Hungry dogs would be expected to choose alternatives leading to more food rather than less food. But just as with humans and monkeys, they sometimes show a “less is more” effect. Thus conclude Kristina Pattison and Thomas Zentall of the University of Kentucky in the US, who tested the principle by feeding baby carrots and string cheese to ten dogs of various breeds. The findings are published in Springer’s journal Animal Cognition.
The research was conducted on dogs that would willingly eat cheese and baby carrots when offered, but showed a preference for the cheese. However, when given a choice between one slice of cheese, or the cheese together with a piece of carrot, nine of the ten dogs chose the cheese alone. That is, they chose less food over more food.
The “less is more” effect is considered an affect heuristic or mental shortcut that sometimes shows a preference for the qualitative over the quantitative when considering different options. It appears that the dogs averaged the quality of the cheese plus carrot, rather than sum up the quantity of food. This quick decision making was first demonstrated in humans, and later in monkeys. People, for instance, tend to place greater value on a set of six baseball cards that are in perfect condition, than on the same set of six perfect cards together with three more cards in fair condition. A similar effect was also reported in studies of monkeys where the animals would eat both grapes and cucumbers, but preferred one grape over one grape plus a slice of cucumber when given the option.
The researchers believe that this paradoxical choice occurs because in most cases it is easier to judge the average quality than the overall quantity of alternatives. In cases where rapid decisions must be made, quick solution-driven heuristics such as the “less is more” effect may therefore come in handy. For instance, it is helpful when members of the same species, such as a pack of dogs, feed together. The one that hesitates may lose food to faster-choosing competitors. Such heuristics may also help prey in the wild to make rapid decisions rather than become supper. But the fact that one in ten dogs did choose the cheese-and-carrot combination suggests that levels of motivation may play a role in this effect. The outlier dog, for instance, had a history of living in shelters and fending for himself.
“The present research indicates that the less is more effect is not unique to humans and other primates but can occur in other mammalian species, at least those that are socially organized such as carnivores like wolves, dogs and jackals,” says Pattison. She believes that further research is needed to find out if the “less is more” effect also occurs in less socially organized species such as rats, or non-mammalian species such as birds.
Reference:
Pattison, K.F. & Zentall, T. (2014). Suboptimal Choice by Dogs: When Less is Better than More,Animal Cognition. DOI 10.1007/s10071-014-0735-2.
This is a great article. I learned a lot about the less is more concept. Not only do dogs show that the concept is true but so do humans and monkeys. My dog was lost for three days and I thought that she would indulge herself with food as soon as she got home. She surprised me by eating only a small amount. She waited until the next day to again eat only a small amount. This surprised me because this article proves the point that my dog was pursuing the less as more theory. Not because she didn’t want to eat more, or because she didn’t think she was going to get more. But, because her body was not used to eating she portioned it out to protect her stomach. She would have gotten sick. Dogs also keep in mind that if their owner leaves, they also portion out their food because they are unaware of the time their owner will be gone. They eat when they understand that their owner will give them more food. It is important for everyone to include a healthy diet. Dogs and people will eat when the food is presented and they know more will be given to them. Others portion out their food in the less is more theory as well as the belief that they will be fed again.
It is interesting to learn that in some aspects humans and dogs are similar in their decision making process. It is also interesting to learn that the quantity over quality decisions were key to animal survival, i did not know this, i always thought that animals would simply eat what they hunted, forested or scavenged for without their being any decisions to be made. But couldn’t the dogs have chosen the one slice of cheese over the baby carrots because they didn’t like them? If we as humans have preferences with our food my can’t animals?