself in a mirror is an exceedingly rare capacity in the animal kingdom. To date, only humans and great apes have shown convincing evidence of mirror self-recognition. Two dolphins were exposed to reflective surfaces, and both demonstrated responses consistent with the use of the mirror to investigate marked parts of the body. This ability to use a mirror to inspect parts of the body is a striking example of evolutionary convergence with great apes and humans. Osborn Laboratories of Marine Sciences, New York Aquarium, Wildlife Conservation Society, Brooklyn, NY 11224, USA. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11331768
Delfour F and Marten K (2001). Mirror image processing in three marine mammal species: killer whales (Orcinus orca), false killer whales (Pseudorca crassidens) and California sea lions (Zalophus californianus). Behav Processes 53: 181-190. Dolphins (Tursiops truncatus) and their relatives might be expected to show mirror-induced contingency checking, a prerequisite to self-recognition, because of their high brain development, their complex social life and their demonstrated abilities in bodily imitation. A study of killer whales'(Orcinus orca) behaviour in front of a mirror is presented, including a mark test. Shorter investigations of mirror behaviour are also described in false killer whales (Pseudorca crassidens) and California sea lions (Zalophus californianus). Contingency checking was present in killer whales and possibly also in false killer whales, but no clear contingency checking was observed in sea lions. The mark test on killer whales suggested that the marked animal anticipated that its image would look different. This study shows that killer whales and false killer whales, like bottlenose dolphins, appear to possess the cognitive abilities required for self-recognition. 13 Impasse A. Marfaing, 31400, Toulouse, France http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11334706
Jokisch D, Daum I and Troje NF (2006). Self recognition versus recognition of others by biological motion: viewpoint-dependent effects. Perception 35: 911-20. We investigated the influence of viewing angle on performance in recognising the identity of one's own person and familiar individuals such as friends or colleagues from walking patterns. Viewpoint-dependent recognition performance was tested in two groups of twelve persons who knew each other very well. Participants' motion data were acquired by recording their walking patterns in three-dimensional space with the use of a motion capture system. Size-normalised point-light displays of biological motion of these walking patterns, including one's own, were presented to the same group members on a computer screen in frontal view, half-profile view, and profile view. Observers were requested to assign the person's name to the individual gait pattern. No feedback was given. Whereas recognition performance of one's own walking patterns was viewpoint independent, recognition rate for other familiar individuals was better for frontal and half-profile view than for profile view. These findings are discussed in the context of the theory of common coding of motor and visual body representations. Institute of Cognitive Neuroscience, Ruhr University Bochum, Germany. Daniel.Jokisch@fcdonders.ru.nl http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16970200
Sugiura M, Sassa Y, Jeong H, Miura N, Akitsuki Y, Horie K, Sato S and Kawashima R (2006). Multiple brain networks for visual self-recognition with different sensitivity for motion and body part. Neuroimage 32: 1905-17. Multiple brain networks may support visual self-recognition. It has been hypothesized that the left ventral occipito-temporal cortex processes one's own face as a symbol, and the right parieto-frontal network processes self-image in association with motion-action contingency. Using functional magnetic resonance imaging, we first tested these hypotheses based on the prediction that these networks preferentially respond to a static self-face and to moving one's whole body, respectively. Brain activation specifically related to self-image during familiarity judgment was compared across four stimulus conditions comprising a two factorial design: factor Motion contrasted picture (Picture) and movie (Movie), and factor Body part a face (Face) and whole body (Body). Second, we attempted to segregate self-specific networks using a principal component analysis (PCA), assuming an independent pattern of inter-subject variability in activation over the four stimulus conditions in each network. The bilateral ventral occipito-temporal and the right parietal and frontal cortices exhibited self-specific activation. The left ventral occipito-temporal cortex exhibited greater self-specific activation for Face than for Body, in Picture, consistent with the prediction for this region. The activation profiles of the right parietal and frontal cortices did not show preference for Movie Body predicted by the assumed roles of these regions. The PCA extracted two cortical networks, one with its peaks in the right posterior, and another in frontal cortices; their possible roles in visuo-spatial and conceptual self-representations, respectively, were suggested by previous findings. The results thus supported and provided evidence of multiple brain networks for visual self-recognition. Miyagi University of Education, Aramaki-Aza-Aoba 149, Aoba-ku, Sendai 980-0845, Japan. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16806977
