1A: Intro & Psychophysics Flashcards
What is Perception?
A Biological process that requires a stimulus
What is a Stimulus?
A physical energy that initiates a physiological chain of events
What are the goals of Perception?
To effectively interact with the enviroment
What is Perceptions 3 Step Process?
Detection, Discrimination, and Identification
Define Detection
Register presence of a Stimulus
Define Discrimination
The ability to notice/ distinguish 2+ Stimuli/ stimulus change.
Define Identification
Recognize a Stimulus
What is Localization
The ability to detect where objects are in space.
Why is Perception not always accurate?
It is subject to influence; attention, expectation, and content.
What is Psychophysics?
the relationship between physiological and psychological events. (Sound intensity and perceived loudness)
What is Absolute Threshold?
The minimum stimulus intensity required for detection 50% of the time.
What is the Method of Constant Stimuli?
A. Provide multiple presentations of a fixed stimuli varying in intensity in random order.
B. observer indicates whether he/she detects the stimulus on each trial.
C. measure number of “yes” responses for each stimulus
D. graph a frequency distribution and determine the absolute threshold
What is the Method of Limits (Adjustment)?
a. increase (or decrease) stimulus intensity gradually until response changes
b. adjusted by the experimenter (limits) or observer (adjustment)
c. Absolute Threshold = average change point for ascending and descending series
d. requires multiple runs
What is Difference Threshold (JND)?
- the smallest difference required to discriminate between two stimuli
a. k.a., just-noticeable difference (JND)
What is Weber’s Law & Fechner’s Law?
As intensity of the standard increases, so does the JND
The JND is a constant fraction of the comparison stimulus
