Manipulations of attention dissociate fragile visual short-term memory from visual working memory

► Previous research has suggested that visual short-term memory (VSTM) can be divided into three stages: short-lived iconic memory, intermediate-lived fragile VSTM and long-lived visual working memory. ► In this study, we manipulated attention to see whether fragile VSTM and visual working memory differ in their dependency on attention. ► We found that when attention is diverted during presentation of a memory array, visual working memory capacity suffers. ► When attention is diverted during presentation of a memory array, fragile VSTM capacity stays intact. ► It is proposed that the mechanisms underlying the storage of items in memory can be separated from the mechanisms underlying the selection of these items for manipulations or report. The latter is proposed to depend on attention, while the former can occur independent of attention. People often rely on information that is no longer in view, but maintained in visual short-term memory (VSTM). Traditionally, VSTM is thought to operate on either a short time-scale with high capacity – iconic memory – or a long time scale with small capacity – visual working memory. Recent research suggests that in addition, an intermediate stage of memory in between iconic memory and visual working memory exists. This intermediate stage has a large capacity and a lifetime of several seconds, but is easily overwritten by new stimulation. We therefore termed it fragile VSTM. In previous studies, fragile VSTM has been dissociated from iconic memory by the characteristics of the memory trace. In the present study, we dissociated fragile VSTM from visual working memory by showing a differentiation in their dependency on attention. A decrease in attention during presentation of the stimulus array greatly reduced the capacity of visual working memory, while this had only a small effect on the capacity of fragile VSTM. We conclude that fragile VSTM is a separate memory store from visual working memory. Thus, a tripartite division of VSTM appears to be in place, comprising iconic memory, fragile VSTM and visual working memory.