Volitional media multitasking: awareness of performance costs and modulation of media multitasking as a function of task demand.

In two experiments, we sought to determine whether (a) people are aware of the frequently observed performance costs associated with engaging in media multitasking (Experiment 1), and (b) if so, whether they modulate the extent to which they engage in multitasking as a function of task demand (Experiment 2). In Experiment 1, participants completed a high-demand task (2-back) both independently and while a video was simultaneously presented. To determine whether people were sensitive to the impact that the concurrent video had on primary-task performance, subjective estimates of performance were collected following both trial types (No-Video vs. Video trials), as were explicit beliefs about the influence of the video on performance. In Experiment 2, we modified our paradigm by allowing participants to turn the video on and off at their discretion, and had them complete either a high-demand task (2-back) or a low-demand task (0-back). Findings from Experiment 1 indicated that people are sensitive to the magnitude of the decrement that media multitasking has on primary-task performance. In addition, findings from Experiment 2 indicated that people modulate the extent to which they engage in media multitasking in accordance with the demands of their primary task. In particular, participants completing the high-demand task were more likely to turn off the optional video stream compared to those completing the low-demand task. The results suggest that people media multitask in a strategic manner by balancing considerations of task performance with other potential concerns.

Sensory processing patterns predict the integration of information held in visual working memory.

Given the limited resources of visual working memory, multiple items may be remembered as an averaged group or ensemble. As a result, local information may be ill-defined, but these ensemble representations provide accurate diagnostics of the natural world by combining gist information with item-level information held in visual working memory. Some neurodevelopmental disorders are characterized by sensory processing profiles that predispose individuals to avoid or seek-out sensory stimulation, fundamentally altering their perceptual experience. Here, we report such processing styles will affect the computation of ensemble statistics in the general population. We identified stable adult sensory processing patterns to demonstrate that individuals with low sensory thresholds who show a greater proclivity to engage in active response strategies to prevent sensory overstimulation are less likely to integrate mean size information across a set of similar items and are therefore more likely to be biased away from the mean size representation of an ensemble display. We therefore propose the study of ensemble processing should extend beyond the statistics of the display, and should also consider the statistics of the observer. (PsycINFO Database Record

The scope of no return: Openness predicts the spatial distribution of Inhibition of Return.

How and what we attend to is foundational in determining the content of our experience, thus differences in attention contribute significantly to how we perceive the world, learn, and develop. Personality also plays a role in constraining how we learn to perceive the world and it is conceivable that some facets of personality interact with visual attention; however, the relationship between these two constitutional aspects of psychology remains unclear. To address this interplay between cognition and personality, we looked at how the Big Five personality traits relate to the spatial scope of attention, as indexed by the spatial distribution of Inhibition of Return (IOR). IOR is marked by a decrement in reaction time when a target appears at a cued location, more than 200 ms after that cue. As the cue/target distance increases there is a release from inhibition, providing a measure of the spatial distribution of IOR and reflecting the spatial scope of attention. The results presented here show personality does predict the distribution of IOR. Specifically, higher trait Openness is associated with a broader distribution of IOR and attention. This finding suggests there is an intimate connection between personality, particularly Openness, and the spatial allocation of attention.

The spatially asymmetric cost of memory load on visual perception: transient stimulus-centered neglect.

Recent evidence suggests that visual working memory (VWM) load reduces performance accuracy on a concurrent visual recognition task, particularly for objects presented in the left hemifield. It has also been shown that high VWM load causes suppression of activity in the right temporoparietal junction (TPJ). Given the resemblance of VWM load effects to symptoms of unilateral neglect (i.e., impaired perception on the left side and lesion to the right TPJ), we investigated whether VWM load effects are restricted to the left side of space or extend to object-centered reference frames. In other words, akin to object-centered neglect, can high VWM load cause a perceptual cost in attending to the left side of the stimulus? We addressed this question using an object recognition task (Experiment 1) and a visual search task (Experiment 2) showing that this transient left-neglect can indeed be modulated by an object-centered frame of reference. These findings suggest that load-induced impairments of visual attention are spatially asymmetric and can emerge within multiple spatial reference frames. Therefore, the attentional consequences of high VWM load on conscious perception may serve as a useful model of unilateral perceptual neglect.

To bind or not to bind: addressing the question of object representation in visual short-term memory.

Visual short-term memory (VSTM) is a capacity limited resource, which is consistently estimated to hold about four visual items at a time. There is, however, debate in the literature about what constitutes an "item" and how resources are allocated within VSTM. Some research suggests information is stored in VSTM as discrete objects; however, there is also evidence suggesting that within-object features alter VSTM performance. The present study addresses the question of whether VSTM load effects reflect the number of discrete objects and/or the number of within-object features. An electrophysiological correlate of VSTM--the contralateral delay activity (CDA)--was measured while participants performed a lateralized change-detection task, in which to-be-remembered items varied in the number of features and locations. Each trial contained either a solitary simple feature (shape, color, or orientation) or one of two multifeature arrays: three features presented at three separate locations or three features bound at one location. While presenting multiple features--regardless of whether they are at discrete locations or bound within a single object--resulted in greater CDA amplitude relative to a solitary feature, there was a dissociation in the distribution of activity between the two multifeature conditions, such that the CDA at site P1/P2 was sensitive to the number of discrete objects, while activity at P7/P8 was most enhanced when multiple features were bound in one object. The findings demonstrate the inhomogeneity of the CDA and suggest this electrophysiological marker may reflect both discrete object individuation/separation and flexible feature-feature binding in VSTM.

In and out of consciousness: sustained electrophysiological activity reflects individual differences in perceptual awareness.

Although significant advances in our understanding of the cognitive and neural processes involved in conscious awareness have occurred in recent years, the precise mechanisms that support consciousness remain elusive. Examining the neural correlates associated with the moment a stimulus enters or exits conscious awareness is one way to potentially identify the neural mechanisms that give rise to consciousness. In the present study, we recorded neural activity using electroencephalography (EEG) while participants observed a bilateral shape-from-motion (SFM) display. While the display is in motion, the observer perceives an object that is immediately segregated from a noisy background. After the motion stops, the observer's experience of the object remains momentarily in awareness, before it eventually fades out of consciousness back into the noisy background. Consistent with subjective reports of perceptual experience, we observed a prominent sustained posterior contralateral negativity known as the contralateral delay activity (CDA). This activity was sustained only in conditions associated with sustained awareness. Interestingly, the amplitude of the CDA was correlated with individual differences in visual awareness, suggesting that this activity plays a significant role in the maintenance of objects in consciousness. The CDA is typically associated with visual short-term memory (VSTM), suggesting that conscious visual awareness may be mediated by the same neural and cognitive mechanisms that support VSTM. Our results demonstrate that the CDA may reflect the contents of conscious awareness, and therefore can provide a measure to track when information moves in and out of consciousness.