PSYA02H3: Ch10-11 (Mtuner 2 Review)

Helen  Li     PSYA02H3   Chapter 11: Hunger and Eating • Motivation: concerns the physiological and psychological processes underlying the initiation of behaviors that direct organisms toward specific goals o Initiating factors/ motives -> thoughts, feelings, sensations, bodily process that lead to goal- directed behavior o Essential to individual’s survival -> contributes to homeostasis: body’s physiological processes that allow it to maintain consistent internal states in response to outer environment ▯ Physiological needs -> appropriate body temp, hunger, thirst ▯ Social in nature -> form social bonds -> achieving success at school or work • Drives: the physiological triggers that tell us we may be deprived of something and cause us to seek out what is needed, such as food • We also respond to incentives (or goals): the stimuli we seek to reduce the drives such as social approval and companionship, food, water, and other needs • Satiation: the point in a meal when we are no longer motivated to eat o Homeostasis of food intake is balanced between hunger motives & satiation Helen  Li     PSYA02H3   • On/ off switches involved in hunger -> hypothalamus o Researches found that electrically stimulating the lateral hypothalamus causes rats to begin to eat -> this structure serves as “on” switch o The ventromedial region of hypothalamus -> serve as “off” switch ▯ Damage to this area -> obesity in lab animals o The paraventricular nucleus of hypothalamus -> signals time to stop eating by inhibiting lateral hypothalamus • Hypothalamus -> doesn’t work alone o Busy hub of activity that sends & receives signals throughout body o When it comes to eating/ hunger -> receives info about tastes, textures, smells through nerves coming from mouth & nose & exchanges this info with front cortex o Monitoring blood chemistry for indicators of levels of sugars & hormones involved in energy ▯ Hypothalamus detects changes in level of glucose: a sugar that serves as a primary energy source for the brain and rest of the body • Vital energy source for human body; it’s levels monitored by nervous system ▯ Highly specialized neurons called glucostats -> can detect glucose levels in fluid outside of cell ▯ When glucose level drops, glucostats signal hypothalamus that energy supplies = low => hunger increases • After food reaches stomach & intestines, sugars absorbed into bloodstream & transported throughout body • Insulin: hormone secreted by the pancreas -> helps cells store this circulating glucose for future use • As insulin level rise in response of meal -> hunger decreases & so does glucose levels -> hunger eventually rises a few hours later • Ghrelin: hormone secreted in stomach that stimulates stomach contractions & appetite o Also released by hypothalamus => functions to decrease appetite • Another key chemical in regulating hunger -> cholecystokinin (CKK) o As intestines expand -> neurons release CKK -> communicates to hypothalamus that it’s time to stop eating Helen  Li     PSYA02H3   • Food can be more powerful reinforcer than highly addictive drugs o Cravings for a “sugar fix” – a term that seems to imply that addiction to candy bars is comparable to an addiction to a drug like heroin ▯ Possible that sugar act like a drug? ▯ Ordinary sucrose- plain white granulated sugar- can stimulate release of neurotransmitter dopamine in nucleus accumbens, brain region associated with reinforcing effects of substances such as amphetamines & cocaine • Taste -> another powerful force to motivate o Eating more than just maintaining homeostasis • Scientists not 100% sure -> we crave fats because we have specialized receptors on the tongue that are sensitive to fat content of food o Experiments -> used brain imaging technology -> participants tasted various substances - > overall; they rated fatty substance favorably & brain scans showed activation in regions of brain associated with pleasure sensations when they tasted fat • Scientific studies -> confirmed health risks brought on by high-fat diets • When chemical receptors in mouth & nose are detecting tastes & smells -> touch receptors in mouth are detecting textures of food & relaying this info to the orbitofrontal cortex -> contributes info to overall sensation of eating o These cells help distinguish runny spaghetti sauce from thick one o Other cells -> between fatty & lean meats -> spicy and bland foods • Tube feeding: technique used with hospitalized patients who cannot chew or swallow on their own o Satisfies body’s nutritional needs by delivering nutrients directly to stomach o Experiment -> even tough the tube-fed volunteers received all the nutrition they needed, they were still motivated to eat Helen  Li     PSYA02H3   • Impression management: Eating less o Sometimes people self-consciously control their behavior so that others will see them a certain way o Eg. Polite to chew with your mouth closed • Minimal eating norm: suggests that another aspect of good manners- some social & cultural settings- is to eat small amounts to avoid seeming rude • Modeling: Eating whatever they eat o Eg. Employee will notice no one eats much & everyone takes their time -> newcomer will see others as models -> later, he may be introduced to friends family reunion where everyone eats more than one plate -> more likely to eat more even if he’s full • In Europe, the typical container of fruit & yogurt is roughly 6 ounces. In the US, the same food item is usually packaged in 8-ounce containers. o The unit bias suggest that a French person in the US would be likely to eat entire container, even tough it contains 25% more than the typical French serving • Obesity: disorder is positive energy balance, in which energy intake exceeds energy expenditure o Epidemic that spread in US -> other parts of world o On major problem -> difficulty in ensuring long-term maintenance of weight loss ▯ E.g. ads tell people that they can lose weight without exercising, just by taking a pill • Hard shedding pounds -> impossible o Several studies shown that girls & adolescents who self-report dieting are heavier later in life o Research studies suggests that people who are obese have an increased sensitivity to food & food- related cutes ▯ Suggest that people with obesity have more intense, rewarding sensory experiences when it comes to food -> but doesn’t tell us whether increased sensitivity to food cues causes obesity, or vice versa ▯ Brain imaging studies show greater activity in obese individuals brains in response to food compared to brains of people of normal weight • In late 1940’s, group of scientists in Minnesota -> young men to participate in extreme food deprivation on physiology & behavior Helen  Li     PSYA02H3   o Not only lost weight -> reduced pulse, respiration & blood pressure o Became depressed, developed abnormal feeding patterns such as binging o Anorexia nervosa: an eating disorder that involves: 1. Self starvation 2. Intense fear of weight gain and distorted perception of body image 3. Denial of serious consequences of severely low weight ▯ Other problems -> female: consecutive loss of menstrual periods (amenorrhea) -> male: loss of sexual motivation ▯ Usually occur during mid- late adolescence & on rise during 20 century • Bulimia nervosa: eating disorder that is characterized by periods of food deprivation, binge- eating and purging o Involves short, but intense episodes of massive calorie consumption marked by lack of regulation of how many calories the body actually needs -> purging (self-induced vomiting, most common type), fasting, laxative or diuretic use, intense exercise o People with anorexia may also purge -> less common than people who have bulimia o More prevalent in late adolescence and young adulthood o Males -> less problems, still develop eating disorders (achieve muscle mass) • One concern to eating disorders -> culture o People with regular exposure to Western culture are more likely to develop bulimia than members without o Exposure to idealized version of body type & thinness -> more likely predictor of someone’s chances of developing eating disorder/ obesity Chapter 11.2: Sexual Motivation • Libido: the motivation for sexual activity and pleasure o Sex drive? o On avg, men more sexually aroused, fantasize more, masturbate more, desire more sexual partners than do women • Sex serves many purposes other than biological purposes o Masturbation occurs in some primate species, bonobo chimpanzee engages in frequent genital contact, touching, other sexual behaviors, without actually copulating • Difficult for psychologists to study -> sex generally happens in private -> interviews & questionnaires are least intrusive techniques (common) • First scientist to tackle human sexual behavior => zoology professor Alfred Kinsey o Fact that Kinsey dared to apply science to sexuality -> offended many people o During time where “sexual orientation” didn’t exist -> he reported 37% of males whom he interviewed had at least 1 homosexual experience resulting in orgasm -> shocking o Believed that heterosexuality and homosexuality fell on continuous scale o His studies opened further opportunities for current researchers to find -> motivate humans o Study conducted by psychologists Cindy Meston & David Buss -> asked more than 1,500 college students to identify reasons for having sex -> reproduction isn’t primary reason to have sex ▯ Physical reasons -> “The person’s physical appearance turned me on” ▯ To help attain a goal -> “I wanted to get a raise” ▯ For emotional reasons -> “I realized I was in love” Helen  Li     PSYA02H3   ▯ Because of insecurity -> “I felt obligated to” • Reasons for avoiding sex -> unplanned/ unwanted effects of sexual behavior such as pregnancy, sexually transmitted diseases or being in relationship that may be abusive or simply too complex for younger person to handle • Starting in 190’s -> William Masters & Virginia Johnson described human sexual response cycle based on their observations of 27 male and 118 female prostitutes who agreed to masturbate/ have intercourse while under observation o Monitored with heart rate & blood pressure equipment o Penile plethysmograph, vaginal photoplethysmograph ▯ Measure blood flow to genitalia in men & women o Sexual response cycle: describes the phases of physiological change during sexual activity, , which comprises four primary stages: excitement, plateau, orgasm, and resolution ▯ Allows researchers to describe cascade of physiological changes that occur during sexual behavior ▯ Applies to men & women • Men usually experience a single orgasm followed by a refractory period: a time