No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
The “olfactory mirror” and other recent attempts to demonstrate self-recognition in non-primate species
Abstract
The recent attempt by Horowitz (2017) to develop an "olfactory mirror" test of self-recognition in domestic dogs raises some important questions about the kind of data that are required to provide definitive evidence for self-recognition in dogs and other species. We conclude that the "olfactory mirror" constitutes a compelling analog to the mark test for mirror self-recognition in primates, but despite claims to the contrary neither dogs, elephants, dolphins, magpies, horses, manta rays, squid, or ants have shown compelling, reproducible evidence for self-recognition in any modality.
... Burghardt et al. [25] found that male gartersnakes, but not females, spent more time investigating their own soiled bedding than that of a familiar same-sex conspecific. Although these findings suggest chemical-based self-recognition, these tasks have been criticized for failing to capture key aspects of self-recognition and for lacking important control conditions [28]. ...
... Third, it has been suggested that effects similar to our data might result from dishabituation [28]. On this view, snakes are habituated to their own scent and the addition of the mark dishabituates them, making them explore that stimulus more. ...
... There have been several sharp criticisms of chemical-based self-recognition paradigms, suggesting that they do not provide evidence for self-recognition comparable to visual MSR experiments [18,28]. We have addressed some of these criticisms in considering alternate explanations of our results above. ...
Mark tests, in which an animal uses a mirror to locate and examine an otherwise unnoticeable mark on its own body, are commonly used to assess self-recognition, which may have implications for self-awareness. Recently, several olfactory-reliant species have appeared to pass odour-based versions of the mark test, though it has never been attempted in reptiles. We conducted an odour-based mark test on two species of snakes, Eastern gartersnakes and ball pythons, with widely divergent ecologies (i.e. terrestrial foragers that communally brumate versus semi-arboreal ambush predators that do not). We find that gartersnakes, but not ball pythons, pass the test, and a range of control tests suggest this is based on self-recognition. Gartersnakes are more social than ball pythons, supporting recent suggestions that social species are more likely to self-recognize. These results open the door to examination of the ecology of self-recognition, and suggest that this ability may evolve in response to species-specific ecological challenges, some of which may align with complexity of social structures.
... This can be further exacerbated by the presence of compensatory mechanisms unconsciously adopted to overcome the uneven supporting and propulsive action of the two limbs. Secondly, the reduced capability to optimally coordinate left and right limbs during gait might be due to reduced efficiency in the neural communication pathways between the two cerebral hemispheres, particularly as regards the fiber bundle connecting the primary motor cortices [52]. Moreover, imaging studies have highlighted the existence of a significant correlation between asymmetries in electrophysiological deficits for both arms and legs and asymmetric anatomic changes in the spinal cord's normal-appearing white matter, thus suggesting that the functional asymmetries are associated with microstructural damage of the spinal cord [53]. ...
... The recent reviews by Rudroff and Proessl [9] and Ramari et al. [54], which analyzed the effect of asymmetries in muscular strength and limb loading on walking capabilities of pwMS (in particular gait speed and performance on timed tests) raised strong doubts about the possibility of defining a clear relationship between them. However, recent studies that investigated asymmetry through calculation of the phase relationship between the step timing of the left and right legs (the so-called Phase Coordination Index, PCI [55]) reported that bilateral coordination of gait was negatively correlated with gait speed and performance in 6 m and Timed 25-foot walking tests [52,56]. Even from a quantitative point of view, such results are fully consistent with those of the present study, thus suggesting that even when assessed with completely independent methods, bilateral coordination negatively affects gait speed and stride length [49]. ...
... Still today, a plethora of studies are being conducted to identify further CPG elements and characteristics. Based on some of them, it is now generally accepted that the CPG is composed of genetically identified cells such as the HB9, V0, V1, V2, and Shox2 interneurons (for left-right coordination or rhythm and speed control), intrinsic cellular properties such as endogenous bursting neurons and Ih current (for pacemaker-like generation), specific pharmacological properties such as 5-HT1 and D1 receptors (for CPG activation), and complex network connections that support synaptic interactions as those proposed in the ring model, flexor burst model, or two-level organization model for distinct and selective rhythm and pattern adaptation [52]. ...
Human movements and posture often show lateral asymmetries in healthy, young, older, frail and pathological subjects. Why are there asymmetries in motor behaviour? These asymmetries have not been fully identified and are likely to stem from different components of motor function, such as the sensory (perception), central (central integration) and motor (movement command and control) components. The neural mechanisms involved are also not yet understood at different neurological levels (peripheral, spinal, subcortical and cortical). Therefore, exploratory research is needed in order to understand symmetry or asymmetry in terms of human movement and posture. This Special Issue, “Neuroscience, Neurophysiology and Symmetry”, presents experimental or theoretical data that provide answers to these questions, focusing mainly on asymmetry in human movement and posture.
... Second, an invisible mark has to be used to exclude that physical irritation caused by the mark itself or the process of marking is triggering the behaviour (Gallup 1970). Third, a mark has to be applied in a spot that can be seen without the use of the mirror to confirm the subjects' motivation to remove marks in general (Gallup and Anderson 2018). Humans, most great apes, elephants, dolphins and cleaner fish show MSR (Gallup 1970;Gallup et al. 2011;Kohda et al. 2019;2022;Loth et al. 2022;Plotnik et al. 2006;Reiss and Marino 2001). ...
... Humans, most great apes, elephants, dolphins and cleaner fish show MSR (Gallup 1970;Gallup et al. 2011;Kohda et al. 2019;2022;Loth et al. 2022;Plotnik et al. 2006;Reiss and Marino 2001). The evidence from species other than humans and great apes has, however, led to controversial discussion (Gallup and Anderson 2018;. ...
... Furthermore, they sniff their own odour longer when it is modified than the chemical used for modification by itself (Horowitz 2017). Nonetheless, some researchers have criticised these studies as not being a true equivalent to the MSR test because dogs do not show self-directed behaviour in the sniff-test which is an important control in the MSR test even without a mark present (Gallup and Anderson 2018;. ...
Self-recognition is the ability to recognise stimuli originating from oneself. Humans and some non-human animals show evidence of true visual self-recognition in the mirror test. They use their reflection to inspect themselves and to remove a mark that is only visible in the mirror. Not all animals, however, rely primarily on vision. In lizards, chemical cues are crucial in social interactions, and therefore, lizards would benefit from a chemical self-other distinction. Here, we test the tokay gecko (Gekko gecko), a social species, on their ability to discriminate their own skin and faecal chemicals from those of same-sex, unfamiliar conspecifics. We predicted that individuals would show more self-directed behaviour when confronted with the chemicals from unfamiliar individuals within their home enclosure as a sign of the need for increased comparison. Geckos showed higher self-directed responses towards chemicals from unfamiliar individuals compared to self-produced chemicals and a water control. Furthermore, scat and skin chemicals (regardless of origin) elicited similar but stronger responses than peppermint oil pointing towards a possible social function of scat piles. Although further tests and controls are needed, our study provides evidence towards chemical self-recognition and for a social function of scat piling in tokay geckos.
... But humans and other animals may use non-visual markers of the self. Auditory and especially pheromone or chemical self-recognition may also be used in distinguishing oneself from others, but the typical 'removal' criterion used in mirror recognition studies is not available (Gallup & Anderson, 2018). Never the less, several recent papers have studied olfactory selfrecognition based on sniffing and odour choice preferences in dogs and wolves (Cazzolla Gatti, 2016;Horowitz, 2017;Cazzolla Gatti et al., 2021). ...
... Never the less, several recent papers have studied olfactory selfrecognition based on sniffing and odour choice preferences in dogs and wolves (Cazzolla Gatti, 2016;Horowitz, 2017;Cazzolla Gatti et al., 2021). The Cazzolla Gatti et al. study specifically tried to deal with the methodological caveats of Gallup & Anderson (2018, 2019 and showed some positive evidence of chemical self-recognition. Such conflicting claims for an 'olfactory mirror' are revisited at some length in the discussion. ...
... The TF/A ratio may be a useful behavioural index proxy for exploratory and related behaviour responses in squamate reptiles. Gallup & Anderson (2018, 2019 are very sceptical of any non-visual selfrecognition studies and also refute any evidence not based on multi-modal recognition of oneself. Furthermore, they assert that an analogue of the visual mark test must be used and also stimuli from conspecifics (which was done in the present study). ...
Although self-recognition or self-awareness has been studied with the visually-based mirror test, passed by several species, primarily apes, the possibility of a chemically-based analogue is controversial. Prior studies suggested that chemical self-recognition may occur in some squamate reptiles. To evaluate this possibility, we studied 24 individually housed gartersnakes, Thamnophis sirtalis , raised from birth on either earthworm or fish diets and tested 12 male and 12 female snakes with cage liners that were either clean, their own, or from same-sex siblings fed their own or the opposite diet. Tongue flicking and activity were recorded in 30-minute video-recorded trials in a balanced design. After initial habituation to the stimuli, male, but not female, snakes discriminated between their own stimuli and those from littermates fed the same diet. Combined with other data and studies, the possibility that a chemical ‘mirror’ form of self-recognition exists in squamate reptiles is supported.
... In non-human animals, subjects sometimes choose their own odor over a novel odor from a familiar or unfamiliar individual in a twochoice test (Cichlids, Pelvicachromis taeniatus (Thünken et al., 2009), Storm-petrel chicks, Hydrobates pelagicus (De León et al., 2003). On the other hand, other species prefer to investigate, or choose novel odors compared to their own odor [dogs Canis familiaris (Gallup & Anderson, 2018;Horowitz, 2017), seabirds Pachyptila desolata, Halobena caerulea Mardon & Bonadonna, 2009)]. These differences in response behavior to self-odor versus the odor of conspecifics are interpreted as "self-recognition" or "selfdiscrimination." Notably, understanding of self-recognition in nonhuman animals has generally been elusive due to limited data and methodological difficulties (Bekoff & Sherman, 2004). ...
