psychology
the science of behavior and mental processes
nature-nurture issue
the long-standing controversy over the relative contributions that genes and experience make to the development of psychological traits and behaviors
natural selection
the principle that, among the range of inherited trait variations, those contributing to reproduction and survival will most likely be passed on to succeeding generations
neuroscience
the perspective of psychological science that deals with how the body and brain create emotions, memories, and sensory experiences
evolutionary
the perspective of psychological science that deals with how nature selects traits that promote the perpetuation of one's genes
behavior genetics
the perspective of psychological science that deals with how much our genes, and our environment, influence our individual differences
psychodynamic
the perspective of psychological science that deals with how behavior springs from unconscious drives and conflicts
behavioral
the perspective of psychological science that deals with how we learn observable responses
cognitive
the perspective of psychological science that deals with how we encode, process, store, and retrieve information
social-cultural
the perspective of psychological science that deals with how behavior and thinking vary across situations and cultures
basic research
pure science that aims to increase the scientific knowledge base
applied research
scientific study that aims to solve practical problems
clinical psychology
a branch of psychology that studies, assesses, and treats people with psychological disorders
psychiatry
a branch of medicine dealing with psychological disorders, practiced by physicians who sometimes provide medical (for example, drug) treatments as well as psychological therapy
hindsight bias (I-knew-it-all-along phenomenon)
the tendency to believe, after learning an outcome, that one would have foreseen it
critical thinking
thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions
theory
an explanation using an integrated set of principles that organizes and predicts observations
hypothesis
a testable prediction, often implied by a theory
operational definition
a statement of the procedures (operations) used to define research variables. For example, intelligence may be operationally defined as what an intelligence test measures
replication
repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding generalizes to other participants and circumstances
case study
an observation technique in which one person is studied in depth in the hope of revealing universal principles
survey
a technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them
false consensus effect
the tendency to overestimate the extent to which others share our beliefs and behaviors
population
all the cases in a group, from which samples may be drawn for a study
random sample
a sample that fairly represents a population because each member has an equal chance of inclusion
naturalistic observation
observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation
correlation coefficient
a statistical measure of the extent to which two factors vary together, and thus of how well either factor predicts the other
scatterplot
a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of correlation (little scatter indic
illusory correlation
the perception of a relationship where none exists
experiment
a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants the experimenter controls other rele
placebo
an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent
double-blind procedure
an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.
placebo effect
any effect on behavior caused by a placebo
experimental condition
the condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable
control condition
the condition of an experiment that contrasts with the experimental condition and serves as a comparison for evaluation the effect of the treatment
random assignment
assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups
independent variable
the experimental factor that is manipulated; the variable whose effect if being studied
dependent variable
the experimental factor--in psychology, the behavior or mental process--that is being measured; the variable that may change in response to the manipulations of the independent variable
mode
the most frequently occurring score in a distribution
mean
the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores
median
the middle score in a distribution; the scores are above it and half are below it
range
the difference between the highest and lowest scores in a distribution
standard deviation
a computed measure of how much scores vary around the mean score
statistical significance
a statistical criterion for rejecting the assumption of no differences in a particular study
culture
the enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next
Biological psychology
concerned with links between biology and behavior
Neuron
building blocks of the nervous system
Dendrite
Branches designed to receive/send/and transport information
Axon
transports messages to different muscles/glands in the body
Action potential
a neural impulse; a brief electrical charge that travels down an axon. The action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane.
Myelin sheath
a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next
Threshold
the level of stimulation required to trigger a neural impulse
Synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or cleft
Neurotransmitters
chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural
Acetylcholine
a neurotransmitter that, among its functions, triggers muscle contraction
Endorphins
morphine within" - natural, opiatelike neurotransmitters linked to pain control and to pleasure.
Nervous system
the body's speedy, electrochemical communication system, consisting of all the nerve cells of the peripheral and central nervous systems.
Central nervous system (CNS)
the brain and spinal cord
Peripheral nervous system (PNS)
The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body
Nerves
Neural "cables" containing many axons. These bundled axons, which are part of the peripheral nervous system, connect the central nervous system with muscles, glands, and sense organs
Sensory neurons
neurons that carry incoming information from the sense receptors to the central nervous system
Interneurons
central nervous system neurons that intervene between the sensory inputs and motor outputs
Motor neurons
The neurons that carry outgoing information from the central nervous system to the muscles and glands
Somatic nervous system
the division of the peripheral nervous sytem that controls the body's skeletal muscles.
Autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
Sympathetic nervous system
The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations
Parasympathetic nervous system
The division of the autonomic nervous system that calms the body, conserving its energy
Reflex
a simple, automatic, inborn response to a sensory stimulus, such as the knee-jerk response
Neural networks
interconnected neural cells. With experience, networks can learn, as feedback strengthens or inhibits connections that produce certain results. Computer stimulations of neural networks show analogous learning.
Phrenology
an ill-fated theory that claimed bumps on the skull could reveal our mental abilities and our character traits.
lesion
tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue
EEG (electroencephalogram)
an amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp
CT (computed tomography)
a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body
PET (positron emission tomography)
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
MRI (magnetic resonance imaging)
a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain
brainstem
the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions
medulla
the base of the brainstem; controls heartbeat and breathing
reticular formation
a nerve network in the brainstem that plays an important role in controlling arousal
thalamus
the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla
cerebellum
the "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance
limbic system
a doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions such as fear and aggression and drives such as those for food and sex. Includes the hippocampus, amygdala, and hypothalamus
amygdala
two almond-shaped neural clusters that are components of the limbic system and are linked to emotion
hypothalamus
a neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion
cerebral cortex
the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center
glial cells
cells in the nervous system that are not neurons but that support, nourish, and protect neurons
frontal lobes
the portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgement
parietal lobes
the portion of the cerebral cortex lying at the top of the head and toward the rear; includes the sensory cortex
occipital lobes
the portion of the cerebral cortex lying at the back of the head; includes the visual areas, which receive visual information from the opposite visual field
temporal lobes
the portion of the cerebral cortex lying roughly above the ears, includes the auditory areas, each of which receives auditory information primarily from the opposite ear
motor cortex
an area at the rear of the frontal lobes that controls voluntary movements
sensory cortex
the area at the front of the parietal lobes that registers and processes body sensations
association areas
areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking
aphasia
impairment of language, usually caused by left hemisphere damage to either Broca's area (impairing speaking) or to Wernicke's area (impairing understanding)
Broca's Area
an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech
Wernicke's area
a brain area involved in language comprehension and expression; usually in the left temporal lobe
plasticity
the brain's capacity for modification, as evident in the brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development
corpus callosum
the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
split brain
a condition in which the two hemispheres of the brain at isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them
endocrine system
the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream
hormones
chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another
adrenal glands
a pair of endocrine glands just above the kidneys. The adrenals secrete the hormones epinephrine (adrenaline) and norepinephrine (nonadrenaline), which help to arouse the body in times of stress
pituitary gland
the endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.
learning
a relatively permanent change in an organism's behavior due to experience
associative learning
learning that certain events occur together. The events may be two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning)
behaviorism
the view that psychology 1) should be an objective science that 2) studies behavior without reference to mental processes. Most research psychologists today agree with 1) but not with 2).
classical conditioning
a type of learning in which an organism comes to associate stimuli. A neutral stimulus that signals an unconditioned stimulus (UCS) begins to produce a response that anticipates and prepares for the unconditioned stimulus.
unconditioned response (UCR)
in classical conditioning, the unlearned, naturally occurring response to the unconditioned stimulus (UCS), such as salivation when food is in the mouth.
unconditioned stimulus (UCS)
in classical conditioning, a stimulus that unconditionally--naturally and automatically--triggers a response.
