Do Dogs Prefer Food or Praise?
Brain scans look at dogs' responses to food versus praise from their owners.
Posted Aug 23, 2016
There are a number of cynics (and some scientists) who feel that the affection that dogs show to humans is simply based on the fact that humans provide food for dogs. They argue that from the dog's perspective it is the food which is most important and, given a choice between a person and a food bowl, most dogs would opt for the edible snack rather than social interaction. However a new study suggests that the cynics might be wrong.
The argument as to the relative importance of food versus social contact in our relationship to dogs has raged for years. Some data seems to suggest that food is most important, especially when we are training our dogs (click here for more about that). While other times it appears that just being near a person is rewarding for dogs (click here to read about that).
In the middle of the 20th century a similar argument was raging — only then it was focused on the nature of mother-love. It was argued that the strong bond between a child and its mother simply came about because the mother was the person who provided food for the child. A psychologist, Harry Harlow from the University of Wisconsin at Madison, used infant monkeys to show that certain aspects of the interaction between a child and its mother were more important for establishing a loving bond than simply providing nourishment to the youngster. In a series of studies he used surrogate mothers (constructions made of wire or constructions wrapped in soft terrycloth either of which could provide food for the young monkey) to show that feeding was not the critical variable. A surrogate mother who provided food but did not encourage physical contact never received much affection. On the other hand, a surrogate mother who provided contact comfort, similar to sort that we might provide by touching and petting a dog, became an object of affection.
A scientific report that was recently accepted for publication in the journal Social, Cognitive, and Affective Neuroscience* presents data about what is happening in the dog's brain when he is presented with a food reward versus a social reward (verbal praise). The investigation was conducted by a group of researchers from Emory University in Atlanta, Georgia and the team was headed by Peter Cook of the psychology department.
A sample of 15 dogs were given fMRI brain scans. As opposed to the standard MRI scan, which looks at the structure of the brain, the fMRI looks at the changes in the activity of regions of the brain when certain events occur. Giving an fMRI scan to a dog is difficult, not only because it requires a dog to remain motionless in a confined space for a period of time, but also because MRI machines make a lot of noise, loud clanks, bangs, and grinding gear sounds. Normally such noises might startle or frighten a dog and cause him to move, or even to try to run away. So extensive training is needed to be able to test a dog in this equipment, and for the dog to remain stationary during the procedure.
In this current study the researchers concentrated on changes in activity in an older part of the brain called the caudate nucleus. Changes in this brain center can be triggered merely by the anticipation that something pleasant is about to happen, and some researchers have called this the "feel good center" of the brain (click here for more about the fMRI and the caudate nucleus).
In the first phase of the research dogs were placed in the MRI apparatus and were shown one of three objects (each attached to a stick so that it could be shown to the dog without a person appearing in view at the same time). The first object was a pink toy car which was shown to the dog and then 10 seconds later it was followed by the appearance of the dog's owner who spent a few seconds praising the dog. The second object was a blue toy horse, and it was followed by a piece of hot dog provided to the dog on the end of the feeding stick. The third object was a hairbrush which served as a control condition since nothing happened after it was presented.
The results showed that there was no clear victor in the competition between food and praise from the owner. For 9 out of the 15 dogs tested the response of the caudate nucleus of the brain was virtually identical. However, a few of the dogs did seem to have a clear preference for one or the other since 4 showed a stronger reaction to praise than to food, while 2 dogs consistently showed a more intense reaction to food than to praise.
The researchers recognized that the dogs responses while confined in an MRI chamber constituted a very artificial situation. So they next decided to to see if these fMRI brain responses predicted what the dogs would do if they were given an actual choice between their owner and some food in the real world. Thus in a final experiment the dogs were led into a room with a Y-shaped maze-like apparatus. The dog entered the Y at the bottom of the stem and then walked to a point where it could see down both branches of the Y. Down one branch it could see its owner sitting on the chair with their back toward the dog, while down the other branch it could see a bowl which contained some food treats. If the dog chose the side with the food it got to eat it, while if it chose its owner it got a short interaction of petting and verbal praise. Over the course of 20 tests, it turns out that the brain scans predicted exactly what the dogs would do. Those dogs whose fMRI lit up most strongly at the thought of their owners praise went directly to their person with no hesitation. The dogs whose response was clearly stronger for food headed straight for the bowl. The majority of dogs, however, alternated between heading for the food and heading toward their owner during the set of test runs. Videos of the dog's performances showed that these dogs really seemed to struggle once they have reached the point where they have to make a choice. They obviously want the food, but they also want their owner's display of affection.
The conclusion that the researchers reach is that for most dogs it is pretty much a tossup between whether food or social interaction is most rewarding. These researchers feel that their results flies in the face of the cynics who believe that the fact that we feed our dogs is the basis for their affectionate bond with us. They note that "On a practical level, our results emphasize the importance of social reinforcement to dogs." They further go on to say that their findings "suggest that the majority of our participants found social interaction at least as reinforcing as food."
Stanley Coren is the author of many books including: Gods, Ghosts and Black Dogs; The Wisdom of Dogs; Do Dogs Dream? Born to Bark; The Modern Dog; Why Do Dogs Have Wet Noses? The Pawprints of History; How Dogs Think; How To Speak Dog; Why We Love the Dogs We Do; What Do Dogs Know? The Intelligence of Dogs; Why Does My Dog Act That Way? Understanding Dogs for Dummies; Sleep Thieves; The Left-hander Syndrome
Copyright SC Psychological Enterprises Ltd. May not be reprinted or reposted without permission
Data from: Peter F. Cook, Ashley Prichard, Mark Spivak, and Gregory S. Berns (2016). Awake Canine fMRI Predicts Dogs’ Preference for Praise Versus Food. Social, Cognitive, and Affective Neuroscience, first published online August 12, 2016 doi:10.1093/scan/nsw102