1: Introduction to Perception Flashcards
What is distal stimulus? Proximal stimulus?
Distal: “distant”
Proximal: “in proximity” to receptors
What is principle of transformation? Principle of representation?
Transformation: stimuli and responses created by stimuli are transformed, or changed, between the distal stimulus and perception.
Representation: everything person perceives based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and the resulting activity in the person’s nervous system.
When visual receptors that line the back of the eye receive light, they do what two things?
Transform environmental energy into electrical energy.
Shape perception by the way they respond to different properties of stimuli.
Visual receptors transform light energy into electrical energy because they contain a light-sensitive chemical called what?
Visual pigment.
What is transduction?
Transformation of one form of energy (light energy) to another form (electrical energy).
What are the primary receiving areas for vision, hearing, and skin senses? What lobe receives signals from all the senses?
Vision: occipital
Hearing: temporal
Skin senses: parietal
Signals from all senses: frontal
Distinguish between perception and recognition.
Perception: conscious awareness
Recognition: placing object in a category (e.g. “tree”)
What vision disorder marks the inability to recognize objects?
Visual form agnosia.
What is the oblique effect?
People see vertical or horizontal lines better than lines oriented obliquely (at any orientation other than vertical or horizontal).
What are the three relationships pertinent to psychophysics?
Stimulus-perception relationship
Stimulus-physiology relationship
Physiology-perception relationship
What is grating acuity and what relationship does it demonstrate?
Smallest width of lines that subjects can detect. Demonstrates stimulus-perception relationship.
Knowledge, memories, and expectations are described as what factors?
Cognitive influences on perception.
What are thresholds?
Measure limits of sensory systems; measures of minimums.
Fechner proposed that the mind could be studied by measuring what?
The relationship between changes in physical stimulation and a person’s experience.
Fechner’s proposal is based on what observation?
By increasing the intensity of a light, the person’s perception of the brightness of the light also increases.
Describe the method of limits.
Presents stimuli in either ascending order (intensity is increased) or descending order (intensity is decreased).
Detect tone = crossover
Threshold = average of crossovers
Describe the method of adjustment.
Stimulus intensity is adjusted continuously until observer detects it.
Repeated trials averaged for threshold.
Describe the method of constant stimuli.
Several stimuli of different intensities are presented in random order, multiple trials presented.
Threshold is the intensity that results in detection in 50% of trials.
What are absolute thresholds and difference thresholds?
Absolute threshold: smallest stimulus level that can be detected.
Difference threshold: smallest difference between two stimuli that enables us to tell the difference between them.
What is Weber’s Law?
DL / s = k
DL = difference threshold s = standard stimulus k = Weber fraction
For a given stimulus, measure Weber fraction (DL / s).
With known Weber fraction and a new stimulus, calculate DL (k x s).
The function that shows how the threshold becomes smaller as the person spends more time in the dark is called what?
Dark adaptation curve.
What is magnitude estimation?
Observer is given a standard stimulus and a value for its intensity, compares the standard stimulus to test stimuli by assigning numbers relative to the standard.
What is response compression? Response expansion?
Response compression: Intensity increases, perceived magnitude increases more slowly than intensity.
Response expansion: Intensity increases, perceived magnitude increases more quickly than intensity.
Describing what is out there is called…
Phenomenological report.
What parts of the electromagnetic spectrum are we able to perceive?
400nm - 700nm
