PSYCH 2010 Lecture Notes - Lecture 10: Arcuate Nucleus, Blood Sugar, Leptin
30 Apr 2018
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Chapter 9: Motivation
Motivation
I. Goal directed behavior
II. Behavior: effort or choice
III. Drive theories: people seek homeostasis (physiological equilibrium, self-
correcting)
IV. Incentive theories: reward/punishment (chapter 6)
V. Evolutionary theories: maximize reproductive success
Motivation of Hunger
I. 1/3 of Americans are normal weight, 1/3 are overweight and 1/3 are obese
a. Now almost 40% of Americans are obese
II. Set point: ertai uer of fat ells i the od eaig eight does’t change much-
NOT TRUE
III. Settling point: weight remains stable without durable changes
IV. Genetics: vulnerability, not set in stone
V. Biological factors affecting hunger
a. Brain regulation in the hypothalamus
i. Arcuate nucleus
ii. Focusing on neural circuits (pathways not structures)
b. Glucose and digestive regulation
i. Glucostats: neurons sensitive to glucose levels
ii. Glucostatic theory: fluctuations in blood glucose influence hunger
iii. Cells i the stoah sed sigals to the rai to tell us that e’re full
1. Type 1: how much the stomach has stretched
2. Type 2: how nutritious the food was
c. Hormonal regulations
i. Insulin: has to be present to use glucose
1. Increase in glucose increases hunger
ii. Sight and smell of food can increase hunger
iii. Ghrelin: secreted by the stomach after not eating
1. Causes the stomach to contract
2. Increase in ghrelinincrease in hunger
iv. CCK: secreted by the stomach after eating
1. Increase CCKdecrease in hunger
v. Leptin: produced by fat cells throughout the body
1. Increase levels of fatmore leptin produceddecrease in hunger
VI. Environmental factors affecting hunger
a. Increase in food quantity: eat more
i. Portion size has been steadily increasing
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b. Increase in variety of food: eat more
i. Sensory specific satiety: incentive value drops so we eat less
c. Eat with other people: eat more
i. Exception: women on dates (the more attractive the guy, the less she
eats)
d. Food on a smaller plate: eat less
e. Better tasting food: eat more
f. Stress increase: eat more
i. Women stress eat more, men tend to turn to alcohol
ii. People on diets stress eat more
Motivation of Sex
I. Sexual orientation: preference for same, opposite, or both sexes
II. Kinsey
a. Continuum (not distinct groups)
b. Homosexuality (5%) of the population
i. Psychoanalytical: NO
1. Freud: weak dad + an overprotective mom
ii. Behaviorism: NO
1. Pairing-No but can lead to fetishes
iii. Biological: most research
1. 75-90% of feminine boys became gay
2. Religion science
3. Behaviorpredisposition
III. Biological origins of sexual behavior:
a. Genetic
i. Identical twins: 52%
ii. Fraternal twins: 22%
iii. Adopted siblings: 11%
b. The brain
i. Hypothalamus
1. Cluster cells: 2x larger in heterosexual males compared to females
and homosexual males
2. “traight oe ould sell e’s seat ad the sexual arousal
area of the hypothalamus would light up
a. Gay men had the same result
b. In straight men their brain did not light up, but it did for
female sweat
ii. Anterior commissure: 1/3 larger in gay men compared to straight men
iii. EEG (Spatial recognition): gay men scored closer to women
c. Hormones
i. Current hormonal levels cannot reliably predict sexuality
ii. Reliable in-utero
Monkey study: female
monkeys preferred to
play with dolls and
males preferred toy
trucks
If one brother is gay, how likely is it for
the other sibling to be?
Brain plasticity: how easily
shaped by culture or
circumstances
-men are more
biologically driven
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1. Men with older brothers are more likely to be gay
a. Regardless if raised in the same home or not
2. Finger print studies: finger prints of gays and women are more
similar
3. Cochlea in ear study: gay women
a. Lesbians have a similar cochlea shape to men than women
iii. Women that are given androgen while pregnant are more likely to have a
lesbian daughter
Motivation of Emotion
I. Emotion: complex evaluative feelings which often includes physiological arousal
II. Three components of emotion
a. Cognitive: positive or negative, complex
b. Physiological: bodily arousal
i. In the amygdala
ii. Can act independently of cognitive
c. Behavioral: nonverbal
i. Facial expressions
1. 7 primary innate emotions
2. Facial feedback hypothesis: face muscles send back messages to
the brain
a. Ex: if you make yourself smile it sends signals to the brain
to make you happier
III. Happiness
a. Most people are happy
b. The nun study
c. 50% genetic, 10% circumstance (money or education) ,40% intentional activity
d. Poor predictors of happiness
i. Money
1. Begin to get used to the amount of money around $75,000
a. Hedonic adaptation
2. Hedonic treadmill: neutral (getting used to) point keeps increasing
ii. Age
iii. Gender
iv. IQ
v. Attractiveness
e. Good predictors of happiness
i. Social relationships (friends and family)
ii. Work
iii. Optimism
iv. Health
v. Religion
People tend to be happier on
Botox because they cannot
frown
Republicans tend to be happier
compared to Democrats
Prospective theory: loses loom longer
-pain of losing $20 is stronger than the joy of finding
$20
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