Attention & Cognition Lab

Object-based Attention: Prioritization Revealed by the Temporal Order Judgment Method (Donovan)

Recent studies suggest that object-based attentional guidance is a result of attentional prioritization. It is proposed that in the absence of an alternative strategy, items appearing on the same object are prioritized over items appearing on a different object (Shomstein & Yantis, 2002; Drummond & Shomstein, 2010). It should be noted, however, that studies providing evidence for attentional prioritization have relied, with some exceptions, on spatial cuing paradigms. As such it is not clear whether attentional prioritization emerges from spatial orienting or is independent of it. Here, we use a novel method – the
temporal order judgment (TOJ) – to examine whether attentional prioritization emerges in the absence of spatial cuing. (Click on title to view latest presentation, Vision Sciences Society 2011)

Preferred Retinal Locus of Individuals with Macular Degeneration Measured Using the Temporal Order Judgment Method (Donovan)

Individuals with macular degeneration (MD) no longer receive bottom-up visual information from the fovea. To cope with this deficit, MD patients use a particular area in their peripheral visual field at which they prefer to focus. This 'Preferred Retinal Locus' (PRL) has been studied recently in order to elucidate how its use effects perception and what benefits it provides for those with MD. However, there remains no reliable behavioral measure for the role of PRL. We are testing controls and MD patients using the Temporal Order Judgment Method (TOJ) in order to assess to what extent items that appear in the PRL are perceived as appearing before those in other retinal loci. If this is the case, our paradigm would represent an intuitive and reliable method for measuring the consequences of consistent, long-term use of a non-fovea PRL.

Object-based Attention: Cross-Modal Attentional Orienting (Bilger)

Most of what we know about object-based attention has been derived from various paradigms focused entirely within the visual modality. This line of research aims to examine the extent to which object-based attentional selection is an exclusive property of the visual system, or whether this type of selection reflects a general multi-modal attentional selection mechanism. Using a variant of the standard object-based attention paradigm (Egly, Driver, & Rafal, 1994), we attempt to elicit object-based attentional guidance using cues in one modality and targets in a different modality (visual to auditory, and vice versa). Thus far we have found object based attention with visual cues and auditory targets and with auditory cues and visual targets. These findings suggests that object-based attentional mechanism is useful not only for the visual system, but for the auditory system as well, reflecting a general property of attentional allocation. (Click on title to view latest presentation, Vision Sciences Society 2011)

Object-based Attention: Prioritization in Cases of Certainty (Weiss)

Previous research demonstrated that object-based attentional selection is driven by spatial uncertainty of target location (Shomstein & Yantis, 2002; Drummond & Shomstein, 2010). Recent studies, however, challenge this conclusion by suggesting that target-to-object relationship is the critical factor in producing object based effects (Chen & Cave, 2006; Richard, Lee & Vecera, 2008). In this project, we elucidate in fine-grained detail the contribution of spatial uncertainty and target-to-object relationship to object-based attentional guidance.

Attentional Capture & Aging: Increased Salience (Weiss)

Attentional orienting is the consequence of a finely tuned interplay between top-down (goal directed) and bottom-up (stimulus-driven) attentional allocation. While the contribution of each type of orienting is well understood in young adults, the degree to which this interplay is affected by aging remains poorly understood. The purpose of this project is to investigate how the interplay between goal-directed (top-down) vs. stimulus-driven (bottom-up) attentional allocation is affected by the aging process. Specifically, we are investigating the extent to which an aging population relies on bottom-up vs. top-down processes while engaged in an attentional capture task. (Click on title to view latest presentation, Vision Sciences Society 2011)

Matrix Mayhem: The Effect of Posterior Cortical Atrophy on Pre-Attentive Processes (Weiss)

Posterior Cortical Atrophy (PCA) is a type of Alzheimer's disease that causes atrophy of the posterior part of the cerebral cortex, resulting in visual processing deficits. It is still unclear as to whether or not the visual deficits induced by PCA are affecting earlier stages of visual processing, later stages of visual processing, or both. The purpose of this project is to present PCA patients with a pre-attentive perceptual grouping task adapted from Moore & Egeth (1997) in order to establish the extent of PCA's effect on early visual processes. If PCA affects higher order visual processes exclusively, then pre-attentive perceptual grouping should be unaffected. If PCA affects visual processing at all stages, then pre-attentive perceptual grouping will be affected.

Reward Bottom-up to Top-down Transfer (Lee)

The purpose of the study is to examine whether the reward manipulation can modulate bottom-up attention, and the reward modulation effect can be generalized from a feature search task to a conjunction search task. To investigate this, feature search tasks in which targets are defined by orientation are interleaved with conjunction search tasks in which targets are defined by orientation and color. In the feature task, a specific orientation is more rewarded than the other orientation. If reward manipulation can modulate bottom-up attention, the reaction time for the more rewarded orientation would be faster than that for the less rewarded orientation. Also, if this reward modulation effect is carried over to the conjunction search task, the search slope for the targets with previously less rewarded orientation would be steeper than that for the targets with previously more rewarded orientation. Results obtained up to date strongly support this hypothesis, demonstrating that reward-based attentional orienting is flexible and shows transfer from one more of attentional orienting to another. (Click on title to view latest presentation, Psychonomics 2011)

Reward and Orientation Tuning (Lee)

Recent studies suggest that reward modulates attentional guidance and alters neuronal tuning function (i.e., preference profile of individual neurons). It is unclear how reward alters neuronal tuning function and what determines the tuning characteristics. The purpose of this experiment is to investigate the effect of a target-distractor relationship on reward-based modulation of orientation tuning. Our hypothesis is that a target-distractor relationship would determine the shape of reward-based modulation of tuning function. When a target and distractors are dissimilar, the orientation tuning function would show sharpening for the highly-rewarded target feature. However, when a target and distractors are very similar, the orientation tuning function would show shifting in the direction of exaggeration for the highly-rewarded target feature.

Neglect, Reward (Drummond)

The purpose of this investigation is to examine whether visuo-spatial neglect – the attentional deficit to the left side of space acquired after a right parietal stroke – can be improved by the introduction of reward. Patients with neglect do not voluntarily attend to the left side of their environment, as demonstrated by large behavioral deficits: items on the left are often ignored completely or attended much later than items on the right. Previous research suggests that orienting to the neglected side can be improved by the use of goals, either with explicit instructions or by implicit cue-to-target contingencies in the display (Snow & Mattingley, 2006; Geng & Behrmann, 2002; Maunsell, 2004). Goals can bias attention towards stimuli or responses that result in better performance (e.g., faster reaction times or higher accuracy). What is not known currently is whether reward-based influences on attentional allocation can be employed in order to improve attentional orienting (bias) toward the neglected side. If reward proves to effectively modulate and improve attentional orienting in patients, it will have important implications for the rehabilitation of visual neglect and shed light and further constrain theories of attentional orienting. (Click on title to view latest presentation, Vision Sciences Society, 2011)