... Female pouched rats discriminated between self-odor and odor from a novel same-sex conspecific, behavior consistent with "selfrecognition." Sex differences in self-recognition of odor have been demonstrated in humans (Platek et al., 2001); however, the ability to determine whether animals can use odors to self-recognize is limited by difficulties in assessing whether animals habituate to self-odor or "conceptualize" that their odor is "theirs" (Gallup & Anderson, 2018). ...
... Functionally, self-recognition (or, ongoing habituation to self-odor) is thought to underlie self-referent phenotype matching, which modulates behavior toward kin and the avoidance of inbreeding (Gallup & Anderson, 2018;Mateo & Johnston, 2000;Thünken et al., 2009). ...
Rodents are known to signal using odors to communicate information including their sex, age, reproductive state, and unique identity. Conspecifics can recognize these signals and behaviorally respond in sex‐specific ways. However, we know little about how males and females might differ in their responses to signals from individuals or how the sexes might differ in their ability to recognize their own identity. Such signals of identity are important because they can modulate the behavior of receivers, and allow for responses related to aggression, territory maintenance, affiliation, and reproduction. To assess how males and females might differ in their responses to individual familiar and novel social signals, and their own individual signals compared to novel same‐sex conspecifics, we tested southern giant pouched rats (Cricetomys ansorgei) using a habituation–discrimination paradigm. Only females showed individual recognition and discriminated among males, preferring novel males. Females also discriminated between their own scent and a novel conspecific odor. Males did not discriminate or demonstrate individual recognition. Male and female differences in response to opposite‐sex odors demonstrated that males do not discriminate between familiar and novel reproductively available females, but females discriminate and prefer to investigate novel males. Female pouched rats discriminated between urine odors from novel and familiar males, but male pouched rats did not discriminate between urine odors from novel and familiar females. Other sex differences in social odor discrimination are discussed to understand sex‐specific behaviors.
... Since Gallup, Jr.'s, (1970) original mirror self-recognition (MSR) tests in chimpanzees, many other animals have been tested with ambiguous or failing results (e.g., squid [Sepioteuthis lessoniana], Ikeda & Matsumoto, 2007; manta rays [likely Manta birostris], Ari & D'Agostino, 2016;pigeon [Columba liva domestica], Epstein et al., 1981;magpie [Pica pica], Prior et al., 2008; Rhesus monkeys [Macaca mulatta], Rajala et al., 2010;ants [Myrmica sabuleti, M. rubra, M. ruginodis], Cammaerts Tricot & Cammaerts, 2015; horses [Equus caballus], Baragli et al., 2017; cotton-top tamarins [Saguinus oedipus], Hauser et al., 1995;Hauser et al., 2001). According to some researchers, extremely convincing evidence of self-recognition is rare (Anderson & Gallup, 2011;Chang et al., 2017;Gallup et al., 2002;Gallup & Anderson, 2017). With respect to mammals, apart from chimpanzees, MSR appears to have only been demonstrated in other highly social animals including just two common bottlenose dolphins (Tursiops truncatus; Reiss & Marino, 2001), one Asian elephant (Elephas maximus; Plotnik et al., 2006), and only in trained (they did not spontaneously show MSR) Rhesus monkeys (Macaca mulatta; Chang et al., 2017). ...
... Some scientists have suggested that because the MSR test relies on vision, rather than scent, it is therefore an inappropriate test for dogs or wolves (Bekoff, 2014;Cazzolla Gatti, 2016;Horowitz, 2017; but also see Gallup & Anderson, 2017). However, we suggest that the well-developed sense of smell in wolves does not preclude them from passing the visual-based MSR test. ...
... Recent domestic dog self-cognizance research has focused on scent-based tests conducted with the subject's own urine representing "self" (Bekoff, 2001(Bekoff, , 2014Cazolla Gatti, 2016;Horowitz, 2017). However, some assert that additional olfactory tests are needed that include a control for comparable changes in other familiar odors beyond just the dog's own urine (Gallup & Anderson, 2017). It has also been argued that because the dogs in the Horowitz (2017) study did not attempt to smell themselves after smelling the self-altered odor, they did not demonstrate self-recognition per the criteria of the MSR test (Gallup & Anderson, 2017, 2020. ...
Mirror self-recognition (MSR) tests have been conducted in a variety of species to assess whether these animals exhibit self-awareness. To date, the majority of animals that have convincingly passed are highly social mammals whose wild counterparts live in complex societies, though there is much debate concerning what constitutes “passing” and what passing means in terms of self-awareness. Amid recent reports that a fish (cleaner wrasse, Labroides dimidiatus) passed, it is intriguing that a mammal as highly social, tolerant, attentive, and cooperative as the gray wolf (Canis lupus) has reportedly failed the test. Given the many possible reasons for failure, we were interested in reexamining wolves as a case study of MSR in socially complex mammals as part of a broader overview of the MSR test. We aimed to elucidate the wolves’ responses at various stages of the MSR test to pinpoint potential problem areas where species-specific modifications to the test may be needed. We evaluated 6 socialized, captive gray wolves during July 2017. At a minimum, wolves did not respond to their reflection as an unfamiliar conspecific. Unfortunately, the wolves rapidly lost interest in the mirror and were uninterested in the applied marks. We note limitations of the MSR test for this species, recommend changes for future MSR tests of wolves, discuss other emerging self-cognizance methods for socially complex canids, and highlight the need for a suite of ecologically relevant, potentially scalable self-cognizance methods. Our findings and recommendations may aid in understanding self-cognizance in other MSR-untested, highly social, cooperatively-hunting, coursing, terrestrial carnivores such as African wild dogs (Lycaon pictus), spotted hyenas (Crocuta crocuta), and African lions (Panthera leo).
... Dogs seemed capable of distinguishing between the olfactory "image" of themselves when modified. Nevertheless, Gallup and Anderson (2018) proposed at least two improvements to provide definitive evidence for selfrecognition in dogs, and also to make the sniff test comparable to the mirror test. The first improvement calls for the need to check the sniffing and post-sniffing behavior towards modified familiar odors because there is a possibility that dogs would show the same response to comparable changes in other familiar odors, such as that of another companion dog ("familiarity hypothesis"). ...
... Here we applied the STSR test to a dog-related species, the grey wolf (Canis lupus). In this test, we incorporated the controls suggested by Gallup and Anderson (2018) and included in the preliminary test performed in Cazzolla Gatti (2016). We applied five trials of the sniff-test for self-recognition to a group of four captive grey wolves, living in malefemale couples in two different enclosures at the Wolf Park in Indiana, USA. ...
... The first trials were a combination of self (S) and self-modified (SM, i.e. each wolf's own urine marked with anise essential oil) scents with a third canister containing: (i) the mark by itself (M), to check the pure interest in the mark; (ii) the urine of the know (partner) wolf modified with the mark (KM), to check the interest in a modified companion's odor; and (iii) the urine of a dog (D), to check the interest in a completely unknown and heterospecific odor. Then, to definitively disentangle the "familiarity hypothesis and the unfamiliarity preference" suggested by Gallup and Anderson (2018), we performed a fourth and a fifth trial with a combination of self (S), known (K; urine from the partner wolf), unknown (U; urine from a nonpartner wolf), and the marked modifications of known and unknown (KM and UM, respectively). These two additional trials were added as further controls to check the ability of wolves to (1) differentiate the "self" odor from "known" (familiar) and "unknown" (unfamiliar) odors, and (2) discern between marked "known" (familiar modified) and "unknown" (unfamiliar modified) odors. ...
Although there are recent claims of a lack of evidence of self-consciousness in many tested species, the ability to recognize oneself in a mirror, which seems an exceedingly rare capacity in the animal kingdom, may not be the only way to check for animal self-awareness (i.e. the capacity to become the object of your own attention). A new testing approach, based on a different sensory modality (such as the sniff-test for self-recognition, STSR), recently proved to be effective with dogs. We applied this sniff test to a group of four captive grey wolves, living in male-female couples in two different enclosures at the Wolf Park in Indiana, USA. In this preliminary study, wolves showed some signs of the ability to recognize themselves through the “olfactory mirror” and exhibited some clues of mark-directed responses, particularly scent-rolling, which may shed more light on this still unclear behavior and represent a sort of olfactory equivalent to passing the original mirror test.
... Since Gallup (1970) designed the mark test, the mirror selfrecognition paradigm has been widely used to assess selfrecognition in a wide range of species. Individuals may respond by ignoring the mirror image or considering it as a conspecific (de Waal, Dindo, Freeman, & Hall, 2005;Kusayama, Bischof, & Watanabe, 2000;Medina, Taylor, Hunt, & Gray, 2011;Roma et al., 2007;Shaffer & Renner, 2000;Watanabe, 2002) or much more rarely, showing self-directed behavior in front of the mirror, a response that has only been found in just a few species having very large brains (Gallup, 1970;Gallup & Anderson, 2018;Plotnik, de Waal, & Reiss, 2006;Prior, Schwarz, & Güntürkün, 2008;Reiss & Marino, 2001). Until the beginning of the 21st century, only large-brained mammals had passed the mark test, and thus, considering the vast differences between mammals and birds in the organization of their forebrains (Güntürkün, 2012), it was thought that a mammalian neocortex was necessary for self-recognition. ...
