Anticipatory Memory for Regular and Random Patterns.

Real-world scenes elicit anticipatory representation in long-term memory (LTM) and working memory (WM) resulting in boundary extension (BE). Would the same results hold for nonscene patterns of objects? In Experiment 1A (LTM-paradigm), 15 regular or 15 random object-patterns were sequentially presented (10 s each); a boundary-rating-task followed. Both pattern-types elicited BE. Surprisingly, regularity (greater pattern predictability) did not enhance BE. Instead, random patterns more consistently yielded BE. Perhaps random object-groupings enhance BE (e.g., more scene-like). Objects within regular patterns were colored to create object-groupings; this increased BE compared to regular patterns without color groups, but only in 1 of the 2 tests (Experiment 1B, LTM-paradigm). In Experiment 2 (WM-paradigm), a briefly presented pattern, regular or random, was followed by a 2-s masked interval and a boundary-rating-task on each trial. Here, results reversed: patterns now elicited boundary restriction (whether or not a concurrent task had been presented to prevent verbalization). Under time pressure, without real-world layout and meaning, pattern elements may not have cohered into a unified expanse, failing to elicit BE and resulting in loss of peripheral content. We propose 2 classes of visual content that may determine anticipatory representation: content that embellishes space versus content that defines space. Public Significance Statement: When viewing real-world scenes, the brain anticipates surrounding layout; this study showed that novel patterns also elicited anticipatory representation given sufficient time, but not when the same patterns were briefly presented. Not only was anticipatory processing halted, but also participants lost memory for the peripheral elements of the patterns. This demonstrates the critical role of top-down knowledge and expectations in supporting anticipatory representation, which may be crucial for a moving observer's successful interaction with the surrounding world. [ABSTRACT FROM AUTHOR]