Rebecca R. Goldstein

Disrupting perceptual grouping of face parts impairs holistic face processing

Face perception is widely believed to involve integration of facial features into a holistic perceptual unit, but the mechanisms underlying this integration are relatively unknown. We examined whether perceptual grouping cues influence a classic marker of holistic face perception, the “composite-face effect.” Participants made same–different judgments about a cued part of sequentially presented chimeric faces, and holistic processing was indexed as the degree to which the task-irrelevant face halves impacted performance. Grouping was encouraged or discouraged by adjusting the backgrounds behind the face halves: Although the face halves were always aligned, their respective backgrounds could be misaligned and of different colors. Holistic processing of face, but not of nonface, stimuli was significantly reduced when the backgrounds were misaligned and of different colors, cues that discouraged grouping of the face halves into a cohesive unit (Exp. 1). This effect was sensitive to stimulus orientation at short (200 ms) but not at long (2,500 ms) encoding durations, consistent with the previously documented temporal properties of the holistic processing of upright and inverted faces (Exps. 2 and 3). These results suggest that grouping mechanisms, typically involved in the perception of objecthood more generally, might contribute in important ways to the holistic perception of faces.

Searching in clutter: Visual attention strategies of expert pilots

Clutter can slow visual search. However, experts may develop attention strategies that alleviate the effects of clutter on search performance. In the current study we examined the effects of global and local clutter on visual search performance and attention strategies. Pilots and undergraduates searched for an elevation marker in charts of high, medium, and low global clutter. The target was in a low or high local clutter region of the chart or it was absent. High global and local clutter slowed search performance for both pilots and undergraduates. Pilots were more accurate but slower. Pilots’ search strategies differed from undergraduates in the following ways: they had more conservative criteria for responding target absent and spent more time processing the information within each fixation. Pilots and undergraduates used a coarse-to-fine search strategy in which, as the trial progressed, fixation durations increased and saccade distance decreased.

Inattentional blindness: A combination of a relational set and a feature inhibition set?

Two experiments were conducted to directly test the feature set hypothesis and the relational set hypothesis in an inattentional blindness task. The feature set hypothesis predicts that unexpected objects that match the to-be-attended stimuli will be reported most. The relational set hypothesis predicts that unexpected objects that match the relationship between the to-be-attended and the to-be-ignored stimuli will be reported the most. Experiment 1 manipulated the luminance of the stimuli. Participants were instructed to monitor the gray letter shapes and to ignore either black or white letter shapes. The unexpected objects that exhibited the luminance relation of the to-be-attended to the to-be-ignored stimuli were reported by participants the most. Experiment 2 manipulated the color of the stimuli. Participants were instructed to monitor the yellower orange or the redder orange letter shapes and to ignore the redder orange or yellower letter shapes. The unexpected objects that exhibited the color relation of the to-be-attended to the to-be-ignored stimuli were reported the most. The results do not support the use of a feature set to accomplish the task and instead support the use of a relational set. In addition, the results point to the concurrent use of multiple attentional sets that are both excitatory and inhibitory.

The Effect of Distractor Presentation Frequency on Saccade Reaction Times and Curvature

Saccade Reaction Times • The appearance of an irrelevant stimulus 160 ms or more before the onset of a target has been shown to produce a decrease in saccade reaction times (Walker, Kentridge, & Findlay, 1995). • Hermens & Walker (2010) found presenting a peripheral distractor 300 ms prior to the target on 75% of the trials produced faster saccade reaction times compared to no distractor trials. • Irrelevant distractors may act as a temporal warning cue as a result of sufficient processing time (Hermens & Walker, 2010; Walker, et al., 1995), but frequency might also be a factor.

Visual search with varying versus consistent attentional templates: Effects on target template establishment, comparison, and guidance.

