Chapter 5 - Sensation and Perception
Psychological perspectives
- combination of cognitive and behavioral psychology
GESTALT PSYCHOLOGY
- the whole is different from the sum of the parts
- we perceive things from the senses in predictable ways
- figure-ground relationship: we see things as either main figure or background,
and this affects our perception (esp. in optical illusions)
- perceptual hypotheses are decisions we make to interpret sensory information
- principles of perceptual organization
- proximity (grouping by distance)
- continuity (following a line)
- similarity (colors and patterns)
- closure (filling in the gaps, looking at the whole and not the parts)
Sensation: stimulation of sensory receptors, detection of signals in the environment
Perception: conscious organization and interpretation of the information sensed
★ What we perceive is not always what is there
Signal detection theory
- we don’t perceive everything that stimulates the nerve cells
- example: a mother will wake up from the quiet murmur of a child but not louder
things
- transduction: conversion from sensory stimulus energy to action potential
- study of how much we notice things based on a sensory and decision process
- absolute threshold: minimum amount of stimulation needed to detect a
sensory input
- example: put someone in a dark room and add light gradually, how
much sensory stimulus is necessary for us to know we saw something
- subliminal messages are below this threshold and are unconscious
- just noticeable difference measures how much change is necessary for us to
notice change has taken place
- sensory adaptation is when a continuous stimulus is normalized and ignored
Attention
- ability to filter unimportant info and focus on specific tasks
- sensory adaptation: ability to adapt to stimuli that are constant and
unimportant, avoids sensory overload (wearing clothes, background
noise)
- selective attention: choosing one stimulus to follow and block out
others
Psychological perspectives
- combination of cognitive and behavioral psychology
GESTALT PSYCHOLOGY
- the whole is different from the sum of the parts
- we perceive things from the senses in predictable ways
- figure-ground relationship: we see things as either main figure or background,
and this affects our perception (esp. in optical illusions)
- perceptual hypotheses are decisions we make to interpret sensory information
- principles of perceptual organization
- proximity (grouping by distance)
- continuity (following a line)
- similarity (colors and patterns)
- closure (filling in the gaps, looking at the whole and not the parts)
Sensation: stimulation of sensory receptors, detection of signals in the environment
Perception: conscious organization and interpretation of the information sensed
★ What we perceive is not always what is there
Signal detection theory
- we don’t perceive everything that stimulates the nerve cells
- example: a mother will wake up from the quiet murmur of a child but not louder
things
- transduction: conversion from sensory stimulus energy to action potential
- study of how much we notice things based on a sensory and decision process
- absolute threshold: minimum amount of stimulation needed to detect a
sensory input
- example: put someone in a dark room and add light gradually, how
much sensory stimulus is necessary for us to know we saw something
- subliminal messages are below this threshold and are unconscious
- just noticeable difference measures how much change is necessary for us to
notice change has taken place
- sensory adaptation is when a continuous stimulus is normalized and ignored
Attention
- ability to filter unimportant info and focus on specific tasks
- sensory adaptation: ability to adapt to stimuli that are constant and
unimportant, avoids sensory overload (wearing clothes, background
noise)
- selective attention: choosing one stimulus to follow and block out
others
