Numerous philosophers accept the differentiation condition, according to which one does not see an object unless one visually differentiates it from its immediate surroundings. This paper, however, sounds a sceptical note. Based on suggestions by Dretske (2007) and Gibson (2002 [1972]), I articulate two ‘principles of occlusion’ and argue that each principle admits of a reading on which it is both plausible and incompatible with the differentiation condition. To resolve the inconsistency, I suggest we abandon the differentiation condition.

Previous work suggests that threat-related stimuli are stored to a greater degree in working memory compared to neutral stimuli. However, most of this research has focused on stimuli with physically salient threat attributes, failing to account for how a “neutral” stimulus that has acquired threat-related associations through differential aversive conditioning influences working memory. The current study examined how differentially conditioned safe and threat stimuli are stored in working memory relative to a novel, non-associated stimuli. Participants completed a (...) class='Hi'>differential fear conditioning task followed by a change detection task consisting of three conditions across two loads. Results revealed individuals successfully learned to distinguishing CS+ from CS– conditions during the differential aversive conditioning task. Our working memory outcomes indicated successful load manipulation effects, but no statistically significant differences in accuracy, response time, or Pashler’s K measures of working memory capacity between CS+, CS–, or N conditions. However, we observed significantly reduced RT difference scores for the CS+ compared to CS– condition, indicating greater RT differences between the CS+ and N condition vs. the CS– and N condition. These findings suggest that differentially conditioned stimuli have little impact on behavioral outcomes of working memory compared to novel stimuli that had not been associated with previous safe of aversive outcomes, at least in healthy populations. (shrink)