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 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.