Platek SM, Loughead JW, Gur RC, Busch S, Ruparel K, Phend N, Panyavin IS and Langleben DD (2006). Neural substrates for functionally discriminating self-face from personally familiar faces. Hum Brain Mapp 27: 91-8. Understanding the neurobiological substrates of self-recognition yields important insight into socially and clinically critical cognitive functions such as theory of mind. Experimental evidence suggests that right frontal and parietal lobes preferentially process self-referent information. Recognition of one's own face is an important parameter of self-recognition, but well-controlled experimental data on the brain substrates of self-face recognition is limited. The goal of this study was to characterize the activation specific to self-face in comparison with control conditions of two levels of familiarity: unknown unfamiliar face and the more stringent control of a personally familiar face. We studied 12 healthy volunteers who made "unknown," "familiar," and "self" judgments about photographs of three types of faces: six different novel faces, a personally familiar face (participant's fraternity brother), and their own face during an event-related functional MRI (fMRI) experiment. Contrasting unknown faces with baseline showed activation of the inferior occipital lobe, which supports previous findings suggesting the presence of a generalized face-processing area within the inferior occipital-temporal region. Activation in response to a familiar face, when contrasted with an unknown face, invoked insula, middle temporal, inferior parietal, and medial frontal lobe activation, which is consistent with an existing hypothesis suggesting familiar face recognition taps neural substrates that are different from those involved in general facial processing. Brain response to self-face, when contrasted with familiar face, revealed activation in the right superior frontal gyrus, medial frontal and inferior parietal lobes, and left middle temporal gyrus. The contrast familiar vs. self produced activation only in the anterior cingulate gyrus. Our results support the existence of a bilateral network for both perceptual and executive aspects of self-face processing that cannot be accounted for by a simple hemispheric dominance model. This network is similar to those implicated in social cognition, mirror neuron matching, and face-name matching. Our findings also show that some regions of the medial frontal and parietal lobes are specifically activated by familiar faces but not unknown or self-faces, indicating that these regions may serve as markers of face familiarity and that the differences between activation associated with self-face recognition and familiar face recognition are subtle and appear to be localized to lateral frontal, parietal, and temporal regions. Department of Psychology, Drexel University, and Department of Psychiatry, Brain Behavior Laboratory, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16035037
Uddin LQ, Kaplan JT, Molnar-Szakacs I, Zaidel E and Iacoboni M (2005). Self-face recognition activates a frontoparietal "mirror" network in the right hemisphere: an event-related fMRI study. Neuroimage 25: 926-35. Self-recognition has been demonstrated by a select number of primate species and is often used as an index of self-awareness. Whether a specialized neural mechanism for self-face recognition in humans exists remains unclear. We used event-related fMRI to investigate brain regions selectively activated by images of one's own face. Ten right-handed normal subjects viewed digital morphs between their own face and a gender-matched familiar other presented in a random sequence. Subjects were instructed to press a button with the right hand if the image looked like their own face, and another button if it looked like a familiar or scrambled face. Contrasting the trials in which images contain more "self" with those containing more familiar "other" revealed signal changes in the right hemisphere (RH) including the inferior parietal lobule, inferior frontal gyrus, and inferior occipital gyrus. The opposite contrast revealed voxels with higher signal intensity for images of "other" than for "self" in the medial prefrontal cortex and precuneus. Additional contrasts against baseline revealed that activity in the "self" minus "other" contrasts represent signal increases compared to baseline (null events) in "self" trials, while activity in the "other" minus "self" contrasts represent deactivations relative to baseline during "self" trials. Thus, a unique network involving frontoparietal structures described as part of the "mirror neuron system" in the RH underlies self-face recognition, while regions comprising the "default/resting state" network deactivate less for familiar others. We provide a model that reconciles these findings and previously published work to account for the modulations in these two networks previously implicated in social cognition. Department of Psychology, University of California, Box 951563, B627 Franz Hall, Los Angeles, CA 90095, USA. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15808992
Turk DJ, Heatherton TF, Kelley WM, Funnell MG, Gazzaniga MS and Macrae CN (2002). Mike or me? Self-recognition in a split-brain patient. Nat Neurosci 5: 841-2. A split-brain patient (epileptic individual whose corpus callosum had been severed to minimize the spread of seizure activity) was asked to recognize morphed facial stimuli--presented separately to each hemisphere--as either himself or a familiar other. Both hemispheres were capable of face recognition, but the left hemisphere showed a recognition bias for self and the right hemisphere a bias for familiar others. These findings suggest a possible dissociation between self-recognition and more generalized face processing within the human brain. Department of Psychological and Brain Sciences, Center for Cognitive Neuroscience, Moore Hall, Dartmouth College, Hanover, New Hampshire 03755, USA. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12195428
Kircher TT, Senior C, Phillips ML, Rabe-Hesketh S, Benson PJ, Bullmore ET, Brammer M, Simmons A, Bartels M and David AS (2001). Recognizing one's own face. Cognition 78: B1-B15. We report two studies of facial self-perception using individually tailored, standardized facial photographs of a group of volunteers and their partners. A computerized morphing procedure was used to merge each target face with an unknown control face. In the first set of experiments, a discrimination task revealed a delayed response time for the more extensively morphed self-face stimuli. In a second set of experiments, functional magnetic resonance imaging (fMRI) was used to measure brain activation while subjects viewed morphed versions of either their own or their partner's face, alternating in blocks with presentation of an unknown face. When subjects viewed themselves (minus activation for viewing an unknown face), increased blood oxygenation was detected in right limbic (hippocampal formation, insula, anterior cingulate), left prefrontal cortex and superior temporal cortex. In the partner (versus unknown) experiment, only the right insula was activated. We suggest that a neural network involving the right hemisphere in conjunction with left-sided associative and executive regions underlies the process of visual self-recognition. Together, this combination produces the unique experience of self-awareness. Department of Psychiatry, University of Tuebingen, Osianderstrasse 24, D-72076, Tubingen, Germany. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11062324
