Transcript Document 7160264
Theories of Motivation Hunger Motivation Eating Disorders
Intro Psych Module 26 Nov 2-6, 2009 Classes #28-30
Motivation
The underlying processes that initiate, direct and sustain behavior in order to satisfy physiological and psychological needs or wants
Theories of Motivation
Instinct Theory Drive Reduction Theory Arousal Theory
Optimal Level Hypothesis
Incentive Theory
Instinct Theory
Instinct
Complex unlearned response triggered by a stimulus or complex stimulus
Do humans have instincts?
Early Darwinian Theory (1800’s) proposed the idea of instinct, arising from genetic endowment William James (1890) proposed an instinct theory in humans Instincts were goal directed predispositions to behavior
Instinct Theory
Paradox in Psychology:
As others were showing that animal behavior could be modified by learning (Thorndike), James was proposing that much of human behavior was unlearned William McDougall (1908) followed… Suggested their were 18 instincts
Instinct Theory
McDougall (1908) theorized that motivated behaviors are instinctual:
Unlearned Uniform in expression (do not change with practice) Universal (all members of a species show the same behavior)
Too many limitations…
By 1924 instinct theory was becoming obsolete as there were several criticisms:
Too many instincts
Researchers came up with 5759 of them
Logic was circular
i.e. the only evidence that an instinct exists was the behavior it supposedly explained He’s an “overachiever” because he’s “hard-working” She’s “hard-working” because she’s an “overachiever”
Just meaningless labels with no explanations
Drive Reduction Theory (Hull, 1943)
Supporters of this theory believe that when a need requires satisfaction, it produces drives
These are tensions that energize behavior in order to satisfy a need Thirst and hunger are, for instance, drives for satisfying the needs of eating and drinking, respectively
Drive Reduction Theory
Drives have been generally established as primary and secondary…
Primary drives satisfy biological needs and must be fulfilled in order to survive Homeostasis is the motivational phenomenon for primary drives that preserves our internal equilibrium. This is true, for example, for hunger or thirst Secondary drives satisfy needs that are not crucial to a person's life
Criticism
Critics felt that this theory was inadequate in explaining secondary drives
Arousal Theories
Optimal Level Hypothesis
Optimum Arousal Theory:
Hebb (1955) and Zuckerman (1984)
This theory argues that we all have optimal levels of stimulation that we try to maintain…
Optimal Level Hypothesis
we seek an optimal level of arousal too little stimulation, we seek an increase too much, we seek to decrease
Eysenck (1967)
Extraversion Introversion
Introverts were over aroused individuals therefore they try to keep stimulation to a minimum Extroverts were under aroused individuals, therefore they tried to increase stimulation
Eysenck (1967)
Cortical Arousal Differences
Eysenck suggests that the difference between introverts and extroverts depends on the ascending reticular activating system (ARAS) Causes introverts to be “stimulus shy” Causes extroverts to be “stimulus hungry”
Cortical Arousal Differences
Geen (1984)
Introverts and extraverts choose different levels of stimulation, but equivalent in arousal under chosen stimulation Extroverts chose to hear louder noises than introverts After put in their chosen environment their HR’s are the same This seems to suggest that being at their preferred level of stimulation results in the same overall level of arousal for both groups
Geen (1984)
Researcher tested four other groups: Introverts introverts placed in environment that other had chosen ( II ) Introverts placed in environment that extroverts had chosen ( I E ) Extroverts extroverts placed in environment that other had chosen ( EE ) Extroverts placed in environment that introverts had chosen ( E I )
Geen (1984)
II = similar HR as free choice introverts I E = higher HR than free choice introverts when forced to listen to extroverts’ noise EE = similar HR as free choice extroverts E I = lower HR than free choice extraverts when forced to listen to introverts’ noise
Geen (1984)
Performance on a learning task was also affected: Introverts did best in introvert-selected environment Extraverts did better in extravert-selected environment Practical implications: Roommates?
Mate Selection?
Does it explain the psychopathic behaviors???
Serial killer
Criticism of Optimum Arousal Theories
People differ greatly in the optimal level of arousal they seek… These theories do not explain why
Incentive Theory
Viewpoint on motivation that is different than instinct, drive , and arousal theories Suggests that behavior is pulled rather than pushed… Emphasizes the role of environmental stimuli that can motivate behavior by pulling people toward them rather than pushing people to satisfy a need (as in the drive reduction theory) Suggesting that people act to obtain positive incentives and avoid negative incentives
Explains secondary drives much better than drive-reduction theory
Criticism
Some behaviors seem to be pushed as well
Abraham Maslow (1908-1970)
Born in Brooklyn, NY His parents were uneducated Jewish immigrants from Russia Hoping for the best for their children – they pushed them hard towards education He became very lonely as a youth and found his refuge in books To satisfy his parents, he entered law school at CCNY and then Cornell
Abraham Maslow
Against his parents wishes, he married his first cousin and moved with her to Wisconsin where he became interested in psychology and gets his BA in 1930, MA in 1931, and Ph.D. in 1934 at the Univ. of Wisconsin In 1935, he returns to NY and works with Thorndike at Columbia and eventually begins teaching full-time at Brooklyn College and then becomes chair of psych department at Brandeis where he begins his crusade for humanistic psychology
Maslow’s Hierarchy of Needs (1970)
Abraham Maslow proposed that there are five levels of motives, or needs, arranged in a hierarchy:
Physiological Safety Belongingness and love Esteem Self-actualization
We must satisfy needs or motives low on the hierarchy before we are motivated to satisfy needs at the next level
Physiological Needs
Physiological needs are basic, instinctual needs for air, food, water, and sex, among others. These needs must be at least partially met in order to ascend the hierarchy.
These needs can also be arranged in their own hierarchy.
Safety Needs
Safety needs include things such as shelter, security, and protection from physical and emotional harm.
Belonging Needs
These needs are met by having meaningful relationships, such as significant others, friends and children
Esteem Needs
This level has two sub levels Low esteem needs are the needs for the respect of others – need for recognition, etc.
Higher esteem needs are the needs for self respect – to achieve, to be competent, to be independent, etc.
Self Actualization
Self actualization involves becoming the most complete person that you can be – your full potential
Criticisms
Some critics felt that it is possible to skip levels Others felt that they could not be applied universally
Theories of Hunger Motivation What triggers our motivation to eat?
Internal Factors
An empty stomach?
Body Chemistry Hypothalamus Set Point Theory
External Factors
Externality Hypothesis
Other Factors
Emotion Habit Attention
Internal Factors
An empty stomach?
Early researchers thought that hunger pangs were important - caused by contraction of stomach
Cannon and Washburn (1912)
hypothesis that the contraction of the stomach is the cue to start eating tested the Tested this by having Washburn swallow a balloon and measuring contractions of the stomach by looking at contractions of the balloon (changes in air pressure go out stomach via tube to measuring device)
An empty stomach?
Tsang (1938)
Removed rats stomachs and attached their esophagus to their small intestine They still displayed actions associated with hunger
Body Chemistry
Blood Glucose
This is a simple sugar used by most cells in the body for energy - most food ultimately gets converted to blood glucose
Decreasing blood glucose levels
sense of hunger Insulin
This is a hormone that increases the flow of glucose into body cells, diminishing the amount of glucose in the blood by converting it into stored fat
Decreasing blood glucose levels
sense of hunger
Body Chemistry
Glucagon
This hormone helps convert stored energy supplies (stored fat) back into blood glucose
Increasing blood glucose levels
hunger decreases
Lesions of Hypothalamus
The destruction or stimulation of the lateral and ventromedial areas causes animals to ravenously decrease or increase their weight See picture on page 375 for example of increase
Set Point Theory
Set point is the weight that your body wants to be…
It is a self-regulatory system that maintains your body weight If you starve yourself the hypothalamus activates compensatory mechanisms, your metabolism slows so that energy stores are used more sparingly and the amount of insulin that is produced increases so that more of the food that you take in remains as fat (this makes it possible to maintain weight on a meager diet)
What triggers our motivation to eat?
External Incentives
Rodin (1981) Like Pavlov’s dogs people learn to salivate in anticipation of appealing foods
Externality Hypothesis (Schacter, 1978)
Did research on obese humans They argue that the difference between obese and normal weight subjects is that the obese are overly responsive to external stimuli (cues for eating)
Externality Hypothesis
VMH-lesioned rats and obese humans are similar in interesting ways:
Both are more "finicky" than controls. Both are less willing to work for food VMH-lesioned rats don't eat as much of a bad tasting food as do control rats Obese humans don't drink as much of a bad-tasting milk shake as do control humans VMH-lesioned rats don't bar-press for food on "lean" schedules as readily as do the control rats Obese humans eat fewer peanuts than do control humans if they have to shell them, but more if they don't have to do this work
Externality Hypothesis
These findings support Schacter's conclusion that both VMH-lesioned rats and obese humans are more sensitive to external cues related to food than to the internal cues provided by their bodies. Obese humans are more likely to eat more when they are misled into thinking it's lunchtime than are control humans again evidence of the influence of external cues Social Factor is another external cue Eating around others often increases food intake
Other Factors
Emotion
Depressed people may eat too much or too little
Habit
Meal time - ancient Romans only ate two meals a day. We eat three - if we miss a meal, we feel hungry at that meal time
Attention
Awareness vs. non-awareness
Eating Disorders
Obesity Anorexia Nervosa Bulimia Nervosa
Obesity
Weight which is 20-40% above the normal standard for a person’s height (BMI over 30 kg/m2) Rates of obesity are climbing and have risen from 12 to 20 percent of the population since 1991. An ominous statistic which indicates that the epidemic of obesity may get even worse is that the percentage of children and adolescents who are obese has doubled in the last 20 years
Why is this happening?
Basal Metabolic Rate
Basal metabolic rate (BMR) fasting in humans). is the amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state (meaning that the digestive system is inactive, which requires about twelve hours of If you've noticed that every year, it becomes harder to eat whatever you want and stay slim, you've also learnt that your BMR decreases as you age. Likewise, depriving yourself of food in hopes of losing weight also decreases your BMR, a foil to your intentions. M > W (more muscle) Exercise increases BMR
Obesity
Weight which is 20-40% above the normal standard for a person’s height Rates of obesity are climbing and have risen from 12 to 20 percent of the population since 1991.
Why is this happening?
Obesity
Why do some people become seriously overweight?
Emotional problems
Depression Anxiety
Sedentary lifestyle
Too much TV and not enough exercise
Genetics
Higher set point
What factors help prevent obesity?
Preventing obesity must begin in childhood Breastfed children less obesity Encouraging children to exercise and eat healthy foods don’t use “special food” as a reward – Stanek et al. (1990) children tend to be more interested in a “forbidden food” –– Mennella et al. (2001) Limiting television watching Problem with adult modeling, increase consumption of snacks low in nutrients and watching TV during meals increase consumption of salty snacks and pop and less fruit and vegetables – Goldberg et al. (2001) Many ads have low-nutrient beverages and sweets – Story and Faulkner (1990)
How is obesity treated?
Fad Diets
Exaggerated claims based on false theories Potentially harmful
Weight Cycling
Set point theory?
Psychological ramification
Weight Cycling
Psychology of Weight Cycling
How is obesity treated?
Eating less and eating smarter Meals in US – much bigger portions than elsewhere Physical Activity - Increasing exercise Activity and BMR- activity increases BMR Activity and appetite control energy released from stores (plasma glucose normal) digestive functions are suppressed setting short-term goals reminders or prompts making behavior fit into daily schedule/ routine
How is obesity treated?
