Theories of MotivationHunger MotivationEating Disorders

Intro PsychModule 26

Mar 31-Apr 5, 2010Class #27-29

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 placed in environment that other

introverts had chosen (II) Introverts placed in environment that extroverts

had chosen (IE) Extroverts placed in environment that other

extroverts had chosen (EE) Extroverts placed in environment that introverts

had chosen (EI)

Geen (1984)

II = similar HR as free choice introverts IE = higher HR than free choice

introverts when forced to listen to extroverts’ noise

EE = similar HR as free choice extroverts

EI = 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) tested the

hypothesis that the contraction of the stomach is the cue to start eating

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) 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 fasting in humans). 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

Eating less

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

AnorexiaAnorexia

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

Amenorrhea Cold hands/feet Constipation Dry skin/hair loss Headaches Fainting/dizziness Lethargy Anorexia

Concentration Decisions Irritability Depression Social withdrawal Obsessiveness

(food)

Physical health Mental health

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

Weight loss Electrolyte

disturbance K CO2

Dental enamel erosion

Hypovolemia Knuckle calluses

Guilt Depression Anxiety Confusion

Physical health Mental health

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.html

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

Weight gain Bloating Fullness Lethargy Salivary gland

enlargement

Guilt Depression Anxiety

Physical health Mental health

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 1 lb/week, Target weight >85% average, if low...

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”

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 car’s gas gauge Eating Disorder broken gas

gauge 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

Physiologic Fact Reframing for patient

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.ppt

#1