Keenan JP, McCutcheon B, Freund S, Gallup GG, Jr., Sanders G and Pascual-Leone A (1999). Left hand advantage in a self-face recognition task. Neuropsychologia 37: 1421-5. Subjects were exposed to pictures of self and others (e.g., friend, stranger, and famous people) to determine if there was an advantage in reaction time and accuracy in identifying the self. It was found that upright and inverted self-faces were identified more rapidly than non-self faces when subjects responded with their left hand, which in other tasks has corresponded with contralateral hemispheric dominance. These data suggest that self-recognition may be correlated with neural activity in the right hemisphere, and that the differences observed may not be unique to self-face recognition. These results are in agreement with previous research indicating that self-directed awareness is correlated with right prefrontal activity. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=10606015
Sugiura M, Watanabe J, Maeda Y, Matsue Y, Fukuda H and Kawashima R (2005). Cortical mechanisms of visual self-recognition. Neuroimage 24: 143-9. Several lines of evidence have suggested that visual self-recognition is supported by a special brain mechanism; however, its functional anatomy is of great controversy. We performed an event-related functional magnetic resonance imaging (fMRI) study to identify brain regions selectively involved in recognition of one's own face. We presented pictures of each subject's own face (SELF) and a prelearned face of an unfamiliar person (CONT), as well as two personally familiar faces with high and low familiarity (HIGH and LOW, respectively) to test selectivity of activation to the SELF face. Compared with the CONT face, activation selective to the SELF face was observed in the right occipito-temporo-parietal junction and frontal operculum, as well as in the left fusiform gyrus. On the contrary, the temporoparietal junction in both the hemispheres and the left anterior temporal cortex, which were activated during recognition of HIGH and/or LOW faces, were not activated during recognition of the SELF face. The results confirmed the partial distinction of the brain mechanism involved in recognition of personally familiar faces and that in recognition of one's own face. The right occipito-temporo-parietal junction and frontal operculum appear to compose a network processing motion-action contingency, a role of which in visual self-recognition has been suggested in previous behavioral studies. Activation of the left fusiform gyrus selective to one's own face was consistent with the results of two previous functional imaging studies and a neuropsychological report, possibly suggesting its relationship with lexical processing. NICHe, Tohoku University, Aramaki Aoba 10, Aoba-ku, Sendai 980-8579, Japan. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15588605
Tsakiris M, Haggard P, Franck N, Mainy N and Sirigu A (2005). A specific role for efferent information in self-recognition. Cognition 96: 215-31. We investigated the specific contribution of efferent information in a self-recognition task. Subjects experienced a passive extension of the right index finger, either as an effect of moving their left hand via a lever ('self-generated action'), or imposed externally by the experimenter ('externally-generated action'). The visual feedback was manipulated so that subjects saw either their own right hand ('view own hand' condition) or someone else's right hand ('view other's hand' condition) during the passive extension of the index finger. Both hands were covered with identical gloves, so that discrimination on the basis of morphological differences was not possible. Participants judged whether the right hand they saw was theirs or not. Self-recognition was significantly more accurate when subjects were themselves the authors of the action, even though visual and proprioceptive information always specified the same posture, and despite the fact that subjects judged the effect and not the action per se. When the passive displacement of the participants right index finger was externally generated, and only afferent information was available, self-recognition performance dropped to near-chance levels. Differences in performance across conditions reflect the distinctive contribution of efferent information to self-recognition, and argue against a dominant role of proprioception in self-recognition. Department of Psychology, Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London, WC1N 3AR, UK. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15996559
van den Bos E and Jeannerod M (2002). Sense of body and sense of action both contribute to self-recognition. Cognition 85: 177-87. Recognizing oneself, easy as it appears to be, seems at least to require awareness of one's body and one's actions. To investigate the contribution of these factors to self-recognition, we presented normal subjects with an image of both their own and the experimenter's hand. The hands could make the same, a different or no movement and could be displayed in various orientations. Subjects had to tell whether the indicated hand was theirs or not. The results showed that a congruence between visual signals and signals indicating the position of the body is one component on which self-recognition is based. Recognition of one's actions is another component. Subjects had most difficulty in recognizing their hand when movements were absent. When the two hands made different movements, subjects relied exclusively on the movement cue and recognition was almost perfect. Our findings are in line with pathological alterations in the sense of body and the sense of action. Leiden University, Section Cognitive Psychology, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12127698
