unit 1 biological basis

Sensation

the relationship between physical stimulation and its psychological effects

Perception

How we recognize, interpret, and organize our sensations

Psychophysics

A branch of psychology that deals with the effects of physical stimuli on sensory response

Absolute Threshold

The minimal amount of stimulation needed to detect a stimulus and cause the neuron to fire 50 percent of the time

Signal Detection Theory (SDT).

This theory takes into consideration that there are four possible outcomes on each trial in a detection experiment: The signal (stimulus) is either present or it is not, and the participants respond that they can detect a signal or they cannot.

Hit

The signal was present, and the participant reported sensing it.

Miss

The signal was present, but the participant did not sense it.

False alarm

The signal was absent, but the participant reported sensing it.

Correct rejection

The signal was absent, and the participant did not report sensing it.

Discrimination threshold

The ability to distinguish the difference between two stimuli

Just Noticeable Difference (JND)/ Difference threshold.

The minimum amount of distance between two stimuli that can be detected as distinct

Ernst Weber (1795-1878)

noticed that at low weights, say one ounce, it was easy to notice one-half-ounce increases or decreases in weight; however, at high weights, say 32 ounces, participants were not well able to judge one-halfounce differences.

Weber's Law

The observation that the JND is a proportion of stimulus intensity; This law states that the greater the magnitude of the stimulus, the larger the differences must be to be noticed.

Subliminal perception

A form of preconscious processing that occurs when we are presented with stimuli so rapidly that we are not consciously aware of them.

Tip-of-the-tongue Phenomenon

Phenomenon in which we try to recall something that we already know is available but is not easily available for conscious awareness. This phenomenon demonstrates that certain preconscious information may be available to the conscious mind but quite difficult to access.

Receptor Cells

Specialized cells in the sensory organ which are designed to detect specific types of energy.

Receptive field.

The area from which our receptor cells receive input

Transduction

A process in which the receptors convert the input, or stimulus, into neural impulses, which are sent to the brain.

Contralateral Shift

Occurs at the level of the thalamus; process in which much of the sensory input from one side of the body travels to the opposite side of the brain

Sensory Coding

The process by which receptors convey such a range of information to the brain.

Single Cell Recording

A technique by which the firing rate and pattern of a single receptor cell can be measured in response to varying sensory input.

Visual Sensation

Occurs when the eye receives light input from the outside world.

Distal Stimulus

The object as it exists in the environment

Proximal Stimulus.

The image of an object on the retina

Cornea

A protective layer on the outside of the eye.

Lens

Under the cornea; The curvature changes to accommodate for distance.; focuses light into the retina

Retina

In the back of the eye and serves as the screen onto which the proximal stimulus is projected.

Rods

Receptor located on the periphery of the retina, are sensitive in low light.

Cones

Concentrated in the center of the retina, are sensitive to bright light and color vision.

Fovea

center of the retina

Bipolar Cells

Eye neurons that receive information from the retinal cells and distribute information to the ganglion cells

Amacrine Cells

Retinal cells found in the inner synaptic layer that make synaptic contacts with bipolar cells, ganglion cells, and one another

Optic Nerve

The nerve that carries neural impulses from the eye to the brain

Optic Chiasm

The point at which optic nerve fibers cross in the brain

Serial processing

Process that occurs when the brain computes information step-by-step in a methodical and linear matter

Parallel processing

Process that happens when the brain computes multiple pieces of information simultaneously.

Feature detector

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement

Convergence

This process, by which information becomes more complex as it travels through the sensory system

Young-Helmholtz/ Trichromatic theory.

According to this theory, the cones in the retina of the eyes are activated by light waves associated with blue, red, and green. We see all colors by mixing these three, much as a television does.

Opponent Process Theory

Theory that contends that cells within the thalamus respond to opponent pairs of receptor sets—namely, black/white, red/green, and blue/yellow. If one color of the set is activated, the other is essentially turned off.

Afterimage

A visual image that persists after a stimulus is removed.

Auditory input

Enters the ear in the form of sound waves; enters the ear by passing the outer ear, the part of the ear that is on the outside of your head, and into the ear canal. The outer ear collects and magnifies sound waves. The vibrations then enter the middle ear, first vibrating the tympanic membrane.

Tympanic Membrane

The eardrum. A structure that separates the outer ear from the middle ear and vibrates in response to sound waves.

Ossicles

The three tiny bones that comprise the middle ear.

Stapes

vibrates against the the oval window. The oval window is the beginning of the inner ear; last of the three auditory ossicles of the middle ear

Cochlea

a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

Vestibular Sacs

organs in the inner ear that connect the semicircular canals and the cochlea and contribute to the body's sense of balance

Place Theory

Theory of hearing that states that our perception of sound depends on where each component frequency produces vibrations along the basilar membrane.