... Two of these issues may be important in magpie studies: the use of stickers as an appropriate replacement for the paint marks used in mammalian mirror studies, and the virtual impossibility of producing a true sham mark control because of the iridescence of magpie feathers. And third, as pointed out by Gallup and Anderson (2018), the two magpies presenting mark-directed behavior in the Prior et al. (2008) study persisted repeatedly in the responses toward their reflection for extended periods of time. This lack of habituation to the mirror is consistent with findings in species not able to pass the mark test, such as monkeys and parrots (Gallup & Suarez, 1991;Pepperberg et al., 1995). ...
... This lack of habituation to the mirror is consistent with findings in species not able to pass the mark test, such as monkeys and parrots (Gallup & Suarez, 1991;Pepperberg et al., 1995). If magpies have the ability of self-recognition it would be expected for them to habituate to the mark, as occurs in chimpanzees (Pan troglodytes): When they realize that it is their behavior that they are observing in the mirror, their interest rapidly diminishes, whereas their self-contingent and mirror-directed exploratory behavior increases (Gallup & Anderson, 2018). ...
Self-recognition in animals is demonstrated when individuals pass the mark test. Formerly, it was thought that self-recognition was restricted to humans, great apes, and certain mammals with large brains and highly evolved social cognition. However, 1 study showed that 2 out of 5 magpies (Pica pica) passed the mark test, suggesting that magpies have a similar level of cognitive abilities to great apes. The scientific advancement depends on confidence in published science, and this confidence can be reached only after rigorous replication of published studies. Here, we present a close replication of the magpie study but using a larger sample size while following a very similar experimental protocol. Like the previous study, in our experiment, magpies showed both social and self-directed behavior more frequently in front of the mirror versus a control cardboard stimulus. However, during the mark test, self-directed behavior proved more frequent in front of the cardboard than in the mirror. Thus, our replication failed to confirm the previous results. Close replications, while not disproving an earlier study, identify results that should be considered with caution. Therefore, more replication studies and additional experimental work is needed to unambiguously demonstrate that magpies are consistently able to pass the mark test. The existence of compelling evidence of self-recognition in other corvid species is discussed in depth. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
... www.nature.com/scientificreports/ MSR is the most influential paradigm for demonstrating self-awareness in animals 24,26,43 . However, the conventional mark test, the most widely used method for investigating MSR, is unreliable for individuals or species demonstrating little interest in an ecologically meaningless mark and lacking motivation for its removal 11,22,33,44 . ...
... This method has the advantage of being simple enough to be applicable to a wide range of species; for example, human infants 45 , dogs 47,48 , crows 49 , snakes 50 , and even bumblebees 51,52 . However, the conventional procedure for demonstrating body size awareness does not reveal self-directed behavior 11,26,43 and is difficult to use as convincing evidence of self-awareness. Self-directed behavior refers to instances in which animals investigate or manipulate personal features, such as self-exploratory behavior using a mirror 1,11,26 . ...
Animals exhibiting mirror self-recognition (MSR) are considered self-aware; however, studies on their level of self-awareness remain inconclusive. Recent research has indicated the potential for cleaner fish (Labroides dimidiatus) to possess a sophisticated level of private self-awareness. However, as this study revealed only an aspect of private self-awareness, further investigation into other elements is essential to substantiate this hypothesis. Here, we show that cleaner fish, having attained MSR, construct a mental image of their bodies by investigating their ability to recall body size. A size-based hierarchy governs the outcomes of their confrontations. The mirror-naïve fish behaved aggressively when presented with photographs of two unfamiliar conspecifics that were 10% larger and 10% smaller than their body sizes. After passing the MSR test, they refrained from aggression toward the larger photographs but still behaved aggressively toward the smaller ones without re-examining their mirror images. These findings suggest that cleaner fish accurately recognize their body size based on mental images of their bodies formed through MSR. Additionally, mirror-experienced fish frequently revisited the mirror when presented with an intimidating larger photograph, implying the potential use of mirrors for assessing body size. Our study established cleaner fish as the first non-human animal to be demonstrated to possess private self-awareness.
... Since Gallup's initial findings, the literature has swayed from conservative (only humans, chimpanzees, and orangutans have self-face recognition) to today with more liberal interpretations that include the addition of animals such as elephants, dolphins, and magpies [52]. ...
... Other attempts to modify the test have included making the test more phenotypically relevant by using olfaction rather than vision [69]. While this is but a brief summary, we remain skeptical about SFR in non-great apes (with the exception of dolphins) and conclude that more evidence is needed before we consider organisms outside of apes and dolphins to have SFR abilities [52]. ...
While the desire to uncover the neural correlates of consciousness has taken numerous directions, self-face recognition has been a constant in attempts to isolate aspects of self-awareness. The neuroimaging revolution of the 1990s brought about systematic attempts to isolate the underlying neural basis of self-face recognition. These studies, including some of the first fMRI (functional magnetic resonance imaging) examinations, revealed a right-hemisphere bias for self-face recognition in a diverse set of regions including the insula, the dorsal frontal lobe, the temporal parietal junction, and the medial temporal cortex. In this systematic review, we provide confirmation of these data (which are correlational) which were provided by TMS (transcranial magnetic stimulation) and patients in which direct inhibition or ablation of right-hemisphere regions leads to a disruption or absence of self-face recognition. These data are consistent with a number of theories including a right-hemisphere dominance for self-awareness and/or a right-hemisphere specialization for identifying significant social relationships, including to oneself.
... Since Gallup's initial findings, the literature has swayed from conservative (only humans, chimpanzees, orangutans have self-face recognition) to today with more liberal interpretations which includes adding animals such as elephants, dolphins and magpies (Gallup & Anderson, 2018). ...
... Full treatment of the role of brain differences in self-awareness is beyond the scope of this article. What is worth noting here is that many organisms appear to get to the level of self-face recognition with very different brain mechanisms (Gallup & Anderson, 2018). Further, self-other distinguishing could be argued to be a basic life requirement (i.e, bacteria) and while self-face processing in humans may be different in what it represents in humans, it may in fact not be. ...
While the desire to uncover the neural correlates of consciousness has taken numerous directions, self-face recognition has been a constant in attempts to isolate aspects of self-awareness. The neuroimaging revolution of the 1990’s bought about systematic attempts to isolate the underlying neural basis self-face recognition. These studies, including some of the first fMRI (functional Magnetic Resonance Imaging) studies, revealed a right hemisphere bias for self-face recognition in a diverse set of regions including the insula, the Dorsal Frontal Lobe, the Temporal Parietal Junction and Medial Temporal Cortex. Confirmation of these data (which are correlational) was provided by TMS (Transcranial Magnetic Stimulation) and patients in which direct inhibition or ablation of right hemisphere regions leads to a disruption or absence of self-face recognition. These data are consistent with a number of theories including a right hemisphere dominance for self-awareness and/or a right hemisphere specialization for identifying significant social relationships including to oneself.
... To date, in the avian field, only a few species have been formally tested for MSR. Among those, only magpies and Indian crows have been reported to successfully pass this test, although the evidence provided is highly controversial (Anderson & Gallup, 2015;Buniyaadi, Taufique, & Kumar, 2020;Gallup & Anderson, 2018;Prior, Schwarz, & Güntürkün, 2008). Somatosensory feedback enhanced by the application of the mark and intrinsic motivational factors have been identified as the main crucial factors that might underline this patchy pattern of findings across avian species, as well as in other species (Anderson & Gallup, 2015;Buniyaadi et al., 2020;De Veer & Van Den Bos, 1999;Gallup & Anderson, 2018;Heyes, 1994Heyes, , 1995Heyes, , 1996Prior et al., 2008;Soler, Pérez-Contreras, & Peralta-Sánchez, 2014;van Buuren, Auersperg, Gajdon, Tebbich, & von Bayern, 2018;Vanhooland, Bugnyar, & Massen, 2020). ...
... Among those, only magpies and Indian crows have been reported to successfully pass this test, although the evidence provided is highly controversial (Anderson & Gallup, 2015;Buniyaadi, Taufique, & Kumar, 2020;Gallup & Anderson, 2018;Prior, Schwarz, & Güntürkün, 2008). Somatosensory feedback enhanced by the application of the mark and intrinsic motivational factors have been identified as the main crucial factors that might underline this patchy pattern of findings across avian species, as well as in other species (Anderson & Gallup, 2015;Buniyaadi et al., 2020;De Veer & Van Den Bos, 1999;Gallup & Anderson, 2018;Heyes, 1994Heyes, , 1995Heyes, , 1996Prior et al., 2008;Soler, Pérez-Contreras, & Peralta-Sánchez, 2014;van Buuren, Auersperg, Gajdon, Tebbich, & von Bayern, 2018;Vanhooland, Bugnyar, & Massen, 2020). ...
Pioneering research on avian behaviour and cognitive neuroscience have highlighted that avian species, mainly corvids and parrots, have a cognitive tool kit comparable with apes and other large-brained mammals, despite conspicuous differences in their neuroarchitecture. This cognitive tool kit is driven by convergent evolution, and consists of complex processes such as casual reasoning, behavioural flexibility, imagination, and prospection. Here, we review experimental studies in corvids and parrots that tested complex cognitive processes within this tool kit. We then provide experimental examples for the potential involvement of metacognitive skills in the expression of the cognitive tool kit. We further expand the discussion of cognitive and metacognitive abilities in avian species, suggesting that an integrated assessment of these processes, together with revised and multiple tasks of mirror self-recognition, might shed light on one of the most highly debated topics in the literature—self-awareness in animals. Comparing the use of multiple assessments of self-awareness within species and across taxa will provide a more informative, richer picture of the level of consciousness in different organisms.
