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Lecture

Chapter 10 Notes -Motivation and Emotion

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Department
Psychology
Course
PSY100Y5
Professor
Ayesha Khan
Semester
Winter

Description
Chapter Ten: Motivation and Emotion Motivational Theories and Concepts • Motivation: involves goal-directed behaviour • Street kids who don’t follow the standards of traditional societies often don’t replace these standards with their own and are therefore living for the “short-term” Drive Theories • They apply the concept of homeostasis to behaviour • Homeostasis: state of physiological equilibrium or stability Drive: An internal state of tension that motivates an organism to engage in activities that should reduce this tension • • According to drive theories, when individuals experience a drive, they’re motivated to pursue action that will lead to drive reduction • Ex. Hungry in class, hunger motive usually conceptualized as drive system (no food = discomfort) therefore internal tension (the drive) motivates you to obtain food and thus reducing drive and restores balance • Drive theories cannot explain all motivation • Motivation may exist without drive arousal Incentive Theories • Propose that external stimuli regulate motivational states • Incentive: external goal that has the capacity to motivate behaviour • Drive and incentive models of motivation often contrasted as push-versus-pull theories • Drive theories: how internal states of tension push people in certain directions •Motivation lies within organism • Incentive theories: how external stimuli pull people in certain direction •Motivation lies outside organism Environmental factors over biological bases of human motivation • • Expected-value models states that one’s motivation to pursue course of action depends on: 1. Expectancy about chances of attaining incentive 2. Value of desired incentive Evolutionary Theories • These theories assert that motives are the products of evolution • Argue that natural selection favours behaviours that maximize reproductive success • Evolutionary analyses of motivation are based on premise that motives can best be understood in terms of the adaptive problems they solved for our ancestors The Range and Diversity of Human Motives • Most theories distinguish between biological motives (originate in bodily needs) and social motives (originate in social experiences) • Limited number of biological needs but can have unlimited social motives through learning and socialization • Choices largely reflect motives psychologists have studied most: hunger, sex, and achievement The Motivation of Hunger and Eating Biological Factors in the Regulation of Hunger • Cannon and Washburn: There’s an association b/w stomach contraction + experience of hunger • Stomach contractions accompany hunger but don’t cause it • People continue experiencing hunger after their stomachs have been removed out of medical necessity Brain Regulation • Experience of hunger controlled in the brain (mainly hypothalamus) • Lateral hypothalamus (LH) and ventromedial nucleus of the hypothalamus (VMH) were believed to be the brain’s on-off switch for hunger in the 1940s and 50s • Current thinking is that lateral and ventromedial areas of hypothalamus are elements in neural circuitry regulating hunger Large role also played by arcuate nucleus and paraventricular nucleus (in hypothalamus) • • Contemporary theories of hunger focus on neural circuits that pass through areas of the hypothalamus • Circuits depend on neurotransmitters and are interconnected with expensive parallel processing Glucose and Digestive Regulation • Much of the food taken into the body is converted into glucose • Glucose: a simple sugar that is an important source of energy Actions decreasing blood glucose level = increase hunger • • Increasing B.G.L = feeling satiated • Glucostatic theory: fluctuations in B.G.L are monitored by the brain where they influence hunger • Arcuate nucleus sensitive to glucostatic fluctuations that contribute to modulation of eating • After consuming food, cells in stomach send signals to brain stem that inhibit further eating Hormonal Regulation • Insulin: hormone secreted by the pancreas and must be present for cells to extract glucose from blood Secretion of insulin associated with increased hunger • • Insulin levels sensitive to fluctuations in the body’s fat stores • Other hormones playing role in short-term regulation of hunger: • Ghrelin: secreted by stomach after not eating for a while and causes stomach contractions/promotes hunger • CCK: released by upper intestine after consuming food and delivers satiety signals to brain which reduces hunger • Leptin: produced by fat cells and released into bloodstream. (higher amount of fat = more leptin). Ultimately provides hypothalamus with info about body’s fat stores • NOTE: when leptin levels high, propensity to feel hungry decreases Environmental Factors in the Regulation of Hunger • Three key environmental factors are: (1) the availability of food (2) learned preferences and habits, and (3) stress Food Availability and