Platek SM, Thomson JW and Gallup GG, Jr. (2004). Cross-modal self-recognition: the role of visual, auditory, and olfactory primes. Conscious Cogn 13: 197-210. Three priming experiments were conducted to determine how information about the self from different sensory modalities/cognitive domains affects self-face recognition. Being exposed to your body odor, seeing your name, and hearing your name all facilitated self-face recognition in a reaction time task. No similar cross-modal facilitation was found among stimuli from familiar or novel individuals. The finding of a left-hand advantage for self-face recognition was replicated when no primes were presented. These data, along with other recent results suggest the brain processes/represents information about the self in highly integrated ways. Department of Psychology, Drexel University, 245 N 15th Street, Mail Stop 626, Philadelphia, PA 19104, USA. Steven.M.Platek@drexel.edu http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14990253
Zeman A (2001). Consciousness. Brain 124: 1263-89. Consciousness is topical, for reasons including its renewed respectability among psychologists, rapid progress in the neuroscience of perception, memory and action, advances in artificial intelligence and dissatisfaction with the dualistic separation of mind and body. Consciousness is an ambiguous term. It can refer to (i) the waking state; (ii) experience; and (iii) the possession of any mental state. Self-consciousness is equally ambiguous, with senses including (i) proneness to embarrassment in social settings; (ii) the ability to detect our own sensations and recall our recent actions; (iii) self-recognition; (iv) the awareness of awareness; and (v) self-knowledge in the broadest sense. The understanding of states of consciousness has been transformed by the delineation of their electrical correlates, of structures in brainstem and diencephalon which regulate the sleep-wake cycle, and of these structures' cellular physiology and regional pharmacology. Clinical studies have defined pathologies of wakefulness: coma, the persistent vegetative state, the 'locked-in' syndrome, akinetic mutism and brain death. Interest in the neural basis of perceptual awareness has focused on vision. Increasingly detailed neuronal correlates of real and illusory visual experience are being defined. Experiments exploiting circumstances in which visual experience changes while external stimulation is held constant are tightening the experimental link between consciousness and its neural correlates. Work on unconscious neural processes provides a complementary approach. 'Unperceived' stimuli have detectable effects on neural events and subsequent action in a range of circumstances: blindsight provides the classical example. Other areas of cognitive neuroscience also promise experimental insights into consciousness, in particular the distinctions between implicit and explicit memory and deliberate and automatic action. Overarching scientific theories of consciousness include neurobiological accounts which specify anatomical or physiological mechanisms for awareness, theories focusing on the role played by conscious processes in information processing and theories envisaging the functions of consciousness in a social context. Whether scientific observation and theory will yield a complete account of consciousness remains a live issue. Physicalism, functionalism, property dualism and dual aspect theories attempt to do justice to three central, but controversial, intuitions about experience: that it is a robust phenomenon which calls for explanation, that it is intimately related to the activity of the brain and that it has an important influence on behaviour. Department of Clinical Neurosciences, Western General Hospital, Edinburgh, UK. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11408323
Mitchell RW (1997). A comparison of the self-awareness and kinesthetic-visual matching theories of self-recognition: autistic children and others. Ann N Y Acad Sci 818: 38-62. Department of Psychology, Eastern Kentucky University, Richmond 40475, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9237464
Cicchetti D, Rogosch FA, Toth SL and Spagnola M (1997). Affect, cognition, and the emergence of self-knowledge in the toddler offspring of depressed mothers. J Exp Child Psychol 67: 338-62. Visual self-recognition was examined utilizing the mirror-rouge paradigm in a sample of 18- to 21-month-old toddlers of depressed (n = 91) and nondepressed (n = 43) mothers in regard to linkages with cognitive and affective development. Overall, attainment of self-recognition was not related to differences in level of cognitive development, pre-rouge affective expression, or maternal depression. However, children of depressed mothers who exhibited self-recognition were more likely than children of nondepressed mothers to display nonpositive affect and to shift affect from positive to nonpositive in the post-rouge condition. Within the group of children of depressed mothers, toddlers who did not evidence self-recognition and who shifted affect were lower in attachment security and had mothers with less positive affect characteristics. Also, self-recognition and affective instability were related to differences in cognitive developmental level among toddlers of depressed mothers. Findings are discussed in terms of implications for understanding the relations between affect and cognition and the influence of maternal depression on affective and cognitive development. Mt. Hope Family Center, University of Rochester, NY 14608, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9440297
Jeannerod M (2003). [Problems in recognizing the self: a neuropsychological approach to the positive symptoms of schizophrenia]. Med Sci (Paris) 19: 621-4. This article present a review of recent work on cognitive neuroscience approaches of schizophrenia. Some of the symptoms displayed by schizophrenic patients can be reconsidered within the framework of disorganization of well identified cognitive functions, like self-recognition. Neuroimaging techniques can reveal in these patients disruption of neural networks normally involved in such functions. Cnrs UMR 5015, Institut des Sciences Cognitives, 67, boulevard Pinel, 69675 Bron, France. Jeannerod@isc.cnrs.fr http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12836397
