How do expectations influence transitions between unconscious and conscious perceptual processing? According to the influential predictive processing framework, perceptual content is determined by predictive models of the causes of sensory signals. On one interpretation, conscious contents arise when predictive models are verified by matching sensory input (minimizing prediction error). On another, conscious contents arise when surprising events falsify current perceptual predictions. Finally, the cognitive impenetrability account posits that conscious perception is not affected by such higher level factors. To discriminate these positions, we combined predictive cueing with continuous flash suppression (CFS) in which the relative contrast of a target image gradually increases over time. In four experiments we established that expected stimuli enter consciousness faster than neutral or unexpected stimuli. These effects are difficult to account for in terms of response priming, pre-existing stimulus associations, or the attentional mechanisms that cause asynchronous temporal order judgments (of simultaneously presented stimuli). Our results further suggest that top-down expectations play a larger role when bottom-up input is ambiguous, in line with predictive processing accounts of perception. Taken together, our findings support the hypothesis that conscious access depends on verification of perceptual predictions.

What is the relationship between top-down and bottom-up attention? Are both types of attention tightly interconnected, or are they independent? We investigated this by testing a large representative sample of the Dutch population on two attentional tasks: a visual search task gauging the efficiency of top-down attention and a singleton capture task gauging bottom-up attention. On both tasks we found typical performance--i.e., participants displayed a significant search slope on the search task and significant slowing caused by the unique, but irrelevant, object on the capture task. Moreover, the high levels of significance we observed indicate that the current set-up provided very high signal to noise ratios, and thus enough power to accurately unveil existing effects. Importantly, in this robust investigation we did not observe any correlation in performance between tasks. The use of Bayesian statistics strongly confirmed that performance on both tasks was uncorrelated. We argue that the current results suggest that there are two attentional systems that operate independently. We hypothesize that this may have implications beyond our understanding of attention. For instance, it may be that attention and consciousness are intertwined differently for top-down attention than for bottom-up attention.

Fragile visual short-term memory (FM) is a recently discovered form of visual short-term memory. Evidence suggests that it provides rich and high-capacity storage, like iconic memory, yet it exists, without interference, almost as long as visual working memory. In the present study, we sought to unveil the functional underpinnings of this memory storage. We found that FM is only completely erased when the new visual scene appears at the same location and consists of the same objects as the to-be-recalled information. This result has two important implications: First, it shows that FM is an object- and location-specific store, and second, it suggests that FM might be used in everyday life when the presentation of visual information is appropriately designed.

In our everyday lives, we are presented with a wide variety of visual stimuli. For adaptive behavior, it is important to select both objects relevant to our goals and objects that might not be directly relevant but have an intrinsic importance. A key discussion in attention research is the interaction between these goals and the intrinsic qualities of objects in the visual field. The discussion revolves around the concept of attentional capture, defined as the involuntarily drawing of attention.According to the bottom-up view, objects carrying a unique feature may automatically capture attention as a result of their relative salience (Theeuwes, 1991). These objects are often referred to as singletons, since they are unique on a certain dimension (Pashler, 1988). For instance, in Theeuwes's (1991) task, people searched for either a diamond among circles or a circle among diamonds. These display types were randomly mixed so that the participants would not know beforehand which shape to look for. Although the task was to look for the odd shape, reaction times (RTs) were about 150 msec longer when a differently colored singleton distractor was also present. Since the singleton was completely irrelevant to the task, Theeuwes (1991) concluded that it captured attention automatically.In a subsequent series of experiments, Theeuwes (1992) replicated his earlier findings, except that now, throughout a block, the target remained the same-that is, within one block, the target was always a diamond among circles, and within another block, it was always a circle among diamonds-while a singleton distractor could be present. The participants were still distracted by the singleton distractor, but now it had a slowing effect of only about 20 msec (as compared with the 150 msec found by Theeuwes, 1991).These findings appear to be difficult to explain from a pure bottom-up view. Note that the stimuli were exactly the same in both studies, the only difference being that, in Theeuwes (1991), target types were mixed and, thus, the participants did not know beforehand what the target would be. Instead, Theeuwes's (1991Theeuwes's ( , 1992 findings suggest that attentional capture by the singleton is task dependent, since target preknowledge influences the distracting effect of the singleton. This seems more in accordance with a top-down view of attentional capture (see also Folk, Remington, & Johnston, 1992;Yantis & Egeth, 1999). Presumably, when the target is uncertain, participants adopt a less restrictive attentional set, to accommodate the differences in target appearance. This less restrictive attentional set then makes the participants more susceptible to singleton distractors. This notion of a more or less restrictive attentional set is in accordance with what Bacon and Egeth (1994) referred to as the difference between the feature search mode and the singleton detection mode of attention. Bacon and Egeth also found that an irrelevant singleton distractor interfered with search, but only if the target itself was also a singleton-...