Allison B Sekuler

McMaster University, Hamilton, Ontario, Canada

Are you Allison B Sekuler?

Claim your profile

Publications (196)630.98 Total impact

  • Journal of Vision 08/2014; 14(10):130-130. DOI:10.1167/14.10.130 · 2.73 Impact Factor
  • Journal of Vision 08/2014; 14(10):573-573. DOI:10.1167/14.10.573 · 2.73 Impact Factor
  • Journal of Vision 08/2014; 14(10):1062-1062. DOI:10.1167/14.10.1062 · 2.73 Impact Factor
  • Journal of Vision 08/2014; 14(10):255-255. DOI:10.1167/14.10.255 · 2.73 Impact Factor
  • M. V. Pachai, A. B. Sekuler, P. J. Bennett
    Journal of Vision 08/2014; 14(10):557-557. DOI:10.1167/14.10.557 · 2.73 Impact Factor
  • A. M. Beers, A. B. Sekuler, P. J. Bennett
    Journal of Vision 08/2014; 14(10):1236-1236. DOI:10.1167/14.10.1236 · 2.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background / Purpose: In order to examine the processing underlying figure/ground perception, we examined neural signals associated with convexity context effects (Peterson and Salvagio, 2008). During a convexity task with 2- and 8-region black and white stimuli that involved indicating which central region was perceived as figure, we recorded electroencephalography of the posterior region of the cortex that was time-locked to stimulus onset. One sample of observers was used to characterize the evoked response potential (ERP) profile and determine spatiotemporal location(s) sensitive to how the stimulus was perceived and a second sample was used to directly test those findings in a replication. Main conclusion: We observed a robust effect on mean amplitude of the ERP that was sensitive to how the stimulus is perceived (convex vs. concave as figure interpretations) in the medial parietal/occipital cortex between 160-180ms post stimulus onset. In combination with the other findings presented, these results are consistent with the idea that the early visual system is sensitive to figure/ground perception and highlight the importance of perceived, 3-dimensionality in the processing underlying it.
    Vision Sciences Society Annual Meeting 2014; 06/2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The standard model of early vision claims that orientation and spatial frequency are encoded with multiple, quasi-independent channels that have fixed spatial frequency and orientation bandwidths. The standard model was developed using detection and discrimination data collected from experiments that used deterministic patterns such as Gabor patches and gratings used as stimuli. However, detection data from experiments using noise as a stimulus suggests that the visual system may use adjustable-bandwidth, rather than fixed-bandwidth, channels. In our previous work, we used classification images as a key piece of evidence against the hypothesis that pattern detection is based on the responses of channels with an adjustable spatial frequency bandwidth. Here we tested the hypothesis that channels with adjustable orientation bandwidths are used to detect two-dimensional, filtered noise targets that varied in orientation bandwidth and were presented in white noise. Consistent with our previous work that examined spatial frequency bandwidth, we found that detection thresholds were consistent with the hypothesis that observers sum information across a broad range of orientations nearly optimally: absolute efficiency for stimulus detection was 20-30% and approximately constant across a wide range of orientation bandwidths. Unlike what we found with spatial frequency bandwidth, the results of our classification image experiment were consistent with the hypothesis that the orientation bandwidth of internal filters were adjustable. Thus, for orientation summation, both detection thresholds and classification images support the adjustable channels hypothesis. Classification images also revealed hallmarks of inhibition or suppression from uninformative spatial frequencies and/or orientations. This work highlights the limitations of the standard model of summation for orientation. The standard model of orientation summation and tuning was chiefly developed with narrow-band stimuli that were not presented in noise, stimuli that are arguably less naturalistic than the variable bandwidth stimuli presented in noise used in our experiments. Finally, the disagreement between the results from our experiments on spatial frequency summation with the data presented in this paper suggests that orientation may be encoded more flexibly than spatial frequency channels.
    Frontiers in Psychology 06/2014; 5:578. DOI:10.3389/fpsyg.2014.00578 · 2.80 Impact Factor
  • Source
    Michael Slugocki, Allison Sekuler, Patrick Bennett
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine whether the global mechanism implicated in processing low RF contours is influenced by local perturbations in a compound lateral masker.
    VSS 2014, St. Pete Beach, Florida; 05/2014
  • Source
    Mark W Greenlee, Allison B Sekuler
    Frontiers in Psychology 05/2014; 5:348. DOI:10.3389/fpsyg.2014.00348 · 2.80 Impact Factor
  • Eugenie Roudaia, Allison B Sekuler, Patrick J Bennett
    [Show abstract] [Hide abstract]
    ABSTRACT: THE: CURRENT EXPERIMENTS EXAMINED THE EFFECT OF HEALTHY AGING ON THE INTEGRATION OF ORIENTATION AND POSITION INFORMATION IN SHAPE PERCEPTION: FOLLOWING DAY AND LOFFLER 2009, CONFLICTING CONTOURS WERE CREATED BY SAMPLING THE ORIENTATIONS OF ONE SHAPE EG, A ROUNDED PENTAGON WITH GABORS, AND POSITIONING THEM ON THE CIRCUMFERENCE OF A DIFFERENT SHAPE EG, A CIRCLE IN EXPERIMENT 1, SUBJECTS JUDGED WHETHER THE CONFLICTING CONTOUR LOOKED MORE CIRCULAR THAN A ROUNDED PENTAGON OF VARYING AMPLITUDE, WHICH ALLOWED US TO ESTIMATE THE PERCEIVED SHAPE OF THE CONFLICTING CONTOUR THE RELATIVE AMOUNT OF POSITION AND ORIENTATION INFORMATION WAS MANIPULATED BY VARYING THE NUMBER OF GABORS COMPRISING THE TARGET CONTOUR ORIENTATION INFORMATION DOMINATED THE PERCEPT FOR CONTOURS SAMPLED WITH 15-40 ELEMENTS, PRODUCING A STRONG SHAPE ILLUSION, BUT POSITION INFORMATION DETERMINED THE SHAPE WITH DENSER SAMPLING THE MAGNITUDE OF THIS ORIENTATION DOMINANCE EFFECT WAS EQUAL IN YOUNGER AND OLDER SUBJECTS ACROSS ALL SAMPLING LEVELS IN EXPERIMENT 2, SUBJECTS DISCRIMINATED FIVE CONTOURS THAT DIFFERED IN ORIENTATION AND/OR POSITION INFORMATION BOTH GROUPS SHOWED POOR DISCRIMINATION BETWEEN CONFLICTING CONTOURS AND THEIR PERCEPTUALLY EQUIVALENT RADIAL FREQUENCY PATTERNS, CONFIRMING THE MAIN FINDING OF EXPERIMENT 1 IN ADDITION, OLDER SUBJECTS SHOWED WORSE DISCRIMINATION BETWEEN TWO NONCIRCULAR RADIAL FREQUENCY PATTERNS THAN YOUNGER SUBJECTS IN SUM, INTEGRATION OF ORIENTATION AND POSITION INFORMATION IN SHAPE PERCEPTION IS PRESERVED WITH AGING; HOWEVER, OLDER ADULTS ARE LESS ABLE TO MAKE FINE SHAPE DISCRIMINATIONS BETWEEN NONCIRCULAR SAMPLED CONTOURS:
    Journal of Vision 05/2014; 14(5). DOI:10.1167/14.5.12 · 2.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Many sensory and cognitive changes accompany normal ageing, including changes to visual attention. Several studies have investigated age-related changes in the control of attention to specific locations (spatial orienting), but it is unknown whether control over the distribution or breadth of attention (spatial focus) also changes with age. In the present study, we employed a dual-stream attentional blink task and assessed changes to the spatial distribution of attention through the joint consequences of temporal lag and spatial separation on second-target accuracy. Experiment 1 compared the rate at which attention narrows in younger (mean age 22.6, SD 4.25) and older (mean age 66.8, SD 4.36) adults. The results showed that whereas young adults can narrow attention to one stream within 133 ms, older adults were unable to do the same within this time period. Experiment 2 showed that older adults can narrow their attention to one stream when given more time (266 ms). Experiment 3 confirmed that age-related changes in retinal illuminance did not account for delayed attentional narrowing in older adults. Considered together, these experiments demonstrate that older adults can narrow their attentional focus, but that they are delayed in initiating this process compared to younger adults. This finding adds to previously reported reductions in attentional dynamics, deficits in inhibitory processes, and reductions in posterior parietal cortex function that accompany normal ageing.
    Psychological Research 12/2013; 79(1). DOI:10.1007/s00426-013-0528-2 · 2.47 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background / Purpose: We aimed to discover when the human visual system detects faces. Main conclusion: The earliest ERP face sensitivity in a sample of 120 subjects (aged 18-81) was already visible at 87 ms [81, 94] post-stimulus.
    European Conference of Visual Perception 2013; 10/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: People with schizophrenia (SCZ) are impaired in several domains of visual processing, including the discrimination and detection of biological motion. However, the mechanisms underlying SCZ-related biological motion processing deficits are unknown. Moreover, whether these impairments are specific to biological motion or represent a more widespread visual motion processing deficit is unclear. In the current study, three experiments were conducted to investigate the contribution of global coherent motion processing to biological motion perception among patients with SCZ. In Experiments 1 and 2, participants with SCZ (n = 33) and healthy controls (n = 33) were asked to discriminate the direction of motion from upright and inverted point-light walkers in the presence and absence of a noise mask. Additionally, participants discriminated the direction of non-biological global coherent motion. In Experiment 3, participants discriminated the direction of motion from upright scrambled walkers (which contained only local motion information) and upright random position walkers (which contained only global form information). Consistent with previous research, results from Experiment 1 and 2 showed that people with SCZ exhibited deficits in the direction discrimination of point-light walkers; however, this impairment was accounted for by decreased performance in the coherent motion control task. Furthermore, results from Experiment 3 demonstrated similar performance in the discrimination of scrambled and random position point-light walkers.
    Frontiers in Psychology 08/2013; 4:507. DOI:10.3389/fpsyg.2013.00507 · 2.80 Impact Factor
