Can ongoing movements be guided by allocentric visual information when the target is visible?

Emily M Crowe,Eli Brenner,Martin Bossard

doi:10.1167/jov.21.1.6

Emily M Crowe, Eli Brenner + Show 1 more

Open Access

https://doi.org/10.1167/jov.21.1.6

Copy DOI

Abstract

People use both egocentric (object-to-self) and allocentric (object-to-object) spatial information to interact with the world. Evidence for allocentric information guiding ongoing actions stems from studies in which people reached to where targets had previously been seen while other objects were moved. Since egocentric position judgments might fade or change when the target is removed, we sought for conditions in which people might benefit from relying on allocentric information when the target remains visible. We used a task that required participants to intercept targets that moved across a screen using a cursor that represented their finger but that moved by a different amount in a different plane. During each attempt, we perturbed the target, cursor, or background individually or all three simultaneously such that their relative positions did not change and there was no need to adjust the ongoing movement. An obvious way to avoid responding to such simultaneous perturbations is by relying on allocentric information. Relying on egocentric information would give a response that resembles the combined responses to the three isolated perturbations. The hand responded in accordance with the responses to the isolated perturbations despite the differences between how the finger and cursor moved. This response remained when the simultaneous perturbation was repeated many times, suggesting that participants hardly relied upon allocentric spatial information to control their ongoing visually guided actions.

Highlights

In order to successfully interact with the world, we must encode, organize, and use spatial information.Such information can be represented in two fundamentally different ways
As in Experiment 1, participants responded to the simultaneous perturbation of the target, background, and cursor in the direction of the perturbation (Figure 4)
We present two experiments that investigated whether ongoing movements can be guided by allocentric visual information when the target remains visible throughout the entire movement

Summary

Introduction

In order to successfully interact with the world, we must encode, organize, and use spatial information.Such information can be represented in two fundamentally different ways. Egocentric information is defined relative to the self, whereas allocentric information describes object-to-object relations independent of the self This distinction is believed to be critical for the way in which the visual system is organized. A ventral visual pathway that is primarily involved in tasks that require persistent relationships, such as recognizing people or objects, is proposed to organize visual input allocentrically, while a dorsal visual pathway primarily guides ongoing actions using instantaneous egocentric spatial information (Goodale & Milner, 1992). Memoryguided actions, for instance, are movements in which a target object is removed from view prior to a motor response Such movements are guided by remembered target positions, so they presumably depend on the ventral system that stores persistent information to some extent (Goodale, 2008).

Objectives

Results

Conclusion