Laboratory for Rehabilitation Neuroscience, University of Florida, 1864 Stadium Road, Gainesville, FL, 32611, USA.
Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.
Atten Percept Psychophys. 2024 May;86(4):1248-1258. doi: 10.3758/s13414-024-02891-w. Epub 2024 Apr 29.
Visual short-term memory (VSTM), the ability to store information no longer visible, is essential for human behavior. VSTM limits vary across the population and are correlated with overall cognitive ability. It has been proposed that low-memory individuals are unable to select only relevant items for storage and that these limitations are greatest when memory demands are high. However, it is unknown whether these effects simply reflect task difficulty and whether they impact the quality of memory representations. Here we varied the number of items presented, or set size, to investigate the effect of memory demands on the performance of visual short-term memory across low- and high-memory groups. Group differences emerged as set size exceeded memory limits, even when task difficulty was controlled. In a change-detection task, the low-memory group performed more poorly when set size exceeded their memory limits. We then predicted that low-memory individuals encoding items beyond measured memory limits would result in the degraded fidelity of memory representations. A continuous report task confirmed that low, but not high, memory individuals demonstrated decreased memory fidelity as set size exceeded measured memory limits. The current study demonstrates that items held in VSTM are stored distinctly across groups and task demands. These results link the ability to maintain high quality representations with overall cognitive ability.
视觉短期记忆（VSTM），即存储不再可见信息的能力，对于人类行为至关重要。VSTM 限制在人群中存在差异，并与整体认知能力相关。有人提出，低记忆个体无法仅选择相关项目进行存储，并且当记忆需求较高时，这些限制最大。然而，尚不清楚这些影响是否仅反映任务难度，以及它们是否会影响记忆表示的质量。在这里，我们改变了呈现的项目数量（即集大小），以研究记忆需求对低记忆和高记忆组的视觉短期记忆性能的影响。即使控制了任务难度，当集大小超过记忆限制时，组间差异也会显现出来。在变化检测任务中，当集大小超过低记忆个体的记忆限制时，他们的表现更差。然后，我们预测在超过测量记忆限制的情况下对项目进行编码的低记忆个体将导致记忆表示的保真度降低。连续报告任务证实，低记忆个体（但不是高记忆个体）的记忆保真度随着集大小超过测量记忆限制而降低。本研究表明，VSTM 中存储的项目在不同群体和任务需求下是明显区分的。这些结果将保持高质量表示的能力与整体认知能力联系起来。
