Sensation

Sensation versus perception

Basic principles

Vision

Sensation versus Perception

Chapter 5 versus Chapter 6

Sensation: detecting physical environment and turning it into neural signals

Perception: interpreting sensations

Example

 

 

Absolute threshold

level of intensity that is detected 50% of time

it varies

signal detection theory

 

 

 

Subliminal Persuasion?

 

 

 

 

 

 

Why do beliefs endure?

Pratkanis blames the popular press

Difference threshold

AKA Just Noticeable Difference (JND)

minimum difference between 2 stimuli that can be detected 50% of the time

Weber's law:

Applications of Weber's law

money

Specific Senses

Vision

 

Vision- Parts of the eye

cornea

pupil

iris

lens

retina

see figure 5.5, page 155

 

Retina

Rods (Table 5.1, p. 158)

Cones

Fovea

optic nerve (blind spot)

VIP- Feature Detection

Specialized neurons in visual cortex

Information then passed along to other areas (temporal, parietal)

other specialized brain cells respond to specific visual scenes (e.g., face)

Parallel Processing

We process information at many levels simultaneously (cf. computer)

explains loss of one aspect of vision

Color vision

Objects do not have a color; it is a construction by our brains

Young-Helmholtz trichromatic theory

Opponent process theory

 


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