Comparative aspects of mirror self-recognition in great apes

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.

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A developmental approach to the origins of self-recognition in great apes

Human Evolution ◽

10.1007/bf02435535 ◽

1991 ◽

Vol 6 (5-6) ◽

pp. 435-449 ◽

Cited By ~ 14

Author(s):

S. T. Parker

Keyword(s):

Great Apes ◽

Developmental Approach ◽

Self Recognition

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The evolution of primate visual self-recognition: evidence of absence in lesser apes

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2008.1754 ◽

2009 ◽

Vol 276 (1662) ◽

pp. 1671-1677 ◽

Cited By ~ 45

Author(s):

Thomas Suddendorf ◽

Emma Collier-Baker

Keyword(s):

Common Ancestor ◽

Great Apes ◽

Comparative Approach ◽

Mirror Surface ◽

Self Recognition ◽

Second Year Of Life ◽

Cognitive Faculties ◽

Second Year ◽

Evidence Of Absence ◽

Lesser Apes

Mirror self-recognition typically emerges in human children in the second year of life and has been documented in great apes. In contrast to monkeys, humans and great apes can use mirrors to inspect unusual marks on their body that cannot be seen directly. Here we show that lesser apes (family Hylobatidae ) fail to use the mirror to find surreptitiously placed marks on their head, in spite of being strongly motivated to retrieve directly visible marks from the mirror surface itself and from their own limbs. These findings suggest that the capacity for visual self-recognition evolved in a common ancestor of all great apes after the split from the line that led to modern lesser apes approximately 18 Myr ago. They also highlight the potential of a comparative approach for identifying the neurological and genetic underpinnings of self-recognition and other higher cognitive faculties.

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Small Mirrors Do the Trick: A Simple, but Effective Method to Study Mirror Self-Recognition in Chimpanzees

Animal Behavior and Cognition ◽

10.26451/abc.08.03.05.2021 ◽

2021 ◽

Vol 8 (3) ◽

pp. 391-404

Author(s):

Kathrin S. Kopp ◽

Sonja J. Ebel ◽

Roman M. Wittig ◽

Daniel B. M. Haun ◽

Catherine Crockford

Keyword(s):

False Negative ◽

Great Apes ◽

Primate Species ◽

Self Awareness ◽

Human Species ◽

Negative Results ◽

Self Recognition ◽

False Negative Results ◽

Species Comparisons ◽

Possible Cause

Mirror self-recognition (MSR) is considered an indicator of self-awareness. Standardized mirror tests reveal compelling evidence for MSR in a few non-human species, including all great apes. However, substantial inter-individual variation of MSR within species resulted in an ongoing methodological controversy, questioning the appropriateness of standard MSR tests for cross-species comparisons. Lack of motivation, in particular, is discussed as one possible cause for false negative results. Here, we compare the spontaneous behavioral response of 47 zoo-housed chimpanzees (Pan troglodytes) to (i) standard body-sized, stationary mirrors and (ii) small, portable hand mirrors. We predicted that the monopolizability and maneuverability of small mirrors increase the chances of identifying MSR across a larger proportion of individuals. Chimpanzees both revealed a substantially higher frequency of general mirror-related behaviors and engaged in significantly more and longer behaviors specifically indicating MSR when provided with small mirrors compared to a large mirror. Handheld mirrors provide a more sensitive measure for MSR within and likely between primate species than the traditional large mirrors, and thereby are a potentially valuable tool for studying self-awareness across species.

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Investigating self-recognition in bonobos: mirror exposure reduces looking time to self but not unfamiliar conspecifics

PeerJ ◽

10.7717/peerj.9685 ◽

2020 ◽

Vol 8 ◽

pp. e9685

Author(s):

Gladez Shorland ◽

Emilie Genty ◽

Jean-Pascal Guéry ◽

Klaus Zuberbühler

Keyword(s):

Pan Paniscus ◽

Preliminary Investigation ◽

Great Apes ◽

Mirror Image ◽

Self Awareness ◽

Video Footage ◽

Self Recognition ◽

Different Types ◽

Before And After ◽

Mirror Exposure

The question of whether animals have some sort of self-awareness is a topic of continued debate. A necessary precondition for self-awareness is the ability to visually discriminate the self from others, which has traditionally been investigated through mirror self-recognition experiments. Although great apes generally pass such experiments, interpretations of results have remained controversial. The aim of this study was to investigate how bonobos (Pan paniscus) respond to different types of images of themselves and others, both before and after prolonged mirror exposure. We first presented presumably mirror-naive subjects with representations of themselves in three different ways (mirror image, contingent and non-contingent video footage) as well as representations of others (video footage of known and unknown conspecifics). We found that subjects paid significantly less attention to contingent images of themselves (mirror image, video footage) than to non-contingent images of themselves and unfamiliar individuals, suggesting they perceived the non-contingent self-images as novel. We then provided subjects with three months of access to a large mirror centrally positioned in the enclosure. Following this manipulation, subjects showed significantly reduced interest in the non-contingent self-images, while interest in unknown individuals remained unchanged, suggesting that the mirror experience has led to a fuller understanding of their own self. We discuss implications of this preliminary investigation for the on-going debate on self-awareness in animals.

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