Motivation and Appetite Flashcards
Define motivation
- driver of directed behaviours; particularly our wants and needs
- involves both biological and social drives
biological (primary) drives includes
thirst, hunger, oxygen, sleep, temperature regulation, waste elimination, sex
social motives (secondary)
achievement, aggression, power, curiosity, play, affiliation, autonomy
Approach motivation
drives propel engagement in some behaviours
avoidance motivation
drives repel engagement in other behaviours
Early approaches to measuring motivation –> Psychodynamic perspective (Freud)
- theorised that behaviours are motivated by unconscious and conscious desires, which are not in unison
- 3 theoretical constructs of psyche which freud proposed:
- -> id: unconscious, instinctual, irrational drives
- -> superego: morally responsible drives, operates at preconscious awareness
- -> ego: conscious, rational mind, ensures id and superego drives manifest appropriately
- criticisms: inability to validate or invalidate these theories - how can we measure unconscious desires?
- introduction of TATs (thematic apperception tests) which claimed to do so
Drive Reduction Theory of motivation
- 1940s
- thirst, hunger and sexual frustration drive us to reduce the aversiveness of these states
- drives are hierarchical
- motivated to maintain psychological homeostasis
- constantly seeking to reduce internal unpleasant states
biological need –> drive –> organism motivated to satisfy drive –> goal directed behaviour –> need satisfied (homeostasis)
Yerkes-Dodson law
- arousal effects strength of drives
- bell curve represents relationship between arousal level and performance quality (under arousal = stimulus hunger)
What are clashing drives?
Approach approach conflict = choosing between 2 desirable options
Avoidance avoidance conflict = choosing between 2 difficult options
Approach avoidance conflict = both attracted and repelled to engage in the same goal (both approach and avoidance tendency increase as you get closer to the desired goal; however, avoidance tendencies increase faster than approach) –> maximum conflict when these intersect
What are incentive theories?
- incentive theories build on Design Reduction theories (the DRT is inadequate as we repeatedly engage in behaviours despite satisfaction of drives) –> we are driven by positive goals
- different types of motivation: intrinsic (internally driven) or extrinsic (externally driven)
- 1973 study suggested that our intrinsic motivation can be devalued by extrinsic reinforcements
What is the relative importance of needs?
- some physical and psychological needs are more important than others
- Murray identified 20 secondary needs belonging to 5 categories: ambition, materialism, power, affection and information
Maslow’s hierarchy of needs
- 1954, formalised thinking in hierarchy of needs theory
- before we satisfy what occurs at the top, we need to satisfy the bottom needs
- top to bottom: self-actualization, self-esteem, love and belonging, safety and security, physiological needs
Elaborate on sexual motivation and libido
- libido = human sexual desire
- psychological drivers of libido include testosterone and DRD4 related to dopamine (i.e. genetic component)
Sexual response cycle
- Desire phase
- excitement / plateau phase starting to have physiological reactions
- orgasm phase
- resolution
Goal setting:
- set SMART goals
- Specific
- Measurable
- Action oriented
- Realistic
- time based
Define obesity:
determined by a person’s body mass index where a normal BMI is 18.5-25, overweight is 25-30 and 30+ is obese
What bodily processes influences eating? –> Energy Levels
2 modes of energy storage:
- short term = glucose (less important for intake)
- long term = fat (more important for intake)
Changes in body fat affect appetite: homeostatic system
- fat cells secrete a hormone called leptin
- more fat = more leptin (suppressing appetite)
- less fat = less leptin (allowing food intake to increase)
What bodily processes influences eating? –> sensation
Food flavour drives intake:
• Taste, smell and touch form flavour
• Hardwired to like sweet, salty and fatty things
Sensory specific satiety slows intake in a meal:
• The more we eat of a specific food, to more our liking for it declines
• It acts to signal the end of a meal (before stomach and gut signals tell your brain you are full)
It also drives variety
What bodily processes effect eating? –> Digestive organs
Multiple systems are involved in digesting food and they all send signals to the brain about their status:
• Stomach is distended or empty
• Gut and stomach taste receptors
• Stomach is emptying its nutrient rich content (chyme) into the small intestine
• Gut bacterial signals of fat content
How do these signals communicate to the brain:
• Nerves (e.g. vagus nerve)
• Hormones (e.g. CCK [released when there is food in a stomach] and ghrelin [when the stomach is empty])
Nutrients (e.g. blood lipoproteins)
List the bodily processes that influence eating:
- energy levels
- sensation
- digestive organs
List thing that influence eating in the brain:
- neurochemicals –> serotonin, dopamine, leptin, grhelin
- important locations in brain = hypothalamus, cortical, limbic system
Brain: influences eating through neurochemicals
• Many neurochemicals modulate eating
• 2 important examples are serotonin (SE) and dopamine (DA)
○ Increased levels of both suppress appetite
○ Most commercial appetite suppressants are SE or DA agonists (these drugs bind to SE or DA receptors)
○ Many common psychiatric drugs affect these neurotransmitters and so many also affect body weight as a side effect
• Neurochemicals are modulated by events in the body
○ Leptin (from fat cells) stimulates release of CRH (corticotrophin releasing hormone) in the brain, suppressing appetite
Grhelin (from stomach) stimulates release of NY (neuropeptide Y) in the brain increasing appetite
Brain: influences eating through these important brain locations:
- hypothalamus
- -> (ventromedial nucleus = stop eating)
- -> lateral hypothalamus = start eating
- cortical (studying car accident victims with frontal lobe damage - consequences of impulsivity is overeating due to a decreased ability to regulate oneself)
- -> frontal (impulsivity)
- -> insula (interoception)
- limbic system (hippocampus - memory)
How does the environment affect the way we eat?
- showing food: will trigger a desire to eat and a cephalic phase response (salivation, insulin release)
- being habit bound: i.e. eating at the same time and place each day
- people and leisure: physical presence of co-eaters and anticipation increases eating
- appetite stimulant = TV
- portion and plate: people tend to eat what is in front of them
Take into account all these factors that contribute to our eating:
• When and how much we eat is mainly driven by environmental factors that we are not usually aware of - mindless eating - environment / brain
• Biological factors are probably only important at the extremes (starvation/gross over-indulgence) - body/brain
Conscious control of food intake probably only plays a small role - brain/self
