8 Perception

Perception

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Selective Attention 

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By one estimate our senses take in about 11,000,000 bits of information per second. Of that we consciously process about 40, yet intuitively make use of the other 10,999,960 bits. The Cocktail Party effect – selective listening Change blindness – not noticing changes due to selective attention

Perceptual Organization 

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Visual Capture – the tendency for vision to dominate the other senses. Gestalt – A German word meaning “whole.” Gestalt psychologists emphasize how perception integrates many pieces of information into a meaningful “whole.”

Visual Form Perception 

Figure-ground – refers to the brains tendency to organize the visual field into figures or objects and backgrounds.

Grouping 

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The brain will organize visual data according to certain rules, one is grouping. Proximity Similarity Continuity Connectedness Closure

Depth Perception 

Seeing objects in three dimensions is called depth perception. You are born with depth perception and a fear of heights. Scientists used the famous visual cliff experiment (trying to get babies to crawl over a table’s edge with glass over it) to determine this.

Depth Perception 

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Binocular cues – Depth perception cues that depend on the use of both eyes Retinal Disparity – a binocular cue, the brain’s use of the discrepancy between the two pictures created by each eye for depth perception Convergence – a binocular cue that measures the angle of your eyes and calculates the distance an object must be for you to focus on it with both eyes.

Depth Perception

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Monocular Cues – refer to depth perception cues such as linear perspective and overlap that you can see with one eye. Relative size, if we assume we know the size of something the smaller it is the farther away it is (like cars viewed from an airplane)

Depth Perception 

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Interposition – one object blocking the view of another because its closer. Relative clarity – if something is hazy looking we assume its farther away. Texture Gradient – objects farther away are smaller and more densely packed

Depth Perception 

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Relative motion – also called motion parallax. When driving if you look at the road near you it appears to go by very fast, but if you look at a building farther away it appears to go by slower. Linear perspective – Parallel lines such as railroad tracks appear to converge with distance. Light and shadow – closer objects reflect more light, object farther away are dimmer.

Motion Perception 

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Your brain perceives motion mostly by assuming objects that are getting larger are getting closer and objects getting smaller are moving away, not shrinking. Rapid moving still images will be perceived as motion as movies are. We also use the phi phenomenon where successive blinking lights can be used to cause motion.

Perceptual Constancy 

Even though objects may change in shape size and color due to sensation, our brain will perceive these objects as being the same. For example we know that a car can hold people inside it, even if we see it from far away when it is very small.

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Relative size Shape Color Brightness