Principal component analysis of the memory load effect in a change detection task

•PCA of event-related potentials reveals P3 component sensitive to changes in load.•Relates working memory capacity to P3 amplitude in a change detection task.•Reconciles contradictory findings regarding how P3 changes as a function of load.

Previous research using the change detection task has found little or no relationship between P3 amplitude and working memory load. This contrasts with findings from other paradigms that indicate a decrease in P3 amplitude with increases in working memory load. We adopted a principal component analysis strategy to resolve this discrepancy. After ERPs were decomposed, the P3 component decreased in amplitude when the memory load increased. Its amplitude was also associated with individuals' working memory capacity. In conclusion, P3 plays a critical role in change detection task as it does in other working memory tasks.