Overthinking certain tasks invariably makes your performance worse. Just try riding a bike, playing an instrument, or typing on a keyboard while consciously visualizing and explaining the action.

New research may help explain why a heightened focus sometimes exacerbates the very performance it’s intended to enhance. In a recent experiment, scientists at the University of California Santa Barbara examined how different types of memory processes interact – and interfere – with one another.

The tremendous amount of information our brain retains is generally understood to fall into two broad categories: implicit and explicit memory. An explicit memory can be visualized and explained in conscious, coherent thoughts. Conversely, implicit memories are nebulous and intuitive, circumventing consciousness altogether. Ideally, these two categories should remain distinct areas of function.

However, the scientists found that by stimulating a particular area in the prefrontal cortex of volunteers, the attentional processes associated with one category can be made to interfere with those of the other. A similar interference can be brought on by overthinking an intuitive task – by treating an implicit memory like a conscious, explicit one. The researchers gave the example of a pro golfer leading a tournament up to the 18th hole.

"That should be the time when it all comes out the best, but you just can't think about that sort of thing," said lead author Taraz Lee, a postdoctoral scholar working in the university’s Action Lab. "It just doesn't help you."

In the experiment, subjects were asked to memorize and subsequently describe a sequence of kaleidoscopes. As the subjects observed the images, the scientists used theta-burst transcranial magnetic stimulation (TMS) to disrupt specific functions within the dorsolateral and ventrolatal regions of their prefrontal cortex – the area responsible for implicit and explicit memory.

"After they gave us that answer, we asked whether they remembered a lot of rich details, whether they had a vague impression, or whether they were blindly guessing," explains Lee. "And the participants only did better when they said they were guessing."

The results thus confirm that attentional processes can interfere with each other, and that this can indeed affect sensory information.

"If we ramped down activity in the dorsolateral prefrontal cortex, people remembered the images better," said Lee.

Besides providing a more sophisticated knowledge of the process whereby focus impairs certain performance, the findings may help us understand larger cerebral schemas. Lee believes that by studying functions that paradoxically hurt performance, we can begin to unravel the tremendously complex “rules” of thinking and remembering.

Until then, don’t underestimate the effect of overthinking.

Source: T. G. Lee, R. S. Blumenfeld, M. D'Esposito. Disruption of Dorsolateral But Not Ventrolateral Prefrontal Cortex Improves Unconscious Perceptual Memories. Journal of Neuroscience, 2013; 33 (32): 13233 DOI: