Basic Concepts of Sensation and Perception

How it works

• sensation and perception are used to intake sensory stimuli and use it to recognize meaningful objects and events

• sensory systems convert one form of energy into another

  • vision processes light waves, hearing processes sound waves

• all senses

  • receive sensory stimulation, often using specialized receptors

  • transform that stimulation into neural impulses

  • deliver the neural info to the brain

• field of psychophysics studies relationships between the physical energy we can detect and its effects on our psychological experiences

• we have edges of our awareness to detecting faint stimuli

  • absolute thresholds process minimum stimulation necessary to detect a particular light, sound, pressure, taste, or odor

  • 50% of the time we cannot detect this stimuli, known as subliminal stimuli

• priming can be used with subliminal sensory inputs

• perception is selective and subjective, depends on each person

Lesson 1 Focus Questions

• explain the difference between sensation and perception

• explain the difference between top-down and bottom-up processing

• define perceptual set and identify examples

Sensory adaption

• you become less aware of unchanging stimulus when constantly exposed to it

• our eyes are always moving, so our visual receptors are constantly simulated by the constant changes

• new info taken in by changes in sensory inputs are what constantly capture our attention and shape our experiences

• we perceive the world not exactly as it is, but as useful as it is for us to perceive it

Perceptual set

• expectations for what we will perceive affect top-down processing, and determine what we hear, taste, feel and see

• we can hear/see different things based on what we expected to see/hear in those contexts

• cultural background is an example of what creates and influences our perceptual set

Context, Motivation, and Emotion

• context of a situation, different prompts, a fuller picture, and cultural context/backgrounds all influence perceptual set

• motivation influences perceptual set

  • a long walk seems longer when you’re tired, a ball seems bigger when you have to hit it, water seems closer when you’re thirsty

• emotional state at the time can influence the assumptions you make

  • hearing/reading/interpreting things as grim or hopeless when you’re sad

• all are forms of top-down processing, where the brain influence how we perceive things based on its own assumptions

Lesson 2 Focus Questions

• how do threshold, adaptation, and signal detection impact our perception of the world around us?