Dogs and emotions
Dr Min Hooi Yong discusses the scientific evidence that suggests that dogs can differentiate positive and negative emotions.
We often treat our dogs as a family member, and like all family members, we expect them to know some things. For example, emotions. Specifically, our emotions. We tend to anthropomorphise – giving human traits to our dogs – when we talk about our dogs. For example – my dog is feeling sad today or we are not going for a walk today and so he’s angry with me. Emotion is a complex abstract because it involves feelings. We have ample research evidence on how our brain responds to different emotions in humans, but does this also apply to dogs?
For example, can dogs recognise some primary emotions in humans such as happiness, anger or sadness? Daniel Mills and colleagues (2005) tested 10 dogs with two commands - “sit” and “come” - in either neutral, happy, sad or angry tones with the experimenter hidden behind a screen . The dogs were first trained with a neutral tone, and then the last command was carried out in one of the emotional tones. They found that when a neutral tone was followed with a happy tone, dogs were more obedient, compared to neutral tones followed by negative tones. It appears that they like positive words, just like us. Recent studies have provided evidence that dogs are capable of discriminating human expressions of happiness and anger when viewing on a computer screen [2,3].
But what about negative emotions – can dogs feel sad?
But what about negative emotions e.g. sad? Humans can differentiate the urgency of crying by either increasing attention to it , or find crying aversive . The increased attention (behavioural response) and together with an increase in cortisol levels (a stress hormone), is considered as a form of empathic response in human adult studies [6,7]. Our main interest was in the human vocal expressions of sadness, particularly crying. We investigated whether dogs demonstrate physiological response, similar to young adult humans when listening to an infant crying . We tested 75 domestic dogs and 74 young adult humans, and collected salivary cortisol before and after listening to a sound (a baby crying, a baby babbling or white noise), and observed dogs’ behaviour while the sound was being played. Our results showed that both dogs and humans had increased cortisol levels to crying only, but not to babbling and white noise [see Figure 1]. Dogs also showed a combination of alertness and submissiveness to crying, and this combination is not observed in babbling and white noise.
Figure 1. Cortisol response in humans and dogs. Mean cortisol levels of humans (n = 74) and dogs (n = 75) before and after listening to crying, babbling or white noise. * p < .05.
Dogs are able to understand the differences between positive and negative emotions
Taken together, these findings have provided some evidence that dogs are able to understand the differences between positive and negative emotions. As shown in our study, our study suggests crying elicits the presence of emotional contagion, a rudimentary form of empathy, in dogs. That is, similar to humans, dogs also experience a physiological response to human infant crying, and a clear evidence of cross-species empathy (dogs responding to human infant distress).
 Mills, D. S., Fukuzawa, M., & Cooper, J. J. (2005). The effect of emotional content of verbal commands on the response of dogs (Canis familiaris). In D. S. Mills, E. Levine, G. Landsberg, D. Horwitz, M. Duxbury, P. Mertens, … J. Willard (Eds.), Current issues and research in veterinary behavioral medicine (pp. 217–220). West Lafayette: Purdue University Press.
 Albuquerque, N., Guo, K., Wilkinson, A., Savalli, C., Otta, E., & Mills, D. (2016). Dogs recognize dog and human emotions. Biology Letters, 12(1).
 Müller, C. A., Schmitt, K., Barber, A. L. A., & Huber, L. (2015). Dogs can discriminate emotional expressions of human faces. Current Biology, 25(5), 601–605.
 Boukydis, C. F. Z., & Burgess, R. L. (1982). Adult physiological response to infant cries: Effects of temperament of infant, parental status, and gender. Child Development, 53, 1291–1298.
 Murray, A. D. (1985). Aversiveness is in the mind of the beholder. In B. M. Lester & C. F. Z. Boukydis (Eds.), Infant crying (pp. 217–239). Springer US.
 Fleming, A. S., Corter, C., Stallings, J., & Steiner, M. (2002). Testosterone and prolactin are associated with emotional responses to infant cries in new fathers. Hormones and Behavior, 42(4), 399–413.
 Giardino, J., Gonzalez, A., Steiner, M., & Fleming, A. S. (2008). Effects of motherhood on physiological and subjective responses to infant cries in teenage mothers: A comparison with non-mothers and adult mothers. Hormones and Behavior, 53(1), 149–158.
 Yong, M. H., & Ruffman, T. (2014). Emotional contagion: Dogs and humans show a similar physiological response to human infant crying. Behavioural Processes, 108, 155–165.
* This is a personal blog. Any views or opinions represented in this blog belong solely to the blog owner and do not necessarily represent the views or policies of World Animal Protection.