'Hollow-Face Illusion' Affects Estimates of Distance and Reaching Tasks

June 27, 2005

A person's prior knowledge of the geometry of faces affects his or her ability to estimate distance and complete visually guided reaching tasks according to a study published in the June issue of Journal of Vision, an online, free access publication of the Association for Research in Vision and Ophthalmology (ARVO).

In a joint study by the University of Minnesota in Minneapolis, and the University of Giessen and the Max-Planck-Institute Tuebingen, both in Germany, researchers used the "hollow-face illusion" to test if the perceived shape of a face also affects participants' reaches and verbal estimates of distance. "Hollow-face illusion," in which a hollow mask viewed from a distance looks like a normal convex, occurs because prior knowledge of the shape of the face is sufficient to override the true depth indicated by other cues such as binocular disparity.

Study participants viewed concave and convex faces and made verbal and reach estimates that indicated their perceived shape of the face. In the verbal task, participants gave a verbal estimate of the distance from their viewing position to either the nose or the cheek of the faces.

In the reaching task, participants touched either the nose or cheek of the face within a certain period of time. The time limit was imposed to ensure the response time was similar to that of the verbal task. The study's data show that the magnitude of the hollow-face illusion is similar for reaching tasks and verbal tasks.

Volker H. Franz, PhD, one of the study's researchers says, "We show that prior knowledge about the general shape of faces can interact with the information the person acquires from vision at the time of the action. Without the knowledge that they are reaching to a face and what the typical shape of a face is, participants would perform the reaching movements differently. This stresses the importance of object recognition even for very simple motor tasks and shows that humans perform these actions in a more complex way than, for example, typical applications in robotics which do not take into account prior knowledge about objects."

Explore further: When kids talk to robots: Enhancing engagement and learning

Related Stories

When kids talk to robots: Enhancing engagement and learning

June 26, 2017

Conversational robots and virtual characters can enhance learning and expand entertainment options for children, a trio of studies by Disney Research shows, though exactly how these autonomous agents interact with children ...

Tourette syndrome—finally, something to shout about

June 9, 2017

Tourette syndrome is a mysterious medical curiosity that has puzzled doctors for more than a century. People who have it suffer from tics and other behavioral problems, such as obsessive compulsive traits and attention deficit ...

Recommended for you

Galaxy NGC 1132 has a disturbed hot halo, study finds

June 27, 2017

(Phys.org)—A new study recently published on arXiv.org reveals that the fossil group galaxy NGC 1132 (also known as UGC 2359) has a disturbed and asymmetrical hot halo. The findings provide new insights into the formation ...

Scientists illuminate structures vital to virus replication

June 27, 2017

In the fight against the viruses that invade everyday life, seeing and understanding the battleground is essential. Scientists at the Morgridge Institute for Research have, for the first time, imaged molecular structures ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.