Phillips ML (1996). "Mirror, Mirror on the Wall, Who...?": Towards a Model of Visual Self-recognition. Cognit Neuropsychiatry 1: 153-64. Self-recognition and self-awareness are processes fundamental to human development. This report describes the case of an 80-year-old woman who demonstrated the ''mirror sign'', an inability to recognise the reflection of oneself in a mirror. An attempt has been made to provide a cognitive neuropsychological explanation for this profound impairment in visual self-recognition, incorporating current cognitive theories of delusion formation and, specifically, delusions involving distorted appreciation of the self or others. We speculate that the impairment in visual self-recognition arises from deficits in visual and personal semantic memory related to bilateral hippocampal lesions, and that the greater extent of impairment in visual self-recognition compared with that for other familiar persons is possible evidence for a specific self-recognition process, represented as a separate ''self-identity node'' in the current face-processing model of Bruce and Young (1986). http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16571480
Nielsen M, Suddendorf T and Slaughter V (2006). Mirror self-recognition beyond the face. Child Dev 77: 176-85. Three studies (N=144) investigated how toddlers aged 18 and 24 months pass the surprise-mark test of self-recognition. In Study 1, toddlers were surreptitiously marked in successive conditions on their legs and faces with stickers visible only in a mirror. Rates of sticker touching did not differ significantly between conditions. In Study 2, toddlers failed to touch a sticker on their legs that had been disguised before being marked. In Study 3, having been given 30-s exposure to their disguised legs before testing, toddlers touched the stickers on their legs and faces at equivalent levels. These results suggest that toddlers pass the mark test based on expectations about what they look like, expectations that are not restricted to the face. University of Queensland, Australia. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16460532
Zelazo PD, Sommerville JA and Nichols S (1999). Age-related changes in children's use of external representations. Dev Psychol 35: 1059-71. This study explored children's use of external representations. Experiment 1 focused on representations of self: Self-recognition was assessed by a mark test as a function of age (3 vs. 4 years), delay (5 s vs. 3 min), and media (photographs vs. drawings). Four-year-olds outperformed 3-year-olds; children performed better with photographs than drawings; and there was no effect of delay. In Experiment 2, 3- and 4-year-olds used a delayed video image to locate a sticker on themselves (self task) or a stuffed animal (other task). The 2 tasks were positively correlated with age and vocabulary partialed out. Experiment 3 used a search task to assess whether children have particular difficulty using external representations that conflict with their expectations: 3- and 4-year-olds were informed of an object's location verbally or through video: on half of the trials, this information conflicted with children's initial belief. Three-year-olds performed worse than 4-year-olds on conflict trials, indicating that assessments of self and other understanding may reflect children's ability to reason about conflicting external representations. Department of Psychology, University of Toronto, Ontario, Canada. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=10442874
Povinelli DJ, Landau KR and Perilloux HK (1996). Self-recognition in young children using delayed versus live feedback: evidence of a developmental asynchrony. Child Dev 67: 1540-54. The ability of young children to recognize themselves in delayed videotapes and recent photographs was investigated using a delayed analog of the mirror mark test, as well as verbal reports. In Experiment 1, 42 2-4-year-old children were videotaped while playing an unusual game. During the game an experimenter covertly placed a large sticker on the child's head. The videotape was played back 3 min later to the children. Older, but not younger, children reached up to remove the sticker when the tape revealed it being placed on their heads. In Experiment 2, a similar procedure was used with 60 3- and 4-year-olds where Polaroid photographs were taken during and after the act of the sticker being placed on the child's head. When allowed to look at the photographs, young 3-year-olds did not reach up to search for the sticker, whereas older 3- and 4-year-olds did. Almost all of the children who did not appear to realize that there was a sticker on their head from the information provided by the photographs did provide a correct verbal label for the image, and reached up to remove the sticker when presented with a mirror. Experiment 3 compared the reaction of 48 2 1/2-3 1/2-year-olds to live versus delayed video feedback and indicated an effect of the temporal aspect of the stimulus. The results are discussed in the context of the different forms of self-conception that may underwrite the 2 manifestations of self-recognition. Laboratory of Comparative Behavioral Biology, USL-New Iberia Research Center 70560, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8890499
Skouteris H, Spataro J and Lazaridis M (2006). Young children's use of a delayed video representation to solve a retrieval problem pertaining to self. Dev Sci 9: 505-17. The experiments reported here were concerned with the development of delayed self-recognition. Children were videotaped playing a game and were marked covertly with a sticker on their forehead while doing so. The findings, of both a cross-sectional sample and a prospective longitudinal one, revealed that 3- but not 2.5-year-old children reached to remove this sticker reliably during video playback only after they had been trained to use the video to guide their search for an object that was not directly visible to the unaided eye. It appears that by 3 years of age children understand that their briefly delayed self video-representation is related to their present self. In contrast, while 2.5-year-olds can use delayed video information to locate objects in space that cannot be seen by the unaided eye, they cannot use this type of information to locate an object that pertains to a part of self that is not directly visible, such as a sticker on one's hair. The findings are discussed in terms of the emergence of an extended sense of self. School of Psychological Science, La Trobe University, Australia. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16911453
