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Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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Title: Self-consciousness: beyond the looking-glass and what dogs found there
Author: Roberto Cazzolla Gatti
1*
Affiliation:
1
Biological Diversity and Ecology Laboratory, Bio-Clim-Land Centre of Excellence, Tomsk
State University (TSU), 36 Lenin Prospekt, Tomsk, 634050, Russia
*corresponding author: robertocazzollagatti@mail.tsu.ru
Article type: Forum article
Abstract:
The recognition of one's own self, i.e. self-recognition, has been studied by the mirror test mainly by examining the
responses of some animal species and children. It emerged that the ability to recognize oneself in a mirror is an
exceedingly rare capacity in the animal kingdom and in species whom passed the test, such as great apes (excluding
gorillas) and humans, this response is weak in young individuals and increases with the age. A wide range of species
have been reported to fail the test including dogs. They, as dolphins, show an high level of behavioural and cognitive
complexity, but attempts to demonstrate self-recognition in these animals have been inconclusive because of
difficulties in implementing adequate controls necessary to obtain robust evidence from the mirror test. In this study I
suggest that, being dogs considerably less affected by visual events than are humans and most apes, it is likely that the
failure of MSR in dogs and other animals is due to the sensory modality used to test self-awareness. Some attempts to
verify this idea have been previously realized, but most of them were only observational or lacked empirical and
further proofs and, overall, were carried out with only one individual per time. Here I show that, even when checked
on different individuals living in group, and with different age and sex, the sniff test of self-recognition (STSR) provides
significant evidences of dogs’ self-awareness and can play a pivotal role in demonstrating that this capacity is not a
feature specific to great apes and humans (and few other animals), but it depends on the way researchers test it. The
hope is that this novel approach can represent a step in a new direction towards a better understanding of animal
cognition.
Keywords: self-recognition; self-awareness; self-consciousness; dogs; mirror test; sniffing test
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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The state of art of animal cognition and awareness’ studies
Self-recognition, that is the recognition of one's own self, has been studied mainly by examining animals and children
responses to their reflections in mirrors (Gallup et al. 2002). The definitive test is whether or not a subject is capable
of using the reflection to notice and respond to a mark on the face, head or other parts of the body by touching the
mark (Bard et al. 2006). The mark, which is placed on the subjects when they are distracted or under anaesthesia, is
only visible to the subject when they look at themselves in a mirror. The basic idea behind the test is that the subject
whom understands the concepts of "self" and "others," can differentiate between the two, and can recognize himself
in the reflection (Swartz et al. 1999). Based on these results other behavioural skills can be inferred, e.g. the empathy
(Bischof-Köhler, D. 2012).
Indeed, the capacity to differentiate one’s own self from others is often thought of as a prerequisite for
understanding that someone else might be happy or sad, even if the beholder is not (Turner 1982). As a general
pattern, studies agree that this response increases with the age and could decline in old age(Bischof-Köhler 2012).
However, the ability to recognize oneself in a mirror is an exceedingly rare capacity in the animal kingdom (Bekoff et al.
2004). Up to now, only great apes (an so, humans) have shown extremely convincing evidence of mirror self-
recognition (Povinelli et al. 1993). Moreover, the mirror test can yield false negatives because if an individual fails the
test it does not necessarily mean that the species is not self-conscious (Bekoff et al. 2004).
The first evidence for self-awareness in a nonhuman species was experimentally demonstrated in the common
chimpanzee (Gallup 1970), but numerous subsequent attempts showed no convincing evidence of self-recognition in a
variety of other primates and non-primates, including monkeys, lesser apes, African gray parrots, one species of spider
and elephants (Westergaard & Hyatt 1994; Clark, R.J., & Jackson, R.R. 1994; Pepperberg 1995; Plotnik et al. 2006; Prior
et al. 2008). All of these species demonstrate the ability to use a mirror to mediate or guide their behaviour. As of
2015, only the great apes (excluding gorillas), a single Asiatic elephant, dolphins, the Eurasian magpie, and some ants
(Hill et al. 2015; Cammaerts & Cammaerts, 2015; Ma et al. 2015), have passed the mirror self-recognition test (MSR).
A wide range of species have been reported to fail the test including gorillas, several monkey species, giant pandas,
sea lions, pigeons and dogs (Delfour and Marten 2001; Ma et al. 2015). Social ecology, ethology, and neurobiology of
other species have been investigated since the acknowledgment of the only apparent confinement of self-recognition
to great apes and humans (Gallup 1997; Parker et al. 1994).
