psych 30 midterm 1

dualism

the body is physical and the mind is not (they are separate things)

materialism

the mind and body are physical and connected

panpsychism

idea that the mind exists as a property of all matter

psychophysics

the relationship between external stimuli and perception

two-point touch threshold

smallest distance btwn 2 points required for a person to feel touch on 2 points of the skin instead of one

just noticeable difference (JND) or difference threshold

smallest change in a stimulus that can be detected

Weber’s Law (or Weber’s fraction)

Weber’s fraction = just noticeable difference / stimulus intensity

—> the set fraction to help quantify change in stimulus required for noticeable difference

unconscious inference

when you brain tries to fill in the unknown by interpreting ambiguous visual data

Fechner’s law

S = k log R

—> explains that the perception of a stimulus intensity increasing is slower than the actual stimulus increasing

absolute threshold

minimum intensity of a stimulus that can be detected

what are the three methods to measure the absolute threshold?

method of constant stimuli, method of limits, method of adjustment

method of constant stimuli

stimuli of different intensities are shown randomly and multiple times to help estimate sensory thresholds

method of limits

gradually increase and decrease the intensity of a stimulus and measure when person either starts or stops hearing the stimulus - since ppl tend hear the stimulus start later when increasing the intensity and hear it stop earlier when decreasing it, balance this noise out to get an average threshold

method of adjustment

technique where the subject themselves controls the intensity of stimulus to identify thresholds

magnitude estimation

subject assigns a numerical value to the intensity of a stimulus (ex - if sensation is 2x as strong for something, the number they assign is likely to be double that too)

Stevens’s power law

the sensation/perception of a stimulus scales as an exponent (which varies depending on the type of sensation being measured) of the intensity

cross-modality matching

matching the same intensity across different types of stimuli (like finding a light that seems to be the same amount of brightness as a piece of music is loud)

signal detection theory

a way to measure people’s choices when they are uncertain about a stimulus being present or absent (hit, false alarm, miss, false rejection)

criterion (in signal detection theory) vs absolute threshold

criterion: subjective threshold that determines whether a person chooses to decide if a signal is present or absent (can adjust criterion based on person’s objectives - ex) can lower criterion if listening for important phone call))

absolute threshold: (more objective) minimum intensity of a stimulus for person to detect it 50% of time

sensitivity (in signal detection theory)

value shows the ease in which a person can differentiate the presence and absence of signals (higher number = larger difference / more clearly can differentiate when signal is present and when it is absent)

—> value is literally the difference between the average detection of a present signal strength with the average detection that a signal is absent

receiver operating characteristic (ROC) curve

a graph showing how well a model/subject identifies or denies a stimulus