Introduction: Ch 4

Chapter 4

Sensation and Perception

Basic Principles Sensation receiving stimulus energies from the external environment

Perception organizing and interpreting sensory information

Sensory Thresholds Absolute Threshold the minimum amount of energy an organism can detect 50% of the time

Attention Attention Process of focusing awareness on a narrowed aspect of the environment

Selective Attention Act of focusing on a specific aspect of experience while ignoring others

Noise irrelevant and competing stimuli

Stroop Effect

Visual Perception organizing and interpreting visual signals Dimensions: -­‐ shape -­‐ depth -­‐ motion -­‐ constancy

Visual Perception: Shape Gestalt Psychology – perceptions are naturally organized according to certain patterns – whole is different from the sum of the parts

Figure-­‐Ground Relationship

Gestalt Principles

Visual Perception: Depth the brain constructs perception of 3D from 2D images processed by the retina

Visual Perception: Depth Pictorial Cues

• familiar size • height in the field of view • linear perspective • overlap • shading • texture gradients

Motion Perception

Apparent Movement: perceive a stationary object as moving

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Visual Perception: Constancy Perceptual Constancies – recognition that objects do not physically change despite changes in vantage point and viewing conditions – sensory information (retinal image) changes, but perceptual interpretation does not

Size, Shape, and Color Constancies

Contours objective = real subjective = generated by your brain

Illusions when our perception does not match the true physical characteristics of an object

Perceptual set we see what we expect to see

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