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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