Sensation and Perception Chapters 5 & 6

Some Basic Questions How do we sense the world?

Some Basic Questions How do we sense the world? How do we perceive color?

Some Basic Questions How do we sense the world? How do we perceive color? How do we perceive motion?

Some Basic Questions How do we sense the world? How do we perceive color? How do we perceive motion? How do we perceive size and shape?

Some Basic Principles Sensation  Detecting physical energy from the environment and encoding it as neural signals Perception  Select, organize, and interpret our sensations  How our mind interprets what our senses detect Sensation and Perception do not always cooperate

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  Our sensory and perceptual processes work together to help us sort out complext processes

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)

Difference Threshold  Weber’s Law-  to perceive as different, two stimuli must differ by a constant minimum percentage  light intensity- 8%  weight- 2%  tone frequency- 0.3%

Are these two colors the same?

Sensation- Thresholds  Subliminal  When stimuli are below one’s absolute threshold for conscious awareness Low Absolute threshold Medium Intensity of stimulus Percentage of correct detections Subliminal stimuli

Subliminal Advertising

Subliminal Messages Do subliminal messages work in songs? Lets find out!

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

Can you spot the “C” OOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOCOOOO OOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOO

Can you spot the “N” MMMMMMMMMMMMMMMMMMMMMM MMMMMMMMMMMMMMMMMMMMMM MMMMMMMMMMMMMMMMMMMMMM MMMMMMMMMMMMMMMMMMMMMM MMMMMMMMMMMMMMMMMMMMMM MMMMNMMMMMMMMMMMMMMMMM MMMMMMMMMMMMMMMMMMMMMM

Can you spot the “R”? BBBBBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBB

 Sensory adaptation-  diminished sensitivity as a consequence of constant stimulation