Beyond distance and direction: The brain represents target locations non-metrically
Bibliographic record
Abstract
In their day-to-day activities human beings are constantly generating behavior, such as pointing, grasping or verbal reports, on the basis of visible target locations. The question arises how the brain represents target locations. One possibility is that the brain represents them metrically, i.e. in terms of distance and direction. Another equally plausible possibility is that the brain represents locations non-metrically, using for example ordered geometry or topology. Here we report two experiments that were designed to test if the brain represents locations metrically or non-metrically. We measured accuracy and variability of visually guided reach-to-point movements (Experiment 1) and probe-stimulus adjustments (Experiment 2). The specific procedure of informing subjects about the relevant response on each trial enabled us to dissociate the use of non-metric target location from the use of metric distance and direction in head/eye-centered, hand-centered and externally defined (allocentric) coordinates. The behavioral data show that subjects' responses are least variable when they can direct their response at a visible target location, the only condition that permitted the use of non-metric information about target location in our experiments. Data from Experiments 1 and 2 correspond well quantitatively. Response variability in non-metric conditions cannot be predicted based on response variability in metric conditions. We conclude that the brain uses non-metric geometrical structure to represent locations.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".