1. How does motivation direct and energize behavior?
Variety of approaches in psychology

2. Instinct approaches Channels behavior in appropriate direction
Instincts
Energy

3. Instinct approach Behavior “hard-wired” into the nervous system
Provide survival value
More common in lower animals
Doesn’t meet the complexity of most human behavior
Modified by experience

4. Drive reduction approach
Satisfying our needs
Primary drives for Biological needs
Examples: hunger and thrist
Secondary drives based on prior experience
Examples: achievement and belongingness

5. Drive reduction Strengths: Primary drives satisfied
Homeostasis for bio needs
Weaknesses:
Humans and other animals seek new experiences

6. Drive reduction doesn’t explain
Curiosity
Sensation seeking
Animals want to increase level of arousal
Exploration
Risk taking

7. Incentive approaches Motivation’s “pull”
Behavior not always motivated internally
External motivation
Incentives

8. Contrasting approaches
Drive reduction
“push”
5 hours since last meal
hunger
Incentive theory
“pull”
Ice cream truck
Palatability (good tasting)

9. What are biological and social factors that underlie hunger?

10. Biological and Social Biological: based on primary drive
Social: preferences heavily influenced by experience and culture
Ex: Grasshoppers and Worms in tacos
Ok in Mexico
Not Ok at Taco Bell in New Britain

11. Primary drive Internal mechanisms regulate the quantity of food intake
And kinds of food desired
Animals given the choice of wide variety of foods
Choose a fairly well-balanced diet
Very rarely gain weight (except pets)

12. Biological factors Chemical composition of blood (glucose)
Factor in controlling eating
Monitored by hypothalamus
On and off switches

13. Hypothalamus as monitor
Acts like thermostat in heating system
Heat comes on
Reaches temperature
Heat shuts off
Negative feedback loop

14. Hunger switches Damage lateral hypothalamus (LH) Animal refuses to eat
LH may act as “on” switch
Hunger sensor
Damage ventromedial hypothalamus (VMH)
Animal eats too much
VMH may act as “off” switch
Satiation sensor

15. VMH rat 400% wt increase Finicky Prefer good tasting food (palatable)
Not willing to work for food
Make great house guests

16. Human weight regulation
Weight set point a key factor
Particular level of weight the body strives to maintain

17. Changing set point Food consumption increases Raise set point
Lower set point
Food consumption decreases

18. Set point and genetics High metabolic rate Eat without gaining wt
Low metabolic rate
Gain wt easily

19. Other factors which affect eating
Meals by the clock
Meal size unrelated to energy expended
Highly palatable foods may be high in calories
Eat for emotional or social reasons

20. Theory 1: External cues and obesity
Oversensitivity to external cues
Based on social convention
(Sight, availability, time of day)
Obesity
Insensitivity to internal cues
(stomach contractions)

21. Ignoring internal cues
Stanley Schacter
Early work by Stunkard
Subjects swallow gastric balloon
Balloon registers stomach contractions
Normal wt subjects reported hunger when stomach contracted
Obese subject paid little attention to internal cues

22. Govern eating by external cues
Palatability
Subjects given either “decent” vanilla shake or one spiked with bitter quinine
decent bitter
Normal oz oz
Obese oz oz
Average amount of shake consumed

23. Availability Have to work to get food
Bag of almonds on desk while waiting
How many subjects ate almonds
with shells without shells
Normal / /20
Obese / /20

24. Other external cues Eat by the clock Sight of other people eating
Social settings

25. Why oversentive?
Schacter: oversensitivity to external cues causes overeating
Richard Nisbett (grad student with Schacter):
Just the reverse
Overeating causes increase in sensitivity
Overeating alters body’s set point for weight

26. Theory 2: Set point Higher set point Obese Person
Eat more to feel satisfied
Higher set point
Obese Person
If eat less, become very sensitive to external cues

27. Set Point theory
Set Point

28. Gaining weight Increase in body weight
Increase in # and size of fat cells
Raises set point

29. Losing weight Any loss of weight after age of two
No decrease in # of fat cells
Decrease in size
Weight set point doesn’t drop
Lowest possible weight gets “stuck”

30. Restrained eaters Fighting to loose weight
Body sending out starvation signals
Can hold themselves back (restrain)
Stay on strict diet
Give in to desire to eat
Likely to binge

31. Yo-Yo effect 95 % of wt lost is regained within a year
Some dieters put on more wt than lost
Famine hypothesis
Fat cells “think” there must be a famine while dieting
Rebound when person stops diet to help body survive the next “famine”

32. Theory 3: Settling point
Rapid rise in obesity in USA
10% population in 1980, 31% in 1991
Settling point: combo of genetics and the environment we live in
Cultural differences in diet
Americans versus Asians
Fast food nation

33. Advice from weight loss experts
There is no easy route to wt loss
Permanent changes in your lifestyle
Set reasonable goals
Exercise: critical factor in long run
Avoid fad diets
Don’t feel guilty