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Updated: Jul 10, 2026
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Cross-Modal Multivariate Pattern Analysis
Published on: November 9, 2011
Internal domain generality for ensemble perception of average orientation: Comparing and integrating information from
Greer Gillies1, Keisuke Fukuda2, Jonathan S Cant3
1Department of Psychology, University of Toronto.
Journal of Experimental Psychology. General
|July 9, 2026
Summary
Ensemble perception for orientation shows domain generality across different visual stimuli. However, mixed stimulus ensembles can introduce biases, like a "triangle bias," affecting accuracy.
Area of Science:
- Visual perception
- Cognitive psychology
- Ensemble coding
Background:
- Ensemble perception extracts summary statistics from groups of objects.
- It typically operates on homogeneous stimuli, but natural environments are heterogeneous.
- The generalizability of ensemble mechanisms across different stimulus types (internal domain generality) is unclear.
Purpose of the Study:
- To investigate if ensemble perception for orientation generalizes across diverse stimulus types.
- To determine if mixed stimulus ensembles affect the extraction of summary statistics.
Main Methods:
- Experiment 1: Compared orientation judgments in homogeneous ensembles of same vs. different stimulus types (faces, shoes, triangles).
- Experiments 2A & 2B: Assessed orientation judgments in pure (single stimulus type) vs. mixed (two stimulus types) ensembles.
- Experiment 3: Employed a continuous report task to further examine biases in mixed ensembles.
Main Results:
- Participants showed equal accuracy comparing orientations in same vs. different stimulus type ensembles (Experiment 1).
- Minimal differences were found in pure ensembles, but mixed ensembles revealed stimulus specificities (Experiments 2A & 2B).
- A significant bias towards the orientation of triangles was observed in mixed ensembles (Experiments 2A, 2B, & 3).
Conclusions:
- Ensemble perception for orientation demonstrates internal domain generality when stimuli are homogeneous.
- The presence of multiple stimulus types within a single ensemble can interfere with summary statistic extraction and introduce biases.
- Specific stimulus characteristics can emerge and influence perception in mixed ensembles.
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