1. Sensation & Perception ATTENTION, PROCESSING, THRESHOLDS

2. Goals  Contrast sensation & perception; understand how we process & attend to stimuli in the environment.

3. Sensation Process by which our sensory receptors and nervous system receive and represent stimulus energy

4. Perception Process of organizing & interpreting sensory information, enabling us to recognize meaningful objects and events

5. Bottom-up Processing Analyze stimulus beginning w/sensory receptors and work up to brain’s integration of sensory info Sensory cortex Auditory cortex Visual cortex

6. Top-down Processing Process info by higher-level mental processes Draw upon experiences & expectations

7. Selective Attention: Focusing conscious awareness “Cocktail party affect” – attending to one sound/voice in an environment Inattentional blindness – missing stimuli in environment due to selective attention Change blindness – missing changes in stimuli due to selective attention

8. Goal  Distinguish between absolute thresholds and difference thresholds.

9. What is the absolute threshold? Weakest amount of a stimulus that a person can detect 50% of the time

10. 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

11. Subliminal Perception Below one’s absolute threshold for conscious awareness Priming will activate your conscious mind, predisposing one’s perception, memory, or response

12. 0 25 50 75 100 Low Absolute threshold Medium Intensity of stimulus Percentage of correct detections Subliminal stimuli

13. What is the difference threshold? Minimal difference or change in intensity of a stimulus that a person can notice 50% of the time –i.e. Change in volume on the radio, change in lighting

14. Sensory Adaptation Decreased sensation due to constant stimulation. Decreased sensitivity to stimulus