Performance on cognitive tasks during learning is used to measure knowledge, yet it remains controversial since such testing is susceptible to contextual factors. To what extent does a performance during learning depend on the testing context, rather than underlying knowledge?
In a new study by the Johns Hopkins University, scientists showed a distinction between knowledge and performance, and provide insight into how the environment can affect the two.
Previous studies had only focused on ow humans and other animals learn ‘content’ or knowledge. This new study suggests that there are original two parallel learning processes: one for content and one for context, or environment. Separating how these two pathways work, one can find ways to improve performance.
However, scientists were aware that the presence of reinforcement, or reward, can change how animals behave. But, it was unclear how rewards affect learning versus performance.
Now, this study has found the answer. According to the study, rewards are necessary for learning, but may actually mask true knowledge.
Kishore Kuchibhotla, an assistant professor in The Johns Hopkins University’s department of psychological and brain sciences explained, “An example of the difference between learning and performance, is the difference between a student studying and knowing the answers at home, and a student demonstrating that knowledge on a 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.”
To understand what animals know in hopes of better understanding learning, scientists trained mice, rats, and ferrets on a series of tasks, and measured how accurately they performed the tasks with and without rewards.
During the first experiment, scientists trained the mice to lick for water using a lick tube after hearing one tone and to not lick after hearing a different, unrewarded tone. Mice took almost two weeks to learn this task in the presence of the water reward. At a time point early in learning, around days 3-5, the mice performed the task at chance levels (about 50%) when the lick tube/reward was present.
When the team removed the lick tube entirely on these early days, however, the mice performed the task at more than 90% accuracy. The mice, therefore, seemed to understand the task many days before they expressed knowledge in the presence of a reward.
To confirm this finding with other tasks and animals, the team also had mice press a lever for water when they heard a certain tone; prompted rats to look for food in a cup if they heard a tone, but not if a light appeared before the tone; had rats press a lever for sugar water when a light was presented before a tone; had rats push lever for sugar water when they heard a certain tone, and prompted ferrets to differentiate between two different sounds for water. In all experiments, the animals performed better when rewards weren’t available.
Kuchibhotla said, “Rewards, it seems, help improve learning incrementally, but can mask the knowledge animals have actually attained, particularly early in learning. Furthermore, the finding that all animals’ performance improved across the board without rewards, suggesting that variability in learning rates may be due to differences in the animals’ sensitivity to reward context rather than differences in intelligence.”
“The dissociation between learning and performance may someday help us isolate the root causes of poor performance. While the study involved only rodents and ferrets, Kuchibhotla says it may be possible to someday help animals and humans alike better access content when they need it if the right mechanisms within the brain can be identified and manipulated.”
The findings are published May 14 in Nature Communications.