Rochat P (1998). Self-perception and action in infancy. Exp Brain Res 123: 102-9. By 2-3 months, infants engage in exploration of their own body as it moves and acts in the environment. They babble and touch their own body, attracted and actively involved in investigating the rich intermodal redundancies, temporal contingencies, and spatial congruence of self-perception. Recent research is presented, which investigates the spatial and temporal determinants of self-perception and action infancy. This research shows that, in the course of the first weeks of life, infants develop an ability to detect intermodal invariants and regularities in their sensorimotor experience, which specify themselves as separate entities agent in the environment. Recent observations on the detection of intermodal invariants regarding self-produced leg movements and auditory feedback of sucking by young infants are reported. These observations demonstrate that, early in development and long before mirror self-recognition, infants develop a perceptual ability to specify themselves. It is tentatively proposed that young infants' propensity to engage in self-perception and systematic exploration of the perceptual consequences of their own action plays an important role in the intermodal calibration of the body and is probably at the origin of an early sense of self: the ecological self. Department of Psychology, Emory University, Atlanta, GA 30322, USA. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9835398
Legerstee M, Anderson D and Schaffer A (1998). Five- and eight-month-old infants recognize their faces and voices as familiar and social stimuli. Child Dev 69: 37-50. Five- and 8-month-old infants were presented with silent moving and static video images of self, peer, and doll and with sounds of self, peer, and nonsocial objects. In the visual conditions, infants at both ages showed a significant looking preference to peer over self when the faces were moving. When the faces were static, older infants showed the same significant discriminations, but the younger infants showed a significant looking preference for their own faces over peer and doll. These data suggest that recognition of one's own image develops through experience with dynamic facial stimulation during the first 8 months of life. In the auditory conditions, infants at both ages showed significant looking preferences for sounds of peer over self or nonsocial objects. In general, infants of both ages smiled and produced more vocalizations to social faces and social sounds than to nonsocial faces and nonsocial sounds. Thus, at 5 months infants treat their faces and voices as familiar and social stimuli. The findings forge important links among studies of self-perception, self-recognition, and social knowledge. Department of Psychology, York University, North York, Ontario. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9499555
Priel B and de Schonen S (1986). Self-recognition: a study of a population without mirrors. J Exp Child Psychol 41: 237-50. The study of the influence of familiarity with mirrors on children's capacity to identify their reflected images permitted differentiation between two problems that confront the child in the mirror situation: (a) the identity of the image and (b) the capacity to relate mirror space to real space. Sixty children, 6 to 26 months old, without previous experience with mirrors, were observed systematically while discovering their mirror image and a reflected object. Their behavior was compared to a control group with habitual mirror familiarity. The results suggest that (a) self-recognition in the mirror is independent of the child's familiarity with reflecting surfaces and (b) the capacity to relate mirror to real space seems to be strongly influenced by previous experience with mirrors. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=3701250
Spiker D and Ricks M (1984). Visual self-recognition in autistic children: developmental relationships. Child Dev 55: 214-25. Employing a mirror procedure, 52 autistic children (CA = 3-7 to 12-8, means = 7-7) were tested for visual self-recognition. Substantial behavioral and psychometric data were collected from school records, teacher interviews, and classroom observations. Of the 52 children, 36 (69%) showed evidence of mirror self-recognition, while 16 (31%) failed to give clear indications of recognizing their mirror images. The 2 groups did not differ on CA. Severity of language impairment appeared to be a major factor differentiating the 2 groups: those who failed to show evidence of visual self-recognition were more likely than those who did show evidence of visual recognition to be mute or lacking in communicative speech (p less than .001). Other indices of impairment indicated that the children who showed the capacity for visual self-recognition had higher levels of functioning. The results are discussed in terms of an organizational perspective. This perspective argues that the study of atypical populations may elucidate the process of development by describing the coordination or sequential organization of different behavioral systems. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=6705623
Dawson G and McKissick FC (1984). Self-recognition in autistic children. J Autism Dev Disord 14: 383-94. The hypothesis that the autistic child's impairment in social relatedness stems in part from underlying deficits in self-recognition was explored. Fifteen autistic children ranging from 4 to 6 years of age were assessed for visual self-recognition ability, as well as for skills in two cognitive areas that are believed to be related to the development of self-recognition--object permanence and gestural imitation. It was found that 13 of 15 autistic children showed evidence of self-recognition. The two autistic children who lacked self-recognition were the only two children to perform poorly on the object permanence tasks, which suggests that these two cognitive domains may be closely linked in development. In contrast, there appeared to be no consistent relationship between motor imitation ability and self-recognition. It was concluded that the autistic child's social deficits are not due to a basic lack of differentiation between self and other. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=6520093
