Vertical meridian asymmetry in spatial resolution: visual and attentional factors.

Full Abstract

We investigated whether spatial resolution would be the same in the lower and upper halves of the vertical meridian (VM) of our visual field and whether attention would affect them differentially. It has been reported that (1) attending to the target's location improves performance in a texture segregation task when the observer's spatial resolution is too low (peripheral locations) but impairs it when resolution is already too high (central locations) for the task. This finding indicates an enhanced spatial resolution at the attended location (Yeshurun & Carrasco, 1998,2000), (2) observers' contrast sensitivity is higher in the lower than in the upper VM, a phenomenon known as vertical meridian asymmetry (VMA), an asymmetry determined by visual rather than by attentional factors (Carrasco, Talgar, & Cameron, 2001). In the present texture segregation task, performance was assessed under neutral- and peripheral-cue conditions. Transient covert attention was systematically manipulated by using a peripheral cue that indicated the target's location and its onset. Observers reported the interval containing a target patch appearing at one of a number of eccentricities in a large texture pattern along the VM. We found that (1) performance peaked at farther eccentricities in the lower than in the upper visual VM, indicating that resolution was higher in the lower half, and (2) the peripheral cue affected performance along the VM uniformly, indicating that the degree of enhanced resolution brought about by transient attention was constant along the VM. Thus, we conclude that the VMA for spatial resolution is determined by visual, not transient covert attentional, constraints.

Learn Faster Today Improve your study skills

Author information

Author/s: Talgar, Cigdem P (CP); Carrasco, Marisa (M);

Affiliation: New York University, New York, New York,10003, USA.

Journal and publication information

Publication Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.

Journal: Psychonomic bulletin & review (Psychon Bull Rev), published in United States. (Language: eng)

Reference: 2002-Dec; vol 9 (issue 4) : pp 714-22

Dates: Created 2003/03/04; Completed 2003/07/03; Revised 2006/11/15;

PMID: 12613674, status: MEDLINE (last retrieval date: 11/6/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

This article has not been indexed for related articles as yet, however you can still use the live related article search links below.

See 100+ related articles.