Marilynn Mackay

University of Waterloo, Waterloo, Quebec, Canada

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Publications (4)11.93 Total impact

  • Source
    Pierre Jolicoeur, Shimon Ullman, Marilynn Mackay
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    ABSTRACT: Subjects decided whether 2 dots were on the same curve or 2 different curves, and the curvature of the curves or the proximity of other (distractor) curves to the target curve was varied. Response time increased as the arc length of the curve connecting the 2 dots increased, suggesting that the curve was traced to perform the task. Tracing rate was faster for low- than high-curvature contours and was increasingly slower as distractor contours were increasingly proximal to the traced curve. Proximity results were predicted by a model in which response time depends on the ratio of the distance between the dots and the distance between adjacent lines. Curve tracing operations used to integrate information along contours are sensitive to several properties of the contours. The implications of the sensitivity of tracing operations to these curve properties are discussed.
    Journal of Experimental Psychology Human Perception & Performance 12/1991; 17(4):997-1022. DOI:10.1037/0096-1523.17.4.997 · 3.11 Impact Factor
  • Merrill Hiscock, Marilynn Mackay
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    ABSTRACT: Dichotic digit names were presented to normal right-handed adults in two experiments, the first of which used a standard free report procedure and the second of which used a signal detection procedure. Prior to each test, a priming bias was generated by having subjects monitor either the left or right ear for 30 selective listening trials. The expected priming effect was found in Experiment 1: ear asymmetry and order of report were altered according to the ear previously monitored. In contrast, no priming effect was observed with the signal detection procedure used in Experiment 2. There was a right-ear advantage in sensitivity irrespective of the ear previously monitored. The findings suggest that priming biases act by altering the order in which multiple stimuli are processed and reported.
    Neuropsychologia 02/1987; 25(3):507-17. DOI:10.1016/0028-3932(87)90075-3 · 3.45 Impact Factor
  • Source
    Pierre Jolicoeur, Shimon Ullman, Marilynn Mackay
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    ABSTRACT: The two experiments in this study suggest that fast internal tracing of curves is employed by the visual system in the perception of certain shape properties and spatial relations. The experimental task in the first experiment was to determine, as rapidly as possible, whether two Xs lay on the same curve or on different curves in a visual display. Mean response time for “same” responses increased monotonically with increasing distance along the curve between the Xs. The task in the second experiment was to decide either that a curve joining two Xs was unbroken or that the curve had a gap. Decision times again increased as the length of the curve joining the Xs was increased. The results of both experiments suggest that people can trace curves in a visual display internally at high speed (the average rate of tracing was about 40° of visual angle per second). Curve tracing may be an important visual process used to integrate information from different parts of a visual display.
    Memory & Cognition 03/1986; 14(2):129-140. DOI:10.3758/BF03198373 · 1.92 Impact Factor
  • Merrill Hiscock, Marilynn MacKay
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    ABSTRACT: Verbal dichotic listening tests were administered to 477 normal, right-handed adults in five consecutive experiments. None of the five separate analyses yielded a significant sex difference in degree of ear asymmetry, nor was a significant difference found when data were pooled. Supplemental analyses provided some evidence of a sex difference among subjects without familial sinistrality. Nonetheless, subjects' sex accounts for a very small proportion of the total variance in ear asymmetry.
    Neuropsychologia 02/1985; 23(3):441-4. DOI:10.1016/0028-3932(85)90033-8 · 3.45 Impact Factor

Publication Stats

158 Citations
11.93 Total Impact Points

Institutions

  • 1991
    • University of Waterloo
      • Department of Psychology
      Waterloo, Quebec, Canada
  • 1985–1987
    • University of Saskatchewan
      Saskatoon, Saskatchewan, Canada