ResearchBlogging.org

Does your seven month old enjoy snooker?
Infants see causal relationships between events, according to research published in the journal Cognitive Psychology[1].

The authors explain: “When we see a collision between two billiard balls, for example, we do not simply see the cessation of one ball’s motion followed by the onset of motion in the other: instead, we see one ball cause the other’s motion”.

It is not known whether the perception of causal movement is learnt during a person’s lifetime, or whether it has been shaped by evolution. To test the effect it is present in small children George E. Nemwan and colleagues at Yale University studied 7 month-old babies and their perception of causal movement.

The researchers showed the babies short videos of a disk that either to “cause” a pair of disks to move until they became habituated to this type of movement.

The babies were then shown videos of disks that behaved causally, like billiard ball collisions, until they lost interest. They were then shown more videos of “collisions” and videos in which the causal relationship was “broken” by moving one of the disks early or late.

The babies could tell the difference between the two types of events, showing significantly more interest in the “non-causal” videos.

Emotional link to visual awareness

Researchers at the University of Houston, Texas have used binocular rivalry to study the effect of emotion on vision [2].

Twelve subjects were shown pairs of images – one to each eye. The participants’ saw one or the other of the images at any one time, and their perception switched between the two.

The researchers used images from the International Affective Picture System, a library of pictures that have been rated by valence (from “pleasant” to “unpleasant”) and arousal, or the strength of the effect on the viewer’s emotions. A bunch of flowers may is a high valence, low arousal picture, whilst a picture of a badly injured person would have low valence and high arousal.

The study, published in volume 48 of Vision Research, found that the volunteers saw the “nice” pictures earlier and for longer than the “nasty” pictures, as long as the emotional intensity was low. Where the pictures had a stronger emotional effect, the participants saw the unpleasant picture earlier and for longer.

“Our study teases apart the relative effects of the arousal versus valence levels of a stimulus on one’s awareness of it,” Said the authors. “The consequences of not processing a noxious stimulus are direr than the consequences of not processing a pleasing one… On the other hand, if the stimuli are not arousing and therefore, not critical to one’s fitness, the more pleasant stimulus is obviously more pleasurable.”

[1] G NEWMAN, H CHOI, K WYNN, B SCHOLL (2008). The origins of causal perception: Evidence from postdictive processing in infancy☆ Cognitive Psychology, 57 (3), 262-291 DOI: 10.1016/j.cogpsych.2008.02.003

[2] B SHETH, T PHAM (2008). How emotional arousal and valence influence access to awareness Vision Research, 48 (23-24), 2415-2424 DOI: 10.1016/j.visres.2008.07.013

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