Flashcards in Chapter One: Introduction Deck (20):
The ability to detect a stimulus and to turn that detection into a private experience
The act of giving meaning to a detected sensation
A private conscious experience of sensation or perception.
Connect to outside world. Bring in new information. Plan movements. Help adapt to changes in environment.
Published elements of Physiology. Law of Specific Nerve Energies (Nature of sensation depends on which sensory fibers are stimulated, not how fibers are stimulated.)
Field of Study between physical stimuli and human response.
Published Elements of Psychophysics. Absolute threshold and difference threshold. Developed three methods.
Method of adjustment
Ask the subject to adjust the intensity of a tone until it is just barely audible. Determine with some measuring device the amount of energy in the tone at that threshold intensity setting. The amount of energy in the tone is the absolute threshold value for the auditory system of the listener. Controlled by subject. Not reliable.
Method of Limits
Consists of ascending and descending series of stimulus
intensity presentations. Ascending series starts with a small amount of energy in a tone and cannot be heard by the listener. On each trial the intensity of the tone is increased by a small ﬁxed amount until the listener reports hearing the sound.
Method of Constant Stimuli
Produces a psychometric function. This determines what threshold is. Intensities are presented in random order, subject responds yes or no.
Presenting stimulus that vary in intensity and having participants respond whether they detected it or not. Minimum amount of stimulation necessary for a person to detect a stimulus 50% of the time.
Smallest detectable difference between two stimuli
Delta I/i=k (Webers Law). Delta I = difference threshold. K=weber fraction. I = base intensity. JND is a constant fraction of the comparison stimulus.
logR= physical stimulus
Magnitude of subjective sensation increases proportionally to the logarithm of the stimulus intensity.
Steven's Power Law
S = perceived intensity
I = physical intensity
c = constant
n = more important constant
Magnitude of sensation is proportional to stimulus magnitude raised to an exponent
Signal Detection Theory
Quantifies the response of an observer to the presentation of a signal in the presence of noise. D prime. Criterion of Observer. Subject sets criterion to max gains.
Receiver operating characteristic (ROC) curve
In studies of signal detection, the graphical plot of the hit rate as a function of the false alarm rate. Flat line - observer cannot tell difference between presence and absence of signal. As sensitivity increases, curve bows upward. Hit vs. FA.
How complex signals can be simplified to simpler signals
change payoff, rating system