Approaches of perception in cognitive psychology

Approaches of perception – There are diverse views on how we perceive the world. These views can be concise as

• Bottom-up theories
• Top-down theories.

Bottom-Up Theories

These theories usually define approaches where perception starts with the stimuli whose appearance you take in through your eye and they are data driven (i.e., stimulus-driven) theories. Bottom up theories are categorized as:

• Direct perception
• Template theories
• Features matching theories
• Recognizing by components theory

Direct Perception

This theory mentions to the belief that the array of information in human sensory receptors, including the sensory context, is all we need to perceive anything. Let’s take an example How do you know the letter A when you see it? It is quite easy to ask but really hard to answer. Of course, it’s an A because it looks like an A. What makes it look like an A, though, instead of like an H? Just how difficult it is to answer this question becomes apparent when you look at Figure below. You probably will see the image as the words “THE CAT.” However, the H of “THE” is similar to the A of “CAT.” What subjectively feels like a simple process of pattern recognition is almost certainly quite complex.

• Gibson’s Theory of Direct Perception

Rendering to Gibson’s theory of direct perception, by way of the environment supplies us with all the information that we need for perception, this view is sometimes called as ecological perception. Simply we do not need greater cognitive processes or anything else to mediate between our sensory experiences and our perceptions. Present beliefs or higher-level inferential thought processes are not essential for perception.

• Neuroscience and Direct Perception

Neuroscience also shows that direct perception may be involved in person perception. About 30 to 100 milliseconds after a visual stimulus then mirror neurons start firing. Usually mirror neurons are active both when a person acts and when he or she observes that same act made by somebody else. So before we even have time to form premises about what we are perceiving, we may previously be able to recognize the expressions, emotions, and movements of the person we observe.

• Template Theories

Template theories recommend that we have stored in our minds countless sets of templates. They are basically highly detailed models for patterns we possibly might recognize. We recognize a pattern by likening it with our set of templates. We then choose the precise template that perfectly matches what we observe. Fingerprints are matched in the same way. Machines quickly process imprinted numerals on checks by comparing them to templates. Progressively, products of all kinds are identified with universal product codes. They can be scanned and recognized by computers at the time of purchase.

• Neuroscience and Template Theories

Letters of the alphabet are modest than faces and other complex stimuli. But how do we distinguish letters? And does it make a difference to our brain whether we perceive letters or digits? Experiments propose that there is certainly a difference between letters and digits. There is a zone at or near the left fusiform gyrus that is activated significantly more whenever a person is presented with letters than with digits. It is not well defined if this “letter area” only processes letters or if it also plays a more slight role in the processing of digits. Computer have trouble in reading hand writing because the predefined templets in computer are fixed in shape, design and type while the hand writing is usually different in style, shape and design.

• Feature-Matching Theories

According to these theories, attempt to match features of a pattern to features stored in memory, rather than to match a whole pattern to a template or a prototype.

• Pandemonium Model One such kind of feature-matching model has been called Pandemonium “pandemonium” refers to a very noisy, chaotic place and hell. In it, metaphorical “demons” with explicit duties receive and analyze the features of a stimulus.

• Recognition by Components Theory

This theory helps in recognition of objects by combination of various components which are already stored in human memory. Seeing with the Assistance of Geons Irving Biederman recommended that we achieve this by manipulating a number of simple 3-D geometric shapes called geons for geometrical ions. They include objects such as cylinders, bricks, wedges, cones, and their curved axis counterparts.

Top-Down Theories

The top-down is basically constructive approach. In constructive perception, the perceiver constructs a cognitive perception of a stimulus. According to constructivists, for the period of perception we quickly form and test various hypotheses about percepts. The percepts are based on three things:
• what we sense (the sensory data)
• what we know (knowledge stored in memory)
• what we can infer (using high-level cognitive processes).

One reason for preferring the constructive approach is that bottom-up means data driven theories of perception do not fully explain context effects. Context effects are the effects of the surrounding environment on perception. In one study, people were asked to recognize objects after they had viewed the objects in either an appropriate or an inappropriate context for the items. For example, participants might see a scene of a kitchen followed by stimuli such as a loaf of bread, a mailbox, and a drum. Objects that were appropriate to the established context, such as the loaf of bread in this example, were recognized more rapidly than were objects that were inappropriate to the established context. The strength of the context also plays a role in object recognition. Maybe even more striking is a context effect known as the configural-superiority effect by which objects presented in convinced configurations are easier to recognize than the objects presented in separation, even if the objects in the configurations are more complex than those in isolation.

The configural-superiority effect shown below with help of diagram.

Bottom up and top down theories works together for perceiving the world around.

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