period during which erection and orgasm are not psychically possible o Some women experience multiple orgasms without refractory period • Stimulation of breasts, nipples & vaginal areas causes sensory nerves to send signals -> hypothalamus -> stimulates pituitary gland to release hormone called oxytocin (plays role in orgasm & post-orgasm physiology) -> oxytocin released during orgasm in males o Dopamine-rich reward centers of brain become highly active during orgasm • If researcher wanted to study how brain activity changes during sexual activity -> use functional MRI scan • In males, erectile dysfunction (ED): inability to achieve or maintain an erection o Caused by cardiovascular problems such as hypertension o Physicians may prescribe Viagra, that enhance blood flow to genitals • For females, physiological problems may lead to lack of arousal or painful intercourse o Estrogen replacement therapy may be of relief • Adolescents may engage in cybersex- use of internet & computer equipment for sending sexually explicit images & messages to a partner o 1/3 adults today engages in cybersex o Unplanned pregnancy & STDs not immediate risk, however people tend to communicate with less inhabitation vid digital media compared to face-to-face encounters ▯ Impulsive behavior, “sexting” (some states consider it form of pornography -> sex offender) • Sexual orientation: a consistent preference for sexual relations with members of opposite sex (heterosexuality), same sex (homosexuality) or either sex (bisexuality) Helen  Li     PSYA02H3   o Current definitions focus on psychological aspects of sexuality (desire, emotion, identification) o E.g. person can have a sexual orientation but never have sexual contact throughout his/her life o Sigmund Freud advanced theory that male homosexuality could be traced to presence of domineering mother and weak father figure o 1987 -> Ellis & Ames argued that homosexuality could be caused by experiencing seduction from older sibling / playmate o Both theories lack scientific evidence to confirm validity o Modern scientific explanations of homosexuality focus on interactions between biological & sociocultural factors • In early 1990’s Simon LeVay compared brains of deceased gay & heterosexual males o Found that area of hypothalamus was, on avg, smaller in gay men compared to heterosexual men o Created storm of controversy among scientists & public ▯ Differences in hypothalamus could have been due to environmental factors- LeVay’s study was not designed to test either conclusion ▯ “Nature vs Nurture” • Modern research on brain show how environmental factors, contribute to anatomical & functional differences in brain • Scientists -> proved difficult to replicate LeVay’s results o Region of hypothalamus was only smaller on avg in gay men vs heterosexuals, & ranges in size were overlapping ▯ Homosexual men whom LeVay studied died associated with HIV (accounted for diff in brain) o Only diff they found between male-preferring & female-preferring rams is a smaller region of the hypothalamus • Homosexual males & heterosexual females show greater activity in the brain’s reward centers when viewing pictures of genitalia of sexually aroused males o Same pattern of brain activity found in homosexual women & heterosexual men viewing pictures of female genitalia • Testosterone: hormone that is involved in development of sex charactertics and motivation of sexual behavior o Found in both men & women, typically higher in males 1. Surges in testosterone are associated with elevated sexual arouse in both males/ females 2. Testosterone has long-term effects on sexual development Helen  Li     PSYA02H3   • Researches long notes that prenatal hormone levels influence sex-specific behavior & sexual preferences in nnd-humth species o During 2 & 5 , months of pregnancy, when fetal brain is developing rapidly- amount of testosterone the fetus encounters influences behavior later in life o If fetus is female -> high testosterone, increased chance of showing male typical behavior & sometimes homosexual orientation o Low circulating levels of testosterone during prenatal development -> feminization o Males exposed to low prenatal testosterone levels more -> feminine pursuits & show homosexual preferences • Heterosexual females tend to have index & ring fingers of equal length • Heterosexual males have longer ring fingers than index fingers • On avg, homosexual males tend to have feminized (equal) ratios & lesbians have masculine ratios o Though not found in all studies o Point here -> finger length has some particular relevance to sexual orientation • Gay males tend to have larger number of older brothers than do heterosexual males o Expecting mother’s immune system o At birth, some mixing of blood between mother & newborn occurs o If newborn is male, mother is thus exposed to proteins that we are specific to males -> triggers an immune response by mother o If subsequent fetuses are male -> maternal immune system may transport the antibodies of her immune system that she built up from previous birth across placenta o Result -> inhabitation of testosterone circulation in developing male o Limited testosterone exposure -> feminized brain o Absence of corresponding birth order effect in lesbians -> affects male fetuses • Sexual orientation may be