Is that fear? Domestic dogs’ use of social referencing signals from an unfamiliar person
Highlights
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- Canine responding following a human expression of fear could indicate confusion instead social referencing.
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- We compared an experimenter's happy and fearful responses to a control expression to dogs.
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- Dogs responded similarly in the fear and control conditions compared to happy.
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- It is not clear that dogs have a true understanding of human expressions of fear.
Abstract
The
aim of this study was to investigate whether dogs could successfully
interpret a ‘social referencing’ cue (either happiness or fear) toward
an object after viewing a human emotional expression. Fearful
expressions are more likely to be unfamiliar to dogs, and thus they may
not understand the meaning of such expressions. When confused, dogs
could avoid contact with an object as in Merola et al., 2012 and Merola et al., 2011.
The present study compared an experimenter's fearful or happy response
when an ambiguous object appeared with a control condition (experimenter
was confusing). We examined 114 dogs in one of three conditions;
happiness, fearful and the control. We found that dogs were more
attentive to the experimenter when she displayed the fearful and control
expressions compared to when happy, with no difference between the
control and fear conditions. When left alone with the toy, they showed a
similar pattern – more interest in the toy in both the fearful and
control conditions. Our findings suggest that dogs may not understand
the cues in the fearful and control conditions and instead respond with a
possible attempt to gain more information from the experimenter.
Keywords
- Domestic dogs;
- Social referencing;
- Fear
1. Introduction
Social
referencing, a form of referential communication, is often tested in an
ambiguous situation and requires a reference towards another to guide
one's actions (Klinnert et al., 1986 and Stenberg and Hagekull, 2007).
For instance, a mother expresses either fear or happiness toward an
object and then observes a human infant's reaction to the object.
Studies have investigated facial expressions (Sorce et al., 1985), vocal expressions (Mumme et al., 1996), as well as combined facial and vocal signals (Kim et al., 2010)
with similar conclusions. When a mother expresses fear toward an
object, infants tend to avoid the object. In contrast, infants tend to
approach the object when viewing a mother's happy expression.
Furthermore, studies with a familiar (parent) (Rosen et al., 1992) or unfamiliar (experimenter) person (Klinnert et al., 1986) as the informant produce similar responses in infants.
Studies involving nonhuman primates such as chimpanzees (Pan troglodytes), ( Itakura, 1995 and Russell et al., 1997), and macaques (Macaca sylvanus) ( Roberts et al., 2008)
have provided evidence that social referencing can occur both within
and between species. Infant chimpanzees witnessed happy or fearful
expressions toward a familiar object by a human caregiver ( Russell et al., 1997).
The infant chimpanzees avoided the object when a fearful expression was
given, but looked longer at the object when a happy expression was
given.
Because dogs have
been domesticated, with certain qualities selected for in breeding over
others, one might assume that they could reference a human
experimenter's facial or vocal gestures, and therefore, regulate their
behavior towards an object. Even if dogs had no innate tendency for
social referencing, domestication might have assisted dogs in learning
this skill for it is beneficial to recognize human emotions because
happy humans tend to be more attentive compared to sad ones (Seligman, 2002).
Two
canine social referencing studies showed that dogs may not have
understood neutral expressions in a human’s face and find it confusing (Buttelmann and Tomasello, 2013; Merola et al., 2013). Dogs had no preference for choosing a box when the experimenter displayed happiness and neutral (Buttelmann and Tomasello, 2013), while in another study, dogs preferred the positive expression versus neutral (Merola et al., 2013).
Two studies tested social referencing in dogs using a fan with green ribbons as the ambiguous stimulus (Merola et al., 2012 and Merola et al., 2011)
with familiar and unfamiliar informants presenting emotional
expressions to dogs. Dog owners presented the emotional expressions in
the first study (Merola et al., 2011), and in the second study, the informants were either the owners (“familiar”) or the experimenter (“unfamiliar”) (Merola et al., 2012).
Regardless of familiarity, dogs explored the fan when the emoter
expressed happiness and were less willing to explore the fan when the
emoter expressed fear. Expressions were conveyed through a combination
of facial, vocal and bodily cues. The consistent findings over these two
studies suggest that the emoter's familiarity to the dog is not crucial
to whether they socially reference in ambiguous situations. However, in
a third study, when the emoter displayed happiness toward one box and
fear toward another, dogs chose a box randomly when the emoter was a
stranger, but chose insightfully when the emoter was the owner (Merola et al., 2013).
The researchers argue that dogs are more familiar with their owner's
expression of happiness compared to that of the stranger, and suggest
that dogs might perform somewhat better when the informant is familiar.
Nevertheless, there remain doubts regarding the interpretation of canine
success on this task. Canine reluctance to explore the fan can be
perceived as insightful (indicating an understanding of the threat
conveyed by fear and the absence of threat conveyed by happiness) or
non-insightful (with a fearful expression creating confusion, or
wariness though emotional contagion in the dog, leading the dog to avoid
the object).
