Chapter 2.1 Flashcards
What is the difference between distal and proximal stimuli
Proximal
- > directly affect sensory receptors
- > inform the observer about the presence of distal stimuli
- > eg; photoreceptors respond to light
Distal
- > stimuli that originate outside the body
- > they are part of the outside world
- > eg; campfire
What relationship does psychophysics look at
- it looks at the relationship between:
- > physical nature of stimuli and
- > sensations/perceptions that these stimuli evoke
What is a threshold an example of? What does it state
-threshold indicates the minimum amount of a stimulus that renders a difference in perception
What are the three types of thresholds
1) Absolute threshold
2) Threshold of conscious perception
3) Difference Threshold
What is the absolute threshold? Is it a threshold in sensation or perception
- it is the minimum stimulus energy that is needed to activate the sensory system
- > it has to do with sensation
-it has to do with how bright, loud, or intense a stimulus must be before it is sensed
What is the threshold of conscious perception? What kind of stimuli does it refer to? Do these stimuli arrive at the central nervous system? Are they transcuded?
- it is referred to stimuli that reach the central nervous system
- > but that are not perceived
- > stimuli is too subtle to demand our attention
- > or too brief of a duration for the brain to fully process it
- this is where the term subliminal comes in
- > stimuli that are below a given threshold
- > they arrive at the CNS and are transduced
- > but do not reach higher-order brain regions that control attention and consciousness
What is psychophysical discrimination testing and what theory of threshold does it refer to?
- a participant is presented with one stimulus
- the participant is then presented with another stimulus and is asked if there is a difference
- > this goes on for many stimuli
- > the difference between the original and current stimulus is increased until the participant reports a difference
-psychophysical discrimination testing refers to the theory of threshold of conscious perception
What does the difference threshold or just noticeable difference refer to
- it refers to the minimum difference
- >in magnitude between two stimuli before one can perceive the difference
What is the Weber’s law
- there is a constant ratio between change in stimulus needed to produce a just noticeable difference
- > and the magnitude of the original stimulus
- therefore, to discriminate a stimuli
- > the difference between the original and the new stimuli must be greater than the jnd
What does signal detection theory say perception can be affected by
- perception can be affected by:
- > nonsensory factors
- > such as experiences, motives and expectations
-change of stimuli depends on both internal and external factors
How can signal detection theory allows us to explore response bias
- response bias refers to the tendency of subjects to respond to a stimulus in a particular way
- > due to nonsensory factors
Describe the signal detection theory experiment that exposes response bias
- there are many trials
- trials in which stimuli are presented are catch trials
- trials in which stimuli are not presented are noise trials
- > after each trial, participants indicate whether the stimuli was presented or not
- hits= subject correctly perceives stimuli to be there
- miss=subject fails to perceive a given signal
- false alarm= subject says signals is there but none was given
- correct negative= subject correctly identifies that no signal was given
-significant proportion of misses or false alarms given an indication of response bias
What is adaptation? Can adaptation have a physiological and a psychological component?
- adaptation is a way for our body to focus our attention to the more relevant stimuli
- > which are usually the changes in the environment around us
- it does have a physiological component(sensory) and a psychological component(perceptual)
- > eg; we adapt to cold water and it does not seem cold anymore(psychological)
- > pupils of eyes dilate in the dark(physiological adaptation)