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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Dogs, in particular, showed no interest even in watching the mirrors, but they usually sniff or urinate around them (De
Waal et al. 2005) or use them to solve a problem (Howell and Pauleen 2011; Howell et al. 2013). Dogs and wolves, as
dolphins, show an high level of behavioural and cognitive complexity (Reiss & Marino 2001; Marino 1998; Connor et
al. 1992), but previous attempts to demonstrate self-recognition in these animals have been inconclusive because of
difficulties in implementing and interpreting adequate controls necessary to obtain robust evidence from the mirror
test in animals unable to display self-recognition by touching a marked part of the body with a hand, even if they
could display something like MSR with other parts of the body (Taylor et al. 2006; Marten & Psarakos 1994).
In this study I suggest a new approach, which can shed light on different ways to check for animal cognition and open
a renewed discussion on self-awareness.
I argue that, being dogs considerably less affected by visual events than are humans and most apes (Bekoff 2003), it is
likely that the failure of MSR in dogs and other animals is due to the sensory modality used to test self-awareness.
Some attempts to verify this idea have been previously realized, but most of them were only observational or lacked
empirical and further proofs and, overall, were carried out only with one individual per time (e.g. Bekoff (2001) used a
"yellow snow test" to measured how long the dog sniffed his own of other dogs’ urine patches. The experiment was
conducted with only one subject, author’s own dog, and not repeated with other individuals, and particularly with
other dogs of different sex and age).
Therefore, conclusive evidence of self-recognition in a species as phylogenetically distant from primates (so with
different display and sensory modality) as dog was not reached (Bekoff 2003).
Here I show that, even when checked on different individuals living in group, and with different age and sex, the sniff
test of self-recognition (STSR) provides significant evidences of dogs self-awareness and can play a pivotal role in
demonstrating that this capacity is not a feature specific to great apes and humans (and few other animals), but it
depends on the way researchers test it.
An alternative test for dog self-cognition
Data reported in this study were collected once per season during 2010 (4 replicates) and then elaborated after the
stimulating, but uncertain and potentially affected by bias, evidences proposed on the same topic by Bekoff in 2003. I
employed for the test 4 mongrel domestic dogs (Canis familiaris): one (vasectomized) male 10 years old, and 3
(ovariectomized) females 3, 7, and 9 years old. All the dogs were stray until they were one year old, at least, and then
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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they were grown in semi-freedom (winter inside and summer outside a private-non-commercial enclosure). The test
site was an open-air enclosure of 200 m
2
where these animals have been living during the previous years (at least 8
months per year). Urine samples of each dog were collected, once per season, by pressing absorbent cotton, wearing
latex gloves (and taking precautions to minimize odour cues), on their urinary organs at the end of each urinary
episode during 2 days preceding the test. The samples of each dog were preserved in sterilized closed airtight
containers, at a temperature of 5°C, for the 2 days of collection. 20 urine samples on absorbent cotton for each dog
were collected, divided and preserved in 5 containers associated to each DogID, every seasons.
The third day, after the two of collection, the animals were submitted to the test. I repeated the test 4 times during
the year, at the beginning of each season. This test consisted of a modified version of the MSR, carried out to check
olfaction, and not vision, as the main sense for self-awareness.
The 4 dogs were taken out from the enclosure and 5 containers (with ID number referred to each dog) were randomly
placed and fixed in holes on the ground, along a line at 1 m of distance each other, inside the cage. 4 out of 5
contained urine samples of each dog and one was a “blank sample”, filled only with absorbent cotton and no urine
smells. The containers were then open.
Each dog was introduced alone within the cage and released at 3 m from the samples and then left free to move for 5
minutes (Fig. 1). From that moment the time spent by each dog sniffing (or being interested in the proximity: closer
than 10 cm from) each sample was recorded with a stopwatch by two observers, one taking the time and the other
noting the values referred to each sample. The total time (in seconds) spent by each dog sniffing each sample was
calculated irrespective if it was continuous or split in different episodes during the 5 minutes.
The presence of only one male reduced to zero the times he urinated over (scent-marked) the samples, being absent
any competitions with other males. Similarly, no episode of urination over females’ urine samples by the male, and
the opposite, was recorded.
Before entering the next dogs the 5 samples were replaced by new ones with the same scheme abovementioned
(4+1). The dogs taken outside the enclosure were not allowed to watch inside to avoid any visual influence.
After testing the four dog isolated (the male was the last in every season), a final replicate of the 5 samples (4+1) was
introduced and the dogs were allowed to enter together within the enclosure. The behaviour of the dogs during this
final round was observed for 5 minutes, without recording the time spent by each dog around samples.
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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A χ
2
test (=
was calculated to test the observed (O) mean time spent by each dog sniffing the samples and the
expected (E) values (i.e. H
0
= interaction time spent smelling is identical for all the samples). Correlation coefficient and
t-test were calculated to check a potential relation between age and total % time spent smelling (interest towards the
samples age-dependent). Finally, a t-student test was calculated to check the significance of mean time spent by
females sniffing male’s vs. other females’ samples.
