Image credit: Gerd Altmann (CC BY 4.0)
When we memorize a grocery list before heading into the store, we make use of our working memory. This type of neural process allows us to temporarily store the knowledge needed for a task, yet its capacity is limited. Having to recall more than one type of information at the same time, in particular, can quickly create challenges. Exactly how the brain maximizes the use of this limited working memory space remains unclear.
One possible strategy would be to take advantage of the patterns or connections that exist between seemingly unrelated pieces of information – for example, by remembering to buy apples, oranges and bananas under one broader ‘fruit’ category. To explore if this may be the case, Qiaoli Huang and Huan Luo designed a memory task in which two types of information were either connected through an underlying pattern (aligned trajectory condition) or completely independent (misaligned trajectory condition). Participants watched three colored dots appearing on screen one after the other, in such a way that they seemed to ‘travel’ around an imaginary circle. The volunteers were then asked to recall, in order, the location and color of each dot. Performance increased when color and location information were structured in the same way – that is, when both emerged from the three dots traveling around a circle or a color wheel with the same trajectory.
Recording the brain activity of the participants ‘live’ as they performed the task indicates that, in the aligned trajectory condition, the brain ‘compresses’ both types of information and extracts their common structure. Even when participants were asked to recall only the location of the dots, their brain also spontaneously replayed the related color information. Taken together, these findings provide new insights into how working memory aids in multitasking, a crucial aspect of our daily lives, and lay the groundwork for further exploration of this capability.
