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Glennerster, A.

Publications and source records attributed to Glennerster, A..

2 recordsLinked to original sources

Human pointing errors suggest a flattened, task-dependent representation of space

People are able to keep track of objects as they navigate through space, even when objects are out of sight. This requires some kind of representation of the scene and of the observers location but the form this representation might take is debated. We tested the accuracy and reliability of observers estimates of the visual direction of previously-viewed targets. Participants viewed 4 objects from one location, with binocular vision and small head movements giving information about the 3D locations of the objects. Without any further sight of the targets, participants walked to another location and pointed towards them. All the conditions were tested in an immersive virtual environment and some were also carried out in a real scene. Participants made large, consistent pointing errors that are poorly explained by any consistent 3D representation. Instead, if a 3D representation is to account for the data it would need to be one where the target boxes were squashed, almost into a plane, quite far away from the true location of the boxes and in different places depending on the orientation of the obscuring wall at the moment the participant points. In short, our data show that the mechanisms for updating visual direction of unseen targets are not based on a stable 3D model of the scene, even a distorted one.

neuroscience

Pointing Errors in Non-Metric Virtual Environments

There have been suggestions that human navigation may depend on representations that have no metric, Euclidean interpretation but that hypothesis remains contentious. An alternative is that observers build a consistent 3D representation of space. Using immersive virtual reality, we measured the ability of observers to point to targets in mazes that had zero, one or three wormholes - regions where the maze changed in configuration (invisibly). In one model, we allowed the configuration of the maze to vary to best explain the pointing data; in a second model we also allowed the local reference frame to be rotated through 90, 180 or 270 degrees. The latter model outperformed the former in the wormhole conditions, inconsistent with a Euclidean cognitive map.

animal behavior and cognition