Evidences of dog’s self-cognition
The association between each dog (the three females D1, D2 and D3 of 7, 3 and 9 years old, respectively and the male
D4 of 10 years old) and the containers (i.e. Sample 1, S1 contained the urine sample of Dog 1, D1; Sample 2 , S2
contained the urine sample of Dog 2, D2; and so on) is reported in Tab. 1 as mean values averaged among the 4
recording times (seasons). Sample 5, S5 is the control sample (“blank sample”).
After checked with χ
2
test (Tab. 2), the associations between the time spent by each dog and the samples show high
significance (P<0.01) for D1, D3 and D4 and significance (P<0.05) for D2. Moreover, D2 was the dog who spent lesser %
time sniffing during the 5 minutes.
I also plotted the age of each dog against the % time spent sniffing (or being interested in) the all samples (Fig. 2) for a
correlation analysis.
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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The correlation between the age and the interest towards the sample is significant (r=0.92; t
g.d.l.=6
=5.84, P<0.05).
Finally, I checked a potential relation between the time spent by females sniffing the samples of other females and the
time they spent to sniff the sample of the male (Tab. 3). Even if there is a prevalence in the mean time spent by
females sniffing male’s rather than other females’ samples (31.6±9.62 sec vs. 26.87±7.01 sec), the difference is not
significant (t=0.37, P>0.05).
Are dogs self-aware and self-conscious?
The higher time spent by each dog to sniff the others’ urine samples rather than their own and the generality of this
behaviour, for all the 4 individuals tested, confirms the hypothesis that dogs seem to know exactly their own smell
and be self-aware. It has been suggested that, even if these evidences were demonstrated, with an empirical research
as this presented here, we could have not established whether dogs have a sense of "I-ness" rather than a sense of
"body-ness", i.e. whether they are self-conscious or “only” self-aware (for more details on these concepts see Bekoff
et al. 2004 and a summary below).
Hitherto, I will refer to self-recognition, or self-referencing as a perceptual process involving matching phenotypic
characteristics of a target individual against the phenotype of the discriminator, which compares labels of the target
(such as of odor or appearance) against labels learned from their own phenotype, and accept or reject that target
based on the degree of similarity (this process can be conscious or non-conscious); to self-awareness, or body-ness or
mine-ness as the cognitive process that enables an individual to discriminate between its own body and those of
others (a brain is required for this level of self-cognizance, although the actual discrimination can be conscious or
unconscious); and to self-consciousness, or I-ness as possessing the sense of one’s own body as a named self, knowing
that ‘this body is me’ and thinking about one’s self and one’s own behavior in relation to the actions of others (here
also a brain is required and the underlying processes are conscious). The feeling of possessing and owning the parts of
one’s own body is strictly related to the sense of "mine-ness", i.e. self-awareness: the sense of what belongs to
oneself and what belongs to others (Bekoff et al. 2004). For a dog this latter includes also the awareness of its own
territory, toys, kennels, etc. But the self-recognition (self-consciousness) and the sense of “body-ness” (self-
awareness) are very close concepts, and the only difference could be due to the abstraction capacity of imagine one’s
own self, of which we did not clearly confirmed the existence even in other animals whom passed the mirror test
(Reznikova 2007).
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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Furthermore, 3 out of 4 dogs tested in this study spent more time sniffing the blank than the their own urine sample.
One reason could be that they were completely uninterested to their own scent but they seemed to expect to smell
something in the control sample, even if it was blank and so they checked more carefully.
Moreover, the correlation between the age and the time spent in sniffing urine samples strongly supports the idea
that self-recognition increases with the age (Amsterdam 1972; Rochat 2003), as demonstrated in other species such as
chimpanzee (Povinelli et al. 1993). The evidence of an age-dependency in dogs’ self-awareness could also disentangle
the ambiguity between “I-ness” and “mine-ness” because, for instance, puppies are well-known to be aware of, and
devoted to, their own toys, baskets, bones, etc., so the minor interest in others’ smells by younger dogs could be more
related to and age-dependent self-recognition than to the sense of mine.
Anyway, this last consideration could be biased by two facts: first that, within packs of wild dogs living together,
youngest individuals are also subordinated to adult dominants and the lack of responsibility towards the group (Silk
2007) could make them freer in paying attention to external signs (such as smells); second that ,the dogs were all
between 3 and 10 years old and can all be considered as adults. I suggest that in future a test with young puppies and
isolated young dogs could clarify this point.
The more interest of females towards male’s than towards the other females’ samples, being statistically not
significant, confirms that they were not consistently influenced by the scent of the other sex in paying more attention
to others samples. In other words, their own urine samples were not ignored because females were much more
interested in male’s sample than in other individuals’ samples, but because each individual was aware of his own
smell.
