3/4/2013
Motivation
Motivation
• Activation
• Selection
• Energization
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3/4/2013
Motivation
• Instinct theories
– William James; McDougall; Freud
– Reaction to rationalist viewpoint; lives can
be controlled in part by unconscious
– Source of individual differences: genes
Motivation
• Instinct theories
– William James; McDougall; Freud
– Reaction to rationalist viewpoint; lives can
be controlled in part by unconscious
– Source of individual differences: genes
– Problems
• downplayed environment too much
• List of instincts long and arbitrary
• Post-hoc explanation
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3/4/2013
Motivation
• Instinct theories
• Drive theories
– Biological needs
– Psychological Drives
Motivation
• Instinct theories
• Drive theories (Hull)
– Biological needs
– Psychological Drives
• Drive as general activator
• Drive and learning (selection)
– Drive reduction responsibility for learning
– Drive as discriminative stimulus (specific activation)
• Drive as energizer
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3/4/2013
Motivation
• Instinct theories
• Drive theories
– Related motivation to learning
• Selection and specific activation learned
• Individual differences due to learning differences
• General activation and energization functions multiplied
learned behavior
• Emphasized internal states’ pushing behavior
(endogenous sources of motivation)
• Related motivation to physiological regulation
(homeostasis)
Motivation
• Instinct theories
• Drive theories
– Related motivation to learning
– Problems with drive theories
• Do things that increase drives
• Downplayed incentive properties of external world (only
indirect influence via drive reduction)
• Require that we readily distinguish internal states
(Schachter experiment)
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3/4/2013
Motivation
• Instinct theories
• Drive theories
• Hedonistic theories
– Behavior not driven by needs, but guided by
desires
– Pleasure-seeking rather than drive-reducing
– Food is motivator because it tastes good, not
because it reduces hunger
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3/4/2013
Motivation
• Instinct theories
• Drive theories
• Hedonistic theories
– Behavior is guided by desires
– Problems
• Circularity: How do you define “liking”
“pleasure” etc.?
– Evolutionary arguments
– Brain circuits (VTA-NAc dopamine pathways)
Motivation
•
•
•
•
Instinct theories
Drive theories
Hedonistic theories
Incentive theories
– Behavior is guided by external (exogenous)
events or learned expectancies of those events
– Behavior pulled from without, rather than pushed
from within
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3/4/2013
Motivation
•
•
•
•
•
Instinct theories
Drive theories
Hedonistic theories
Incentive theories
Modern integrative approaches to
motivation
Hunger and eating
• Important in daily life (normal and
abnormal)
• Powerful motivator
– strong sensations
– strong
g behaviors
• Internal and external cues (drives and
incentives) both play critical roles
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3/4/2013
Internal cues for hunger/eating,
and for satiation/cessation
Internal cues for hunger/eating,
and for satiation/cessation
• Stomach pangs,
pangs empty feeling (stomach
contractions, undistended stomach); Full
feeling (distended stomach)
– Cannon/Washburn experiment
– amount of distension controls cessation
– stomach/duodenum can sense nutrients (calories)
(
)
but mostly for cessation (nutritious vs
nonnutritious loads)
– release of CCK, eating-suppressing hormone
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3/4/2013
Internal cues for hunger/eating,
and for satiation/cessation
• Weakness
Weakness, headache
headache, inability to
concentrate, tense, grouchy
– Related to sugar metabolism
• receptors in liver register conversion of
glycogen into glucose, stimulate eating
• register conversion of glucose into glycogen
glycogen,
suppresses eating
– Related to dehydration (prandial drinking)
Internal cues for hunger/eating,
and for satiation/cessation
• Other internal cues you don’t
don t notice
– fat levels; leptins suppress eating
– neuropeptides work both ways
– body temperature
– roles of hypothalamus
• lateral
• ventromedial
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3/4/2013
Vmh lesion
LH stimulation
External cues for hunger/eating
• incentives (taste/smells)
• learned incentives (habits and cravings)
• social cues (social facilitation)
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3/4/2013
External cues for hunger/eating
• incentives (taste/smells)
• learned incentives (habits and cravings)
• social cues (social facilitation)
• Morbid obesity and externality/internality
distinction (Schachter experiments)
Schachter experiments
consumption (grams)
Incentive effect
160
140
120
100
80
60
obese
non-obese
40
20
0
bland
tasty
Food quality
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3/4/2013
Schachter experiments
Learned incentive (time of day)
100
120
100
80
60
consumption (grams)
consumption (grams)
Incentive effect
160
140
obese
non-obese
40
20
0
80
60
obese
40
non-obese
20
0
bland
tasty
accurate
Food quality
fast
Clock
Schachter experiments
Learned incentive (time of day)
100
120
100
80
60
consumption (grams)
160
140
obese
non-obese
40
20
0
80
60
obese
40
non-obese
20
0
bland
tasty
accurate
Food quality
fast
Clock
Social facilitation
100
consumption (grams)
consumption (grams)
Incentive effect
80
60
obese
40
non-obese
20
0
alone
group
Group
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3/4/2013
Problems with
externality/internality hypothesis
not as well-related to personality type as
originally thought

Diet-busting effect
250
consumptiion (grams)
– For example, “restraint”
is another important
variable: Restrained
eaters suppress their
responses to external
cues initially, but binge
once eating initiated
(relate to prefrontal
cortex?)
200
150
restrained
100
unrestrained
50
0
0
1
2
Preload (# milkshakes)
Problems with
externality/internality hypothesis
• not as well
well-related
related to personality type as
originally thought
• Determinants of eating are more
complex than just internal vs external
– Interactions of internal and external cues
• external cues produce internal ones (e
(e.g.,
g
learned digestive responses; cravings)
• internal states modulated effectiveness of
external cues
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3/4/2013
Problems with externality/internality
hypothesis
• not as well-related to personality type as
originally
g
y thought
g
• Determinants of eating are more complex
than just internal vs external
– Interactions of internal and external cues
• external cues produce internal ones (e.g., learned
digestive responses; cravings)
• internal states modulate effectiveness of external cues
• role of amygdala
– Physiological consequences of obesity
• fat cells and positive feedback
• Insulin resistance
• replacement of nonfat by fat decreases metabolic rate
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