Related Cues • Some theorists emphasize: incentive value of food + that humans and other animals are often motivated to eat by the anticipated pleasure of eating • The following variables exert significant influence over food consumption: 1) Palatability: the better food tastes, the more you will consume 2) Quantity available: the more you’re served, the more you eat 3) Variety: increased consumption when greater variety of foods is available 4) Presence of others: on average, people eat 44% more when they eat in the company of others • Eating can be triggered by environmental cues that have been associated with eating (i.e. Television commercials) • Hunger and eating governed in part by the incentive qualities of food • Eating is often a social action • Herman, Polivy, and colleagues suggest that the presence of others generally inhibits eating • Suggest our eating is influenced by extant social norms determined by the behaviour of the others around us at the time Learned Preferences and Habits • Different cultures = different patterns of food consumption • Humans do have some innate taste preferences of a general sort (ex. Sweet tastes preferred at birth) • Taste preferences are partly a function of learned associations formed through classical conditioning • Eating habits are also shaped by observational learning • Food preferences are somewhat a matter of exposure Repeated exposure to new food usually lead to increased liking • Stress and Eating • Stress leads to increased eating in substantial portion of people • Little evidence to support belief that people eat while stressed because they expect these treats will make them feel better Eating and Weight: The Roots of Obesity • Obesity: the condition of being overweight • Body Mass Index (BMI): an individual’s weight (in kilograms) divided b height (in metres) squared • BMI over 30 = obese; between 25 - 29.9 = overweight Overall rate of obesity in Canada from 2007 to 2009 was 10% points lower than in the USA • • Having obese parents increases odds of obesity in children • Obesity elevates one’s mortality risk • Overweight people vulnerable to: cardiovascular disease, diabetes, hypertension, respiratory problems.... • Evolutionary-oriented researchers: dramatic increase in obesity due to warm-blooded foraging animals consuming more food than normal if there was competition and food would not be available in the future • This approach to eating remains adaptive in most species of animals hat continue to struggle wit the ebb and flow of unpredictable food supplies • People in food-replete environments tend to overeat in relation to their physiological needs • Weight loss efforts involving moderate changes in eating/exercise = more beneficial than harmful • Mortality rates among moderately overweight people not elevated in today’s population • The above has been explained due to treatment of cardiovascular diseases neutralizing dangers associated with being slightly overweight Genetic Predisposition • A study comparing adults raised by adoptive parents and their biological and adoptive parents in regard to body mass index found the adoptees resembled biological parents more than adoptive • Thus, it appears some people inherit a genetic vulnerability to obesity Excessive Eating and Inadequate Exercise • Overweight people => energy intake from food consumption chronically exceeds their energy expenditure from physical activities and resting metabolic processes (eat too much in relation to their exercise level) • Tendency to overeat in North America due to fattening, caloric foods being advertised and readily available • Bloated cues about what represents “normal” food consumption fuels increased eating and obesity • Modern conveniences (ex. Cars) makes our lives more sedentary • Lower-income Canadians seem more vulnerable to inactivity Sensitivity to External Cues • Stanley Schachter - “externality hypothesis” - obese people are extra sensitive to external cues that affect hunger and insensitive to internal physiological signals • Schachter found external cues (how tasty food appears...) influence eating behaviour of overweight people more than normal- weight people • Judith Rodin questioned Schachter’s studies and found his hypothesis was oversimplified • Stroebe concluded that external cues do have a greater impact on food intake of obese individuals than individuals of normal weight • Herman and Polivy make distinction between normative compared to sensory external cues to clarify how external cues relate to obesity • Normative cues: indicators of socially appropriate food intake • Sensory cues: characteristics of the food itself that make people more/less likely to consume it The Concept of Set Point • Trouble keeping on/keeping off weight suggest body may have a set point (natural point) of stability in body weight • Set-point theory: proposes that the body monitors fat-cell levels to keep them (and weight) fairly stable • Apparently, when fat stores slip below crucial point, body compensates for change, leading to increased hunger and decreased metabolism • Alternative to this theory is called settling-point