Operant conditioning approaches Make small changes to behavior Having the support of family members, and friends – social support Other self-control approaches Behavior and Attitude
stimuli
behavior
consequence
Awareness of behavior why do I eat, when, where
Anorexia
Anorexia Nervosa
Anorexia Nervosa
Self-starvation and severe weight loss Usually starts as an innocent diet that went out of control They eat less and exercise more Often they come from high-achieving or over protective families At first, self-esteem was raised – “you look great”
Symptoms Of Inadequate Energy Intake
Physical health
Amenorrhea Cold hands/feet Constipation Dry skin/hair loss Headaches Fainting/dizziness Lethargy Anorexia Mental health
Concentration Decisions Irritability Depression Social withdrawal Obsessiveness (food)
Anorexia Nervosa
Complications
Hypothermia may result Results when the body’s natural isolation fat stores become non-existent and the victim becomes cold all the time Some must be tube-fed to prevent death Some will die from heart failure
Anorexia Nervosa
Prognosis
With individual, group, and family therapy there is a good chance for improvement and hopefully recovery Anti-depressants are often combined with these therapies
It is a life-long process though
Anorexia Nervosa (pursuit of thinness
)
Successful Weight Loss – Hallmark of Anorexia
Defined as 15% below expected weight Intense fear of obesity and losing control over eating Anorexics show a relentless pursuit of thinness, often beginning with dieting
DSM-IV Subtypes of Anorexia
Restricting subtype – Limit caloric intake via diet and fasting Binge-eating-purging subtype – About 50% of anorexics
Associated Features
Most show marked disturbance in body image Most are comorbid for other psychological disorders Methods of weight loss can have severe life threatening medical consequences
Anorexia: Facts and Statistics
0.5-5% 15-19 year old females Majority are female (90-95%) and white (> 95%), from middle-to-upper middle class families Usually develops around age 13 or early adolescence Tends to be more chronic and resistant to treatment than bulimia 3rd most common chronic illness in adolescents
Major Systems Affected
Metabolic
Hypometabolism/ Refeeding Syndrome Cardiovascular
Arrhythmias Musculoskeletal
Osteoporosis Reproductive
Amenorrhea
Bulimia Nervosa (avoidance of obesity)
Associated Features
Most are within 10% of target body weight Most are over concerned with body shape, fear gaining weight Most are comorbid for other psychological disorders Purging methods can result in severe medical problems
Bulimia Nervosa
Disorder characterized by repeated binge purge episodes of overeating followed by vomiting or using a laxative Again, mostly women in their early teens These individuals can be thin, average in weight or even overweight – so this one is more likely to go unnoticed by family or friends
Bulimia Nervosa
Symptoms of Bulimia
Eating binges Purging Sore throat Mouth and throat ulcers Swollen salivary glands Destruction of tooth enamel Depression, obsessive-compulsive symptoms
Bulimia Nervosa
Prognosis
With the long-term psychotherapy combined with group and family therapy the patient will likely improve Often, anti-depressants are combined with therapy Again, this is a life-long process
Bulimia: Facts and Statistics
Bulimia Majority are female, with onset around 16 to 19 years of age Lifetime prevalence is about 1.1% for females, 0.1% for males 5-10% of college women suffer from bulimia Tends to be chronic if left untreated
Signs And Symptoms Of Vomiting Or Laxative Abuse
Physical health Weight loss Electrolyte disturbance
K
CO 2 Dental enamel erosion Hypovolemia Knuckle calluses Mental health
Guilt Depression Anxiety Confusion
At-Risk Groups for both AN and BN
Adolescent females with low self-esteem Gymnasts Dancers (ballet) Wrestlers Runners When thinness is related to success
AN & BN: Engaging Parents in Treatment
Developmental framework (child
adult)
Discuss blame, fault, guilt openly
Realignment of roles in family
Positive framing of family attributes
Future orientation
Authority to treat, and empowerment of, professionals comes from parents
Problems Addressed In Mental Health Treatment
Low Self-esteem Distorted body-image Dysfunctional coping behaviors and habits Depression
SSRIs for BN and weight recovered AN Ineffective communication Conflict resolution Lack of assertiveness Post-trauma recovery (sexual abuse, etc)