  • M. V. Pachai, A. B. Sekuler, P. J. Bennett
    Journal of Vision 07/2013; 13(9):411-411. DOI:10.1167/13.9.411 · 2.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Practice in perceptual tasks over hundreds or thousands of trials often leads to long-lasting improvements in performance that generalize only partially to new stimuli. However, the time courses of the general and stimulus-specific aspects of learning are still debated. Some researchers argue that general aspects of the task are learned first in an initial rapid phase of learning and that stimulus-specificity emerges more slowly. In contrast, Hussain et al. (Front Psychol. 2012; 3:226) reported that 105 trials in a 10-AFC face identification task on Day 1 was sufficient to produce stimulus-specific learning in a test phase on Day 2, suggesting that stimulus-specific improvements can emerge rapidly. The current experiments extend these findings by examining 1) whether similar, rapid stimulus-specific learning occurs in a 10-AFC texture identification task; 2) if this rapid stimulus-specificity is long-lasting by increasing the interval between Days 1 and 2 from 24 hours to 1 week; and 3) the effects of reducing practice on Day 1 from 840 to just 21 trials. On Day 1, subjects performed a 10-AFC identification task with band-pass random textures embedded in three levels of external noise. The textures were presented at 7 contrasts that spanned the threshold range; hence the signal-to-noise ratio varied significantly across trials. On Day 2, subjects performed the task with the same or a novel set of textures. The dependent variable was response accuracy, and stimulus-specificity was measured by comparing performance with the same and novel textures on Day 2. We found stimulus-specific learning in subjects who received 840, 105, and 63 trials of practice, but not in subjects who received 21 trials of practice. Our results are consistent with the idea that stimulus-specific learning can emerge rapidly during practice and that this rapid learning is long lasting.Meeting abstract presented at VSS 2013
    Journal of Vision 07/2013; 13(9-9):1090. DOI:10.1167/13.9.1090 · 2.73 Impact Factor
  • L. E. Rosen, A. B. Sekuler, P. J. Bennett
    Journal of Vision 07/2013; 13(9):372-372. DOI:10.1167/13.9.372 · 2.73 Impact Factor
  • Journal of Vision 07/2013; 13(9):719-719. DOI:10.1167/13.9.719 · 2.73 Impact Factor
  • S. E. Creighton, A. B. Sekuler, P. J. Bennett
    [Show abstract] [Hide abstract]
    ABSTRACT: In the Whole-Part Effect (WPE) we are better able to discriminate a face part (e.g., eyes, nose, or mouth) when the part is embedded in a face than when it is presented in isolation. The results of a recent study (Konar, VSS 2011) suggest that the magnitude of the WPE may depend on the presence of uninformative external features (e.g., neck, chin, ears, hair). The current experiments attempted to replicate this effect, and to determine if the WPE is correlated with the face inversion effect. A same-different task was used to measure the discriminability of eyes, noses, or mouths presented in isolation or within an uninformative facial context that did or did not include external features. In Experiment 1, the target part was indicated by a word cue ("eyes," "nose," or "mouth") that appeared at the top of the response screen on each trial. In Experiments 2 and 3, the cue was a word plus a short horizontal line displayed at the same height as the target part. Experiment 1 failed to find a significant WPE: response accuracy was the same for parts presented in isolation or within a full face. However, Experiments 2 and 3 found a significant WPE for upright but not inverted faces. Averaged across experiments, there was a small but significant effect of external face parts: the WPE was slightly larger when the stimuli contained a neck, chin, ears, and hair. Since the external features are uninformative, and the spatial cues are present on each trial, their influence on the WPE was unexpected. Finally, we failed to find a significant correlation between the WPE and the magnitude of the face inversion effect. Overall, our results suggest that the WPE is highly unstable, and suggest a role for spatial attention in modulating the strength of the effect.
    Vision Sciences Society 2013; 07/2013
  • Journal of Vision 07/2013; 13(9):189-189. DOI:10.1167/13.9.189 · 2.73 Impact Factor

Publication Stats

4k Citations
630.98 Total Impact Points

Institutions

  • 2001–2014
    • McMaster University
      • • Department of Psychology, Neuroscience & Behaviour
      • • Department of Psychology, Neuroscience, and Behavior
      Hamilton, Ontario, Canada
  • 2009
    • York University
      • Centre for Vision Research
      Toronto, Ontario, Canada
  • 2005
    • University of Pennsylvania
      • Department of Psychology
      Philadelphia, PA, United States
  • 2003
    • University of Waterloo
      Ватерлоо, Ontario, Canada
  • 1993–2003
    • University of Toronto
      • Department of Psychology
      Toronto, Ontario, Canada
  • 1990–1991
    • University of California, Berkeley
      • • School of Optometry
      • • Department of Psychology
      Berkeley, California, United States
    • Brandeis University
      Волтам, Massachusetts, United States