A Double Dissociation Between Perception and Action Using Sander's Parallelogram: Demand Characteristics Come Up Short
Bibliographic record
Abstract
According to the Interface Theory of Perception, perceptual representations reflect evolutionary entrainment to utility rather than reality. In contrast to perception, object-directed action involves physical interaction which can be harmful or beneficial to the agent. Thus, actions need to be accurate and the representations that underlie them need to be veridical. Arguably, utility and physical reality are perfectly aligned for action. Consistent with this view, a number of studies have shown that object-directed actions resist pictorial illusions. Nevertheless, this work has largely ignored the fact that one's belief about the properties of a stimulus can contradict moment-to-moment visual experience. It is therefore possible that actions resist illusions because they are guided by veridical beliefs whereas perceptual estimations are guided by 'fooled' visual experience. In short, demand characteristics might be responsible for dissociating action and perception. Here, we tested this possibility directly. We asked participants to manually estimate the length of different 3D-target bars embedded in Sander's Parallelogram illusion or to reach out and pick them up. Critically, we positioned the bars such that the physically-shorter ones could appear longer than their physically-longer counterparts. This arrangement served a dual role, pitting perception and action against one another while reducing demand characteristics; pictorial displays that can reverse the apparent difference in target length are rarer than the more 'traditional' displays which induce an apparent difference in target length when no difference exists. The results revealed a double dissociation: grasps reflected the real difference in target length whereas manual estimates reflected the illusory difference. At the end of the study, participants were asked whether or not they believed the targets differed in physical length. A large majority affirmed a difference existed, indicating that the difference was in the direction of the illusion. Thus, demand characteristics based on belief cannot explain the perception-action dissociation. Meeting abstract presented at VSS 2016
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.011 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.001 | 0.005 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".