theory • Settling-point theory: proposes that weight tends to drift around the level at which the constellation of factors that determine food consumption and energy expenditure achieves an equilibrium • Thus, weight remains stables as long as there aren’t durable changes in any of the factors influencing it • Differences between these theories: (1) settling-point theory casts wider net, which attributes weight stability to very specific physiological processes, (2) set-point theory assets that obese person’s body will initiate processes that actively defend an excessive weight, whereas settling-point theory suggests if obese person makes long-term changes in eating/exercise, their settling point will drift downward without active resistance Dietary Restraint • Some investigators propose that vacillations in dietary restraint contribute to obesity • They believe chronic dieters = restrained eaters --> people who consciously work overtime to control eating impulses and feel guilty when they fail • Restrained eaters go hungry to lose weight but constantly think of food • When their cognitive control is disrupted, they become disinhibited and eat to excess • Restrained eaters think they’re either dieting or able to eat out of control Dietary restraint is thought to lead to frequent overeating and therefore obesity • • Dietary restraint also contributes to the tendency to overeat just before beginning a diet (restrained eaters fall off the wagon before getting on • Anticipation of food deprivation seems to act as another inhibitor • They also seem sensitive to media’s portrayal of thin body types Eating Disorders • Late 1960s saw the increased prevalence of what was a rare disorder: anorexia nervosa • Bulimia nervosa increased in the 1970s • Bulimia became more known by Canadians when Carling Bassett-Seguso (famous tennis player) announced she suffered from bulimia • Eating disorders more prevalent in women compared to men, affecting 3% of Canadian women • Factors in the occurrence of eating disorders: biological, psychological, developmental, and social factors Sexual Motivation and Behaviour The Human Sexual Response • Not many studies about sex were published until very recently • Masters and Johnson used physiological recording devices to monitor the bodily changes of volunteers engaging ins sexual activities • Masters and Johnson divide the sexual response cycle in four stages: excitement, plateau, orgasm, and resolution • Excitement stage: • During first phase, level of physical arousal rises rapidly • Both sexes experience quick increase in muscle tension, respiration rate, heart rate, blood pressure • Vasocongestion (engorgement of blood vessels) produces penile erection + swollen testes in males • In females it leads to swelling and hardening of clitoris, expansion of vaginal lips + vaginal lubrication • Plateau Phase: • Physiological arousal continues building at slower pace • Women: vaginal entrance tightens, clitoris withdraws under clitoral hood Men: secrete bit of fluid at tip of penis • • Fluctuation of arousal for both sexes but more apparent in men • Orgasm Phase • Orgasm: when sexual arousal reaches its peak intensity, it discharges in a series of muscular contractions that pulsate through pelvic area • Heart, respiration rate and blood pressure increase sharply • Women more likely to be multiorgasmic but more likely to not have an orgasm then men during intercourse • Can be argued that males’ greater orgasmic consistency must be a product of evolution • Orgasm consistency seems to be influenced by relationship quality more in women than in men • Resolution Phase • Physiological changes produced by sexual arousal subside • After orgasm, men experience a refractory period • Refractory period: a time following orgasm during which males are largely unresponsive to further stimulation Evolutionary Analyses of Human Sexual Behaviour • The thinking in this area has been guided by Robert Trivers’s parental investment theory • His theory maintains that a species’ mating patterns depend on what each sex has to invest to produce/nurture offspring • Human males’ productive potential is maximized by mating with as many females as possible since they are required to invest little in the production of offspring • Females invest much more and this have little to no incentive for mating with many males • Females can optimize their reproductive potential by being selective in mating Parental investment theory predicts that in comparison to women, men will show more interest in sexual activity • • Females are thought to be conservative and highly selective • This selectivity entails finding a partner who can contribute the most to feeding/caring for offspring because our ancestors would have needed this especially when finding food and shelter Gender Differences in Patterns of Sexual Activity • Males: • Generally have greater interest in sex than females Initiate sex more often • • More frequent/varied sexual fantasies • Subjective rating of sex drive tend to be higher • Tend to overestimate women’s sexual intere
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