Spatial Organization in Self-Initiated Visual Working Memory.

Ample research in visual working memory (VWM) has demonstrated that the memorized items are maintained in integrated spatial configurations, even when the spatial context is task irrelevant. These insights were obtained in studies in which participants were provided with the information they memorized. However, the encoding of provided information is only one aspect of memory.

Working memory for self-initiated and provided spatial configurations.

During a typical day, people temporarily memorise information provided to them. However, they memorise as often information they actively choose themselves. Although prevalent in everyday behaviour, this aspect of working memory (WM), we term self-initiated WM, has been largely unexplored.

Estimation in self-initiated working memory for spatial locations.

The short-term maintenance of precise location information is fundamental in many daily activities. Often, individuals memorize spatial information provided to them, but in many other occasions memory is self-initiated, meaning that individuals memorize locations they selected themselves. While prevalent in everyday behavior, research on self-initiated working memory (WM) is scarce.

Perceptual overloading reveals illusory contour perception without awareness of the inducers.

Unconscious perception is frequently examined by restricting visual input (e.g., using short stimulus durations followed by masking) to prevent that information from entering visual awareness.

Neural evidence for sequential selection of object features.

Behavioral and neural evidence suggests that attention selects entire objects, amplifying all of their features regardless of task relevance. A new magnetoencephalography (MEG) study by Schoenfeld et al. elucidates the time course of this selection, showing that object features are activated sequentially, with attention spreading from task-relevant to task-irrelevant modules.

Amodal completion of unconsciously presented objects.

In the visual environment, objects often appear behind occluding surfaces, yet they are automatically and effortlessly perceived as complete. Here, we examined whether visually occluded objects that are presented below the threshold of awareness are amodally completed. We used a priming paradigm in which participants responded to consciously perceived targets that were preceded by unconsciously presented primes.

Saliency affects feedforward more than feedback processing in early visual cortex.

Early visual cortex activity is influenced by both bottom-up and top-down factors. To investigate the influences of bottom-up (saliency) and top-down (task) factors on different stages of visual processing, we used transcranial magnetic stimulation (TMS) of areas V1/V2 to induce visual suppression at varying temporal intervals. Subjects were asked to detect and discriminate the color or the orientation of briefly-presented small lines that varied on color saliency based on color contrast with the surround.

Unconscious processing of unattended features in human visual cortex.

Unconscious processing has been convincingly demonstrated for task-relevant feature dimensions. However, it is possible that the visual system is capable of more complex unconscious operations, extracting visual features even when they are unattended and task irrelevant. In the current study, we addressed this question by measuring unconscious priming using a task in which human participants attended to a target object's shape while ignoring its color.

Statistical processing: not so implausible after all.

Myczek and Simons (2008) have shown that findings attributed to a statistical mode of perceptual processing can, instead, be explained by focused attention to samples of just a few items. Some new findings raise questions about this claim. (1) Participants, given conditions that would require different focused attention strategies, did no worse when the conditions were randomly mixed than when they were blocked.

Dividing attention across feature dimensions in statistical processing of perceptual groups.

Statistical processing has been shown in the perception of several visual dimensions, including size, speed, direction of motion, and orientation. Chong and Treisman (2005) found no decrement when people simultaneously averaged two sets on a single dimension, size. What happens when attention is divided between different dimensions? In two experiments, we investigated judgments of mean size and speed, either within the same objects or in two separate sets.

Mechanisms of feature- and space-based attention: response modulation and baseline increases.

Selective attention modulates neural activity in the visual system both in the presence and in the absence of visual stimuli. When subjects direct attention to a particular location in a visual scene in anticipation of the stimulus onset, there is an increase in baseline activity. How do such baseline increases relate to the attentional modulation of stimulus-driven activity? Using functional magnetic resonance imaging, we demonstrate that baseline increases related to the expectation of motion or color stimuli at a peripheral target location do not predict the modulation of neural responses evoked by these stimuli when attended.