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Motivation
Why did you choose St. FX?
Context and Sources of
Motivation
Context
Source of Motivation
Primarily
Biological
Alone
With
Others
Primarily Social
desire for possessions, desire
hunger, thirst, for learning, need for relief of
defense, sleep boredom, need for
achievement
need for reassurance, need
sex
for prestige, need for approval
What distinguishes biological motives from social
motives?
Functions of Motivation
 Activates or energizes behaviour.
 Directs behaviour.
 Creates persistence in behaviour.
 Strength determines activation and
direction in face of competing motives.
Two Major Perspectives
 Regulatory perspective
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Motivation involves biological, internal states
Focused on underlying biology
Motivation is driven by homeostasis
Negative feedback model
 System variable—room temperature
 Set point—20 C degrees
 Detector—thermometer
 System regulator—thermostat
 Biological negative feedback model
 System variable—pulse, respiration, weight
 Set point—normal pulse, respiration, weight
 Detector—hypothalamus
 System regulator—autonomic nervous system.
Two Major Perspectives
 Purposive perspective
 Behaviour has a purpose.
 Social aspects of motivation
 Based on goals (directed behaviour)
Terminology
 Terms frequently used in discussion of motivated
behaviour:
 Needs—indicates a lack of something, now used for
both biological and social motives.
 Drives—the body state that is activated to meet a
need.
 Instincts—unlearned and automatic behaviour
triggered by an external stimulus. Now talk of
arousal.
 Rewards—things that provide pleasure and thereby
motivate us to earn them.
Regulatory Theories of Motivation
 Instinct Theories
 These argued that instincts are the basis for
all behaviour.
 Many, many instincts were identified (e.g.,
pleasure, curiosity, achievement, friendly,
aggression) that could be combined to explain
our motives for anything.
 Problems
 Don’t account for behavioural differences across
cultures.
 Do they really explain anything?
Regulatory Theories of Motivation
 Drive Reduction Theories
 Hunger, thirst, and sex were once considered
drives, or activators of behaviour.
 The organism is led to reduce that drive by
behaviour that is reinforcing.
 The drive produces discomfort that energizes
the organism to action to reduce the drive
and achieve equilibrium (homeostasis).
 The reduction of the tension is reinforcing so
we tend repeat the behaviour in a similar
situation.
Regulatory Theories of Motivation
 Drive Reduction Theories (cont’d)
 Physiology of Reinforcement
 More modern approach to understanding “drive reduction.”
 Dopamine circuits in the brain are activated when we engage
in reinforcing behaviour like eating or drinking, or in
behaviour the permits these, such as barpressing or key
pecking in research animals.
 Seems to strengthen the link between the perceptual system
that detects the stimulus and the motor system that directs
the response.
 Problems
 Implies that all human behaviour is motivated to reduce
tension, and we sometimes seek it out. Many reinforcing
activities do not reduce the drive; instead we want more!
 How do we measure drives, especially those like curiosity or
excitement?
Regulatory Theories of Motivation
 Optimal Level Theories
 We seek an optimal level of arousal.
 Sometimes seek to reduce stimulation, to
avoid excitement and stimulation.
 Stimulation too low, indulge in positively
reinforced behaviour. Stimulation to high,
indulge in negatively reinforced behaviour.
 Also acknowledges that we may be motivated
by external incentives.
 Has the same problems of measuring drives
and level of arousal.
Regulatory Theories of Motivation
 Perseverance Views of Motivation
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Clear indicator of motivation
Intermittent reinforcement?
Conditioned reinforcers?
Failure to persist—learned helplessness.
 Studies with dogs.
 Perhaps this accounts for depression.
Purposive Theories of Motivation
 Need Based Theories (Humanistic
Theories)
 We are motivated to fill a deficiency, a need.
 There clearly are biological deficiencies that
we are motivated to fill, but it can also be
argued there are psychological needs as well.
 Psychological needs are social—need to be
with other people, to have power, to achieve.
 These theories consider that humans are
motivated to fulfill themselves.
Purposive Theories of Motivation
 Maslow’s Hierarchy of Needs
 We are motivated to achieve personal fulfillment.
 The ultimate goal is self-actualization, the
achievement of personal goals and aspirations.
 We have many classes of needs that can be ordered
in a hierarchy.
 We must achieve the lower order needs before we
can move on to fulfill the later ones.
 Maslow has been influential in education and
business but difficult to test empirically.
 For more about Maslow:
http://www.ping.be/jvwit/Maslovmotivation.html
Purposive Theories of Motivation
Maslow’s Hierarchy of Needs
Currently
unsatisfied but
felt needs are
motivators.
Sources of Motivation
 These are the reinforcers that keep us striving
toward our goals.
 Extrinsic—do it for the reward or to avoid
punishment
 External rewards: praise, good grades, tokens,
payment for services, etc.
 Intrinsic—do it for its own sake
 Internal pleasures: play, creativity, learning
 May become less reinforcing if external rewards are
given.
Eating as Motivated Behaviour
 Physiological mechanisms:
 What happens at the physiological level to motivate
eating?
 What motivates stopping of eating?
 Psychological mechanisms
 Social factors
 External cues
 Why do we overeat?
 Obesity affects 1/3 of North Americans
 Eating disorders
 Anorexia
 Bulimia
Eating as Motivated Behaviour
 Early Theories
 Link between hunger and stomach
contractions.
