When the subjects were asked questions about the cards afterward, they did much better on the task they learned without the distraction. On the task they learned with the distraction, they could not extrapolate; in scientific terms, their knowledge was much less "flexible."
This result demonstrates a reduced capacity to recall memories when placed in a different context, Poldrack said.
"Our results suggest that learning facts and concepts will be worse if you learn them while you're distracted," Poldrack said.
Different forms of memory are processed by separate systems in the brain, he noted. When you recall what you did last weekend or try to remember someone's name or your driver's license number, you are using a type of memory retrieval called declarative memory. (Patients with Alzheimer disease have damage in these brain areas.) When you remember how to ride a bicycle or how to play tennis, you are using what is called procedural memory; this requires a different set of brain areas than those used for learning facts and concepts, which rely on the declarative memory system. The beeps in the study disrupted declarative memory, said Poldrack, who also studies how the types of memory are related.
The brain's hippocampus -- a sea-horse-shaped structure that plays critical roles in processing, storing and recalling information -- is necessary for declarative memory, Poldrack said. For the task learned without distraction, the hippocampus was involved. However, for the task learned with the distraction of the beeps, the hippocampus was not involved; but the striatum was, which is the brain system that underlies our ability to learn new skills.
The striatum is the brain system damaged in patients with Parkinson disease, Poldrack noted. Patients with Parkinson's have trouble learning new motor skills but do not have trouble remembering the past.