conditioned response (CR)
in classical conditioning, the learned response to a previously neutral conditioned stimulus (CS)
conditioned stimulus (CS)
in classical conditioning, an originally irrelevant stimulus that, after association with an unconditioned stimulus (UCS), comes to trigger a conditioned response (CR)
acquisition
the initial stage in classical conditioning; the phase associating a neutral stimulus with an unconditioned stimulus so that the neutral stimulus comes to elicit a conditioned response. In operant conditioning, the strengthening of a reinforced response
extinction
the diminishing of a conditioned response; occurs in classical conditioning when an unconditioned stimulus (UCS) does not follow a conditioned stimulus (CS); occurs in operant conditioning when a response is no longer reinforced
spontaneous recovery
the reappearance, after a rest period, of an extinguished conditioned response
generalization
the tendency, once a response has been conditioned, for stimuli similar to the conditioned stimulus to elicit similar responses
discrimination
in classical conditioning, the learned ability to distinguished between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus
operant conditioning
a type of learning in which behavior is strengthened if followed by reinforcement or diminished if followed by punishment
respondent behavior
behavior that occurs as an automatic response to some stimulus; Skinner's term for behavior learned through classical conditioning
operant behavior
behavior that operates on the environment, producing consequences
law of effect
Thorndike's principle that behaviors followed by favorable consequences become more likely, and that behaviors followed by unfavorable consequences become less likely
operant chamber ("Skinner box")
a chamber containing a bar or key that an animal can manipulate to obtain a food or water reinforcer, with attached devices to record the animal's rate of bar pressing or key pecking. Used in operant conditioning research
shaping
an operant conditioning procedure in which reinforcers guide behavior toward closer and closer approximation of a desired goal
reinforcer
in operant conditioning, an event that strengthens the behavior it follows
primary reinforcer
an innately reinforcing stimulus, such as one that satisfies a biological need
conditioned reinforcer (or secondary reinforcer)
a stimulus that gains its reinforcing power through its association with a primary reinforcer
continuous reinforcement
reinforcing the desired response every time it occurs
partial (intermittent) reinforcement
reinforcing a response only part of the time; results in slower acquisition of a response but much greater resistance to extinction than does continuous reinforcement
fixed-ratio schedule
in operant conditioning, a schedule of reinforcement that reinforces a response only after a specified number of responses
variable-ratio schedule
in operant conditioning, a schedule of reinforcement that reinforces a response after an unpredictable number of responses
fixed-interval schedule
in operant conditioning, a schedule of reinforcement that reinforces a response only after a specified time has elapsed.
variable-interval schedule
in operant conditioning, a schedule of reinforcement that reinforces a response at unpredictable time intervals
punishment
an event that decreases the behavior that it follows
cognitive map
a mental representation of the layout of one's environment. For example, after exploring a maze, rats act as if they have learned a cognitive map of it.
latent learning
learning that occurs but is not apparent until there is an incentive to demonstrate it
overjustification effect
the effect of promising a reward for doing what one already likes to do. The person may now see the reward, rather than intrinsic interest, as the motivation for performing the task.
observational learning
learning by observing others
modeling
the process of observing and imitating a specific behavior
prosocial behavior
positive, constructive, helpful behavior. The opposite of antisocial behavior.
memory
the persistence of learning over time through the storage and retrieval of information
flashbulb memory
a clear memory of an emotionally significant moment or event
encoding
the processing of information into the memory system--for example, by extracting meaning
storage
the retention of encoded information over time
retrieval
the process of getting information out of memory storage
sensory memory
the immediate, initial recording of sensory information in the memory system
short-term memory
activated memory that holds a few items briefly, such as the seven digits of a phone number while dialing, before the information is stored or forgotten
long-term memory
the relatively permanent and limitless storehouse of the memory system
working memory
a similar concept that focuses more on the processing of briefly stored information
automatic processing
unconscious encoding of incidental information, such as space, time, and frequency, and of well-learned information, such as word meaning
effortful processing
encoding that requires attention and conscious effort
rehearsal
the conscious repetition of information, either to maintain it in consciousness or to encode it for storage
spacing effect
the tendency for distributed study or practice to yield better long-term retention than is achieved through massed study or practiced
serial position effect
our tendency to recall best the last and first items in a list
semantic encoding
the encoding of meaning, including the meaning of words
acoustic encoding
the encoding of sound, especially the sound of words
visual encoding
the encoding of picture images
imagery