... Few animals possess MSR. They include humans, chimps, and orangutans for sure; magpies, dolphins and elephants as probable/possible (Anderson & Gallup, 2011;Gallup & Anderson, 2018). Even in those that do, such as the chimps, levels are about 50% not passing the test. ...
... Além disso, em muitos experimentos, são criadas situações artifi ciais e distantes do contexto natural dos animais, como o clássico teste do espelho, utilizado para verifi car se certos animais têm capacidade de autorreconhecimento. Embora seja um teste apropriado para algumas espécies, essa abordagem pode não ser efi caz para animais cuja modalidade sensorial não depende principalmente da visão, como os cães (Gallup & Anderson, 2018;Generoso, 2021). Além da possibilidade de submeter os animais a condições ecologicamente irrelevantes para sua espécie (Savalli et al., 2016), certas situações experimentais também podem colocar em risco o bem-estar dos indivíduos, como a privação de contato social enfrentada por muitos primatas não humanos submetidos a experimentações em cativeiro (Bard & Leavens, 2014). ...
... In the modified olfactory version of MSR, dogs investigated their own urine longer when it was modified with some other stimulus; this behavior was interpreted as implying a recognition of the odor as being of or from "themselves" (Horowitz, 2017). Nevertheless, the original developers of the MSR have provided detailed critique for these studies, suggesting that these results have not controlled for simple habituation for one's own odor, and the evidence is lacking about the connection of the odor perception with self-awareness (Gallup and Anderson, 2018). As we now know more about canine brain wiring between the olfactory and visual cortices (Andrews et al., 2022), we expect more extensive and robust studies of the canine processing of self and other in the future. ...
Domestic dogs (Canis familiaris) have excellent olfactory processing capabilities that are utilized widely in human society e.g., working with customs, police, and army; their scent detection is also used in guarding, hunting, mold-sniffing, searching for missing people or animals, and facilitating the life of the disabled. Sniffing and searching for odors is a natural, species-typical behavior and essential for the dog's welfare. While taking advantage of this canine ability widely, we understand its foundations and implications quite poorly. We can improve animal welfare by better understanding their olfactory world. In this review, we outline the olfactory processing of dogs in the nervous system, summarize the current knowledge of scent detection and differentiation; the effect of odors on the dogs’ cognitive and emotional processes and the dog-human bond; and consider the methodological advancements that could be developed further to aid in our understanding of the canine world of odors.
... These experiments reported that these species discriminate their own smell from that of others. As interesting this finding is, the interpretation of these results as a proof of self-recognition remains ambiguous [49]. ...
Touching a mark on the own body when seeing this mark in a mirror is regarded as a correlate of self-awareness and seems confined to great apes and a few further species. However, this paradigm often produces false-negative results and possibly dichotomizes a gradual evolutionary transition of self-recognition. We hypothesized that this ability is more widespread if ecologically tested and developed such a procedure for a most unlikely candidate: chickens (Gallus gallus domesticus). Roosters warn conspecifics when seeing an aerial predator, but not when alone. Exploiting this natural behavior, we tested individual roosters alone, with another male, or with a mirror while a hawk’s silhouette flew above them. Roosters mainly emitted alarm calls in the presence of another individual but not when alone or seeing themselves in the mirror. In contrast, our birds failed the classic mirror test. Thus, chickens possibly recognize their reflection as their own, strikingly showing how much cognition is ecologically embedded.
... Not much is known about the behavior of lampreys, hagfishes and chimaeras (most of which are deepwater species), but some sharks and rays have recently been found to exhibit unexpectedly complex behavior, and many researchers now informally call certain species "intelligent". Manta rays (Manta spp.) are among the few animals that have passed the so-called mirror test, generally considered a robust test (2015) Dinets (2015) V. Dinets of self-awareness (Ari and D'Agostino, 2016, although see Gallup and Anderson, 2018). Reticulated freshwater stingrays (Potamotrygon falkneri) can use tools (Kuba et al., 2010) and exhibit social learning (Thonhauser et al., 2013). ...
... Typically the mark test is used: An animal that grooms itself would try to remove a visible mark placed on it that could not be seen without using the mirror. Up until now, this test has been successfully passed by some apes and few other animals Plotnik et al., 2006;Prior et al., 2008;Reiss & Marino, 2001;Suarez & Gallup, 1981;Walraven et al., 1995), although there are objections to all demonstations of self-recognition capabilities in nonprimates, mainly on methodological grounds (Gallup & Anderson, 2018, 2019. ...
... Nevertheless, we cannot simply apply specific definitions of primate contingency checking behaviours to birds because of the huge differences in body structure and behavioural patterns between the two. In addition to the lack of social behaviours and contingent behaviours, we did not observe that it used the mirror to guide spontaneous self-directed behaviours during open mirror exposure, which has been proposed to be a better estimation than the removal of the mark for mirror self-recognition (Anderson & Gallup 2015;Gallup 2018;Gallup & Anderson 2021). Taken together, it is hard to tell that S2 did have mirror selfrecognition, but what is certain is that its understanding of the mirror was different from that of individuals who completely lack mirror self-recognition. ...
So far, only a handful of species have successfully passed the mirror test, showing the mirror self-recognition ability. Birds that have been claimed to show this ability are all corvids. In this study, we conducted a series of mirror-related tests, including open mirror exposure, mirror-mediated foraging task and mark test, to investigate this ability in the African grey parrot. Subjects responded to the mirror on three levels. Three subjects consistently showed social behaviours towards the mirror, two of which repeatedly hit the mirror throughout the test, indicating a complete lack of mirror perception and self-recognition. Two subjects showed social behaviours or hit the mirror almost within the first 10 min of the mirror trial, indicating they initially recognized mirror images as conspecifics but changed this misconception over time. There was only one individual, who not only never hit the mirror and exhibited social behaviours towards the mirror, but also could use the mirror to locate hidden food and mark on the body that was invisible without a mirror. However, considering the lack of contingent behaviours and spontaneous mirror-guided self-directed behaviours, it is hard to assert the African grey parrot possesses mirror self-recognition. All in all, we found our subjects responded differently towards the mirror, showing varying levels of understanding of the mirror. Our findings support the gradualist perspective on mirror self-recognition. Different mark methods are also discussed, and we suggest attaching the mark on the mandible in future parrot research.
... To overcome this problem, attempts have been made to measure the "Sense of Self" via standardized, objective methods by studying the construct from a neurobiological and behavioral point of view. It is now clear that the capacity to recognize oneself is central to individual consciousness and cognition, as only the most sophisticated brains in the animal kingdom possess this feature [2]. So, the sense of self is a complex concept that should be observed from different points of view. ...
(1) Background: The Embodied Sense-of-Self Scale (ESSS) is the only validated measure for self-assessing embodiment abnormalities, which differentiate people with anomalous embodied self-representations such as schizophrenic patients from controls. The aim of the current study was to translate the ESSS from English to Italian and to examine its factor structure, reliability, and validity in the Italian context. (2) Methods: We tested the fit of the original three-factor structure (agency, ownership, and narrative identity) across a community sample (N = 269) and the reliability as well as the convergent and divergent validity of the ESSS. (3) Results: The three-factor structure of the ESSS was confirmed. However, three different factors have emerged from our analysis (self-recognition, self-consistence, and self-awareness). Higher internal consistency of the ESSS was obtained by removing six items that seemed problematic. The three ESSS scales show highly intercorrelated constructs. The measure was reliable and positively correlated with schizotypy (via the Perceptual Aberration Scale) and aberrant salience (via the Aberrant Salience Inventory), and negatively correlated with empathy (via the Italian Short Empathy Quotient scale), generalized self-efficacy (via the Generalized Self-Efficacy Scale), and social self-efficacy (via the Perceived Social Self-Efficacy Scale). (4) Conclusions: The 19-item Italian version of the ESSS is a suitable measure with which to assess embodiment abnormalities in Italian samples.
... Insects were able to integrate information across different sensory modalities (Solvi et al., 2020) and form egocentric representations of the world (Barron & Klein, 2016). Critically, this list is not meant to convince readers that elephants, rodents, birds, or insects are conscious (indeed, the validity of some of these markers is disputed; e.g., for a critical review of the mirrortest literature, see Gallup & Anderson, 2018). Instead, it is meant to show that as of April 2022, no single nonverbal behavioral or neural marker of consciousness has been shown to be uniquely human. ...
A target question for the scientific study of consciousness is how dimensions of consciousness, such as the ability to feel pain and pleasure or reflect on one’s own experience, vary in different states and animal species. Considering the tight link between consciousness and moral status, answers to these questions have implications for law and ethics. Here we point out that given this link, the scientific community studying consciousness may face implicit pressure to carry out certain research programs or interpret results in ways that justify current norms rather than challenge them. We show that because consciousness largely determines moral status, the use of nonhuman animals in the scientific study of consciousness introduces a direct conflict between scientific relevance and ethics—the more scientifically valuable an animal model is for studying consciousness, the more difficult it becomes to ethically justify compromises to its well-being for consciousness research. Finally, in light of these considerations, we call for a discussion of the immediate ethical corollaries of the body of knowledge that has accumulated and for a more explicit consideration of the role of ideology and ethics in the scientific study of consciousness.
... Similarly, rapid approaches to the mirror after marking were interpreted as an intention to self-inspect with the alternative (seeking proximity to another dolphin after an unusual event) often ignored, perhaps because it suggests that self-recognition is absent. We think such behavioural categorisations and interpretation are inherently subjective and they have also been criticised in the literature (Gallup and Anderson 2018;Harley 2013;Manger 2013). We tried to avoid such bias using a measureable response variable (looking time) that is unequivocal. ...
