UNIT 4: SENSATION & PERCEPTION

Module 12

Sensation & Perception•Sensation: the process by which you detect physical energy from your environment and encode it as neural signals.• In other words, how we receive information from our environment.•5 Senses: See, hear, touch, taste, & smell.

Sensation & Perception•Perception: the process that organizes sensory information and makes it meaningful.•This is what our body does with the information we sense. • It processes the information and transforms it into something we recognize.

Sensation & Perception•Psychophysics: the study of how physical stimuli (light, sound…) are translated into psychological experience.•Can you detect a stimulus, identify it, differentiate between it and another stimulus, and describe the magnitude of this difference?

Thresholds•Stimulus: a change in environment that can be detected by sensory receptors.•Absolute threshold: the weakest level of a stimulus that can be correctly detected at least half the time (50%). •Your absolute threshold is when you could detect a sound, light, etc. half the time.

Thresholds•The 50-50 recognition point defines your absolute threshold.

Thresholds•Signal detection theory: minimum threshold changes with fatigue, attention, expectations, motivation, emotional distress, and from one person to another.•Ex. I can spot gum chewing even when it is being disguised! • I can hear the chew and see subtle movements in your mouths!

Thresholds•Subliminal stimulation: receiving messages below one’s absolute threshold for conscious awareness.•They can have a momentary, subtle effect on thinking. (Subliminal messages)• Information processing occurs automatically unbeknownst to our conscious mind.

Thresholds•Difference threshold: minimum difference between any two stimuli that a person can detect 50% of the time.• Just noticeable difference (JND): when you experience the difference threshold.•e.g. adding one penny to a container with 10 pennies is more noticeable than if it had 100 pennies in it.

Thresholds•Weber’s Law: two stimuli must differ by a constant minimum percent (rather than a constant amount).

Two objects must differ by 2% to notice.

Thresholds•Sensory adaptation: diminished sensitivity because of constant stimulation.

•Put a band aid on your arm and after a while you don’t feel it.

Selective Attention•Selective attention: the focusing of conscious awareness on a particular stimulus.•Focusing on one thing allows us to block out other things going on. •Did you notice that your nose is in your line of vision?

Selective Attention•Cocktail party effect: ability to focus on one voice in a room full of people speaking.• Inattentional blindness: failing to see visible objects when our attention is directed elsewhere.•Change blindness (changing person) •Change deafness (changing speaker) •Choice blindness (changing choice)

Selective Attention•Pop-out Phenomenon: When a stimulus draws your eye, you can’t help but notice. It demands your attention.