If people are unable to perceive their own errors as they complete a routine, simple task, their skill will decline over time, a new study by Johns Hopkins researchers have suggested.
The researchers report that the human brain does not passively forget our good techniques, but chooses to put aside what it has learned.
The term "motor memories" may conjure images of childhood road trips, but in fact it refers to the reason why we're able to smoothly perform everyday physical tasks. The amount of force needed to lift an empty glass versus a full one, to shut a car door or pick up a box, even to move a limb accurately from one place to another - all of these are motor memories.
In a new study, the Johns Hopkins researchers try to find out how motor memories are formed and lost by focusing on one well-known experimental phenomenon: When people learn to do a task well, but are asked to keep doing it while receiving deliberately misleading feedback indicating that their performance is perfect every time, their actual performance will gradually get worse.
It had been assumed that the decline was due to the decay of memories in the absence of reinforcement, said Reza Shadmehr, Ph.D., a professor in the Department of Biomedical Engineering at the Johns Hopkins University School of Medicine.
But when Shadmehr and graduate student Pavan Vaswani asked volunteers to learn a simple task with a few twists designed to deliberately manipulate the brain's motor control system, they learned otherwise.
Shadmehr stated, "Our results correct a component of knowledge we thought we understood. Neuroscientists thought decay was intrinsic to motor memories, but in fact it's not decay - it's selection."
The finding was published last month in The Journal of Neuroscience.