mental pictures, a powerful aid to effortful processing, especially when combined with semantic encoding
mnemonics
memory aids, especially those techniques that use vivd imagery and organizational devices
chunking
organizing items into familiar, manageable units; often occurs automatically
iconic memory
a momentary sensory memory of visual stimuli; a photographic or picture-image memory lasting no more than a few tenths of a second
echoic memory
momentary sensory memory of auditory stimuli; if attention is elsewhere, sounds and words can still be recalled with 3 or 4 seconds
long-term potentiation (LPT)
an increase in a synapse's firing potential after brief, rapid stimulation. Believed to be a neural basis for learning and memory
amnesia
the loss of memory
implicit memory
retention without conscious recollection (of skills and dispositions) (aka procedural memory)
explicit memory
memory of facts and experiences that one can consciously know and "declare" (aka declarative memory)
hippocampus
a neural center located in the limbic system that helps process explicit memories for storage
recall
a measure of memory in which the person must retrieve information learned earlier, as on a fill-in-the-blank test
recognition
a measure of memory in which the person need only identify items previously learned, as on a multiple-choice test
relearning
a memory measure that assesses the amount of time saved when learning material for a second time
priming
the activation, often unconsciously, of particular associations in memory
d�j� vu
the eerie sense that "I've experienced this before." Cues from the current situation may subconsciously trigger retrieval of an earlier experience
mood-congruent memory
the tendency to recall experiences that are consistent with one's current good or bad mood
proactive interference
the disruptive effect of prior learning on the recall of new information
retroactive interference
the disruptive effect of new learning on the recall of old information
repression
in psychoanalytic theory, the basic defense mechanism that banishes anxiety-arousing thoughts, feelings, and memories from consciousness
misinformation effect
incorporating misleading information into one's memory of an event
source amnesia
attributing to the wrong source an event that we have experienced, heard about, read about, or imagined (aka source misattribution). Source amnesia, along with the misinformation effect, is at the heart of many false memories
cognition
the mental activities associated with thinking, knowing, and remembering
concept
a mental grouping of similar objects, events, ideas, or people
prototype
a mental image of best example of a category. Matching new items to the prototype provides a quick and easy method for including items in a category (as when comparing feathered creatures to a prototypical bird, such as a robin)
algorithm
a methodical, logical rule or procedure that guarantees solving a particular problem. Contrasts with the usually speedier--but also more error-prone--use of heuristics
heuristic
a rule-of-thumb strategy that often allows us to make judgements and solve problems efficiently; usually speedier also more error-prone than algorithms
insight
a sudden and often novel realization of the solution to a problem; it contrasts with strategy-based solutions
confirmation bias
a tendency to search for information that confirms one's preconceptions
fixation
the inability to see a problem from a new perspective; an impediment to problem solving
mental set
a tendency to approach a problem in a particular way, especially a way that has been successful in the past but may or may not be helpful in solving a new problem.
functional fixedness
the tendency to think of things only in terms of their usual functions, an impediment to problem solving
representativeness heuristic
a rule of thumb for judging the likelihood of things in terms of how well they seem to represent, or match, particular prototypes; maybe lead one to ignore other relevant information
availability heuristic
estimating the likelihood of events based on their availability in memory; if instances come readily to mind (perhaps because of their vivdness), we presume such events are common
overconfidence
the tendency to be more confident than correct - to overestimate the accuracy of one's beliefs in judgments
framing
the way an issue is posed; how an issue is framed can significantly affect decisions and judgements
belief bias
the tendency for one's preexisting beliefs to distort logical reasoning, sometimes by making invalid conclusions seem valid, or valid conclusions seem invalid
belief perseverance
clinging to one's initial conceptions after the basis on which they were formed has been discredited
artificial intelligence (AI)
the science of designing and programming computer systems to do intelligent things and to stimulate human thought processes such as intuitive reasoning, learning, and understanding language. Includes practical applications (chess playing, industrial robot
computer neural networks
computer circuits that mimic the brain's interconnected neural cells, performing tasks such as learning to recognize visual patterns and smells.
consciousness
our awareness of ourselves and our environments
fantasy-prone personality
someone who imagines and recalls experiences with lifelike vividness and who spends considerable time fantasizing
biological rhythms
periodic physiological fluctuations
circadian rhythm
the biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle
REM sleep
rapid eye movement sleep, a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep because the muscles are relaxed (except for minor twitches) but other body systems are active.
