1. Chapter 8 Sensation & Perception

2. Sensation & Perception
What occurs when a stimulus activates a receptor.
Perception
The organization of sensory information into meaningful experiences.

3. Psychophysics
The study of the relationships between sensory experiences and the physical stimuli that caused them.

4. Thresholds Absolute threshold Difference threshold
The weakest amount of a stimulus that a person can detect half the time.
Difference threshold
The smallest change in a physical stimulus that can be detected between two stimuli.
Also known as the JND

5. Approximate absolute thresholds for the 5 senses:
Vision - Candle flame seen at miles on a clear, dark night.
Hearing - Tick of a watch under quiet conditions at 20 feet.
Taste - 1 Teaspoon of sugar in 2 gallons of water.
Smell - 1 Drop of perfume diffused into a three-room apartment.
Touch - A bee's wing falling on your cheek from 1 centimeter above.

6. Weber’s Law
For any change in a stimulus to be detected, a constant proportion of that stimulus must be added or subtracted.

7. Sensory Adaptation
Your senses are most responsive to increases and decreases, and to new events rather than to ongoing, unchanging stimulation.

8. Detecting Stimuli Signal-detection theory
The study of people’s tendencies to make correct judgments in detecting the presence of stimuli.

9. The Stroop Effect

10. Stare at the grid only briefly, and you will see areas of gray at the intersections of the white rows and columns.

11. Now, try to count the black dots in this one.