Sensation and Perception

SENSATION AND PERCEPTION APSY 382
Aug 27th, 2012
Chapter 1
Psychophysics – how we measure perception (loose definition)
Sensation = unidimensional = varies in one way (sounds get louder or softer)
Perception = multidimensional = varies in many ways (there are a lot of kinds of books)
Perception – knowing the present
Memory – knowing the past
Thinking – knowing the future Cognition = the influence of perception, memory, and thinking
Aug 29th, 2012
Basic principles of perception
1. Stimulation
- Many kinds of energy implode on the body o Electromagnetic energy (light) o Mechanical energy
 -Pressure waves in air
 Pressure on skin
 Body movement o Thermal energy (heat) o Chemical energy (molecules in air, food)
- Energy changes detected by receptors
2. Information
a. Our sensory systems evolved to pick up information (not just stimulation)
b. In general, information is provided by change
c. Change can occur over time, or over space
3. Transduction
- The process of converting stimulus energy into nerve impulses
- Generally, stimulus energy causes a change in a receptor cell’s electrical potential (voltage)
- If change is enough, it will trigger “nerve impulses”
4. Transmission
- For perception to occur, sensory organs (containing receptors) must transmit nerve impulses to the brain
- Perception occurs in the brain, not in the sensory organs
5. Mediation
- Our perception of the world is mediated by various processes between transduction and our conscious awareness
- These processes alter the neural information
- What we consciously perceive may not be an accurate reflection of the original stimulation
6. Interpretation
- Sensory information is ambiguous (there are ALWAYS multiple possible interpretations)
7. Construction
- Sensory information is “sketchy”; the brain “fills in” missing information
8. Modularity
- Your brain consists of independent “modules”. These modules may construct different, possibly conflicting,