Mirror-guided self-inspection is seen as a cognitive hallmark purportedly indicating the existence of self-recognition. Only a few species of great apes have been reported to pass a standard mark test for mirror self-recognition in which animals attempt to touch a mark. In addition, evidence for passing the mark test was also reported for Asian elephants, two species of corvids, and a species of cleaner fish. Mirror self-recognition has also been claimed for bottlenose dolphins, using exposure of marked areas to a mirror as evidence. However, what counts as self-directed behaviour to see the mark and what does not has been debated. To avoid this problem, we marked the areas around both eyes of the animals at the same time, one with visible and the other with transparent dye to control for haptic cues. This allowed the animal to see the mark easily and us to investigate what side was exposed to the mirror as an indicator for mark observation. We found that the animals actively chose to inspect their visibly marked side while they did not show an increased interest in a marked conspecific in the pool. These results demonstrate that dolphins use the mirror to inspect their marks and, therefore, likely recognise a distinction between self and others.
... As stated elegantly by Wittek et al. (2021), we need to move beyond the pass/fail criteria of the mark test as a measure of self-recognition and adopt a more gradualist approach. The insistence that the mark test is the sole evidence for self-recognition also has led to the refusal to legitimise studies that have demonstrated animals passing the mark test; when they fail the mark test they are said to lack the cognitive capability of self-recognition, but when they pass, it is attributed to arbitrary details in the methods that supposedly gave false positives for mirror self-recognition (Anderson & Gallup, 2015, Gallup & Anderson, 2018, Gallup & Anderson, 2020. ...
... So, there is a potential to create an "olfactory mirror test" that could be used as an innovative mirror test. However, there is no convincing evidence in neither dogs, elephants, dolphins, magpies, horses, manta rays, squid, or ants using the "olfactory mirror test" [18]. Also, the "olfactory mirror test" has limited applications as it can only be used with animals that for animals that use olfactory cues. ...
... As stated elegantly by Wittek et al. (2021), we need to move beyond the pass/fail criteria of the mark test as a measure of self-recognition and adopt a more gradualist approach. The insistence that the mark test is the sole evidence for self-recognition also has led to the refusal to legitimise studies that have demonstrated animals passing the mark test; when they fail the mark test they are said to lack the cognitive capability of self-recognition, but when they pass, it is attributed to arbitrary details in the methods that supposedly gave false positives for mirror self-recognition (Anderson & Gallup, 2015, Gallup & Anderson, 2018, Gallup & Anderson, 2020. ...
The extent to which different species display self-recognition is a controversial topic in comparative cognition. Self-recognition is widely validated through the mark test in which a dye or paint mark is applied surreptitiously to the subject. Mark-directed responses in the presence of a mirror are taken as evidence of self-recognition. Over the past 50 years many different species have been administered the mark test, but only a handful have passed it. Some have suggested that species that pass the mark test are those that have a complex social structure. In this review, we propose, rather, that the reason why an animal fails the mark test is because the study has failed to adequately account for one or more of three crucial elements: mirror understanding, self-exploration, and mark saliency. Alternative methods of validating mirror self-recognition also are discussed.
... Thus, applying adapted versions of the MSR, two studies in dogs (Gatti, 2016;Horowitz, 2017) used olfaction as a mechanism for self-recognition, with dogs being able to recognize their own smell. Nonetheless, Gallup and Anderson (2018) argued that the "olfactory mirror" recognition test lacked important control conditions, undermining the results. Specifically, in his critique to the Horowitz study, he noted that dogs spent more time investigating another dog's odor than their own because they habituate to their own odor. ...
The capacity to be self-aware is regarded as a fundamental difference between humans and other species. However, growing evidence challenges this notion, indicating that many animals show complex signs and behaviors that are consonant with self-awareness. In this review, we suggest that many animals are indeed selfaware, but that the complexity of this process differs among species. We discuss this topic by addressing several different questions regarding self-awareness: what is selfawareness, how has self-awareness been studied experimentally, which species may be self-aware, what are its potential adaptive advantages. We conclude by proposing alternative models for the emergence of self-awareness in relation to species evolutionary paths, indicating future research questions to advance this field further.
... Within the primates, great apes such as chimpanzees, Pan troglodytes (Gallup 1970;Suarez and Gallup 1981;Povinelli et al. 1993) and orangutans, Pongo pygmaeus (Suarez and Gallup 1981) have passed the mirror self-recognition test, and these findings have been independently replicated (Gallup et al. 2011;Anderson and Gallup 2015). Outside of the primates, evidence of self-recognition in mammals such as Asian elephants, Elephas maximus (Plotnik et al. 2006) and bottlenose dolphins, Tursiops truncatus (Reiss and Marino 2001) and birds such as the Eurasian magpie, Pica pica (Prior et al. 2008) have been reported, however, concerns have been raised about these studies due to their small sample sizes, lack of replication or failed replication (Gallup and Anderson 2018;Soler et al. 2020). In addition to those that have passed the mirror selfrecognition test, some species have been suggested to be at an intermediate level between reacting to their reflection as a stranger and recognising it as self (e.g. ...
Responses to mirrors vary in non-human animals. Many species respond socially to mirrors with relatively few species demonstrating self-recognition in mirrors. In this study, we investigated the responses of ferrets to mirrors. Six adult ferrets (3 males, 3 females, all over a year old) were exposed to mirrors and their responses were investigated over three experimental conditions (baseline, mirror preference, mark test) in a repeated measures design. Upon initial presentation, the ferrets showed more approach and sniffing behaviour toward the mirror than the non-reflective surface. The ferrets also showed a preference for the mirror and spent more time in close proximity to the mirror than the non-reflective surface. In the mirror mark test, the ferrets showed more approach, sniffing and self-exploration behaviour when they were marked and presented with the mirror compared to when they were marked and presented with the non-reflective surface, or when they were sham-marked and presented with either surface. Our findings are suggestive that ferrets show interest in mirrors and that further study exploring the responses of ferrets to mirrors is warranted.
... Mammal species that have reported to pass the mirror test include the chimpanzee (Pan troglodytes), the orangutan (Pongo pygmaeus), the bonobo (Pan paniscus), the gorilla (Gorilla gorilla gorilla), the bottlenose dolphin (Tursiops truncatus), the killer whale (Orcinus orca) and the Asian elephant (Elephas maximus) (Gallup, 1970;Lethmate and Dücker, 1973;Marten and Psarakos, 1994;Westergaard and Hyatt, 1994;Delfour and Marten, 2001;Reiss and Marino, 2001;Sarko et al., 2002;Plotnik et al., 2006;Posada and Colell, 2007;Morrison and Reiss, 2018). However, these species except great apes have been questioned with insufficient evidence for showing MSR (Gallup, 2018). Also, the cleaner wrasse (Labroides dimidiatus) is reported to pass the mirror test (Kohda et al., 2019), but this assertion is highly contested (Gallup and Anderson, 2020). ...
Scientists have spent great efforts exploring self-recognition in non-human animals using the mirror test. In avian species, some of the passerines have passed the test, although the findings are still under debate. The present study aimed at investigating mirror self-recognition ability and making a comparative study of mirror responses in two avian species, the common hill myna from the Passeriformes and the African grey parrot from the Psittaciformes. The subjects underwent four stages of experiment: habituation, baseline, mirror exposure and mark test. Our subjects spent significantly longer time in gazing into the mirror than the plexiglass as control. We also found they significantly increased the durations of grooming behaviour when presented with the mirror. No species difference was detected in the above two behaviours. However, the African grey parrots were more likely to approach the mirror than the common hill mynas, indicating their different ways of mirror exploration. All subjects failed to pass the mark test. In this study, we found no evidence of mirror self-recognition in the common hill myna and the African grey parrot.
... These results remain controversial. Gordon Gallup, the creator of the first mirror test in other animals (Gallup 1970) has been a key skeptic of many of the above results (Gallup & Anderson 2018). A full review of MSR (mirror self-recognition) in these many cases is beyond the scope of this paper. ...
... These results remain controversial. Gordon Gallup, the creator of the first mirror test in other animals (Gallup 1970) has been a key skeptic of many of the above results (Gallup & Anderson 2018). A full review of MSR (mirror self-recognition) in these many cases is beyond the scope of this paper. ...
Several influential philosophers and scientists have advanced a framework, often called Neo-Cartesianism (NC), according to which animal suffering is merely apparent. Drawing upon contemporary neuroscience and philosophy of mind, Neo-Cartesians challenge the mainstream position we shall call Evolutionary Continuity (EC), the view that humans are on a nonhierarchical continuum with other species and are thus not likely to be unique in consciously experiencing negative pain affect. We argue that some Neo-Cartesians have misconstrued the underlying science or tendentiously appropriated controversial views in the philosophy of mind. We discuss recent evidence that undermines the simple neuroa-natomical structure-function correlation thesis that under-girds many Neo-Cartesian arguments, has an important bearing on the recent controversy over pain in fish, and places the underlying epistemology framing the debate between NC and EC in a new light that strengthens the EC position.
... Horowitz's study translates the MSR study for dogs (who primarily rely on olfaction) who have shown interest in their own odours, implying the dogs' recognition of the odour that came from them. Gallup and Anderson (2018) have reported their critique of the olfactory mirror with dogs. A task exploiting an ecologically relevant behaviour has been used to assess the self-recognition of Clark's nutcrackers (Nucifraga columbiana) (Clary and Kelly, 2016) and California scrub jays (Aphelocoma californica) (Clary et al., 2019). ...