Indications for Hospitalization
Severe malnutrition: Weight for height <75% Dehydration Electrolyte disturbances Cardiac dysrhythmia Physiologic instability
Severe bradycardia or hypotension
Hypothermia
Orthostatic pulse changes
http://www.adolescenthealth.org/html/eating_disorders.h
tml
Indications for Hospitalization
Arrested growth and development Failure of outpatient treatment Acute food refusal Uncontrollable bingeing and purging Acute medical complication of malnutrition Acute psychiatric emergencies Comorbid diagnosis interfering with treatment (Fisher et al.,1995)
Eating Disorder, Not Otherwise Specified
All criteria for AN, except still menstruating All criteria for AN, except normal weight All criteria for BN, except frequency or duration Compensatory weight control after small amounts of food Chewing/spitting out, but not swallowing, large amounts of food Binge eating disorder
Binge-Eating Disorder
Binge-Eating Disorder – Appendix of DSM-IV Experimental diagnostic category Engage in food binges, but do not engage in compensatory behaviors Associated Features Many persons with binge-eating disorder are obese Most are older than bulimics and anorexics Show more psychopathology than obese people who do not binge Share similar concerns as anorexics and bulimics regarding shape and weight
Signs And Symptoms Of Binge Eating
Physical health
Weight gain Bloating Fullness Lethargy Salivary gland enlargement Mental health
Guilt Depression Anxiety
How do biological factors lead to eating disorders?
Women who have close relative with an eating disorder are 2-3 times more likely to suffer from one More likely to occur in both identical twins than fraternal twins (
higher concordance
) Anorexa sufferers have higher levels of serotonin Bulimia sufferers are less sensitive to serotonin
What psychological factors lead to eating disorders?
Cultural norms
Thinness norm is portrayed in media
Brazilian model Ana Carolina Reston…this 21-year-old anorexic model reportedly weighed just 88 pounds
What psychological factors lead to eating disorders?
Family dynamics Families of women with eating disorders are particularly focused on weight and shape Families of anorexics have potentially dysfunctional dynamics Families of bulimics have more conflict, and less nurturance
What psychological factors lead to eating disorders?
Personality The “perfect child” expectation in families Anorexics: rigid, anxious, perfectionists, and obsessed with order and cleanliness Bulimics: depressed, anxious, lack clear sense of self-identity, have negative self-views
What approaches help prevent eating disorders?
Interventions specifically targeting women with poor body images can be effective
Weight Gain
Rate
low...
1 lb/week, Target weight >85% average, if 70% of weight gain is lean body mass (muscle) Must eat adequately to gain lean body mass
Lean body mass will result in Higher metabolism
More energy
Fewer symptoms
Cognitive-behavioral therapy is used to design programs for weight gain
“But, I’m Not Hungry”
Physiologic Fact Reframing for patient
Body burns calories throughout life Appetite
need to eat Eating Disorder
Appetite
If only respond to appetite, will not get enough energy
If eat on regular schedule, more likely to get energy
Higher energy fuel ensures greater likelihood of getting enough energy Even if you’re not hungry, your body burns calories Appetite gauge
car’s gas gauge Eating Disorder
broken gas If drive car with broken gas gauge can run out of gas Fill car with gas based on miles driven & gas mileage Fat has more energy than carbohydrate or protein and is a necessary body fuel
Lingering issues…
Is obesity really unhealthy?
“upper-body fat” is particularly bad Can eating disorder prevention programs have dangerous effects?
Eating disorder prevention programs can sometimes lead to an increase in disordered behavior Nova film, “Dying to be Thin” - emaciated women are triggering girls who want to be thin. Instead… Show the videos: “Body Talk”, or “Killing Us Softly”. Shows being able to express their body image and resist media messages.
Credits
Some slides in this presentation prepared with the asistance of the following websites: http://www.healthypotato.com/downloads/Glycemic_Index_8 8-05.ppt
http://www2.una.edu/psychology/health/ch08%20obesity2.pp
t#1