id According to Freud, the impulsive and unconscious part of the psyche that operates through the pleasure principle toward the gratification of instinctual drives. 13
identification The tendency to go along with others because we admire and wish to be like them. 18
immune system The body’s “surveillance system,” which guards against foreign invaders (called antigens). 12
immunocompetence The measure of how well the immune system protects the body from illness. 12
implicit memory Memory without conscious awareness. 7
in-groups Those groups with which one identifies. 17
incus One of a set of three tiny, interconnected bones in the middle ear that transmit sound from the eardrum to the cochlea. 4
independent variable A factor that an experimenter deliberately manipulates. 2
indirect perspective A theory of perception that all we process directly are sensory cues about the environment. To make sense of those cues we must supplement them with additional information stored in memory. 4
indirect tests Tests that do not require conscious awareness, such as those involving word fragments that subjects are asked to com-plete. 7
industrial and organizational psychologists Researchers who study all aspects of the relationship between people and their workplace. 1
inferiority complex Alfred Adler’s theory that all children are born with a deep sense of inferiority because of their small size, physical weakness, and lack of knowledge and power in the adult world. 13
information-processing model of memory A theory that divides memory into three types: sensory, short-term, and long-term. 7
information-processing view of intelligence An approach to studying intelligence that looks closely at how people think and reason intelligently. 14
inhibited ejaculation A sexual dysfunction characterized by a man’s inability to ejaculate during sex with a partner. 11
inhibitory potentials Inputs that cause the inside of the cell to become more negative. 3
insomnia Difficulty falling asleep or staying asleep all night. 5
instinct An innate force found in all members of a species that directs behavior in predictable ways in the presence of the right eliciting stimulus. 11
instinctive drift A reversion to a genetically based behavior that competes with a learned behavior. 6
intelligence The capacity to acquire and retain knowledge and to understand concepts and relationships. 14
intelligence quotient (IQ) A measure of mental development computed by dividing a child’s mental age (the average age of those who obtain that child’s score) by the child’s chronological age, and multiplying by 100 to eliminate the decimal point. 14
internal consistency The characteristic of a test that yields the same responses from people to items that measure the same thing. 14
internalization The acceptance of others’ views and actions as appropriate and right. 10, 18
interpersonal (family-systems) perspective The view that psychological disorders arise partly from a person’s network of social relationships, especially the family. 15
intrinsic motivation The internal satisfaction of acting competently that explains behavior; those things that are rewarding “in and of themselves.” 11
intrinsic reinforcement and punishment Those self-reactions such as self-esteem and self-reproach that affect a person’s learning and behavior. 6
iodopsin A light-sensitive chemical pigment found in the retina’s cone cells. 4
ions Electrically charged particles. 3
iris A ring of pigmented tissue that gives the eye its color. It expands and contracts the pupil to control the amount of light that enters the eye. 4