Transcript Motivation * Hunger

Motivation – Hunger
Things to know - Motivation & Emotion:
1) Human motivation is complex, & while
there are a number of theories, none by
itself sufficiently explains our behavior.
1) Biological motivation includes the role of
the hypothalamus, which maintains a
state called homeostasis.
1) Theories of social motivation, including
the need for achievement & hierarchy of
needs, show the importance of
understanding motivation in the
context of our environments.
1) Emotions can be explained through a
variety of theoretical perspectives, each
arguing that emotion emerges in
conjunction with physiological
response to stimuli.
What Triggers Hunger?
•
Physiology
●
Homeostasis
• Set Point
●
Hormones
• Insulin/Glucagon
• Ghrelin/Leptin
●
Hypothalamus
• VMH (satiety)
• LH (hunger)
•
https://www.youtube.com/watch?v=9hdSLiHaJz8
Hunger
• Eating comes naturally
▫ If it was entirely learned
you would probably starve before
learning it
BIOLOGICAL
Copyright ©
MOTIVATION:
Allyn & Bacon
2007
Hypothalamus: region of
brain most often
associated w/ motivation
Motivation: feeding,
fighting, fleeing, &
sexual reproduction.
Physiology of Hunger
Glucose: hormone insulin
Washburn: showed hunger
partially related to the stomach. converts glucose to fat.
**However, those persons who
When glucose levels
have had their stomachs removed drop:
still feel hunger.
HUNGER INCREASES
The Physiology of Hunger
Stomach contractions (pangs) send signals
to the brain making us aware of our hunger.
BIOLOGICAL
MOTIVATION:
Hypothalamus:
region of brain most
often associated w/
motivation
Motivation: feeding,
fighting, fleeing, &
sexual reproduction.
Physiology of Hunger
Washburn: showed hunger partially
related to the stomach.
**However, those persons who have
had their stomachs removed still feel
hunger.
Glucose: hormone insulin converts
glucose to fat.
When glucose levels drop:
HUNGER INCREASES
1960s: Discovered that
hunger comes from the
Brain.
The Brain
The
Hypothalamus
Hypothalamic Centers
Lateral hypothalamus (LH) brings on hunger.
Destroy it and the animal will starve.
Ventromedial hypothalamus (VMH) depresses
hunger (stimulation). Destroy it and the animal eats
excessively.
Richard
Howard
Summary of Hypothalamus & Hunger
Along lower middle section of hypothalamus is the
ventromedial hypothalamus: depresses hunger
Stimulate the ventromedial hypothalamus & the
animal will stop eating
Lesion the ventromedial hypothalamus
the animal will continuously want to eat.
Along the sides of the hypothalamus is the
lateral hypothalamus:
which brings on hunger.
Stimulate the lateral hypothalamus &
even a well fed animal will begin to eat.
Lesion the lateral hypothalamus & a
starving animal will have no interest in food.
Biological Factors of Hunger
1. Activity of the lateral & medial
hypothalamus.
2. Basal Metabolic Rate: Each person burns food at a
different rate & expends energy with different efficiency.
A person with a high metabolic rate can eat more without
gaining weight than someone who is just as active, but has
a lower metabolic rate.
3. Body Set Point: Just as we have a temperature
“thermostat” that keeps our body temp within an
acceptable range, one theory suggests that we have
a weight “set point.”
Newer research suggests we have a “settling point” – a
range of normal weights within which we can vary.
4. Taste sensation: Tastes is an important factor when we
first begin eating.
It encourages us to continue.
Set Point Theory
Hypothalamus acts as a thermostat.
Copyright ©
Allyn & Bacon
We are meant to be in a certain weight
range.
2007
When we fall below weight our body will increase hunger
& decrease energy expenditure (Basal Metabolic Rate)
What happens if we go above our set point?
Theory states we will auto correct to lower point.
Set-Point Theory
Manipulating lateral and ventromedial
hypothalamus alters the body’s “weight
thermostat”…predisposing us to keep our
bodies at a steady weight.
