Lauren N. Hecht, PhD

 
 

Research

Below is a description of the projects I have completed, am currently working on, or hope to begin soon. Please contact me if you are interested in these or any related projects.

A Note to Students Interested in Working With Me:
If you conduct any research (e.g., as part of a research apprenticeship), you will gain exposure to experimental procedures, data collection, data analysis and interpretation of results. You are not required to have an ultimate interest in my specific research program to help in the lab, and at any point, you are invited to discuss the possibility of completing an independent or honors project.  Ideally, all of these projects will result in work that is suitable for publication.

When necessary or upon request, I will teach you programming and computer skills, such as how to use experiment software programs (e.g., MATLAB, E-Prime), imaging software programs (e.g., Photoshop), or sophisticated lab equipment (e.g., eye-tracker), within the context of the project you are currently undertaking.  Initial project meetings focus on developing research skills, but they progressively shift to theoretical discussions of the research. Moreover, you are encouraged to engage in these discussions outside of the laboratory, by presenting research at conferences (e.g., Vision Sciences Society (VSS) conference, Minnesota Undergraduate Psychology Conference (MUPC), Association for Psychological Science (APS) convention).

General Description of Current Research Interests
My research focuses broadly on perception and attention. Specifically, my interests lie in perceptual organization, which is a process that establishes early object representations by grouping visual features together and distinguishing between objects by segregating visual features. In one line of research, I am examining how one organizational process, figure-ground assignment, affects other cognitive processes like temporal processing. Another line of research examines the attentional selection of perceptual groups (i.e., object-based attentional selection).  A selection of studies within each of these lines of research are discussed below.

Figure-ground Assignment

Figure-ground assignment distinguishes a visual region that falls into the foreground (i.e., figures), from regions falling into the background (i.e., grounds). One line of research examines how completion of figure-ground assignment interacts with other perceptual and attention processes. Specific projects include:

Perceptual Processing on Figures: Early and Extended
Figures are often reported as being more salient than background regions. One potential explanation for this phenomenological occurrence is that initiation and duration of perceptual processing may differ between regions given figural status and ground status. To test these ideas, participants completed temporal order judgments, reporting the identity of a target item that on-/offset first (or second). Findings indicate that processing begins earlier and is extended for figures. The extension of processing also predicts that temporal resolution would be less precise as grounds. These ideas are being tested using flicker-fusion and attentional blink paradigms.

Additionally, a model has been proposed using a neutrally plausible model (i.e., dynamic field theory: DFT), which posits that neural populations processing the figure are more active, resulting in activation peaks that build toward and pierce a response threshold earlier than grounds resulting in facilitated onset detection. However, this same enhanced activation for figures is sustained when a target is present, creating difficulties in the perception of the target’s offset. The ground’s peak of activation destabilizes and activation quickly falls below threshold. Consequently, when information is removed from the visual scene (i.e., offsets), the system is able to generate a neural response to the disappearance of the target.

--Lester, Hecht, & Vecera (2009)
--Hecht & Vecera (2011)
--Hecht & Vecera (in review)
--Hecht, Spencer, & Vecera, in preparation

Perceptual Enhancement of Figures
Figural salience may not only result from temporal processing differences between figures and ground; they may also occur from spatial resolution differences. To examine this, participants completed a series of demanding spatial resolution tasks. Following the predictions, targets appearing on figures were discriminated more accurately than those appearing on either ground regions or on neutral regions, suggesting that figures are perceptually enhanced compared to grounds.

-- Hecht, Cosman, & Vecera (in preparation)

Attention, Temporal Processing, and Memory
These experiments aim to examine the effect of attention on temporal processing under circumstances where attentional shifts are driven via memory, rather than visual cues that may prime processing at attended locations. Two types of memory are being targeted: visual short-term memory (VSTM) for objects, and spatial memory. These experiments will again utilize temporal order judgment tasks in which additional information – that may be task relevant – will be remembered during the trial. The prediction is that processing will begin earlier for the item relating to that stored in memory because attention will be captured to its location.

