Temporal characteristics of priming effects on the perception of ambiguous patterns

Abstract

When an ambiguous pattern is viewed once, it may be perceived in two equally compelling ways. When viewed repeatedly, its perception is biased by priming effects: (i) An unambiguous pattern negatively primes a subsequent ambiguous pattern, which is less often perceived in the same way. This “flash suppression” [1] may reflect habituation of the primed percept. (ii) An ambiguous pattern positively primes a subsequent ambiguous pattern, which is more often perceived in the same way [2]. The effect persists across blank periods and reveals a “perceptual memory”.

We presented prime and probe patterns in succession, sometimes with an intervening blank period, to establish time constants for the rise (increase with prime duration) and fall (decrease with pause duration) of positive and negative priming effects in the perception of ambiguous patterns. Kinetic-depth-effect was used as stimulus. Nine observers participated, with mean dominance time [[lt]]T_dom[[gt]] ranging from 1.0 s to 15 s across observers. All time constants are given as multiples of the [[lt]]T_dom[[gt]] for each observer.

Negative priming rises and falls rapidly (observer average t_rise⁻ = 0.3, t_fall⁻ = 0.52). Across observers, neither time-constant correlates significantly with [[lt]]T_dom[[gt]] (r=−0.3, p=0.42; r=0.04, p=0.92, respectively). Positive priming rises more slowly and decays extraordinarily slowly (observer average t_rise⁺ = 0.53, t_fall⁺ = 25). Across observers, both time-constants correlate significantly with [[lt]]T_dom[[gt]] (r=0.42, p=0.02; r=0.84, p=0.02, respectively).

Of the two known priming effects in the perception of ambiguous patterns, only positive priming correlates with the time course of rivalry. We conclude that, contrary to current models, negative priming (habituation) may not provide the elusive cause of perceptual rivalry.

1. J.M. Wolfe. (1984). Reversing ocular dominance and suppression in a single flash. Vision Res. 24(5), 471-8.

2. D. A. Leopold, M. Wilke, etal. (2002). Stable perception of visually ambiguous patterns. Nat Neurosci., 5(6), 605-609.