# Varieties of imagery and perception: the structure of task differences

## TL;DR

This study explores how visual mental imagery and perception are structured in the brain, finding two main processing systems.

## Contribution

The study identifies two distinct processing systems in visual imagery and perception using task-based analysis.

## Key findings

- Two main clusters were found corresponding to object-properties and spatial-properties systems.
- The segregation of these systems was consistent in both imagery and perception tasks.
- Nonmetric multidimensional scaling and principal components analysis supported the two-system model.

## Abstract

This study assessed the dimensions and factors underlying visual mental imagery abilities in young healthy participants. A second purpose was to compare the underlying pattern of factors and dimensions in imagery with those in the corresponding perception tasks.

We administered 15 tasks to 32 participants, assessing a wide range of imagery abilities, including imagery for faces, common objects, colors, words, mental rotation, scanning, image maintenance, auditory imagery, and tactile imagery. Response times and error rates were correlated for the imagery and for the perception tasks separately. The matrices were then analyzed using nonmetric multidimensional scaling and principal components analysis.

All analyses indicated the presence of two main clusters, one that appeared to correspond to tasks that draw on the object-properties “ventral system” and one that appeared to correspond to tasks that draw on the spatial-properties “dorsal system.”

These results indicate a common segregation of the two major processing systems in visual imagery and visual perception.