If weight is lost (go below set point) – food intake
increases and energy expenditure decreases.
If weight is gained (go above set point) – the opposite
takes place.
Set-Point Theory
To maintain set point, the body not only
adjusts food intake and energy output, it
also adjusts its basal metabolic rate, the
body’s resting rate of energy expenditure,
dropping when less activity is occurring
 Not all researchers believe in idea of a set
point b/c believe that slow, sustained
changes in body weight can change set
point
The Psychology of Hunger
External incentives… eat because triggered by the
presence of food, especially tasty (high fat/calorie) food
Eating by the “clock”… eat because it is “time” to eat
lunch/dinner
Social eating… eat at an event because you are “expected”
to
Stress and depression… eat more/less and different types
of foods
Other eating cues… holidays or watching TV/movie
Hunger Drive
Hunger is probably the most researched of all physiological needs.
Arises from a complex mixture of
external and internal factors:
External Factors
Stress - A person may eat to counteract
negative feelings produced by stress.
(Stress- unpleasant, Eating pleasant)
Certain foods release the neurotransmitter
serotonin, which has a calming effect.
Eating habits - Eating at fixed times of the
day, regardless of hunger.
Food-related cues - Eat because food is
appealing to you, even though you are not
hungry. Eating dessert even though you are
full.
Presence of eating cues - If you always
have a snack an hour before going to bed,
when the cock reaches that hour, it
motivates you to go and get food - hungry or
not.
Internal Factors
Hypothalamus - 2 factors, one monitors chemicals
related to the amount of glucose in the body. When
glucose drops, the hypothalamus produces sensation
of hunger. After the need has been met, other
chemicals are released that signal the feeling that you
are full. A second homeostatic system measures the
amount of fats and amino acids stored in the body's
cells. When their levels drop too low, hunger signals
are switched on.
Basal Metabolic Rate - Each person burns food at a
different rate and expends energy with different
efficiency. A person with a high metabolic rate can eat
more without gaining weight than someone who is just
as active, but has a lower metabolic rate.
Body (basal) Set Point - Falling below that "set point"
of weight triggers biological processes that cause us to
get hungry more often.
Taste Sensation - Tastes is an important factor when
we first begin eating. It encourages us to continue.
Before long, the taste buds begin to shut down so that
we are willing to stop eating when we are full.
Hunger & eating are governed in part by a
variety of food-related cues.
Schachter found that obese subjects would
eat more than non-obese subjects when they
were told it was much later in the afternoon
than it actually was.
Also, they would eat more of a tasty ice cream
product than one that was not as tasty.
Taste Preference: Biology or
Culture?
Body chemistry and environmental factors
together influence not only when we feel hunger
but what we feel hungry for!
Beijing street market fare
Eating Disorders
Anorexia Nervosa: Characterized by a normalweight person (usually adolescent women) losing
(dramatic amounts) weight continuously and yet still
feeling overweight.
eprinted by permission of The New England
urnal of Medicine, 207, (Oct 5, 1932), 61317.
Lisa O’Connor/ Zuma/
Corbis
Eating Disorders
Bulimia Nervosa: A disorder characterized
by episodes of overeating, usually of highcalorie foods, followed by vomiting, laxative
use, fasting, or excessive exercise.
Binge eating: recurrent binge eating without any
type of “purging as in bulimia
Body Image (Women)
Western culture tends to over-emphasize thin
body image more than other cultures…
Cultures who put more emphasis on appearance have
higher rates of eating disorders
Summary of Hunger
Activities
Motivational Music—
connect music to
motivational theories
Maslow’s Hierarchy Handout—
apply Maslow’s needs to your
own. What helps you reach selfactualization?
NEXT CLASS
No HOMEWORK tonight.
We’re going to study “sex and
belongingness” reading guide and
activities in class. 
Next class:
You’ll be assigned an activity on the computer.
Then you and your family will need to fashion out how to study and learn
about “sex and belongingness”