Effects of Pattern Complexity on the Retrieval Stage of Visual Short-Term Memory in Relation to Autistic-Like Traits

Abstract

Our study aimed to examine the effects of pattern complexity on visual short-term memory (VSTM) at the retrieval stage in typical developing adults with different autism spectrum quotient (AQ) scores. Participants underwent electroencephalography during a same-different task, in which they judged as rapidly and accurately as possible whether the target pattern (S1) was the same or different from the comparison pattern (S2). In the same-different task, pattern complexity (simple and complex patterns) was manipulated. We analyzed two peaks of waveforms (P3b and positive slow wave [PSW]) elicited by S2 and compared them between the high and low AQ groups (each n = 11). The PSW amplitude was greater in the high AQ group than those in the low AQ group (p < .05; ηp2 = 0.14 to 0.15). In particular, although the low AQ group showed lower PSW amplitude for complex patterns than for simple patterns, the high AQ group showed a high PSW amplitude for both simple and complex patterns. The low AQ group had efficient memory search and distinguished between S1 and S2 only for simple patterns while the high AQ group exhibited them for both simple and complex patterns, because the PSW in the retrieval stage may be related to the memory search modulated by cognitive load. Thus, individual differences were observed especially in a high cognitive load (complex patterns). People with high AQ scores show more specific processing at the retrieval stage of VSTM as compared to those with low AQ scores.