The conscious experience of color constancy and neural responses to subliminal deviations – A behavioral and EEG/ERP oddball study

IntroductionColor constancy, a property of conscious color experience, maintains object color appearance across illuminant changes. We investigated the neural correlates of subliminal vs. conscious stimulus deviations of color constancy manipulations.MethodsBehavioral and Oddball EEG/ERP experiments were conducted (n = 20). Psychophysical illuminant variation discrimination thresholds were first estimated, to establish individual perceptual awareness ranges, allowing for simulation of natural daylight spectral and spatial variations on colored surfaces, at different ambiguity levels.ResultsBehavioral results validated illuminant choice. ERPs showed a significant modulation of posterior P1 component specifically for the subliminal global uniform deviation condition, respecting color constancy. Neural correlates of conscious percepts were identified at posterior N2-P3 latencies, parietal (P3b) and frontal regions.ConclusionsWe identified an early subliminal correlate of low-level illuminant change, which reflects automatic unconscious detection of global color constancy deviations. Its suppression under conscious perception is probably due to top-down suppression according to prediction error models.     

Creating coherence in real‐life decision processes: Reasons,differentiation and consolidation

Svenson, O. & Jakobsson, M. (2009). Creating coherence in real‐life decision processes: Reasons, differentiation and consolidation. Scandinavian Journal of Psychology, 51, 93–102. Differentiation and Consolidation Theory describes human decision making as a process in which attractiveness values are restructured in order to reach a decision and support the decision made. Here, the theory was developed to include reasons pro and con alternatives and tested on students making decisions between two university psychotherapy training programs (cognitive‐behavioral and psychodynamic therapy). Before and also after the decision, the attractiveness of the chosen alternative was upgraded and the non‐chosen alternative downgraded. Different measures of evaluations of an alternative, such as “best” or “worse” converged over time until shortly after the decision. The number of reasons pro and con alternatives give a more complete picture than attractiveness and increased from the first to the last session. The reasons supporting the chosen alternative increased in strength, but reasons against the non‐chosen alternative decreased. In informal comments participants reported that the study also served as a decision aid.