PSYCH 104 Midterm 2 (sensation and perception) Flashcards
Sensation
- Sensation
○ The process by which (objective) stimuli are detected, transduced into nerve impulses and sent to the brain
Perception
- Perception
○ The brains interpretation of raw sensory inputs
Transduction
- Transduction
○ The process of converting an external energy or substance into electrical activity within neurons
Sense receptor
- Sense receptor
○ Specialized cell responsible for converting external stimuli into neural activity for a specific sensory system
Sensory adaptation
- Sensory adaptation
○ Activation is greatest when a stimulus is first detected and then declines in responsiveness
○ Also called neural adaptation
Psychophysics
- Psychophysics
○ The study of how we precieved sensory stimuli based on their physical characteristics
Absolute threshold
- Absolute threshold
§ Lowest level of a stimulus needed for the nervous system to detect a change 50 percent of the time
○ Just noticeable difference (JND)
§ The smallest change in the intensity of s stimulus we can detect
○ Weber’s law
§ There is a constant proportional relationship between the JND and original stimulus intensity
§ I = intensity of the stimulus
§ K = constant
JND
JND: the louder the volume is, the greater the change in volume that is needed to detect a difference
JND (Formula)
JND = K x I
§ I = intensity of the stimulus
§ K = constant (0.10)
Signal detection theory
Signal detection theory
- Asks two questions
○ Was waldo in the image?
○ Did you say waldo was in the image?
Signal
Signal = stimulus to be perceived
Signal detection theory (Noise)
Noise = everything else
What does Increased sensitivity to the signal cause?
Increased sensitivity to the signal causes hits and correct rejections to occur more often
What does Decreased sensitivity to the signal cause?
Decreased sensitivity to the signal causes misses and false alarms to occur more often
How are differences in sensitivity measured?
Differences in sensitivity are measured with a statistic called D-prime
- A measure of the stimulus salience
- Plotted using ROC curves (Receiver operating characteristic curves)