Schneider-Rosen K and Cicchetti D (1984). The relationship between affect and cognition in maltreated infants: quality of attachment and the development of visual self-recognition. Child Dev 55: 648-58. 37 19-month-old infants, 18 maltreated and 19 matched lower-class comparisons, were seen in Ainsworth and Wittig 's Strange Situation in order to document the impact that early maltreatment by the mother has on the attachment relationship. In addition, these infants were observed in the standard mirror-and- rouge paradigm to investigate the hypothesis that individual differences in the emergence of the capacity for visual self-recognition could be related to qualitative differences in the attachment relationship. Consistent with predictions from attachment theory, maltreated infants were found to manifest a significantly greater proportion of insecure attachments than were nonmaltreated infants. When data for the entire sample of infants were analyzed, it was found that those infants who evidenced visual self-recognition were significantly more likely to be securely attached to their mothers. However, a separate analysis of the maltreated and comparison groups of infants revealed a different pattern of results. 90% of the nonmaltreated infants who recognized themselves were securely attached to their caregivers. In contrast, for those maltreated infants who recognized themselves, there was no significant relationship between this capacity and qualitative differences in the security of attachment. Furthermore, an analysis of the affective responses of the infants to their rough-marked noses revealed that nonmaltreated infants were more likely to show an increase in positive affect following the application of rouge , whereas maltreated infants manifested neutral or negative reactions. These results demonstrate that early maltreatment may have deleterious effects for the infant, independent of those risk factors commonly associated with lower-class membership. In addition, they underscore the impact of maltreatment upon the successful achievement of salient developmental tasks and upon the relationship between affective and cognitive development in the maltreated infant. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=6723453
Mans L, Cicchetti D and Sroufe LA (1978). Mirrow reactions of Down's syndrome infants and toddlers: cognitive underpinnings of self-recognition. Child Dev 49: 1247-50. To examine the developmental significance of mirrow self-recognition in early childhood, a cross-sectional study with 55 Down's syndrome children was conducted. When their image is altered by rouge on the nose, normal infants by 22 months indicate self-recognition by touching their noses while looking in the mirror. Only a small percentage of Down's syndrome children touched their noses by this age, confirming the expected lag in this development. However, those young Down's syndrome infants with near-normal development quotient did manifest the reaction. In general, when developmental age was equated, the Down's syndrome children showed parallel development to normal children. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=153832
Fryrear JL, Kodera TL and Kennedy MJ (1981). Self-recognition ability in mentally retarded adolescents. J Psychol 108: 123-31. Self-recognition abilities of 30 mentally retarded adolescents were measured using an optical system and a psychophysical scaling procedure that results in a recognition threshold. Compared with college freshmen, the experimental group had significantly higher thresholds (p = .00003). Males were better than females at recognizing full-face self-images (p = .0238). Results were discussed in terms of the retarded adolescents' greater dependency on specific visual cues. The method is discussed as an advance over previous self-recognition methods because of accuracy and the capability of measuring a range of self-recognition abilities. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7241403
Plotnik JM, de Waal FB and Reiss D (2006). From the Cover: Self-recognition in an Asian elephant. Proc Natl Acad Sci U S A 103: 17053-7. Considered an indicator of self-awareness, mirror self-recognition (MSR) has long seemed limited to humans and apes. In both phylogeny and human ontogeny, MSR is thought to correlate with higher forms of empathy and altruistic behavior. Apart from humans and apes, dolphins and elephants are also known for such capacities. After the recent discovery of MSR in dolphins (Tursiops truncatus), elephants thus were the next logical candidate species. We exposed three Asian elephants (Elephas maximus) to a large mirror to investigate their responses. Animals that possess MSR typically progress through four stages of behavior when facing a mirror: (i) social responses, (ii) physical inspection (e.g., looking behind the mirror), (iii) repetitive mirror-testing behavior, and (iv) realization of seeing themselves. Visible marks and invisible sham-marks were applied to the elephants' heads to test whether they would pass the litmus "mark test" for MSR in which an individual spontaneously uses a mirror to touch an otherwise imperceptible mark on its own body. Here, we report a successful MSR elephant study and report striking parallels in the progression of responses to mirrors among apes, dolphins, and elephants. These parallels suggest convergent cognitive evolution most likely related to complex sociality and cooperation. *Living Links, Yerkes National Primate Research Center, and Department of Psychology, Emory University, Atlanta, GA 30322. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17075063
Marino L (2002). Convergence of complex cognitive abilities in cetaceans and primates. Brain Behav Evol 59: 21-32. What examples of convergence in higher-level complex cognitive characteristics exist in the animal kingdom? In this paper I will provide evidence that convergent intelligence has occurred in two distantly related mammalian taxa. One of these is the order Cetacea (dolphins, whales and porpoises) and the other is our own order Primates, and in particular the suborder anthropoid primates (monkeys, apes, and humans). Despite a deep evolutionary divergence, adaptation to physically dissimilar environments, and very different neuroanatomical organization, some primates and cetaceans show striking convergence in social behavior, artificial 'language' comprehension, and self-recognition ability. Taken together, these findings have important implications for understanding the generality and specificity of those processes that underlie cognition in different species and the nature of the evolution of intelligence. Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Ga. 30322, USA. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12097858
