Animals are constantly gathering signals from the surrounding environment, yet somehow they learn to focus on stimuli important to survival and to ignore, or fail to learn to respond to, other stimuli. Otherwise, a survival-threatening confusion could result. A team of investigators, including Yale neuroscientist Jeansok J. Kim, Ph.D., has found a neurological explanation for this phenomenon called blocking, and has identified the brain structure involved in the blocking process. Dr. Kim and colleagues found that when they chemically severed a brain structure called the inferior olive in rabbits, blocking disappeared and the animals responded to redundant and irrelevant stimuli.

“In order to adapt to its environment,” says Dr. Kim, an assistant professor of psychology, “an animal must respond selectively to stimuli that reliably predict biologically significant events, such as food availability. In the interest of efficiency and simplicity, animals must avoid forming associations with other stimuli that provide no new information. Blocking appears to circumvent such redundant learning.” The study appeared in the journal Science.