alpha waves
the relatively slow brain waves of a relaxed, awake state
sleep
periodic, natural, and reversible loss of consciousness--as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation
hallucinations
false sensory experiences, such as seeing something in the absence of an external visual stimulus
sleep spindles
burst of rapid, rhythmic brainwave activity during Stage 2 sleep
delta waves
the large, slow brain waves associated with deep sleep (stage 4)
insomnia
recurring problems in falling or staying asleep
narcolepsy
a sleep disorder characterized by uncontrollable sleep attacks. the sufferer may lapse directly into REM sleep, often at inopportune times
sleep apnea
a sleep disorder characterized by temporary cessations of breathing during sleep and consequent momentary reawakenings.
night terrors
a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmare, night terrors occur during stage 4 sleep, within 2 or 3 hours of falling sleep, and are seldom remembered
dream
a sequence of images, emotions, and thoughts passing through a sleeping person's mind. Dreams are notable for their hallucinatory imagery, discontinuities, and incongruities, and for the dreamer's delusional acceptance of the content and later difficultie
manifest content
according to Freud, the remembered story line of a dream (as distinct from its latent content)
latent content
according to Freud, the underlying meaning of a dream (as distinct from its manifest content). Freud believed that a dream's latent content functions as a safety valve.
REM rebound
the tendency for REM sleep to increase following REM sleep deprivation
hypnosis
a social interaction in which one person (the hypnotist) suggests to another (the subject) that certain perceptions, feeling, thoughts, or behaviors will spontaneously occur
posthypnotic amnesia
supposed inability to recall what one experienced during hypnosis; induced by the hypnotist's suggestion
posthypnotic suggestion
a suggestion, made during a hypnosis session, to be carried out after the subject is no longer hypnotized; used by some clinicians to help control undesired symptoms and behaviors
dissociation
a split in consciousness, which allows some thoughts and behaviors to occur simultaneously with others
hidden observer
Hilgard's term describing a hypnotized subject's awareness of experiences, such as pain, that go unreported during hypnosis
psychoactive drug
a chemical substance that alters perceptions and mood
tolerance
the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect
withdrawal
the discomfort and distress that follow discontinuing the use of an addictive drug
physical dependence
a physiological need for a drug, marked by unpleasant withdrawal symptoms when the drug is discontinued
psychological dependence
a psychological need to use a drug, such as to relieve negative emotions
depressants
drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions
stimulants
drugs (such as caffeine, nicotine, and the more powerful amphetamines and cocaine) that excite neural activity and speed up body functions
hallucinogens
psychedelic ("mind-manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input
barbiturates
drugs that depress the activity of the central nervous system, reducing anxiety but impairing memory and judgement
opiates
opium and its derivatives, such as morphine and heroin; they suppress neural activity, temporarily lessening pain and anxiety
amphetamines
drugs that stimulate neural activity, causing speeded-up body functions and associated energy and mood changes
LSD
a powerful hallucinogenic drug, aka acid
THC
the major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations
near-death experience
an altered state of consciousness reported after a close brush with death (such as through cardiac arrest); often similar to drug-induced hallucinations
dualism
the presumption that mind and body are two distinct entities that interact
monism
the presumption that mind and body are different aspects of the same thing
selective attention
the focusing of conscious awareness on a particular stimulus, as in the cocktail party effect
visual capture
the tendency for vision to dominate the other senses
gestalt
an organized whole. Gestalt psychologists emphasize our tendency to integrate pieces of information into meaningful wholes
figure-ground
the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)
grouping
the perceptual tendency to organize information into coherent groups
depth perception
the ability to see objects in three dimensions although the images that strike the retina are two-dimensional, allows us to judge distance
visual cliff
a laboratory device for testing depth perception in infants and young animals
binocular cues
depth cues, such as retinal disparity and converge, that depend on the use of two eyes
monocular cues
distance cues, such as linear perspective and overlap, available to either eye alone
retinal disparity
a binocular cue for perceiving depth: the greater the disparity (difference) between the two images the retina receives of an object, the closer the object is to the viewer
convergence
a binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object
interposition
an MC; if one object partially blocks our view of another, we perceive it as closer
relative size
an MC; if we assume that two objects are similar in size, we perceive the one that casts the smaller retinal image as farther away
relative clarity
an MC; because light from distant objects passes through more atmosphere, we perceive hay objects are farther away than sharp, clear objects
texture gradient
an MC; 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
relative height
an MC; we perceive objects higher in our field of vision as farther away
relative motion (motion parallax)
As we move, objects that are actually stable may appear to move
linear perspective
Parallel lines, such as railroad tracks, appear to converge with distance. The more the lines converge, the greater the perceived distance
light and shadow
Nearby objects reflect more light to eyes. Given two identical objects, the dimmer one seems farther away
phi phenomenon
an illusion of movement created when two or more adjacent lights blink on and off in succession
perceptual constancy
perceiving objects as unchanging (having consistent lightness, color, shape, and size) even as illumination and retinal images change
shape constancy
perceiving the same shape for objects, even if retinal image changes
size constancy
perceiving the same size for objects, even if retinal image changes
lightness constancy (aka brightness constancy)
perceiving the same lightness for objects, even if retinal image changes; perceived lightness depends on relative luminance
perceptual adaptation
in vision, the ability to adjust to an artificially displaced or even inverted visual field
perceptual set
a mental predisposition to perceive one thing and not another
human factors psychologists
psychologists that help design appliances, machines, and work settings that harness natural perception sets.