Nissani M, Hoefler-Nissani D, Lay UT and Htun UW (2005). Simultaneous visual discrimination in Asian elephants. J Exp Anal Behav 83: 15-29. Two experiments explored the behavior of 20 Asian elephants (Elephas aximus) in simultaneous visual discrimination tasks. In Experiment 1, 7 Burmese logging elephants acquired a white+/black- discrimination, reaching criterion in a mean of 2.6 sessions and 117 discrete trials, whereas 4 elephants acquired a black+/white- discrimination in 5.3 sessions and 293 trials. One elephant failed to reach criterion in the white+/black- task in 9 sessions and 549 trials, and 2 elephants failed to reach criterion in the black+/white- task in 9 sessions and 452 trials. In Experiment 2, 3 elephants learned a large/small transposition problem, reaching criterion within a mean of 1.7 sessions and 58 trials. Four elephants failed to reach criterion in 4.8 sessions and 193 trials. Data from both the black/white and large/small discriminations showed a surprising age effect, suggesting that elephants beyond the age of 20 to 30 years either may be unable to acquire these visual discriminations or may require an inordinate number of trials to do so. Overall, our results cannot be readily reconciled with the widespread view that elephants possess exceptional intelligence. Department of Interdisciplinary Studies, Wayne State University, Detroit, Michigan 48202, USA. Moti.Nissani@wayne.edu http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15762378
Cozzi B, Spagnoli S and Bruno L (2001). An overview of the central nervous system of the elephant through a critical appraisal of the literature published in the XIX and XX centuries. Brain Res Bull 54: 219-27. The two species of elephants (Indian: Elephas maximus and African: Loxodonta africana) possess the largest brain among land mammals. Due to its size, the elephant brain is discussed in virtually every paper dealing with the evolution of the central nervous system of mammals and comparative brain size. Studies on the social habits of elephants also deal with the skills and the "intelligence" and brain size of these species. Yet most of the descriptions and conclusions reported in comparative studies rely on second-hand data derived from investigations performed several decades before, often dating as far back as the XIX century. Furthermore, many of the original papers actually describing gross and detailed features of the brain of elephants are either no longer available, are written in languages other than English, or are difficult to trace. The present study gives a short description of the anatomy of the central nervous system of elephants, with special attention to its distinctive features, reports all available literature on the subject, and briefly discusses its origins and rationale. Department of Animal Science, University of Padua, Legnaro, Padua, Italy. email@example.com http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11275412
Manger PR (2006). An examination of cetacean brain structure with a novel hypothesis correlating thermogenesis to the evolution of a big brain. Biol Rev Camb Philos Soc 81: 293-338. This review examines aspects of cetacean brain structure related to behaviour and evolution. Major considerations include cetacean brain-body allometry, structure of the cerebral cortex, the hippocampal formation, specialisations of the cetacean brain related to vocalisations and sleep phenomenology, paleoneurology, and brain-body allometry during cetacean evolution. These data are assimilated to demonstrate that there is no neural basis for the often-asserted high intellectual abilities of cetaceans. Despite this, the cetaceans do have volumetrically large brains. A novel hypothesis regarding the evolution of large brain size in cetaceans is put forward. It is shown that a combination of an unusually high number of glial cells and unihemispheric sleep phenomenology make the cetacean brain an efficient thermogenetic organ, which is needed to counteract heat loss to the water. It is demonstrated that water temperature is the major selection pressure driving an altered scaling of brain and body size and an increased actual brain size in cetaceans. A point in the evolutionary history of cetaceans is identified as the moment in which water temperature became a significant selection pressure in cetacean brain evolution. This occurred at the Archaeoceti - modern cetacean faunal transition. The size, structure and scaling of the cetacean brain continues to be shaped by water temperature in extant cetaceans. The alterations in cetacean brain structure, function and scaling, combined with the imperative of producing offspring that can withstand the rate of heat loss experienced in water, within the genetic confines of eutherian mammal reproductive constraints, provides an explanation for the evolution of the large size of the cetacean brain. These observations provide an alternative to the widely held belief of a correlation between brain size and intelligence in cetaceans. School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, Johannesburg, Republic of South Africa. firstname.lastname@example.org http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16573845
Platek SM, Burch RL and Gallup GG, Jr. (2001). Sex differences in olfactory self-recognition. Physiol Behav 73: 635-40. This study investigated sex differences in the ability to recognize one's own body odor accompanied by an attempt to account for variance in this ability by comparing ratings of self-body odor and other odors on a visual analog scale (VAS). Whereas over half (59.4%) of the females were able to identify their own odor, only one out of 18 (5.6%) males were able to recognize their own odor. Females rated their own secretions as significantly lower on a pleasant-positive factor than males rated their own odors (axillary secretions), but there was no difference in ratings between those who could and those who could not identify their own odor. The dimensions tapped by the VAS used in this study do not seem to account for the ability to identify one's own body odors. Department of Psychology, State University of New York at Albany, 1400 Washington Avenue, 12222, Albany, NY, USA. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11495669