Mirror self-recognition (MSR) is considered a crucial step in the emergence of self-cognition. The MSR paradigm has become a standard method for evaluating self-cognition in several species. For example, Eurasian magpies and Indian house crows have passed the mark test for self-cognition, whereas efforts to find MSR in other corvid species have failed. However, no literature has conducted MSR tests on azure-winged magpies, a species of corvids. Therefore, the current research aimed to investigate the MSR behaviours of azure-winged magpies upon looking into a mirror for the first time. The study included four tests: (1) mirror preference and standardised mirror exploration, (2) single vertical mirror test, (3) mark test and (4) mirror-triggered search test. The azure-winged magpies displayed immense curiosity towards the mirror and their images in the mirror in Test 1&2. In the subsequent mark tests, they failed to recognise themselves in the mirror and regarded their images as conspecifics. Behaviour analysis showed no significant difference between marked and unmarked behaviours. Finally they seemed to infer the presence of bait from the image in the mirror, but were found to fail to understand that the location of the bait in the mirror was the same as that in the real world. For a better insight into the MSR behaviour of azure-winged magpies, research studies involving prolonged mirror exposure and training are recommended.
... The behaviour in one animal is automatically triggered by the similar behaviour of others (Zentall, 2001) in primates), and evidence in non-primate species (e.g. elephants) is often based on single individual findings (see Gallup and Anderson, 2018, for a review on MSR in non-primates). Moreover, it remains unresolved whether MSR in animals demonstrates S-O distinction or whether MSR can be explained alternatively, and whether S-O distinction automatically implies self-awareness, as disputed in a recent paper on MSR in cleaner fish (Labroides dimidiatus) (Kohda et al., 2019; but see de Waal, 2019, for a critical discussion of Kohda et al., 2019, and the application of a gradual perspective on MSR, rather than the current binary one). ...
The aim of this review is to discuss recent arguments and findings in the comparative study of empathy. Based on a multidisciplinary approach including psychology and ethology, we review the non-human animal literature concerning theoretical frameworks, methodology, and research outcomes. One specific objective is to highlight discrepancies between theory and empirical findings, and to discuss ambiguities present in current data and their interpretation. In particular, we focus on emotional contagion and its experimental investigation, and on consolation and targeted helping as measures for sympathy. Additionally, we address the feasibility of comparing across species with behavioural data alone. One main conclusion of our review is that animal research on empathy still faces the challenge of closing the gap between theoretical concepts and empirical evidence. To advance our knowledge, we propose to focus more on the emotional basis of empathy, rather than on possibly ambiguous behavioural indicators, and we provide suggestions to overcome the limitations of previous research.
This handbook lays out the science behind how animals think, remember, create, calculate, and remember. It provides concise overviews on major areas of study such as animal communication and language, memory and recall, social cognition, social learning and teaching, numerical and quantitative abilities, as well as innovation and problem solving. The chapters also explore more nuanced topics in greater detail, showing how the research was conducted and how it can be used for further study. The authors range from academics working in renowned university departments to those from research institutions and practitioners in zoos. The volume encompasses a wide variety of species, ensuring the breadth of the field is explored.
Davila and colleagues cover methods and review findings regarding dog olfactory cognition. The chapter begins by introducing the topic of dog cognition. Specific aspects of dog olfactory cognition are explored. The authors review methods and procedures that investigate different aspects of olfaction and memory, including episodic memory, working memory, and long-term memory. Next, olfactory category and concept learning in dogs is reviewed followed by a discussion of the nature of olfactory representations in dogs, as well as studies that involve an olfactory search image. Finally, the last section reviews olfactory quantity judgments. The authors conclude by emphasizing the importance of dog cognition and suggesting a converging operation approach for future research.
Theorists arguing that non-human animals (simply animals from this point forward) are self-aware often make the case on the basis that non-human species understand aspects of themselves and the world, and these forms of understanding indicate self-awareness. But the notion of understanding in this context is often taken for granted. This article aims to analyse the nature of animal understanding to clarify the kind of understanding that matters for discussions of self-awareness, namely, self-understanding. I proceed by drawing on discussions of understanding offered in contemporary epistemology, and then by discussing the relevance of the concept of self-understanding here for discussions of animal self-awareness. I argue that the kind of self-understanding relevant to discussions of animal self-awareness is specifically an animal’s understanding of its own causal influence on the world and on others.KeywordsAnimal mindsAnimal cognitionComparative psychologyPhilosophy of biologySelf-awareness
We examined whether dogs show emotional response to social stimuli played on videos. Secondary, we hypothesized that if dogs recognize themselves in videos, they will show a different emotional response to videos of self and other dogs. We compared heart rate variability among four video stimuli: a video of the owner ignoring another dog (OW-A-IGN), a video of a non-owner interacting with another dog (NOW-A-INT), a video of the owner interacting with another dog (OW-A-INT), and a video of the owner interacting with the dog subject (OW-S-INT). The results showed that root mean square of the difference between adjacent R-R Intervals (RMSSD) and standard deviation of the R-R Interval (SDNN) were lower in NOW-A-INT and OW-S-INT than in OW-A-IGN. There was no statistical difference in the responses to OW-S-INT and OW-A-INT, suggesting that dogs did not distinguish themselves and other dogs in videos. On the other hand, the difference in mean R-R Interval between OW-S-INT and OW-A-INT showed positive correlation with the score of attachment or attention-seeking behavior. Therefore, this study does not completely rule out self-recognition in dogs and there remains the possibility that the more attached a dog to its owner, the more distinct the dog’s emotional response to the difference between the self-video stimulus and the video stimulus of another dog. Further studies are needed to clarify this possibility.
Mirror self-recognition (MSR) assessed by the Mark Test has been the staple test for the study of animal self-awareness. When tested in this paradigm, corvid species return discrepant results, with only the Eurasian magpies and the Indian house crow successfully passing the test so far, whereas multiple other corvid species fail. The lack of replicability of these positive results and the large divergence in applied methodologies calls into question whether the observed differences are in fact phylogenetic or methodological, and, if so, which factors facilitate the expression of MSR in some corvids. In this study, we (1) present new results on the self-recognition abilities of common ravens, (2) replicate results of azure-winged magpies, and (3) compare the mirror responses and performances in the mark test of these two corvid species with a third corvid species: carrion crows, previously tested following the same experimental procedure. Our results show interspecies differences in the approach of and the response to the mirror during the mirror exposure phase of the experiment as well as in the subsequent mark test. However, the performances of these species in the Mark Test do not provide any evidence for their ability of self-recognition. Our results add to the ongoing discussion about the convergent evolution of MSR and we advocate for consistent methodologies and procedures in comparing this ability across species to advance this discussion.
Mirror self-recognition (MSR) is a potential indicator of self-awareness. This capability has been widely investigated among vertebrates, yet it remains largely unstudied in invertebrates. Here we report preliminary data about behavioural responses exhibited by common octopuses (Octopus vulgaris) toward reflected images of themselves and explore a procedure for marking octopus’ skin in order to conduct the Mark test. Octopuses (n = 8) received four familiarization trials with a mirror and four familiarization trials with a control stimulus: a non-reflective panel (Panel group, n = 4) or the sight of a conspecific housed in an adjacent tank (Social group, n = 4). Subsequently, octopuses were marked with non-toxic nail polish in the area where the Frontal White Spots are usually expressed, and they received one test trial with the mirror and one control trial with no mirror. We found that octopuses in the Panel group tended to exhibit a stronger exploratory response toward the mirror than the non-reflective panel, but performed agonistic responses only in the presence of the mirror. In contrast, octopuses in the Social group exhibited comparable exploratory and agonistic behaviours toward the mirror and the sight of the conspecific. In the Mark test, octopuses frequently explored the mark via their arms. However, mark-directed behaviours were also observed in the absence of the mirror and in sham-marked individuals, thus suggesting that proprioceptive stimuli drove these responses. Despite the limitations associated with our marking procedure, the baseline data collected in this pilot study may facilitate the further testing of MSR in the octopus and other cephalopods.
Debates around fishes' ability to feel pain concern sentience: do reactions to tissue damage indicate evaluative consciousness (conscious affect), or mere nociception? Thanks to Braithwaite's research leadership, and concerns that current practices could compromise welfare in countless fish, this issue's importance is beyond dispute. However, nociceptors are merely necessary, not sufficient, for true pain, and many measures held to indicate sentience have the same problem. The question of whether fish feel pain – or indeed anything at all – therefore stimulates sometimes polarized debate. Here, we try to bridge the divide. After reviewing key consciousness concepts, we identify “red herring” measures that should not be used to infer sentience because also present in non-sentient organisms, notably those lacking nervous systems, like plants and protozoa (P); spines disconnected from brains (S); decerebrate mammals and birds (D); and humans in unaware states (U). These “S.P.U.D. subjects” can show approach/withdrawal; react with apparent emotion; change their reactivity with food deprivation or analgesia; discriminate between stimuli; display Pavlovian learning, including some forms of trace conditioning; and even learn simple instrumental responses. Consequently, none of these responses are good indicators of sentience. Potentially more valid are aspects of working memory, operant conditioning, the self-report of state, and forms of higher order cognition. We suggest new experiments on humans to test these hypotheses, as well as modifications to tests for “mental time travel” and self-awareness (e.g., mirror self-recognition) that could allow these to now probe sentience (since currently they reflect perceptual rather than evaluative, affective aspects of consciousness). Because “bullet-proof” neurological and behavioral indicators of sentience are thus still lacking, agnosticism about fish sentience remains widespread. To end, we address how to balance such doubts with welfare protection, discussing concerns raised by key skeptics in this debate. Overall, we celebrate the rigorous evidential standards required by those unconvinced that fish are sentient; laud the compassion and ethical rigor shown by those advocating for welfare protections; and seek to show how precautionary principles still support protecting fish from physical harm.
