Behavioral Sciences Ch2 Flashcards
Sensation and Perception
Transduction
Taking the physical, electromagnetic, auditory, and other information from our internal and external environment and converting this information into electrical signals in the nervous system
Perception
Processing information within the CNS in order to make sense of the information’s significance
Sensory receptors
Neurons that respond to stimuli by triggering electrical signals that carry information to the central nervous system
Distal stimuli
Physical objects outside of the body
Proximal stimuli
Sensory-stimulating byproducts
Psychophysics
The field that studies the relationship between the physical nature of stimuli and the sensations and perceptions these stimuli evoke
Photoreceptors
Respond to electromagnetic waves in the visible spectrum
Mechanoreceptors
Respond to pressure or movement
Nociceptors
Respond to painful or noxious stimuli
Thermoreceptors
Respond to changes in temperature
Osmoreceptors
Respond to the osmolarity of the blood
Olfactory receptors
Respond to volatile compounds
Taste receptors
Respond to dissolve compounds
Sensory thresholds
The minimum amount of a stimulus that renders a difference in perception
Absolute Threshold
The minimum of stimulus energy that is needed to activate a sensory system
- Threshold in sensation not perception
Threshold of conscious perception
The level of intensity that a stimulus must pass in order to be consciously perceived by the brain
Subliminal perception
Information that is received by the CNS but doesn’t cross the threshold of conscious perception
Difference threshold
AKA just-noticeable difference
The minimum change in magnitude required for an observer to perceive that two different stimuli are different
Discrimination testing
- a participant is presented with a stimulus
- The stimulus is then varied slightly and researchers ask the participant to report whether they perceive a change
Weber’s Law
Differences in thresholds are proportional and must be computed as percentages
- Applies to loudness, pitch, brightness and weight
Signal detection theory
Studies how internal (psychological) and external (environmental) factors influence thresholds of sensation and perception
Noise trials
A trail in which the signal is presented
Catch trails
A trail in which the signal is not presented
A Hit
signal present and correctly perceives it
A miss
signal present but nit perceived
A false alarm
Signal not present but perceived
A correct negative
signal not present and not perceived
Blood vessels of the eye
- Choroidal vessels: a complex intermingling of blood vessels between the sclera and the retina
- Retinal Vessels
Duplicity theory of vision
The retina contains two kinds of photoreceptors: those specialized for light-and-dark detection and those for color detection
Path of synapses from rods and cons
- Rods and cones synapse directly with bipolar cells, which highlight gradients between adjacent rods and cones
- Bipolar cells synapse with ganglion cells, the axons of which group together to form the optic nerve
Parallel processing
The brains ability to analyze information regarding color, form, motion, and depth simultaneously using independent pathways in the brain
Form
Refers not only to the shape of an object, but also our ability to discriminate an object of interest from the background by detect its boundaries
Parvocellular cells
Cells in lateral geniculate nucleus that receive information from the fovea
- Have high color spatial resolution
Spatial resolution
Permits us to detect very fine detail when thoroughly examining an object
Magnocellular cells
Cells well-suited for detecting motion, because they have high temporal resolution
- Receives input from the periphery of our vision , allowing more rapid detection of objects approaching us from the sides
Depth perception
Our ability to discriminate the 3D shape of our environment and judge the distance of objects within it, is largely based on discrepancies between the inputs the brain receives from our two eyes
Binocular neurons
neurons responsible for comparing the inputs to each hemisphere and detecting these differences
Feature detector cell
Each feature detector cell type detects a very particular individual feature of an object in the visual field
Place theory
States that the location of a hair cell on the basilar membrane determines the perception of pitch when that hair cell is vibrated
- highest frequency pitches closer to the oval window
- low-frequency pitches at the apex - away from oval window
Olfactory Chemoreceptors
- Located in olfactory epithelium in the upper part of the nasal cavity
- Bind to their respective chemoreceptors to cause a signal
- Large number of specific chemoreceptors allows us to recognize subtle differences in similar scents
Pheromones
Chemicals secreted by one animal that urge another animal to behave in a specific way
Olfactory pathway
- Inhale into nasal cavity
- contact the olfactory nerves in the olfactory epithelium
- Send signals to the olfactory bulb
- relay via the olfactory tract to higher regions of the brain, including the limbic system
What are the five basic tastes
Sweet, sour, salty, bitter, umami
Taste
- Detected by chemoreceptors, which are sensitive to dissolved compounds
- Receptors for taste are groups of cells called taste buds, which are found in little bumps on the tongue called papillae
- From taste buds to the brainstem, then to the taste center in the thalamus before traveling to higher-order brain regions
Pacinian Corpuscles
Respond to deep pressure and vibration
Meissner corpuscles
respond to light touch
Merkel cell
respond to deep pressure and texture
Ruffini endings
respond to stretch
free nerve endings
respond to pain and temperature
Bottom-up processing
Object recognition by parallel processing and feature detection
Top-down processing
Driven by memories and expectations that allow the brain to recognize the whole object and then recognize the components based on these expectations
Perceptual organization
The ability to create a complete picture or idea by combining top-down and bottom-up processing with all of the other sensory clues gathered from an object
Monocular Cues
Only require one eye and include relative size, interposition, linear perspective, motion parallax, and other minor cues
Relative size
The idea that objects appear larger the closer they are
Interposition
When two objects overlap, the one in front is closer
Linear Perspective
The convergence of parallel lines at a distance
- greater the convergence, the further the distance
Motion parallax
the perception that objects closer to us seem to move faster when we change our field of vision
Binocular cues
involve retinal disparity, which refers to the slight difference in images projected on two retinas
Convergence
The brain detects the angle between the two eyes required to bring an object into focus
Constancy
Our ability to perceive that certain characteristics of objects remain the same, despite changes in the environment
Gestalt Principles
A set of general rules that account for the fact that the brain tends to view incomplete stimuli in organized , patterned ways
What are the 5 main gestalt principles?
- Proximity
- Similarity
- Good continuation
- Subjective contours
- Closure
Law of proximity
elements close to one another tend to be perceived as a unit
Law of similarity
objects that are similar tend to be grouped together
Low of good continuation
elements that appear to follow in the same pathway tend to be grouped together
Subjective contours
perceive contours and, therefore, shapes that are not actually present in the stimulus
Law of closure
When a space is enclosed by a contour, the space tends to be perceived as a complete figure
Law of pragnanz
Perceptual organization will always be as regular, simple, and symmetric
- governs gestalts principles
