In a classic still life like here by Jean Siméon Chardin, a person does not perceive all objects at the same time. Image: Wikipedia
Reading aloud If you look at a classic still life, you will not notice all the objects at the same time, despite the opposite impression. Rather, he realizes the different colors and shapes one after the other, American psychologists have shown. Only the distribution of objects in the room is excluded from this type of perception: The positions of the fruit bowl, flowers and water bottle can be recorded simultaneously and processed in parallel. What is consciously perceived, therefore, is not the current content of the optical memory, but what can be retrieved quickly and specifically from other stores, explain the researchers. When viewing a scene, the visual system is based on some basic quantities. These include the color, the shape and the direction of movement of the objects as well as their spatial density, their position and their orientation. Psychologists have long suspected that the perception of these characteristics is not equal. Thus, an observer seems to be able to grasp more than one position in space at the same time, but not more than one color or shape.

To further investigate this relationship, psychologists tested the perceptions of a total of 78 volunteers. To do this they showed them, either simultaneously or one after the other, two superimposed, differently colored squares on a single monitor. Afterwards, the subjects should indicate in another square if they had already seen their position or color before. The result: remembering the position was easier for the participants if they had seen both squares simultaneously. The color, on the other hand, was better remembered when the characters appeared one after the other on the screen. A similar result was also shown in a second test, where subjects should focus on the color and position of one or two squares.

Indeed, several positions can actually be captured simultaneously as a pattern or entity so that they do not compete with each other, researchers conclude. For colors, on the other hand, this does not work: Here each color needs the entire available capacity, so that different colors must be processed one behind the other. Thus, at first glance at a complex image, only the spatial arrangement of a single color is registered, followed by the distribution of the next and so on, the researchers explain. However, this happens so quickly that the time delay is not consciously perceived.

Liqiang Huang (Princeton University, Princeton) et al .: Science, Vol. 317, p. 823 ddp / science.de? Ilka Lehnen-Beyel advertisement

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