May 14 (UPI) -- Food rewards may actually prevent researchers from appreciating the true intelligence of animals.
According to a new study, when animals are given treats for learning and completing tasks, differentiating between a test subject's knowledge and performance, as well as how each are influenced by the environment, becomes more difficult.
"Most learning research focuses on how humans and other animals learn content, or knowledge," Kishore Kuchibhotla, an assistant professor of psychological and brain sciences at Johns Hopkins University, said in a news release. "Here, we suggest that there are two parallel learning processes: one for content and one for context, or environment. If we can separate how these two pathways work, perhaps we can find ways to improve performance."
Until now, scientists were unclear on how positive reinforcement influences knowledge and performance.
The difference between knowledge and performance can be explained by a student who demonstrates knowledge of a subject or concept while studying at home, but performs poorly on a quiz or test at school.
"What we know at any given time can be different than what we show; the ability to access that knowledge in the right environment is what we're interested in," Kuchibhotla said.
For the new study, scientists trained trained mice, rats and ferrets to perform a series of tasks with and without food treats as an incentive. For one test, researchers trained mice to lick a tube after hearing a single tone. They also trained mice to refrain from licking the tube after hearing a different tone.
When a lick tube with water was provided to encourage the mice to learn the task, the mice performed the task at a 50 percent clip. But when scientists removed the lick tube after just a few days, the mice performed at a 90 percent clip.
In a followup test, scientists trained mice, rats and ferrets to perform a variety of tasks. The mice were trained to press lever for water when they heard a specific tone, while the rats were trained to look for food in a cup. The animals were trained to refrain from looking for water and food if a light appeared prior to the tone. Ferrets were trained to differentiate between two sounds.
When the animals were trained to simply press a lever without any food rewards, they were quicker to perform -- or demonstrate -- their knowledge.
"Rewards, it seems, help improve learning incrementally, but can mask the knowledge animals have actually attained, particularly early in learning," said Kuchibhotla.
Kuchibhotla and his research partners published their analysis of the mitigating effects of food rewards this week in the journal Nature Communications.