lec: perceptual organization

Imran Ahmad Sajid

IMRAN AHMAD SAJID Lecturer (Social Work), ISSG,

University of Peshawar

[email protected]

Perception

mailto:[email protected]

Imran Ahmad SajidImran Ahmad Sajid• Because you have been recognizing faces, people, places, animals, objects, and events for as long as you can remember

• You have ability to perceive. Specifically, you have ability to see something in your environment, to be aware of it, and to recognize it -- to see something as a thing of a certain sort.

Imran Ahmad SajidImran Ahmad Sajid

is Bugs the ONLY object you see when you look at image B

• Were you AWARE of all those visual sensations while you attended to the image of Bugs? Alternatively, were you PERCEIVING all those other "things" simultaneously, even the ones at the periphery (edges) of your visual field?


• The answer to each of theses question should be "No."

• Although you can direct your visual attention to any of the objects present in your field of view, you cannot attend to them all simultaneously.

• When you attend to a sensation, you are aware of it.

• Generally speaking, perception requires awareness, sensation does not.

• Hence, humans sense more than they can perceive.


Perception1. Perception is the process of obtaining

knowledge of external objects and events, by means of senses (Ross Stagner and T.F. Karwoski, 1952, p.207).

2. The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and brain (Robert Feldman, p.91).

3.The experience you have when you organize sensations into some meaningful pattern (Rod Plotnik, 1989., p.101)


• Suppose you had been born blind, but now were suddenly able to see. Suppose further that you now see the world as other adults do.

• What do you think, would you know what you are looking at?

• No, you would only see shapes, colours, contours, brightness before you, but what they meant would be a puzzle.

Imran Ahmad SajidImran Ahmad SajidSenden, M. Von

Experiment--1932• 66 blind persons from birth underwent a cataract operation, permitting vision at a delayed age.

• Finding: The patient is aware of being visually stimulated, but he does not identify objects


He could distinguish visually between a ball and a block, but he did not know which was which until allowed to handle them.


The girl could see only a patch of colours coming towards her, but only when she touches it does she exclaims, Wah, that’s Kitty!


Were not able to tell which card was shorter until touched them.


How We Organize Our Perception?

Can you read this sentence when it is upside down?

Probably yes.

Can you read this sentence when it is upside down?


Reason???• Previous Knowledge and experience allowed you to understand the text.

• Without knowledge of the letters shape, you would perceive them meaningless shapes.


Can you perceive the meaning of the following?

• 你你你你你你你你你你你你你你，？ (Chinese)• 你你你你你你你你你你你你你你你你你你你你你你你你你你你？(Japanese)

Most probably, NOT… Because you do not have the knowledge of Chinese or Japanese letters and their shapes.


• Note that in the example above, you did not stop to read every single letter carefully.

• Instead, you probably perceived whole words and phrases.

• You may have also used context to help you figure out what some of the words must beuu

down


How tall do you think this body builder is?

• Perception is an active process in which past experiences influence and even distort reality.

Imran Ahmad SajidImran Ahmad SajidHow do we organize

perception? Why do you see a scene rather than a collection of lines and dots?

does the scene simply emerge from adding all these lines and dots together?


How do we organize perception? • This is a topic of interest in Gestalt psychology.

• According to Gestalt psychologists, the whole is different than the sum of its parts.

• Gestalt is a German word meaning configuration or pattern

• a set of things considered as a whole and regarded as amounting to more than the sum of its parts.

Imran Ahmad SajidImran Ahmad SajidA. Figure-Ground

Approach• According to this approach, perception not only involves organization and grouping, it also involves distinguishing an object from its surroundings.

• Once you perceive an object, the area around that object becomes the background.

• For example, when you look at these slides, the wall and everything else behind it becomes the background.

• The object, or figure, is closer to you, and the background, or ground, is farther away.


• Consider the accompanying illustration 1.

• You may see a white vase as the figure, in which case you will see it displayed on a dark ground.

• However, you may also see two dark faces that point toward one another.

• Notice that when you do so, the white area of the figure becomes the ground.

Point: We do not just passively respond to visual stimuli that happen to fall on our retina. Instead, actively try to organize and make sense of what we see

1


• It is likely that you will perceive the form of a dog in this picture.

• The dog represents a gestalt, or perceptual whole.

• Although you can see the individual parts that make up the figure, putting them together forms something greater than the individual parts.

• The whole is different from the sum of its parts.

Point: We do not just passively respond to visual stimuli that happen to fall on our retina. Instead, actively try to organize and make sense of what we see.


B. Principles of Perception1. Closure2. Proximity3. Similarity4. Simplicity


1. Closure• We prefer complete forms to incomplete forms.

• We tend to ignore the breaks in the given figure and concentrate on the overall form

Closure: something that closes opening


• Thus, in the drawing below, we mentally close the gaps and perceive a picture of a duck.

• This tendency allows us to perceive whole objects from incomplete and imperfect forms.


2. Proximity• Elements that are closer together are grouped together.

• As a result, we tend to see the given circles on the left as in vertical columns, and the circles on the right as grouped into horizontal rows.

• Pair of dots rather than a row of single dots

.. .. .. .. .. .. ..


3. Similarity• Elements that are similar in appearance are grouped together.

• We see, then, vertical columns of circles and squires instead of horizontal mixed rows in the given picture.


4. Simplicity• In a general sense, the overriding gestalt principle is simplicity:

• When we observe a pattern, we perceive it in the most basic, straightforward manner that we can.

• Most of us see the given figure on the right as a square with lines on two sides, rather than as the block letter “W” on top of the letter “M”.

• If we have a choice of interpretations, we generally opt for the simple one.


THANKS Courtesy: Imran Ahmad Sajid, (Social Work), University of Peshawar. [email protected]

mailto:[email protected]

lec: perceptual organization

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