Behavioral Sciences Chapter 2: Sensation and Perception Flashcards
What is sensation?
Sensation is the conversion or transduction of physical, electromagnetic, auditory and other information from the internal and external environment into electrical signals in the nervous system.
What is perception?
Perception is the processing of sensory information to make sense of its significance.
What are sensory receptors?
nerves that respond to stimuli and trigger electrical signals
What are sensory ganglia?
Collections of cell bodies outside the central nervous system - Associated with sensory neurons
What are projection areas?
Sensory stimuli are transmitted to projection areas in the brain, which further analyze the sensory input
What is a threshold?
The minimum stimulus that causes a change in signal transduction.
What is the absolute threshold?
minimum of stimulus energy that is needed to activate a sensory system.
What is the threshold of conscious perception?
minimum of stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness
What is the difference threshold or just noticeable difference?
the minimum difference in magnitude between two stimuli before one can perceive the difference.
What is Weber’s law?
states that the jnd for a stimulus is proportional to the magnitude of the stimulus and that this proportion is constant over most of the range of possible stimuli
What is the Signal detection theory?
effects of nonsensory factors, such as experiences, motives, and expectations on perception of stimuli
What is response bias?
The tendency of subjects to respond systematically to a stimulus in a particular way due to nonsensory factors
What is adaptation?
A decrease in response to stimulus over time.
What does the cornea do?
It gathers and filters incoming light.
What does the iris do?
It divides the front of the eye into the anterior and posterior chamber. It contains two muscles, the dilator and constrictor pupillae, which open and close the pupil.
What does the lens do?
The lens refracts incoming light to focus it on the retina and is held in place by suspensory ligaments connected to the ciliary muscle.
What is the ciliary body?
The ciliary body produces aqueous humor, which drains through the canal of Schlemm.
What two things does the retina contain?
Rods and cones
What do rods do?
Rods detect light and dark
What do cones do?
Cones come in three forms to detect colors
Where is the macula?
Central vision field containing mostly cones, at the center is the fovea, which contains only cones.
Where do rods and cones synapse?
Bipolar cells
Where do bipolar cells synapse?
ganglion cells
What do horizontal and amacrine cells do?
Integrate the signals from ganglion and edge-sharpening
What is the eye supported by?
vitreous on the inside and sclera and choroid on the outside
What is the visual pathway?
Through the optic nerve, optic chiasm, optic tracks, lateral geniculate nucleus of the thalamus, and visual radiations to get to the visual cortex
What is the optic chiasm?
Contains fibers crossing from the nasal side of the retina of both eyes.
Where do the visual radiations run?
Through the temporal and parietal lobes.
Where is the visual cortex?
In the occipital lobe
How is color detected?
By cones
How is shape detected?
by parvocellular cells, with high spacial resolution and low temporal resolution
How is motion detected?
By Magnocellular cells, with low spatial resolution and high temporal resolution.
What is bottom-up (data-driven) processing?
It refers to recognition of objects by parallel processing and feature detection. It is slower, but less prone to mistakes.
What is top-down (conceptually driven) processing?
It refers to recognition of an object by memories and expectations, with little attention to detail. It is faster, but more prone to mistakes.
What is the gestalt principle?
Ways the brain can infer missing parts of a picture when a picture is incomplete.
What is the law of proximity?
Says that elements close to one another tend to be perceived as a unit.
What is the law of similarity?
Objects that are similar appear to be grouped together
What is the law of food continuation?
Says that elements that appear to follow the same pathway appear to be grouped together.
What is subjective contours?
Refers to the perception of nonexistent edges in figures, based on surrounding visual cues.
What is the law of closure?
Says that when a space is enclosed by a group of lines, it is perceived as a complete or closed line.
What is the law of pregnanz?
Says that perceptual organization will always be as regular simple and symmetric as possible
What does the outer ear consist of?
the pinna, external auditory canal and tyrannic membrane
What does the middle ear consist of?
ossicles, malleus, incus and stapes. The footplate of the stepes rests in the oval window of the cochlea. The middle ear is connected to the nasal cavity by the eustachian tube.
What does the inner ear contain?
the bony labyrinth, filled with endolymph. Consists of cochlea, utricle and saccule and semicircular canals
What does the utricle and saccule do?
detect linear acceleration
What does the semicircular canals do?
detect rotational acceleration
Where does the auditory pathway go?
Starts from the cochlea and travels through the vestibulocochlear nerve and medial geniculate nucleus of the thalamus to get to the auditory cortex in the temporal lobe.
Where does sound information project?
to the superior olive, which localizes the sound and the inferior colliculus, which is involved in the startle reflex.
What detects smell?
The olfactory chemoreceptors
Where does the olfactory pathway start?
from the olfactory nerves and travels through the olfactory bulb and olfactory tract to get to higher-order brain areas, such as the limbic system.
What are pheromones?
chemicals given off by animals that have an effect on social, foraging and sexual behavior in other members of that species
How is taste detected?
By the taste buds in papillae – sweet, salty, bitter and savory
What is somatosensation?
refers to the four touch modalities - pressure, vibration, pain and temperature.
What is a two-point threshold?
minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli
What is physiological zero?
The normal temperature of the skim to which objects are compared to determine if they feel warm or cold.
What are nociceptors?
They are responsible for pain perception
What is the gate theory of pain?
States that pain sensation is reduced when other somatosensory signals are present.
What is kinesthetic sense (proprioception)?
Ability to tell where one is in three dimensional space.
