A major problem in constructing a representation of the world is object seg- mentation. Knowing where the lines and bars are located in space is not enough; we need to know which ones go together to form objects. Many lines go this way and that, but somehow we put them together to come up with the perception of a set of objects.
We organize objects into units according to a set of principles called the gestalt principles of organization, after the Gestalt psychologists who first proposed them (e.g., Wertheimer, 1912/1932).
● The principle of proximity: Elements close together tend to organize into units. Thus, we perceive four pairs of lines rather than eight separate lines.
● The principle of similarity: Objects that look alike tend to be grouped together. In this case, we tend to see this array as rows of o’s alternating with rows of x’s.
● The principle of good continuation: We perceive two lines, one from A to B and the other from C to D, although there is no reason why this sketch could not represent another pair of lines, one from A to D and the other from C to B. However, the lines from A to B and from C to D display bet- ter continuation than the lines from A to D and from C to B, which have a sharp turn.
● The principle of proximity: Elements close together tend to organize into units. Thus, we perceive four pairs of lines rather than eight separate lines.
● The principle of similarity: Objects that look alike tend to be grouped together. In this case, we tend to see this array as rows of o’s alternating with rows of x’s.
● The principle of good continuation: We perceive two lines, one from A to B and the other from C to D, although there is no reason why this sketch could not represent another pair of lines, one from A to D and the other from C to B. However, the lines from A to B and from C to D display bet- ter continuation than the lines from A to D and from C to B, which have a sharp turn.
These principles will organize completely novel stimuli into units. Palmer
(1977) studied the recognition of shapes . He first showed participants stimuli and then asked them to decide whether the fragments depicted. Palmer found that participants could recognize the parts most rapidly when they were the segments predicted by the gestalt principles. Thus, we see that recognition depends critically on the initial segmentation of the figure. Recognition can be impaired when this gestalt-based segmentation contradicts the actual pattern structure. FoRiNsTaNcEtHiSsEnTeNcEiShArDtOrEaD. The reasons for this difficulty are (a) that the gestalt principle of similarity makes it hard to perceive adjacent letters of different case as units and (b) that removing the spaces between words has eliminated the proximity cues.
These ideas about segmentation can be extended to describe how more complex 3-D structures are divided. gestaltlike principles can be used to seg- ment an outline representation of an object into subobjects. They observed that where one segment joins another, there is typically a concavity in the line outline. Basically, people exploit the gestalt principle of good continuation: The lines at the points of concavity are not good continuations of one another, and so viewers do not group these parts together.
The current view is that the visual processing underlying the ability to identify the position and shape of an object in 3-D space is largely innate. Young infants appear to be capable of recognizing objects and their shapes and where they are in 3-D space (e.g., Granrud, 1986, 1987).
■ Gestalt principles of organization explain how the brain segments visual scenes into objects.
(1977) studied the recognition of shapes . He first showed participants stimuli and then asked them to decide whether the fragments depicted. Palmer found that participants could recognize the parts most rapidly when they were the segments predicted by the gestalt principles. Thus, we see that recognition depends critically on the initial segmentation of the figure. Recognition can be impaired when this gestalt-based segmentation contradicts the actual pattern structure. FoRiNsTaNcEtHiSsEnTeNcEiShArDtOrEaD. The reasons for this difficulty are (a) that the gestalt principle of similarity makes it hard to perceive adjacent letters of different case as units and (b) that removing the spaces between words has eliminated the proximity cues.
These ideas about segmentation can be extended to describe how more complex 3-D structures are divided. gestaltlike principles can be used to seg- ment an outline representation of an object into subobjects. They observed that where one segment joins another, there is typically a concavity in the line outline. Basically, people exploit the gestalt principle of good continuation: The lines at the points of concavity are not good continuations of one another, and so viewers do not group these parts together.
The current view is that the visual processing underlying the ability to identify the position and shape of an object in 3-D space is largely innate. Young infants appear to be capable of recognizing objects and their shapes and where they are in 3-D space (e.g., Granrud, 1986, 1987).
■ Gestalt principles of organization explain how the brain segments visual scenes into objects.
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