SENSORY,ATTENTIAL AMD PERCEPTIONAL PROCESSES

Activity . the triangle. Those who can do it quickly will be called “field independent”; those who take long time will be called “field dependent”. Cultural Background and Experiences Different experiences and learning opportunities available to people in different cultural settings also influence their perception.

People coming from a pictureless environment fail to recognise objects in pictures. Hudson studied the perception of pictures by African subjects, and noted several difficulties. Many of them were unable to identify objects depicted in pictures (e.g., antelope, spear). They also failed to perceive distance in pictures, and interpreted pictures incorrectly.

Eskimos have been found to make fine distinction among a variety of snow that we may be unable to notice. Some aboriginal groups of Siberian region have been found to differentiate among dozens of skin colours of reindeers, which we would not be able to do. These studies indicate that the perceiver plays a key role in the process of perception. People process and interpret stimuli in their own ways depending on their personal, social and cultural conditions.

Due to these factors our perceptions are not only finely tuned, but also modified. Cognitive Styles Cognitive style refers to a consistent way of dealing with our environment. It significantly affects the way we perceive the environment. There are several cognitive styles that people use in perceiving their environment.

One most extensively used in studies is the “field dependent and field independent” cognitive style. Field dependent people perceive the external world in its totality, i.e. in a global or holistic manner. On the other hand, field independent people perceive the external world by breaking it into smaller units, i.e.

in an analytic or differentiated manner. Look at Fig. . .

Can you find out the triangle hidden in the picture? How much time do you take to locate it? Try to find out the time other students of your class take to locate Fig. .

: An Item to test the ‘Field Dependent’ and ‘Field Independent’ Cognitive Style P RINCIPLES OF P ERCEPTUAL O RGANISATION Our visual field is a collection of different elements, such as points, lines, and colours. However, we perceive these elements as organised wholes or complete objects. For example, we see a bicycle as a complete object, not as a collection of different parts (e.g., saddle, wheel, handle). The process of organising visual field into meaningful wholes is known as form perception .

You may wonder how different parts of an objects are organised into a meaningful whole. You may also ask if there are certain factors that facilitate or inhibit this process of organisation. Several scholars have tried to answer such questions, but the most widely accepted answer has been given by a group of researchers, called Gestalt psychologists . Prominent among them are Köhler, Koffka, and Wertheimer.

Gestalt means a regular figure or a form. According to Gestalt psychologists, we perceive different stimuli not as discrete elements, but as an organised “whole” that carries a definite form. They believe that the form of an object lies in its whole, which is different from the sum of their parts. For example, a flower pot with a bunch of flowers is a whole.

If the flowers are removed, the flower pot still remains a whole. It is the configuration of the flower pot that has changed. Flower pot with flowers is one configuration; without flowers it is another configuration. The Gestalt psychologists also indicate that our cerebral processes are always oriented towards the perception of a good figure or pragnanz .

That is the reason why we perceive everything in an organised form. The most primitive organisation takes place in the form of figure-ground segregation . When we look at a surface, certain aspects of the surface clearly stand out as separate entities, whereas others do not. For example, when we see words on a page, or a painting on a wall, or birds flying in the sky, the words, the painting, and the birds stand out from the background, and are perceived as figures, while the page, wall, and sky stay behind the figure and are perceived as background.

To test this experience, look at the Fig. . given below. You will see either the white part of the figure, which looks like a vase (flower pot), or the black part of the figure, which looks like two faces.

Fig. . : Rubin’s Vase We distinguish figure from the ground on the basis of the following characteristics: . Figure has a definite form, while the background is relatively formless.

. Figure is more organised as compared to its background. . Figure has a clear contour (outline), while the background is contourless.

. Figure stands out from the background, while the background stays behind the figure. . Figure appears more clear, limited, and relatively nearer, while the background appears relatively unclear, unlimited, and away from us.

The discussion presented above indicates that human beings perceive the world in organised wholes rather than in discrete parts. The Gestalt psychologists have given us several laws to explain how and why different stimuli in our visual field are organised into meaningful whole objects. Let us look at some of these principles. The Principle of Proximity Objects that are close together in space or time are perceived as belonging together or as a group.

For example, Fig. . does not look like a square pattern of dots, but as a series of columns of dots. Similarly, Fig.

. also looks like a group of dots together in rows. Fig. .

: Smallness Fig. . : Continuity Fig. .

: Similarity The Principle of Similarity Objects that are similar to one another and have similar characteristics are perceived as a group. In Fig. . the little circles and squares are evenly spaced both horizontally and vertically so that the proximity does not come into play.

Instead, we tend to see alternating columns of circles and squares. The Principle of Continuity This principle states that we tend to perceive objects as belonging together if they appear to form a continuous pattern. For instance, we are more likely to identify two lines a-b and c-d crossing than to identify four lines meeting at the center p . The Principle of Smallness According to this principle, smaller areas tend to be seen as figures against a larger background.

In Fig. . we are more likely to see a black cross rather than a white cross within the circle because of this principle. The Principle of Symmetry This principle suggests that symmetrical areas tend to be seen as figures against asymmetrical backgrounds.

For example, in Fig. . the black areas are seen as figures (as they have symmetrical properties) against their white asymmetrical background. Fig.

. : Symmetry Fig. . : Surroundedness