Negative hysteresis occurs in simple color matching but such serial dependence effects are abolished by perceptual...

Color perception entails multiple processing levels. Perceptual dynamics in color vision and the role of stimulus history can be studied using the phenomenon of hysteresis, well-known in the framework of physical dynamical systems. In perceptual hysteresis paradigms, stimuli change gradually, leading to competition between perceptual stabilization (positive hysteresis) or early change to an alternative percept (negative hysteresis). The former dominates in most perceptual domains, such as motion, letter or emotion recognition. The question remains whether positive hysteresis dominates in color perception like in most other perceptual domains where positive lags dominate. If instead negative hysteresis occurs, color perception changes should occur earlier than expected and be manifested as a negative lag. Adaptation is a possible mechanism underlying negative hysteresis, because it favors earlier perceptual switches. In our study investigating the role of stimulus history, we studied hysteresis in color perception under different conditions using a dynamic color-matching task within Derrington-Krauskopf-Lennie (DKL) color space. Color matching experiments under hysteresis conditions can be used to determine hysteresis lags (negative color matching lag to a reference stimulus implying negative hysteresis). Our color-matching tasks, under manipulation of temporal context, using classical experimental hysteresis approaches, required either comparison of single-color shapes or complex multi-part objects (one serving as the reference and the other as the time varying target) composed by multiple elements and requiring holistic perceptual binding. These color matching tasks were undertaken under conditions of direct visual stimulus presentation or under visual memory guidance (reference only present in short term memory) (N = 20, healthy participants). We specifically examined these processes along two axes: the S-(L + M) and L-M axes in DKL color space. We found that negative hysteresis dominates in color processing . We found that negative hysteresis predominates in simple color-matching tasks (t = -5,81, df 19, p < 0.001, Cohen's d = 2,8), even in the physical absence of the reference, when visual memory is required in contrast with tasks requiring binding (F = 28.1, df = 3, p < 0.001, eta-square = 0.596). This suggests that adaptation, indexed by negative hysteresis, prevails over visual persistence, indexed by positive hysteresis, in color-matching of simple objects. By using more complex holistic color-matching we further asked if perceptual binding is affected by hysteresis. However, negative hysteresis is absent when holistic perceptual binding is necessary, indicating that these processes occur at distinct hierarchical stages of visual processing. This study marks the first exploration of hysteresis in color perception. In sum, negative hysteresis dominates in early color processing (likely at V1 and V2 levels), while holistic perceptual binding and matching of multiple color elements occurs independently of hysteresis, at a subsequent attentive processing stage.