Mirror self-recognition (MSR), widely regarded as an indicator of self-awareness, has not been demonstrated consistently in gorillas. We aimed to examine this issue by setting out a method to evaluate gorilla self-recognition studies that is objective, quantifiable, and easy to replicate. Using Suarez and Gallup’s (J Hum Evol 10:175–183, 1981) study as a reference point, we drew up a list of 15 methodological criteria and assigned scores to all published studies of gorilla MSR for both methodology and outcomes. Key features of studies finding both mark-directed and spontaneous self-directed responses included visually inaccessible marks, controls for tactile and olfactory cues, subjects who were at least 5 years old, and clearly distinguishing between responses in front of versus away from the mirror. Additional important criteria include videotaping the tests, having more than one subject, subjects with adequate social rearing, reporting post-marking observations with mirror absent, and giving mirror exposure in a social versus individual setting. Our prediction that MSR studies would obtain progressively higher scores as procedures and behavioural coding practices improved over time was supported for methods, but not for outcomes. These findings illustrate that methodological rigour does not guarantee stronger evidence of self-recognition in gorillas; methodological differences alone do not explain the inconsistent evidence for MSR in gorillas. By implication, it might be suggested that, in general, gorillas do not show compelling evidence of MSR. We advocate that future MSR studies incorporate the same criteria to optimize the quality of attempts to clarify the self-recognition abilities of gorillas as well as other species.
The recent article by Baragli, Scopa, Maglieri, and Palagi (Anim Cogn https://doi.org/10.1007/s10071-021-01502-7, 2021) that claims to demonstrate mirror self-recognition (MSR) in horses is not based on compelling evidence. We identify problems with their experimental procedures, data, and assertion about “demonstrating MSR at group level.” Examples of these problems include incomplete experimental design, absence of important control conditions, inappropriate terminology, suboptimal mark application procedures and coding of videos, ambiguity of videos presented as supporting evidence, and inconsistencies in data presentation and interpretation. It is not the case that their study “marks a turning point in the analytical technique of MSR exploration.”
Most mirror-image stimulation studies (MIS) have been conducted on social and diurnal animals in order to explore self-recognition, social responses, and personality traits. Small, nocturnal mammals are difficult to study in the wild and are under-represented in experimental behavioral studies. In this pilot study, we explored the behavioral reaction of a small nocturnal solitary forager-the grey mouse lemur (Microcebus murinus)-an emergent animal model in captivity. We assessed whether MIS can be used to detect a repeatable behavioral reaction, whether individuals will present a similar reaction toward a conspecific and the mirror, and whether males and females respond similarly. We tested 12 individuals (six males and six females) twice in three different contexts: with a mirror, with a live conspecific, and with a white board as a neutral control. We detected significant repeatability for the activity component of the behavioral reaction. There was a significant effect of the context and the interaction between presentation context and sex for avoidance during the first session for males but not for females. Males avoided the mirror more than they avoided a live conspecific. This pilot study opens a discussion on the behavioral differences between males and females regarding social interactions and reproduction in the nocturnal solitary species, and suggests that males are more sensitive to context of stimulation than females.
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.
The mirror mark test is generally considered to be an indicator of an animal's ability to recognize itself in the mirror. For this test, an animal is confronted with a mirror and has a mark placed where it can see the mark only with the help of the mirror. When the animal extensively touches or interacts with the mark, compared with control conditions, the mirror mark test is passed. Many nonhuman animal species have been tested, but few have succeeded. After magpies and Indian house crows passed, there has been a sustained interest to find out whether other corvids would pass the mirror mark test. Here, we presented 12 carrion crows (Corvus corone corone) with the mirror mark test. There was no significant increase of mark-directed behavior in the mirror mark test, compared with control conditions. We find very few occasions of mark-directed behaviors and have to interpret them in the context of self-directed behavior more generally. In addition, we show that our crows were motivated to interact with a mark when it was visible to them without the aid of a mirror. We conclude that our crows fail the test, and thereby replicate previous studies showing a similar failure in corvids, and crows in particular. Because our study adds to the growing literature of corvids failing the mirror mark test, the issue of mirror self-recognition in these birds remains controversial. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
Since the pioneering work in chimpanzees, mirror self-recognition (MSR), the ability to recognise oneself in a mirror, has been reported in great apes, Asian elephants, dolphins, and some social birds using the mark test, in which animals that possess MSR touch an imperceptible mark on their own bodies only when a mirror is present. However, giant pandas, which are solitary, failed to pass the mark test, suggesting that MSR evolved solely in highly social animals. In contrast to the increasing evidence of MSR in mammals and birds, little is known about MSR in fish. A Tanganyikan cichlid, Neolamprologus pulcher, is a good candidate for study because these fish live in highly social groups and recognise conspecifics about as rapidly as primates. We examined their responses to a mirror image and tested whether N. pulcher could pass the mark test. When the mirror was first exposed, they stayed in front of the mirror and exhibited aggressive behaviour towards the mirror image. These social behaviours suggested that the focal fish perceived the mirror image as an unfamiliar conspecific. The social responses decreased over the following days, as has generally been the case in animals with MSR. After mark injection, we found no increase in scraping behaviour or prolonged observation of the marked side. These results show a lack of contingency checking and mark-directed behaviours, meaning that N. pulcher failed to pass the mark test and did not recognise their self-image in the mirror.
Introduction
Infant body odor is subjectively pleasant to parents and activates reward areas in the brain. Hence, body odor perception might contribute to parental bonding. However, it is unknown whether the perceived pleasantness of children’s body odor varies over the course of a child’s development.
Methods
Two hundred and thirty-five parents (M = 36.9 years, SD = 7.3) were asked to assess the personal odor pleasantness of their children (N = 367; M = 9.3 years, SD = 6.4).
Results
Odor pleasantness was found to decrease as a function of children’s age. Neither sex of the parent nor sex of the child contributed significantly to this effect.
Conclusions
We propose that the effect of age-related changes on personal odor pleasantness reflects olfactory modulation of parental-child relationships.
Implications
Our study suggests that perception of young children’s personal odor as pleasant may contribute to bonding and thereby caretaking, which is needed to a lesser degree after puberty than before.
Mirror Self-Recognition (MSR) unveils complex cognitive, social and emotional skills and it has been found only in humans and few other species, such as great apes, dolphins, elephants and magpies. In this pilot study, we tested if horses show the capacity of MSR. Four subjects living socially under naturalistic conditions were selected for the experiment. We adopted the classical mark test, which consists in placing a coloured mark on an out-of-view body part, visible only through mirror inspection. If the animal considers the image as its own, it will use its reflection to detect the mark and will try to explore it. We enhanced the classical paradigm by introducing a double-check control. Only in the presence of the reflecting surface, animals performed tactile and olfactory exploration of the mirror and looked behind it. These behaviors suggest that subjects were trying to associate multiple sensory cues (visual, tactile and olfactory) to the image in the mirror. The lack of correspondence between the collected stimuli in front of the mirror and the response to the colored mark lead us to affirm that horses are able to perceive that the reflected image is incongruent when compared with the memorized information of a real horse. However, without replication of data, the self-directed behavior towards the colored marks showed by our horses cannot be sufficient per se to affirm that horses are capable of self-recognition.
We review research on reactions to mirrors and self-recognition in nonhuman primates, focusing on methodological issues. Starting with the initial demonstration in chimpanzees in 1970 and subsequent attempts to extend this to other species, self-recognition in great apes is discussed with emphasis on spontaneous manifestations of mirror-guided self-exploration as well as spontaneous use of the mirror to investigate foreign marks on otherwise nonvisible body parts-the mark test. Attempts to show self-recognition in other primates are examined with particular reference to the lack of convincing examples of spontaneous mirror-guided self-exploration, and efforts to engineer positive mark test responses by modifying the test or using conditioning techniques. Despite intensive efforts to demonstrate self-recognition in other primates, we conclude that to date there is no compelling evidence that prosimians, monkeys, or lesser apes-gibbons and siamangs-are capable of mirror self-recognition.
Some animals are capable of recognizing themselves in a mirror, which is considered to be demonstrated by passing the mark test. Mirror self-recognition capacity has been found in just a few mammals having very large brains and only in one bird, the magpie (Pica pica). The results obtained in magpies have enormous biological and cognitive implications because the fact that magpies were able to pass the mark test meant that this species is at the same cognitive level with great apes, that mirror self-recognition has evolved independently in the magpie and great apes (which diverged 300 million years ago), and that the neocortex (which is not present in the bird's brains) is not a prerequisite for mirror self-recognition as previously believed. Here, we have replicated the experimental design used on magpies to determine whether jackdaws (Corvus monedula) are also capable of mirror self-recognition by passing the mark test. We found that our nine jackdaws showed a very high interest towards the mirror and exhibited self-contingent behavior as soon as mirrors were introduced. However, jackdaws were not able to pass the mark test: both sticker-directed actions and sticker removal were performed with a similar frequency in both the cardboard (control) and the mirror conditions. We conclude that our jackdaws' behaviour raises non-trivial questions about the methodology used in the avian mark test. Our study suggests that the use of self-adhesive stickers on sensitive throat feathers may open the way to artefactual results because birds might perceive the stickers tactilely.
Guidelines for submitting commentsPolicy: Comments that contribute to the discussion of the article will be posted within approximately three business days. We do not accept anonymous comments. Please include your email address; the address will not be displayed in the posted comment. Cell Press Editors will screen the comments to ensure that they are relevant and appropriate but comments will not be edited. The ultimate decision on publication of an online comment is at the Editors' discretion. Formatting: Please include a title for the comment and your affiliation. Note that symbols (e.g. Greek letters) may not transmit properly in this form due to potential software compatibility issues. Please spell out the words in place of the symbols (e.g. replace “α” with “alpha”). Comments should be no more than 8,000 characters (including spaces ) in length. References may be included when necessary but should be kept to a minimum. Be careful if copying and pasting from a Word document. Smart quotes can cause problems in the form. If you experience difficulties, please convert to a plain text file and then copy and paste into the form.
