ISSN 0439-755X
CN 11-1911/B

Acta Psychologica Sinica ›› 2021, Vol. 53 ›› Issue (11): 1189-1202.doi: 10.3724/SP.J.1041.2021.01189

• Reports of Empirical Studies • Previous Articles     Next Articles

Same-category advantage on the capacity of visual working memory

SUN Yanliang1, SONG Jiaru1, XIN Xiaowen2, DING Xiaowei3(), LI Shouxin1()   

  1. 1School of Psychology, Shandong Normal University, Jinan 250358, China
    2Department of Party Committee Student Affairs, China University of Petroleum, Qingdao 266580, China
    3Department of Psychology, Sun Yat-Sen University, Guangzhou 510006, China
  • Received:2020-10-15 Published:2021-11-25 Online:2021-09-23
  • Contact: DING Xiaowei,LI Shouxin;
  • Supported by:
    National Natural Science Foundation of China(31800911);National Natural Science Foundation of China(31871100);Humanities and Social Sciences Research of Ministry of Education(19YJC190004);key cultivation program of young teachers of Sun Yat-Sen University(19WKZD23);Natural Science Foundation of Guangdong Province(2021A1515011103)


Visual working memory (VWM) is a limited-capacity cognitive system that is responsible for temporarily storing up to three or four items, maintaining their availability for current cognitive processing. Although VWM capacity is limited, the limit is not fixed. Factors such as complexity, statistical regularity, real-world spatial regularity, and perceptual grouping principles of memory objects can modulate this capacity. However, the potential influence of higher-order conceptual regularities, such as categorical relationships among memory objects, remains an open and controversial issue. The effect of object category on VWM capacity, if any, has two possibilities: a mixed-category advantage and a same-category advantage. Hence, in the present study, we used behavioral and electrophysiological methods to explore this issue. A 2 (memory load: two or four) × 2 (category: same or different) × 2 (posture: high similarity or low similarity) within-subject design was used in Experiment 1. The results showed that category knowledge modulates the capacity of the VWM and leads to a same-category advantage. In Experiment 2, we changed the presentation of memory items from simultaneous to successive and replicated the findings from Experiment 1, demonstrating that category knowledge leads to larger memory capacity in the same-category rather than in the different-category condition, even if the memory items are sequentially presented. In Experiment 3, in addition to Cowan’s K, the contralateral delay activity (CDA, an electrophysiological index of VWM capacity) was measured to further explore the processing mechanism underlying the same-category advantage. The CDA results show for the first time that same-category objects can induce a smaller CDA than different-category objects. The CDA results combined with behavioral results indicated that category knowledge can help compact the representations of same-category objects and therefore enlarge the total information capacity of VWM. In conclusion, our data clearly demonstrate an advantageous same-category effect on the capacity of VWM, which indicates that categorical relationships among objects play an important role in expanding the capacity of VWM by enabling the grouping of same-category objects.

Key words: visual working memory, category information, contralateral delay activity