Unit 15: Motivation

a need or desire that energizes and directs behavior.
Instinct: a complex behavior that is rigidly patterned throughout a species and is unlearned (e.g., imprinting in birds or the return of salmon to their birthplace to spawn).  Reflexes in human infants are to simple to be considered instincts.
Drive-Reduction Theory: the idea that a physiological NEED creates an aroused state of tension (DRIVE) that motivates an organism to satisfy that need.

NEED (for food or water)→DRIVE (hunger or thirst)→DRIVE-REDUCING BEHAVIORS (eating or drinking).

Drive-Reduction Theory is based on the Concept of Homeostasis.
Homeostasis: a tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level.
Arousal Theory: rather that reducing a physiological need or tension state, some motivated behaviors increase arousal.  Curiosity-driven behaviors, for example, suggest that too little as well as too much stimulation can motivate people to seek an optimum level of arousal.
Incentive Theory: Theory that even if a need or drive is not originally present, positive or negative environmental stimuli may motivate behavior (e.g., after finishing a big meal, and feeling totally satisfied, we may become hungry again if we see or smell a delicious dessert).
Hierarchy of Needs: Maslow's pyramid of human needs, beginning at the base with physiological needs that must first be satisfied before higher-level needs become active.  SEE HANDOUT

the form of sugar that circulates in the blood and provides the major source of energy for body tissues.  When blood glucose levels are low, we feel hungry.

Orexin: When blood-glucose is low, the lateral hypothalamus releases orexin, which makes us even more hungry.
Lateral Hypothalamus: the "hunger center" of the brain.  When blood glucose is low, the lateral hypothalamus kicks on, releases orexin and we feel hungry.
Ventromedial Hypothalamus: the "satiety center" of the brain.  When blood glucose is high (after we have eaten), the ventromedial hypothalamus kicks in and we no longer feel hungry.
Insulin: Substance released from the pancreas.  When blood glucose rises, insulin is released to allow the glucose to move from the blood to the tissues of the body.
Set Point: the point at which an individual's "weight thermostat" is supposedly set. When the body falls below this weight, an increase in hunger and a lowered metabolic rate may act to restore the lost weight.
Basal Metabolic Rate: the body's resting rate of energy expenditure.
                           Eating Disorders
Anorexia Nervosa:
an eating disorder in which a normal-weight person (usually an adolescent female) diets and becomes significantly underweight (15% or more), yet, still feeling fat, continues to diet.
Bulimia Nervosa: an eating disorder characterized by episodes of overeating, usually of high-calorie foods, followed by vomiting, laxative use, fasting, or excessive exercise.  These individuals are not typically underweight.
                    SEXUAL MOTIVATION
Sexual Response Cycle:
the four stages of sexual responding described by Masters and Johnson--excitement, plateau, orgasm, and resolution.
Refractory Period: a resting period after orgasm, during which a man cannot achieve another orgasm.
Sexual Disorder: a problem that consistently impairs sexual arousal or functioning.  They include impotence andpremature ejaculation in men and orgasmic dysfunction in women.
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