Motivation

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Motivation
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Why did you choose St. FX?
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Context and Sources of Motivation
Context Source of Motivation Source of Motivation
Primarily Biological Primarily Social
Alone hunger, thirst, defense, sleep desire for possessions, desire for learning, need for relief of boredom, need for achievement
With Others sex need for reassurance, need for prestige, need for approval
What distinguishes biological motives from social
motives?
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Functions of Motivation

• Activates or energizes behaviour.
• Directs behaviour.
• Creates persistence in behaviour.
• Strength determines activation and direction in
  face of competing motives.

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Two Major Perspectives

• Regulatory perspective
• Motivation involves biological, internal states
• Focused on underlying biology
• Motivation is driven by homeostasis
• Negative feedback model
• System variableroom temperature
• Set point20 C degrees
• Detectorthermometer
• System regulatorthermostat
• Biological negative feedback model
• System variablepulse, respiration, weight
• Set pointnormal pulse, respiration, weight
• Detectorhypothalamus
• System regulatorautonomic nervous system.

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Two Major Perspectives

• Purposive perspective
• Behaviour has a purpose.
• Social aspects of motivation
• Based on goals (directed behaviour)

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Terminology

• Terms frequently used in discussion of motivated
  behaviour
• Needsindicates a lack of something, now used for
  both biological and social motives.
• Drivesthe body state that is activated to meet a
  need.
• Instinctsunlearned and automatic behaviour
  triggered by an external stimulus. Now talk of
  arousal.
• Rewardsthings that provide pleasure and thereby
  motivate us to earn them.

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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
• Dont account for behavioural differences across
  cultures.
• Do they really explain anything?

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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.

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Regulatory Theories of Motivation

• Drive Reduction Theories (contd)
• 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?

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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.

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Regulatory Theories of Motivation

• Perseverance Views of Motivation
• Clear indicator of motivation
• Intermittent reinforcement?
• Conditioned reinforcers?
• Failure to persistlearned helplessness.
• Studies with dogs.
• Perhaps this accounts for depression.

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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 socialneed to be with
  other people, to have power, to achieve.
• These theories consider that humans are motivated
  to fulfill themselves.

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Purposive Theories of Motivation

• Maslows 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/M
  aslovmotivation.html

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Purposive Theories of Motivation Maslows
Hierarchy of Needs
Currently unsatisfied but felt needs are
motivators.
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Sources of Motivation

• These are the reinforcers that keep us striving
  toward our goals.
• Extrinsicdo it for the reward or to avoid
  punishment
• External rewards praise, good grades, tokens,
  payment for services, etc.
• Intrinsicdo it for its own sake
• Internal pleasures play, creativity, learning
• May become less reinforcing if external rewards
  are given.

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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

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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

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Lateral Hyp
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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.

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Role of the HypothalamusDual Centre Theory

• A decline in glucose activates the lateral
  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.

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Dysphagic rat after lesion.
Effect of lesions in the VMH on body weight and
food intake.
http//www.psy.plym.ac.uk/year3/psy337EatingNeural
Factors/PSY337EatingNeuralFactors.htm
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Role of the HypothalamusSet-Point Hypothesis

• Body weight seems to be regulated around a
  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
  cellsthe 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.

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Role of the HypothalamusSet-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
  deprivationreturn to set-point.

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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 habitstime 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.

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Social Factors in Eating

• Each culture has a view of what is an ideal
  appearancea 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 mealsleads to pre-prepared commercial
  food, high in fat and sugar.

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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
  capacitygain weight more easily and are more
  likely to become obese.

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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.

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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 stylesmore
  calories for the same volume of food.

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Eating DisordersAnorexia and Bulimia
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Eating DisordersAnorexia and Bulimia

• Both are severe eating disorders characterized by
  an intense preoccupation with ones weight.
• More common in women.
• Seems to have psychological roots
• Distorted body imagesee 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.

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Eating DisordersAnorexia

• Characterized by refusal to eat because of fear
  of becoming fat.
• Can become preoccupied with exercise in order
  encourage weight loss.

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Eating DisordersAnorexia

• Physical results
• Extreme weight lossnot 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

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Eating DisordersBulimia

• 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.