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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Self-consciousness has been defined (Bekoff et al. 2004) as dependant “on the costs and benefits of previous responses
of conspecifics to the focal individual”. The dogs tested were living together since, at least, the 7 years preceding the
study and they showed interactions typical of a social group, where “individuals benefit from analysing and revising
their own behaviour in light of how specific members of their social group, including actual and potential mates,
responded to their behaviour in the past” (Bekoff et al. 2004). Being these requirements satisfied by the tested group, I
can argue that the dogs showed real self-consciousness, and not only self-awareness.
A key difference between the STSR and MSR is that this latter considers the interaction with the mark apposed on the
body of the subject as the confirmation of a self-recognition. Evidently, with a smell this proof seems difficult to
achieve (even if some chemical modification of dogs’ own urine samples could be tested in future), but when released
together inside the enclosure and left free to move and interact each other and with the 5 samples, the four dogs
repetitively sniffed excretory organs of the others and the containers, sometimes stopping to sniff theirselves.
Interpretation of this latter behaviour (the repetitively sniffing of excretory organs of the others after conducting the
test) could be difficult to interpreter at this stage, but dogs seem to pay much attention to bodies (in general) after
the olfactory test, as other animals (De Waal 2008) after having seen theirselves or other individuals in a mirror
(irrespective whether they have been marked or not).
This study confirms that the scarce results reached with dogs by the mirror test could be due to the preponderance of
olfactory organs over the visual organs in Canidae family and other species.
The approach presented here for testing self-awareness with a sniffing test on a multi-individual approach underlines
the need to shift the paradigm of consciousness to a less anthropocentric idea, towards a species-specific
consideration. We could never expect that a mole or a bat recognize theirselves in a mirror, but we now have strong
empirical supports to believe that if we test them with a chemical or an auditory method, we could get some
unexpected results.
This experimental test for self-awareness (and self-consciousness) in dogs should not be considered definitive, but it
represents a starting point to change the current methods and test with other species. We know well that many
factors could influence olfactory sense and the consequential behaviour, as much as the visual sense, therefore neural
activity techniques seem promising. What, instead, seems conclusive is that by using a mirror to test, self-recognition
won't always work since reflected images have no scent, and therefore are not real or important enough in the mind
of many species, to warrant much attention.
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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Note: this study was not subject to animal ethics approval being the animals employed owned by the author,
observed from a distance and considered as private domestic animals. No additional animals were recruited into
the study
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Tables and table captions
Tab. 1. Mean time spent by each dog (D) sniffing each sample (S) during the 5 minutes. SD=standard deviation.
Dog
ID
Sample
ID
Mean time
sniffing (sec)
Mean time
sniffing (SD)
D1
S1
13.2
2.1
D1
S2
27.9
3.7
D1
S3
28.7
4.1
D1
S4
33.1
2.3
D1
S5
11.5
1.8
D2
S1
22.1
2.9
D2
S2
10.8
1.5
D2
S3
23.5
2.1
D2
S4
27.3
2.7
D2
S5
13.7
1.8
D3
S1
34.2
3.2
D3
S2
24.8
2.6
D3
S3
17.4
1.4
D3
S4
34.4
2.7
D3
S5
14.6
1.3
D4
S1
41.1
4.3
D4
S2
26.7
3.3
D4
S3
41.8
3.8
D4
S4
16.3
4.1
D4
S5
24.7
3.2
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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Tab. 2. χ2 test calculated for each dog’s observed vs. expected interaction time with samples (significant values with P<0.01 are in
bold; D2 value is significant with P<0.05). Percentage of total time (over a total 5 minutes) and mean time spent sniffing all the
samples by each dog (and Standard Deviation, SD) are reported, together with age and sex.
Dog ID
χ2 test
(P=0.05)
Mean time sniffing all the
samples (sec)
Mean time
sniffing (SD)
Tot. time sniffing
all the samples %
(5 min.)
Age
Sex
D1
17.19
22.88
9.83
32.69
7
F
D2
9.90
19.48
6.94
27.83
3
F
D3
13.51
25.08
9.20
35.83
9
F
D4
16.24
30.12
11.06
43.03
10
M
Ethology Ecology and Evolution 11/2015; DOI:10.1080/03949370.2015.1102777
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Tab. 3. Mean time spent by females sniffing male’s vs. other females’ sample. The table should be read from the first column
(Females group, F; mean) towards the first (male’s samples, M) and the second (females’ samples, F) line. SD=standard deviation;
↓ stands for “towards”.
F (↓)
SD
t test
M
31.6
9.62
0.37
F
26.87
7.01
P<0.05
