Chapter 4: Sensing and Perceiving Our World Flashcards
What is a sensation?
Stimulation of our sense organs by outside world
What is perception?
Act of organizing and interpreting sensory experience
What are the two basic sensory processes?
1) Sensory Adaptation - sensitivity of senses diminish with constant stimulation
2) Transduction - when sense organs convert physical stimuli to neural impulses
What influences the way we interpret our senses?
1) Expectation
2) Experience
3) Context
What are the four principles of perception?
1) Absolute Threshold
2) Signal Detection Theory
3) Difference Threshold
4) Perceptual Set
What is Absolute Threshold?
Lowest level of intensity required for you to detect stimulus 50% of the time
What is Signal Detection Theory? What are the types of signals?
Thresholds vary depending on motivation
1) Hit - signal present and see it
2) Miss - signal present and don’t see it
3) False Alarm - signal absent but see it
4) Correct Rejection - signal absent and don’t see it
What is Difference Threshold and Just Noticeable Difference? What is Weber’s Law?
Once you Perceive a stimulus, how much does it have to change for you to notice change (this is the JND)
Weber’s Law - constant fraction tells you how much something needs to change in order to cross the JND line
What is Perceptual Set?
What you expect to see affects what you will see
What are the components of the eye and their function?
1) Cornea - bends light to focus on pupil
2) Pupil - open space lets light through
3) Iris - Colored part of eye. Adjust size of pupil.
4) Lens - Allows you to look at things at different distances (accommodation)
5) Retina - Does transduction
6) Photoreceptors - contains Rods (night vis most in periphery) and Cones (color/bright light most in fovea)
7) Optic Nerve - transmits signals from eye to brain
What are the three components of Depth Perception?
1) Binocular Depth Cues - binocular disparity used to integrate two 2-D images into one 3-D image
2) Monocular Depth Cues - linear perspective, texture gradient, and interposition
3) Perceptual Constancy - Preserve perception despite changes in retinal image
- Size Constancy
- Shape Constancy
What is retinal convergence?
Eyes cross as something gets closer
How do people organize elements of figures into whole objects?
1) Similarity
2) Continuity
3) Proximity
What is the law of closure?
perceive whole object even if small piece missing
Bottom up processing vs. Top down processing?
Bottom up processing: put pieces together then seeing whole
Top down processing: perception of whole guides perception of segment