 Physiological mechanisms:
 Role of the hypothalamus
 Dual Centre Theory
 Set-Point Theory
 Role of the orbitofrontal cortex
Lateral Hyp
Role of the Hypothalamus
 Ventromedial hypothalamus seems to be
responsible for signaling when it is time to stop
eating (satiety).
 Lateral hypothalamus seems to signal when it
is time to eat.
 Both areas contain cells (glucostats) that are
sensitive to blood sugar levels but act in different
ways:
 In the VMH glucostats respond to rising blood sugar
levels
 In the LH glucostats respond to dropping blood sugar
levels.
Role of the Hypothalamus
Dual Centre Theory
 A decline in glucose activates the lateral
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hypothalamus (LH)
Activity within the LH gives rise to hunger
Hunger motivates the search for and
consumption of food
Food is broken down to release glucose
Glucose activates the ventromedial
hypothalamus (VMH)
Activation of the VMH causes a feeling of
satiety
Satiety inhibited further feeding.
Dysphagic
rat after
lesion.
Effect of
lesions in
the VMH
on body
weight
and food
intake.
http://www.psy.plym.ac.uk/year3/psy337EatingNeuralFactors/PSY337EatingNeural
Factors.htm
Role of the Hypothalamus
Set-Point Hypothesis
 Body weight seems to be regulated around a
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set-point, just as other bodily functions.
A hormone, leptin, is released from fat cells at
the same rate that fat is being stored in those
cells—the more fat storage, the more leptin in
the blood stream.
Hypothalamus monitors levels of leptin and very
slowly inhibits eating as levels increase and
probably activates eating as the levels drop.
Thus, the hypothalamus seems to work to
maintain that set point, some predetermined
level of fat storage in the body.
Seems to regulate weight over the long term.
Role of the Hypothalamus
Set-Point Hypothesis
 The number of fat cells in the body is
determined, through genetics and eating
experience, by the age of two.
 What varies from then on the amount of fat
stored in that set number of cells.
 In animals deprived of food the metabolism
slows and less food is required to maintain a
given weight.
 Weight gain occurs rapidly in these animals after
deprivation—return to set-point.
Psychological Factors in Eating
 Our emotional state affects our eating but affects
different people in different ways (depression
can lead to weight gain or weight loss).
 Conditioning affects our eating habits—time of
day, smell of food become triggers for eating.
 These are learned cues that have been
reinforced by our habits or experiences.
 We learn what to eat and how much to eat.
Social Factors in Eating
 Each culture has a view of what is an ideal
appearance—a norm for weight.
 Our present culture:
 We value slimness and constantly see ideal shapes
for a man or woman on TV and in magazines &
movies.
 We are very weight conscious and are preoccupied
with eating, waistlines, and fat.
 The conflict:
 Our modern lifestyles have created a need for quick
meals—leads to pre-prepared commercial food, high
in fat and sugar.
Obesity
 North American levels of obesity are the
highest in history. What contributes to
this?
 The number of fat cells in the body,
determined by both genetics and eating
experience, is set by the age of two.
 From then on, the only change is the amount
of fat in those cells.
 Those with more fat cells have greater
storage capacity—gain weight more easily
and are more likely to become obese.
Obesity
 Animals who are hyperphagic and humans
who are obese have some similar
characteristics, empirically determined:
 Lower sensitivity to internal body cues for
eating and cessation of eating.
 Greater sensitivity to external cues, such as
time of day, food smells, appearance of food,
presence of food and others who are eating.
 Are less active, eat faster, and less willing to
work hard for food.
Obesity
 Why is it so hard to diet, and so hard to keep the
weight off when successful?
 Those who have become obese have more fat cells
than normal weight individuals. If the set point says
those cells have less than the ‘optimal’ amount of fat,
the pressure to eat becomes strong.
 It is harder for obese individuals to know when they
are really hungry.
 Obese individuals are very sensitive to external cues
in a world that is full of pressure to eat.
 Much of what we eat is high in fat and sugar because
of the change in our life styles—more calories for the
same volume of food.
Eating Disorders
Anorexia and Bulimia
Eating Disorders
Anorexia and Bulimia
 Both are severe eating disorders characterized by an
intense preoccupation with one’s weight.
 More common in women.
 Seems to have psychological roots:
 Distorted body image—see themselves as overweight even
when not.
 Can lose huge amounts of weight and still see themselves as fat.
 Typically occurs during adolescence, often triggered by
family crisis or relationship breakup.
 Can lead to death.
 Treatment focuses on the psychological aspects with
dietary management.
Eating Disorders
Anorexia
 Characterized by refusal to eat because of
fear of becoming fat.
 Can become preoccupied with exercise in
order encourage weight loss.
Eating Disorders
Anorexia
 Physical results:
 Extreme weight loss—not unusual to drop weight to
60 – 80 pounds.
 Often unable to maintain bodily processes like body
temperature and menstruation.
 Electrolyte imbalance is common and can cause
death.
 Typical personality
 High achievers and perfectionists.
 Well-behaved
Eating Disorders
Bulimia
 May occur alone, or with anorexia.
 Characterized by bouts of uncontrolled
eating (binges) followed by purging
through self-induced vomiting or use of
laxatives.
 Physical results
 Less likely to have extreme weight loss.
 Damage to esophagus because of vomiting.
 Electrolyte imbalance.