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It started when two canine scientists decide to become pen pals in an era of digital media...

Monday, 9 February 2015

How do dogs and people respond to a crying baby?

Guest post by: Min Hooi Yong, PhD

Does your dog know when you are sad? Puzzling question, perhaps? 

We get a range of answers from dog owners, from the confident Yes!to Maaaaybe?, and the hopeful I like to think so.... Many dogs are considered to be part of the family, and we expect our family members to empathize with us when we are sad.

A recent study found that dogs showed submissive behavior (licking and nuzzling) when an adult person pretended to cry but not when she is humming1. Does the licking and nuzzling behavior mean that the dog understand that we are feeling sad? (I hear YES-es). Or can it be that because we are crying, we ignore everyone including our dog, and so, our dog will nuzzle us seeking attention and/or comfort?

There have been many studies showing that animals (e.g. rodents, birds, chimps) experience distress or concern (empathic response) when observing either kin or non-kin in distress. For example, giving electric shocks to rats and pigeons. The observer experienced a change both behaviourally and physiologically, and these responses are often considered as an experience of emotional contagion, an elementary form of empathy. Emotional contagion is essentially the spreading of all forms of emotion from one person (or animal) to another (like the spreading of joy or distress through a crowd - think of a flash mob dance effect filtering through a crowd)2.

Hearing a baby cry can be quite distressing. What happens to us when we, the observers, hear the cry? We respond by getting up and checking on the crying baby, increased attention. Our body also releases the stress hormone cortisol when we hear the cry, regardless of age or parenting experience3,4. Also, we can tell if the crying is urgent or not. We do, sometimes find crying aversive (imagine a baby crying non-stop throughout your long-distance flight).
In our study, we wanted to know if dogs and humans show a similar physiological response to a baby crying. We had three questions: 
  1. We know that dogs are attached to humans, so would dogs show increased attention to a baby crying and babbling? 
  2. Exposure to uncontrollable white noise is considered aversive and elicits submissive behavior. If dogs find crying aversive, would dogs show submissive behavior towards crying as well as white noise? 
  3. Do dogs show an increased stress response (measured in their salivary cortisol levels) to a baby crying compared to white noise and a baby babbling, similar to humans?
We had 75 dogs and 74 humans listen to one of three sounds. A human baby crying:

A human baby babbling: 

Or white noise:

Each sound was played at an average volume of 82 decibels similar to chamber music in a small auditorium (not loud enough to cause hearing damage, but it is loud). We collected saliva before and after listening to one sound from both dogs and humans for their cortisol levels. We also analyzed dogsbehavior while the sound was played, and collected sound ratings about how aversive people found the sounds.

What did our three questions reveal? First, we found that both dogs and humans showed an increase in cortisol levels only after listening to crying, but no changes to baby babbling and white noise. Second, dogs showed increased attention to both the crying and babbling sounds, but not to white noise. Third, dogs displayed increased submissive behavior (e.g. the dog’s body and head were lowered, the ears were held flat and back, the tail was lowered and sometimes slightly between their legs or wagging rapidly side-to-side, the tongue pro-truded slightly, or the dog raised one leg in a hesitant or placating manner) to the crying and white noise, but not to babbling. Additionally, human participants rated the white noise as more aversive than crying (see table below for a summary). We also analyzed other possible aspects that might have influenced the dogsresponses such as time of testing, demographic data e.g. neutered status and sex, acoustic features in the sounds (pitch and melody), and even dog ownersunintentional cuing. We found that the responses shown were a result of distress, evident from crying.

You might ask why submissive behavior was shown during crying and white noise. Let’s start with white noise. Our human participants perceived white noise as more unpleasant compared to crying. Humans tend to cover their ears and animals also show similar avoidance, and what better way than to lower your head? On the other hand, with crying sounds, one is generally more subdued (sympathetic concern) especially when you can hear the distress meaning in the sound. The combined behavioral indicators during these sounds (e.g. lowered posture, shaking, stimulus avoidance) points toward submissive behavior.

In humans, an increase in cortisol and attention is interpreted as a demonstration of
emotional contagion3,4. This unique pattern of physiological and behavioral responding to crying in our study is most consistent with (a) emotional contagion in dogs, providing first evidence that dogs, like humans, experience a physiological response to human infant crying, and (b) suggests the first clear evidence of cross-species empathy (i.e. canine emotional contagion to human distress). 

Min Hooi Yong has recently completed her PhD under the supervision of Professor Ted Ruffman in the Department of Psychology, University of Otago, New Zealand. You can follow her research, or Prof Ted Ruffman. This study has been published in the journal Behavioural Processes”:

Min Hooi Yong
We would like to thank all the dog owners and their dogs who participated in our study, and to Stephanie McConnon, Mary Saxton, and Barbara Lowen for allowing us to use their dog videos. Mia is a female English Setter aged 3, Annie is a female Border Collie aged 9, and Flack is a male mixed breed (Collie/Husky/Heading) aged 4.

1. Custance, D. & Mayer, J. Empathic-like responding by domestic dogs (Canis familiaris) to distress in humans: An exploratory study. Anim. Cogn. 15, 851–859 (2012).
2. De Waal, F. B. M. Putting the altruism back into altruism: The evolution of empathy. Annu. Rev. Psychol. 59, 279–300 (2008).
3. Fleming, A. S., Corter, C., Stallings, J. & Steiner, M. Testosterone and prolactin are associated with emotional responses to infant cries in new fathers. Horm. Behav. 42, 399–413 (2002).
4. Giardino, J., Gonzalez, A., Steiner, M. & Fleming, A. S. Effects of motherhood on physiological and subjective responses to infant cries in teenage mothers: A comparison with non-mothers and adult mothers. Horm. Behav. 53, 149–158 (2008).

Thank you, Min, for discussing your research on Do You Believe in Dog? View other guest contributors here ~ Julie & Mia 

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