After prolonged exposure to their reflected images in mirrors, chimpanzees marked with red dye showed evidence of being able
to recognize their own reflections. Monkeys did not appear to have this capacity.
Interest in the comparative study of mirror self-recognition persists because of the implications for self-awareness and the possibility of a cognitive divide among primates. Evidence from many studies carried out over 40 years shows that humans and great apes are distinguished from other nonhuman primates by their capacity for self-recognition. We review some recent developments in the field, with critical reference to claims that monkeys show self-recognition. Focusing on methodological issues, we conclude that there is no compelling evidence for mirror self-recognition in any non-ape primate species.
Author Summary
A crucial step in the emergence of self-recognition is the understanding that one's own mirror reflection does not represent another individual but oneself. In nonhuman species and in children, the “mark test” has been used as an indicator of self-recognition. In these experiments, subjects are placed in front of a mirror and provided with a mark that cannot be seen directly but is visible in the mirror. Mirror self-recognition has been shown in apes and, recently, in dolphins and elephants. Although experimental evidence in nonmammalian species has been lacking, some birds from the corvid family show skill in tasks that require perspective taking, a likely prerequisite for the occurrence of mirror self-recognition. Using the mark test, we obtained evidence for mirror self-recognition in the European Magpie, Pica pica. This finding shows that elaborate cognitive skills arose independently in corvids and primates, taxonomic groups with an evolutionary history that diverged about 300 million years ago. It further proves that the neocortex is not a prerequisite for self-recognition.
The habituation of tonic immobility in chickens was examined in six studies. It was shown that repeated elicitation of immobility, and not just handling, was responsible for reduced response durations after multiple exposures to manual restraint. Habituation was a function of the number of stimulus presentations and, in addition, proved surprisingly durable, with diminished reactions using lasting at least 2.5 mo. Strain differences were found in the number of trials required to reach a criteria of habituation, and habituation proceeded faster when immobility termination was self-paced as opposed to experimenter induced. Also, massed trials produced robust sensitization effects rather than diminished responsiveness.
As a result of a long-term, longitudinal project initiated in 1978, a pair of rhesus macaques (Macaca mulatta) housed together in front of a mirror all their lives now exhibit relatively little interest in their reflection. Previous work has shown, however, that simply moving the mirror to a new location produces a short-term reinstatement of social responding to their images. As an extension of these findings, in this study the mirror was left in the same position but turned away from the cage. On turning the mirror back to face the cage 5 days later, both animals reacted as if confronted with another pair of monkeys and directed a burst of social responses at the mirror.
Analyzes the psychological properties of an organism's own reflection in a mirror, and discusses methodological problems associated with mirror research. Many organisms are responsive to mirrors, and reflected images are examined in terms of motivational and social stimulus properties which have been found to extend across a wide variety of species. Reinforcing properties of mirrors are interpreted in terms of novel stimulation with social stimulus overtones. Stimulus change and mimicry are 2 of the most prominent characteristics of an organism's mirror image. An animal in front of a mirror is instrumental in producing changes in the behavior of the reflected image, yet most organisms respond to mirrors as if their image represented another animal. In an attempt to conceptualize both the human and animal data, responses to mirrors and dimensionalized into other- and self-directed behaviors. Implications of mirrors for abnormal behavior and psychotherapy are considered. (63 ref.)
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.
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.
• cognition
• mirror self-recognition
• theory of mind
• intelligence
• empathy
While domestic dogs, Canis familiaris, have been found to be skillful at social cognitive tasks and even some meta-cognitive tasks, they have not passed the test of mirror self-recognition (MSR). Acknowledging the motivational and sensory challenges that might hinder performance, even before the question of self-recognition is broached, this study creates and enacts a novel design extrapolated from the species' natural behaviour. Given dogs' use of olfactory signals in communication, this experiment presents dogs with various canisters for approach and investigation. Each holds an odorous stimulus: in the critical test, either an “olfactory mirror” of the subject − the dog's own urine − or one in which the odour stimulus is modified. By looking at subjects' investigation times of each canister, it is shown that dogs distinguish between the olfactory “image” of themselves when modified: investigating their own odour for longer when it had an additional odour accompanying it than when it did not. Such behaviour implies a recognition of the odour as being of or from “themselves." The ecological validity of this odour presentation is examined by presenting to the subjects odours of other known or unknown dogs: dogs spend longer investigating the odour of other dogs than their own odour. Finally, in a second experiment, subjects spent longer with the modified stimulus than with the modified odour by itself, indicating that novelty alone does not explain the dogs' behavior. This study translates the MSR study for a species whose primary sensory modality is olfaction, and finds both that natural sniffing behaviour can be replicated in the lab and that dogs show more investigative interest in their own odours when modified.
Presents an overview of known facts regarding self-recognition in primates, addressing the issue of how some nonhuman and most human primates come to understand that a reflection, televised image, or photograph can be a representation of themselves. Issues of specific focus include: chimpanzees and the revelation of self-recognition; extensions and inclusions of self-recognition in primates; monkeys and the "monkey in the mirror"; the hypothesis of a qualitative cognitive difference; and challenges to this field of study. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
[examine] the evidence that a monkey looking at itself in a mirror "thinks" its reflection is a conspecific / [suggest that] in both monkeys and many nonprimate species a variety of phenomena normally induced by a conspecific may occur when the conspecific is replaced by a mirror / [argue] that, in the absence of convincing evidence for self-recognition in monkeys, such phenomena reinforce the view that monkeys, like most other animals, do not progress beyond a "social" stage when perceiving their own reflections
exploring species differences / overt social responses to mirrors / visual reinforcement / mirror image as a stand-in for social stimuli (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Cephalopod mollusks are found virtually everywhere throughout the world's oceans. They are highly mobile invertebrates that have evolved behavioral and morphological defenses against vertebrate predators. Unlike other mollusks, the coleoid cephalopods (octopus, cuttlefish, and squid) possess highly developed nervous systems with huge brains equivalent in size to some vertebrate brains. Cephalopod intelligence is also exhibited by their impressive memory and learning abilities. Why have cephalopods developed such huge brains and cognitive ability? One of the keys to answering this question lies in understanding the social interactions of cephalopods, which have thus far not been well documented. In this paper, I will outline our recent behavioral experiments using mirrors with some cephalopods and discuss these experiments in light of the diversity of social and cognitive behaviors of cephalopods.
Heyes’ (1994, Anim. Behav., 97, 909–919; 1995, Anim. Behav., 50, 1533–1542) recent account of chimpanzees’, Pan troglodytes, reactions to mirrors challenged the view that they are capable of recognizing the equivalence between their mirror images and their physical appearance. In particular, she argued that observations that chimpanzees touch surreptitiously placed marks on their faces while in front of mirrors can be explained as an interaction between ambient levels of face touching and procedural artefacts of the anaesthetization and markings of the subjects. Using new analytical techniques, data are reported that falsify the central predictions generated by her account and confirm predictions derived from the self-recognition model.
No abstractCopyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour.
Self-recognition continues to attract attention because of the evidence of a striking difference between the great apes and humans, on the one hand, and all other primates; the former are capable of self recognition,whereas no compelling evidence exists for prosimians, monkeys, or lesser apes. This is inspite of numerous attempts to facilitate mirror self-recognition in other primates. Although all previous attempts to find self-recognition in rhesus macaques have failed, a recent article [Rajala et al., PLoS One9:e12865, 2010] claimed the opposite—that adult male rhesus monkeys did recognize their own image in a mirror. We critically examine this claim, and conclude that the article fails to provide acceptable evidence for self-recognition in rhesus monkeys.
Three studies explored kin recognition through olfaction. In Study I, adults (N=22) were tested for ability to identify the odors of themselves; their mother; their father; a sister; a brother; a familiar, unrelated individual; and a stranger. Acquaintances were identified as accurately as biological kin, implicating an association mechanism. However, biological kin were often confused, implicating phenotypic matching. Same-sex kin were confused more than opposite-sex kin, but mainly when same-sex kin had odors of similar intensity. Study II implicated phenotypic matching. Mothers (N=18) could identify their biological children but not their stepchildren. The preadolescent children (N=37) identified their full siblings but not half-siblings or stepsiblings. Thus, olfactory cues may help mediate favoritism of blood relatives. In Study III, mutual olfactory aversion occurred only in the father-daughter and brother-sister nuclear family relationships. Recognition occurred between opposite-sex siblings but not same-sex siblings. Thus, olfaction may help mediate the development of incest avoidance during childhood (the Westermarck effect).
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.
Are horses capable of self-recognition? A pilot study
- P Baragli
- E Demeru
- C Scopa
- E Palagi
Baragli, P., Demeru, E., Scopa, C., Palagi, E., 2017. Are horses capable of self-recognition?
A pilot study. PLoS One 12 (5), e0176717.
Are ants (Hymenoptera, Formicidae) capable of self-recognition?
- Cammaerts
Cammaerts, M.-C., Caemmaerts, R., 2015. Are ants (Hymenoptera, Formicidae) capable of
self-recognition? J. Sci. 5, 521-532.
The Oxford Handbook of the Self
- G G Gallup
- J R Anderson
- S M Platek
Gallup Jr., G.G., Anderson, J.R., Platek, S.M., 2011. Self-recognition. In: Gallagher, S.
(Ed.), The Oxford Handbook of the Self. Oxford University Press, New York, pp.
80-110.