Attention and the Order of Items in Short-Term Visual Memory

摘要

Subjects first detected a target presented at the left of fixation, and then attempted to report, in order, the first four items (numerals or shapes) in a stream of items presented to the right of fixation. At comparably difficult presentation rates, 10/s for numerals and 5/s for shapes, reports showed a mixture of correctly ordered items with items reported in a direction opposite to their order of presentation. Reports fit a three-parameter attention-gating model (AGM), which assumes that (1) after target detection, an attention gate opens briefly to allow items to enter visual short-term memory (VSTM), and (2) report order is determined by the attention each item receives in VSTM. Items presented either early or late in the stream tend to receive less attention and are thus reported as later than more central items. The fit to the AGM for both numerals and unlabelled shapes provides evidence that reports reflect order in short-term visual (rather than verbal) memory.