Racism Discrimination against people based on their skin color or ethnic heritage.
Range The difference between the highest and the lowest scores in a set of observations; the simplest measure of variability.
Rapid eye movements (REM) A behavioral sign of the phase of sleep during which the sleeper is likely to be experiencing dreamlike mental activity.
Rational-emotive therapy (RET) A comprehensive system of personality change based on changing irrational beliefs that cause undesirable, highly charged emotional reactions such as severe anxiety.
Reasoning The process of thinking in which conclusions are drawn from a set of facts; thinking directed toward a given goal or objective.
Recall A method of retrieval in which an individual is required to reproduce the information previously presented.
Recency effect Improved memory for items at the end of a list.
Receptive field The visual area from which a given ganglion cell receives information.
Reciprocal altruism The idea that people perform altruistic behaviors because they expect that others will perform altruistic behaviors for them in turn.
Reciprocal determinism A concept of Albert Bandura's sociallearning theory that refers to the notion that a complex reciprocal interaction exists among the individual, his or her behavior, and environmental stimuli and that each of these components affects the others.
Reciprocity norm Expectation that favors will be returned-if someone does something for another person, that person should do something in return.
Recognition A method of retrieval in which an individual is required to identify stimuli as having been experienced before.
Reconstructive memory The process of putting information together based on general types of stored knowledge in the absence of a specific memory representation.
Reflex An unlearned response elicited by specific stimuli that have biological relevance for an organism.
Refractory period The period of rest during which a new nerve impulse cannot be activated in a segment of an axon.
Reinforcement contingency A consistent relationship between a response and the changes in the environment that it produces.
Reinforcer Any stimulus that, when made contingent upon a response, increases the probability of that response.
Relative motion parallax A source of information about depth in which the relative distances of objects from a viewer determine the amount and direction of their relative motion in the retinal image.
Relaxation response A condition in which muscle tension, cortical activity, heart rate, and blood pressure decrease and breathing slows.
Reliability The degree to which a test produces similar scores each time it is used; stability or consistency of the scores produced by an instrument.
Representative sample A subset of a population that closely matches the overall characteristics of the population with respect to the distribution of males and females, racial and ethnic groups, and so on.
Representativeness heuristic A cognitive strategy that assigns an object to a category on the basis of a few characteristics regarded as representative of that category.
Repression The basic defense mechanism by which painful or guilt-producing thoughts, feelings, or memories are excluded from conscious awareness.
Residual stress pattern A chronic syndrome in which the emotional responses of posttraumatic stress persist over time.
RESISTANCE The inability or unwillingness of a patient in psychoanalysis to discuss certain ideas, desires, or experiences.
Response bias The systematic tendency as a result of nonsensory factors for an observer to favor responding in a particular way.
Resting potential The polarization of cellular fluid within a neuron, which provides the capability to produce an action potential.
Reticular formation The region of the brain stem that alerts the cerebral cortex to incoming sensory signals and is responsible for maintaining consciousness and awakening from sleep.
Retina The layer at the back of the eye that contains photoreceptors and converts light energy to neural responses.
Retinal disparity The displacement between the horizontal positions of corresponding images in the two eyes.
Retrieval The recovery of stored information from memory.
Retrieval cues Internally or externally generated stimuli available to help with the retrieval of a memory.
Reversal theory Theory that explains human motivation in terms of reversals from one to the other opposing metamotivational states.
Ritual healing Ceremonies that infuse special emotional intensity and meaning into the healing process.
Rods Photoreceptors concentrated in the periphery of the retina that are most active in dim illumination; rods do not produce sensation of color.
RULES Behavioral guidelines for acting in certain ways in certain situations.