Chapter 5 Introduction to Sensation and Perception Sensation

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Chapter 5 Introduction to Sensation and Perception

Chapter 5 Introduction to Sensation and Perception

Sensation § the process by which our sensory receptors and nervous system receive and

Sensation § the process by which our sensory receptors and nervous system receive and represent stimulus energy § Perception § the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Sensation § Our sensory and perceptual processes work together to help us sort out

Sensation § Our sensory and perceptual processes work together to help us sort out complex images

Sensation § Bottom-Up Processing § analysis that begins with the sense receptors and works

Sensation § Bottom-Up Processing § analysis that begins with the sense receptors and works up to the brain’s integration of sensory information § Top-Down Processing § information processing guided by higher-level mental processes § as when we construct perceptions drawing on our experience and expectations

Sensation- Basic Principles § Psychophysics § study of the relationship between physical characteristics of

Sensation- Basic Principles § Psychophysics § study of the relationship between physical characteristics of stimuli and our psychological experience of them § Light- brightness § Sound- volume § Pressure- weight § Taste- sweetness

Sensation- Thresholds § Absolute Threshold § minimum stimulation needed to detect a particular stimulus

Sensation- Thresholds § Absolute Threshold § minimum stimulation needed to detect a particular stimulus 50% of the time § Difference Threshold § minimum difference between two stimuli required for detection 50% of the time § just noticeable difference (JND)

Sensation- Thresholds § Signal Detection Theory § predicts how and when we detect the

Sensation- Thresholds § Signal Detection Theory § predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise) § assumes that there is no single absolute threshold § detection depends partly on person’s § experience § expectations § motivation § level of fatigue

Sensation- Thresholds 100 Percentage of correct detections § Subliminal 75 50 Subliminal stimuli 25

Sensation- Thresholds 100 Percentage of correct detections § Subliminal 75 50 Subliminal stimuli 25 0 Low Absolute threshold Intensity of stimulus Medium § when stimuli are below one’s absolute threshold for conscious awareness

Sensation- Thresholds § Weber’s Law § to be perceived as different, two stimuli must

Sensation- Thresholds § Weber’s Law § to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount) § light intensity- 8% § weight- 2% § tone frequency- 0. 3%

Sensation- Thresholds § Sensory Adaptation § diminished sensitivity as a consequence of constant stimulation

Sensation- Thresholds § Sensory Adaptation § diminished sensitivity as a consequence of constant stimulation § Selective Attention § focusing of conscious awareness on a particular stimulus § as in the cocktail party effect

Now you see it, now you don’t!

Now you see it, now you don’t!