In Landmark Study, USU Scientists Ask: 'Does (Brain) Size Matter?'

Utah State University scientists contributed to a landmark, multi-university study, in which researchers gathered data from 36 animal species to determine evolutionary factors linked to self-control. Comparing cognitive performance of critters ranging from pigeons to elephants, the investigators found brain size matters. Their findings appear in the April 2014 issue of Proceedings of the National Academy of Sciences and in National Geographic.

“Absolute brain size matters — that is, not relative brain size correlated to body size,” says Julie Young, research assistant professor in USU’s Department of Wildland Resources and supervisory wildlife biologist with Millville, Utah’s, Predator Research Field Station for the USDA’s National Wildlife Research Center.

With USU colleague Kerry Jordan, Young tested coyotes’ self-control at the field station and submitted collected data to the study. Self-control, they say, is defined as the ability to restrain one’s self from behaving in a way that is counterproductive to survival.

“This large collaboration is a great example of studying the evolution of one particular cognitive adaptation,” says Jordan, cognitive psychologist and associate professor in USU’s Department of Psychology. “By studying multiple species in tandem, we can discover not only how malleable such traits may be in humans today at any one moment, but we also know what other selective pressures — such as absolute brain size — have correlated with, and perhaps driven, the evolution of such cognitive capabilities on a much longer time scale.”

Coyotes, the researchers found, were quite successful at the study’s cognitive tests, which included learning where to find food and later applying that knowledge to a similar situation.

“The coyotes showed a decent amount of self-control, especially on a particular task involving a plastic cylinder,” Jordan says. “This test required the animals to reach behind a clear plastic cylinder to obtain a treat located there. They had to use self-control in order to inhibit just grabbing at the treat through the plastic.”

The coyotes, she says, correctly reached behind the cylinder 94 percent of the time.

In addition to brain size, the researchers found a varied and more complex diet contributes to cognitive abilities and an animal’s success in performing daily activities.

“The reason why coyotes were good at solving the study’s tests is because they have a wide foraging breadth,” Young says. “They eat a wide diet of mule deer, fruit and insects — even birds and snakes.”

Domestic dogs and wolves tested by other researchers participating in the study also showed a high amount of self-control, as did primates. Self-control is important for all species — including humans, the researchers say, yet little is known about how this trait evolved.

“This study is a step toward better understanding,” Young says.

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