Scale of Attention and Figure-ground Assginment
Another series of experiments examines the influence of spatial attention settings on figure ground assignment. The spatial window of attention influences the interpretation of an entire visual scene (e.g., Navon, 1977; Pan & Eriksen, 1993), such as allowing one to focus on a global shape versus focusing on local elements of that global shape. Because cues giving rise to figural assignment vary along the shared contour, the window of spatial attention may also influence their use for figure-ground segmentation. For example, a figure with a contour shaped like the right side of a ‘B’ contains two convexities, but also contains a single concavity on the ground side (the point at which the loops of the B intersect). If attention is constricted around this single ground convexity, then this convexity cue may demand the opposite figural assignment from what is anticipated when considering the entire contour (i.e., the B shape as figure). When attention is set broadly, figural assignment accounts for the entire shared contour, but narrow attentional focus biased assignment toward the local convexity.

Object-based Attention

Attention can select information not only based on its location in space but also based on the perceptual groups (i.e., objects) present in the visual field (i.e., object-based attention). Many object-based attention studies have examined simple objects, such as a black rectangle. However, the objects in the world are more complex than this. This line of research investigates the impact of an object's structure or features on object-based attentional selection. Specific projects include:

The Role of Surfaces and Edges in Completing Occluded Objects
Grouping cues, such as color similarity, may influence the ability to complete an object. We examined the role of this surface feature on forming object representations under optimal and under degraded conditions. Using a modified object-based attention task (e.g., Egly et al., 1994; Vecera, 1994), observers demonstrated an object-based effect for unoccluded objects containing dissimilar surface information when continuous edge information was present. When part of these same objects was degraded by occlusion, however, the object-based effect was no longer present, suggesting that edge information alone is not sufficient to from the objects of attention when the object representations are degraded.

Selecting Multipart Objects: Is Uniformity Necessary?
Can attention can select non-uniform objects under appropriate circumstances? If so, then objects with regions that are dissimilar in color may be selected as easily as uniform objects when uniformity changes occur at the part-boundary. Using a modified object-based attention task (see Egly et al., 1994; Vecera, 1994), observers viewed two rectangle or hourglass stimuli, with their colors changing at meaningful (i.e., part boundary) or non-meaningful (i.e., midway through a part) locations. Object-based effects were only found when changes in color, for example, occurs at a plausible location, such as a part-boundary.

Object-based attention: Complex Objects
Several studies aim to explore object-based attention in relation to more complex objects. For example, many spatial cueing demonstrations examine attentional selection of single-part objects (i.e., rectanges), and many experiments primarily address visual object-based attention. Thus, several studies are examining object-based attentional selection of multipart and multisensory objects.

Student Projects in the Lab: Current to Previous

Perception and Portion Sizes
A Feeks ('13)
This research program is investigating and extending recent findings that color perception of table setting components (e.g., plates, tablecloths) biases administration of food portions, suggesting alteration of perceived portion sizes.

Distraction and Attentional Reorienting
N Doerrmann ('13)
This project will examine the ERP components associated with attentional distraction and reorientation. In particular, comparisons will be made between visual and auditory distraction.

Change Blindness
K Ofstad ('13), J Nowariak ('13), M Bartley ('12), S Xiong ('12)
Several projects within the lab have focused on change blindness. Most recently, Ofstad is examining the impact of subliminal priming and performance in a change blindness task. Previously, a group of students examined the relationship between prior experience and change blindness.

Meta-Awareness Selectivity Modulates Exocentric and Egocentric Spatial Judgments
JP Noel ('12), A Mefford ('12)
The dependence of higher-order cognitive processes on sensorial experience is well established. However, the rising demonstration of how different physical and metaphorical understandings of the concept of distance influence one another seems to imply that humans’ conceptual world could influence how the physical world is represented. In this study, meta-awareness was construed as a conceptual distance from oneself, and its effect on egocentric and exocentric distance estimates was examined. By means of the SART, Experiment 1 showed that participants under a mental state categorized as meta-aware, as opposed to not meta-aware, produced more accurate estimates of exocentric distance. Experiment 2, contrarily, revealed that this effect is not replicated for egocentric distances. The findings of the present study seem to imply a selective modulatory role of introspective awareness on distance estimates.