DEF: goal-directed behavior MOTIVATION DEF: goal-directed behavior

HUNGER---BRAIN REGULATION Hypothalamus Lateral hypothalamus (LH) triggers when to start eating Ventromedial nucleus of the hypothalamus (VMH) triggers when to stop Paraventricular nucleus (PVN) uses neurotransmitters to regulate hunger

GLUCOSE REGULATION Glucose is a simple sugar; an important source of energy Glucostatic theory: fluctuations in blood glucose level are monitored by glucostats: neurons sensitive to glucose in the surrounding fluid Glucostats in the liver signal hypothalamus through the vagus nerve

DIGESTIVE REGULATION The stomach has 2 types of signal to inhibit further eating: 1) vagus nerve monitors stretching of stomach wall 2) other nerves monitor nutrients in the contents of the stomach

HORMONAL REGULATION Insulin: secreted by the pancreas; must be present for cells to extract glucose from the blood Leptin: produced by fat cells; provide hypothalamus w/info about body’s fat stores

ENVIRONMENTAL FACTORS IN REGULATION OF HUNGER Learned preferences and habits Food related cues Stress, arousal

EATING AND WEIGHT: ROOTS OF OBESITY Obesity: the condition of being overweight (exceeding ideal weight by 20%) Health risks: cardiovascular diseases, diabetes, hypertension, stroke, arthritis, and back problems

GENETIC PREDISPOSITION TO OBESITY Adoption studies Body mass index (BMI): weight (kg) divided by height (m) squared kg/m2 Genetic factors account for 61% of variation in weight for men and 73% for women

CONCEPT OF A SET POINT Set point: natural point of stability in body weight Set point theory: body monitors fat-cell levels to keep them fairly stable

Sexual motivation and behavior

HORMONAL REGULATION Estrogens: principal gonadal hormones in females Androgens: principal gonadal hormones in males Increased levels of testosterone correlate w/higher rates of sexual activity

PHEROMONES DEF: a chemical secreted by one animal that affects the behavior of another Aphrodisiacs: substances thought to increase sexual desire There is no “Spanish Fly”

EROTIC MATERIALS Pornography does not appear to incite overpowering sexual urges May alter attitudes toward sexual behavior May create unrealistic expectations

ATTRACTION TO A PARTNER Coolidge Effect: the preference for variety in sexual partners seen in males of many species Most species are selective

EVOLUTIONARY ANALYSES OF HUMAN SEXUAL BEHAVIOR Parental investment theory: the sex that makes the smaller investment will compete for mating opportunities with the sex that makes the larger investment, and the sex with the larger investment will tend to be more discriminating in selecting its partners

EVOLUTIONARY ANALYSES Human males are required to invest little Females invest 9 months Therefore females are selective with mates

GENDER DIFFERENCES IN PATTERNS OF SEXUAL BEHAVIOR Men think about sex more often Men more motivated to have sex w/a variety Men more likely to have sex w/someone they have known for a short period of time

GENDER DIFFERENCES IN MATE PREFERENCES Males place more emphasis on youthfulness and attractiveness Females place more emphasis on intelligence, ambition, income, and social status

GENDER DIFFERENCES IN RELATIONSHIP JEALOUSY Males of many species worry about paternity uncertainty Males will guard the female from other males Sexual infidelity is threatening Male emotional infidelity is threatening to females

MYSTERY OF SEXUAL ORIENTATION DEF: a person’s preference for emotional and sexual relationships with individuals of the same sex, the opposite sex, or both Heterosexual Homosexual Bisexual

SEXUAL ORIENTATION CONTINUED Alfred Kinsey (1948, 1953) described sexuality as a continuum---heterosexuality on one end, homosexuality on the other 10% of the population could be characterized as homosexual

ENVIRONMENTAL THEORIES Freudian: homosexuality stems from being raised by an ineffectual father and overprotective mother Behaviorist: acquired through experience Feminine boys and masculine girls tend to grow up homosexual

BIOLOGICAL THEORIES Research in the last 15 years has shown a biological basis for homosexuality Possible brain structure

INTERACTIONIST VIEW AND SOCIOPOLITICAL IMPLICATIONS Genes and hormones shape temperament that ultimately shapes sexual orientation Interactions w/peers solidifies arousal for same sex Gays are still discriminated against

HUMAN SEXUAL RESPONSE The birds and the bees

EXCITEMENT PHASE Muscle tension, respiration rate, heart rate, and blood pressure increase rapidly Vasocongestion: engorgement of the blood vessels

PLATEAU PHASE Physiological arousal continues to grow, but at a slower pace Further vasocongestion

ORGASM PHASE Orgasm: when sexual arousal reaches its peak intensity and is discharged in a series of muscular contractions that pulsate through the pelvic area There are gender differences but they are extremely similar in both sexes

RESOLUTION PHASE Refractory period: a time following orgasm during which males are largely unresponsive to further stimulation From a few minutes to hours---increases w/age