Frequency Theory

Theory of hearing that states that we sense pitch because the rate of neural impulses is equal to the frequency of a particular sound.

Deafness

Occurs from damage to the ear structure or the neural pathway.

Conductive deafness

Injury to the outer or middle ear structures, such as the eardrum.

Sensorineural

hearing loss caused by permanent or temporary damage to the sensory cells or nerve fibers of the inner ear

Olfaction

Sense of smell

Gustation

Sense of taste

Cutaneous Receptors

Nerve receptors in the skin that respond to pressure, temperature, or pain

Tactile Receptors

Nerve receptors in the skin that provide sensations of touch, pressure, and vibration

Cold fibers

Neurons that fire in response to cold stimuli

Warm fibers

Neurons that fire in response to warm stimuli

vestibular sense

Sense of balance

Kinesthesis

Found in the joints and ligaments, transmits information about the location and position of the limbs and body parts.

Adaptation

An unconscious, temporary change in response to environmental stimuli.

Habituation

The process by which we become accustomed to a stimulus, and notice it less and less over time

Dishabituation

Occurs when a change in the stimulus, even a small change, causes us to notice it again; also occurs when a stimulus is removed and then re-presented.

Attention

Processing through cognition of a select portion of the massive amount of information incoming from the senses and contained in memory

selective attention

attending to one thing while ignoring another.

cocktail party phenomenon

A phenomenon in which people tune in one message even while they filter out others nearby

Filter theories

Propose that stimuli must pass through some form of screen or filter to enter into attention.

Attentional resource theories

Posit that we have only a fixed amount of attention, and this resource can be divided up as is required in a given situation.

Divided attention

Focusing on more than one task at a time, is most difficult when attending to two or more stimuli that activate the same sense

Perceptual Process

A sequence of steps leading from the environment to perception of a stimulus, recognition of the stimulus, and action with regard to the stimulus.

Bottom-up processing

Analysis that achieves recognition of an object by breaking it down into its component parts. It relies heavily on the sensory receptors; is the brain's analysis and acknowledgement of the raw data.

Top-down processing

Analysis in which the the brain labels a particular stimulus or experience.

Visual perception

the ability to interpret the surrounding environment by processing information that is contained in visible light

Monocular depth

cues that we need only one eye to see. As such, they can be depicted in two-dimensional representations.

Relative size

a monocular cue for perceiving depth; the smaller retinal image is farther away; the fact that images that are farther from us project a smaller image on the retina than do those that are closer to us.

Texture gradient

a monocular cue for perceiving depth; a gradual change from a coarse distinct texture to a fine, indistinct texture signals increasing distance. objects far away appear smaller and more densely packed

Interposition

occurs when a near object partially blocks the view of an object behind it.

Linear perspective

a monocular cue based on the perception that parallel lines seem to draw closer together as the lines recede into the distance.

vanishing point

the point at which the two lines become indistinguishable from a single line and then disappear.

Aerial perspective

perceptual cue based on the observation that atmospheric moisture and dust tend to obscure objects in the distance more than they do nearby objects.

Relative clarity

a perceptual clue that explains why less distinct, fuzzy images appear to be more distant

Motion parallax

the difference in the apparent movement of objects at different distances, when the observer is in motion.

Binocular depth cues

cues that rely on both eyes viewing an image. They result from the fact that each eye sees a given image from a slightly different angle.

Stereopsis

the three-dimensional image of the world resulting from binocular vision

Retinal convergence

a depth cue that results from the fact that your eyes must turn inward slightly to focus on near objects.

binocular disparity

process that results from the fact that the closer an object is, the less similar the information arriving at each eye will be.

Eleanor Gibson and Richard Walk

developed the visual cliff to test depth perception

Visual cliff

a lab device for testing depth perception in infants and young animals

Gestalt approach

A psychological school of thought originating in Germany that proposed that the whole of a perception must be understood rather than trying to deconstruct perception into its parts

Proximity

the tendency to see objects near to each other as forming groups

Similarity

the tendency to prefer to group like objects together

Symmetry

the tendency to perceive preferentially forms that make up mirror images

Continuity

the tendency to perceive preferentially fluid or continuous forms, rather than jagged or irregular ones

Closure

the tendency preferentially to see closed objects rather than those that are not complete

Law of Prägnanz/ Law of simplicity

when several perceptual organizations are possible, the perceptual interpretation that occurs will be the one that produces the "best, simplest, and most stable shape"

feature detector approach

An approach that reduces an image to its simplest form by positing that organisms respond to specific aspects of a particular stimulus.

Constancy

the tendency to perceive certain objects in the same way regardless of changing angle, distance, or lighting

motion detection

Determining an object's change in position in relation to its surroundings.

apparent motion

the perception of movement as a result of alternating signals appearing in rapid succession in different locations

Physiological Psychology

The study of behavior as influenced by biology