U.S. medical scientists have determined infants are able to detect at least some three-dimensional images.

New York University researcher Sarah Shuwairi and colleagues used pictures or illusions of three-dimensional images that do not make any visual sense -- deceptions that result from our ability to create three-dimensional objects from two-dimensional images.

Inevitably, people end up staring at such images for several moments, attempting to make sense of the impossible.

To determine when humans develop the ability to perceive coherence in three-dimensional objects, the researchers placed 30 4-month-old infants in front of computer screens displaying alternating "possible" and "impossible" 3-D images and recorded how long the infants looked at each of the objects.

The result was that infants looked significantly longer at impossible figures, suggesting humans have the ability as young as 4 months of age to detect at least some three-dimensional features that give rise to the perception of object coherence.

Shuwairi says the finding provides important insights into how infants develop an understanding of the physical world around them.

The study appears in the journal Psychological Science.

Copyright 2007 by United Press International