influenced by combo of genes • Higher for identical twins than fraternal twin pairs Chapter 11.3: Social and Achievement Motivation Helen  Li     PSYA02H3   • Need to belong (sometimes known as affiliation motivation): the motivation to maintain relationships that involve pleasant feelings such as warmth, affection, appreciation and mutual concern for each person’s well-being o Need to have at least few permanent meaningful relationships • Terror management theory: psychological perspective asserting that the human fear of mortality motivates behavior, particularly those that preserve self-esteem and sense of belonging o Suggests that individuals are motivated to belong to families, religious groups, and nationalities as a means to control their death-related anxiety • Mortality salience- an increased awareness of death- with simple reminders o E.g. volunteers may write 1-2 paragraph what happened when people die, while control group write something unpleasant that does not make mortality more apparent (salient) such as discomfort of a root canal or other dental pain ▯ In experiments, simply writing about death is enough to motivate individuals to increasingly defend their own worldview (their spiritual and political beliefs) ▯ Used to reduce impact of mortality salience -> e.g., psychologists followed mortality salience stimulus by asking participants to think positive thoughts about their parents, the effect of mortality salience disappeared ▯ Mortality salience is powerful motivator regardless of one’s nationality/ political persuasion • Maslow (love & belonging; his hierarchy) -> individuals generally must take care of physiological needs first, but must satisfy love & belonging needs before developing healthy self-esteem • Achievement motivation: drive to perform at high levels & accomplish significant goals o Often involves need to compete with & outperform other individuals o Seen in desire to master a task, with or without other incentives or rewards o Can be observes in students approach to school, entrepreneurs desire to build a business, athletes hopes of winning a gold medal • Mastery motives: motives that reflect a desire to understand or overcome a challenge Helen  Li     PSYA02H3   o E.g. desire to master a task • Performance motives: generally those motives that are geared toward gaining rewards/ public recognition • Approach goals: enjoyable & pleasant incentives that we are drawn toward o E.g. praise, or financial reward • Avoidance goals: unpleasant outcomes we try to avoid o E.g. shame, embarrassment, emotional pain • If a student is a pre-med major because he is curious about how the body works & how it recovers from disease, psychologists would say that he has mastery motives -> if student is studying pre-med only because he thinks this major will impress people, then psychologists would say he has performance motives • People are least likely to procrastinate when they are genuinely interested in task & believe they can gain something from it -> master-approach goal • If you are studying math problems because you really want to win an award, psychologists would say you have approach goals; if you are just hoping that you do not get the lowest score in the class, you are exhibiting avoidance goals Chapter 11.4: Emotion • Emotion: psychological experience involving three components: 1. Subjective thoughts & experiences with 2. Accompanying patterns of physical arousal 3. Characteristic behavioral expressions o E.g. anger may involve thoughts & feelings of frustration, aggravation & ill will ▯ Increased heart rate, expressed with clenched teeth & fists, tightly pursed lips & pinched brow Helen  Li     PSYA02H3   • Autonomic arousal prepares body to response to real/ perceived threats • Imagine taking peaceful walk, suddenly -> charging, snarling dog comes at you OR giant auditorium where you have to give a speech o Physiological aspect of this emotional experiences would involve division of ANS called sympathetic nervous system -> increases energy & alertness to enable you to handle frightening/ dangerous situations -> activating fight-or-flight response ▯ Increased heart rate, respiration, sweat, alertness ▯ Draws energy away from bodily functions that can wait until end of emergency, such as immune responses & sexual arousal • Once you finished speech/ dog is gone -> feel calming effects regulated by another division of ANS -> parasympathetic nervous system -> typically uses energy more sparingly, bringing heart rate & respiration back to resting rates & focusing on non- emergency tasks, such as digestion • Polygraph -> “lie detector” -> measures respiration, blood pressure, palm sweat – autonomic nervous system responses that should increase when someone lies o Most U.S courts don’t accept this as valid evidence o Some researchers -> turning to brain imaging in search fro more reliable lie detection methods ▯ Reported that increased brain activity in regions of frontal & parietal lobes when subjects are being deceptive, compared to when they tell truth ▯ E.g. Paul Ekman -> showed that people can be trained to detect very subtle non- verbal “microexpressions” indicative of lying • Limbic system -> critical to emotional processing o Includes hippocampus, hypothalamus, amygdala, & various cortical regions o Amygdala -> interest to