Attentional templates can be represented in visual working memory (VWM) when the target varies from trial-to-trial and can be represented in long-term memory (LTM) when the target is consistent during trial runs. Given that attentional templates can be represented in either VWM or LTM, are there any differences in how these representations impact visual search when targets are consistent compared with varying? The current study tested the consistent template hypothesis, which predicts faster performance with a consistent target compared with a varying target. Experiment 1 examined whether consistent targets could lead to consistent templates that would improve template establishment, guidance, and/or comparison of the template to search items. Search response time was faster for consistent targets, and consistent targets produced faster comparison processes, but not more efficient guidance. Experiment 2 examined the consistent template restoration hypothesis, which predicts faster template establishment and comparison processes for a previously encountered consistent target. Experiment 2 replicated the consistent template hypothesis and supported the consistent template restoration hypothesis. These studies demonstrate that although attentional guidance is similar with varying and consistent attentional templates, consistent templates improve search performance by speeding template establishment and comparison processes.

Attending Globally or Locally: Incidental Learning of Optimal Visual Attention Allocation.

Attention allocation determines the information that is encoded into memory. Can participants learn to optimally allocate attention based on what types of information are most likely to change? The current study examined whether participants could incidentally learn that changes to either high spatial frequency (HSF) or low spatial frequency (LSF) Gabor patches were more probable and to use this incidentally learned probability information to bias attention during encoding. Participants detected changes in orientation in arrays of 6 Gabor patches: 3 HSF and 3 LSF. For half of the participants, an HSF patch changed orientation on 75% of the trials, and for the other half, an LSF patch changed orientation on 75% of the trials. Experiment 1 demonstrated a change probability effect and an attention allocation effect. Specifically, change detection performance was highest for the probable-change type, and participants learned to use a global spread of attention (fixating between Gabor patches) when LSF patches were most likely to change and to use a local allocation of attention (fixating directly on Gabor patches) when HSF patches were most likely to change. Experiments 2 and 3 replicated these effects and demonstrated that an internal monitoring system is sufficient for these effects. That is, the effects do not require explicit feedback or point rewards. This study demonstrates that incidental learning of probability information can affect the allocation of attention during encoding and can therefore affect what information is stored in visual working memory.

Evidence for Bound Scene Gist Representations: Statistical Summary Representations across Multiple Dimensions.

Are statistical summary representations (SSRs) for multiple dimensions processed independently or are they part of a bound scene gist representation? Previous research suggests that multiple SSRs, the means for two sets of circles, can be computed with no cost (Chong & Treisman, 2005). However, there appears to be a cost for encoding averages from multiple dimensions. Emmanouil and Treisman (2008) presented participants with arrays of objects that varied on two dimensions and then either pre-cued or post-cued which average should be reported. Post-cue performance was lower than pre-cue performance, however the cost may have occurred during reporting rather than encoding. If a bound scene gist representation is stored, performance may be impaired when only one dimension is reported. In the current study, participants viewed arrays of 16 lines that varied in length, orientation, or both. Across four blocks of trials, participants were asked to adjust a test line to the (1) average orientation of a group of lines that varied only in orientation, (2) the average length of a group of lines that varied in only length, (3) the average length and orientation of a group of lines that varied in both, or (4) the average length or orientation (determined via a post cue) for a group of lines that varied in both dimensions. Orientation performance supported the bound gist representation hypothesis: Although there was a cost for reporting only orientation when both orientation and location were encoded (post-cue condition), encoding and reporting both was just as accurate as encoding and reporting only orientation. However, for length performance, encoding and reporting both resulted in greater errors than encoding and reporting length alone. These results suggest that all dimensions are not encoded equally; orientation and length may be encoded as a bound unit, while length may also be encoded independently. Meeting abstract presented at VSS 2015.

Capture and tracking: Where does attention go?

Expected Findings • More changes in trajectory will lead to lower tracking accuracy. • If changes in trajectory capture attention. o Probe detection will be better for probes on items that have just changed trajectory. § Indicating attentional attraction/capture. o Probe detection will be better when more changes in trajectory occur. § Suggesting frequent reallocations of attention. o Reaction times will be faster to probes on items that have recently changed trajectory. § Suggesting frequent reallocations of attention. 3.