extrasensory perception (ESP)
the controversial claim that perception can occur apart from sensory input. Said to include telepathy, clairvoyance, and precognition
parapsychology
the study of paranormal phenomena, including ESp and psychokinesis
telepathy
mind-to-mind communication
clairvoyance
perceiving remote events, ie that a friend's house is on fire
precognition
perceiving future events, ie a political leader's death or a sporting event's outcome
psychokinesis
mind over matter" ie levitating a table or influencing the roll of a die
cocktail party effect
ability to attend to only one voice among many
proximity
the effect of grouping nearby figures together
similarity
the effect of grouping similar figures together
continuity
the effect of perceiving smooth, continuous patterns rather than discontinuous ones
connectedness
the effect of perceiving spots, lines, or areas as a single unit
closure
the effect of filling in gaps to create a complete whole object
sensation
the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
perception
the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
bottom-up processing
analysis that begins with the sense receptors and works up to the brain's integration of sensory information
top-down processing
information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations
psychophysics
the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.
absolute threshold
the minimum stimulation needed to detect a particular stimulus 50 percent of the time
signal detection theory
predicts how and when we detect the presence of a faint stimulus ("signal") amid background stimulation ("noise"). Assumes that there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and
subliminal
below one's absolute threshold for conscious awareness
difference threshold
the minimum difference that a person can detect between two stimuli. We experience the difference threshold as a just noticeable difference (aka jnd)
Weber's Law
the principle that, to perceive their difference, two stimuli must differ by a constant minimum percentage (rather than a constant amount)
sensory adaptation
diminished sensitivity as a consequence of constant stimulation
transduction
conversion of one form of energy into another. In sensation, the transforming of stimulus energies into neural impulses
wavelength
the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission
hue
the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth
intensity
the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude
pupil
the adjustable opening in the center of the eye through which light enters
iris
a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
lens
the transparent structure behind the pupil that changes shape to focus images on the retina
accommodation
the process by which the eye's lens changes shape to focus the image of near objects on the retina
retina
the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information
acuity
the sharpness of vision
nearsightedness
a condition in which nearby objects are seen more clearly than distant objects because the lens focuses the image of distance objects in front of the retina
farsightedness
a condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind the retina
rods
retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond
cones
receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.
optic nerve
the nerve that carries neural impulses from the eye to the brain
blind spot
the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there
fovea
the central focal point in the retina, around which the eye's cones cluster
parallel processing
the processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision. Contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving.
Young-Helmholtz trichromatic (three-color) theory
the theory that the retina contains three different color receptors--one most sensitive to red, one to green, and one to blue--which when stimulated in combination can produce the perception of any color
opponent-process theory
the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green. (complete explanation pg 187)
color constancy
perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
audition
the sense of hearing
frequency
the number of complete wavelengths that pass a point in a given time (for example, per second)
pitch
a tone's highness or lowness; depends on frequency
middle ear
the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window
inner ear
the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs
cochlea
a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses
place theory
in hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated
frequency theory
in hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch
conduction hearing loss
hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea
sensorineural hearing loss
hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness
gate-control theory
theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or
sensory interaction
the principle that one sense may influence another, as when the smell of food influences its taste
kinesthesis
the system for sensing the position and movement of individual body parts
vestibular sense
the sense of body movement and position, including the sense of balance