Oct. 14, 2021
  PSY 101    [Psychology Images] Class 21: Motivation I Theories & Hunger as Motivated Behavior (Outline)

Motivation => Goal-Directed Behavior

Why do you and I do the things that we do???
What is it that you want or desire?

Motivational Theories and Concepts

Body temperature as
                      homeostatic1. Drive Theories ("push")
  • homeostasis (balance)
  • allostasis (process of reaching balance by physical or behavioral change)
  • Drive =
  • (a) internal state of tension which
  • (b) motivates an organism
  • (c) to act to reduce the tension
  • 2. Incentive Theories ("pull")

    • Incentive = external goal which can motivate behavior
    3. Evolutionary Theories
    • maximize reproductive success, e.g.,
      • dominance
      • affiliation (need for belonging)

    4. Diversity of Motivation

     Biological Social

    Originate in bodily need

    • Hunger
    • Thirst
    • Sex
    • Sleep, etc.

     Originate in social experiences

    • Achievement
    • Affiliation
    • Nurturance 
    • Play

     Hunger & Eating

    What can we say about the causes of Homer Simpson's insatiable appetite for doughnuts?

    A very complicated set of interrelated & interacting forces & mechanisms

    Multifactorial causation!

    Biological Factors in the Regulation of Hunger

    [Brain Hypothalamus]       hypothalamus     Hypothalamus (Visible Human Female)

    Hypothalamic control of eatingA. Brain: Interconnected neural circuits in the hypothalamus

    • Lateral Hypothalamus (LH): Initiate eating
    • Ventromedial Hypothalamus (VMH): Stop eating
    • Arcuate Nucleus: Dual set of neurons: start & stop
    • Paraventricular Hypothalamus (PVH): modulation of hunger
    • Neurotransmitters:
      • neuropeptide Y ( carbs) & serotonin ( fats, food)

    B. Digestive & Hormonal Regulation

    Signals from stomach


    • Ghrelin
    • CCK (cholecystokinin)
    • Insulin
    • Leptin

    [bakery]Environmental Factors

    A. Food Cues: Incentives

    • Palatability
    • Quantity
    • Variety (Sensory-specific satiety)
    • Presence of Others
    • Stress
    • Exposure to Cues

    B. Learning

    • Innate (in-born)
    • Observation of others eating

    The Roots of Obesity: Eating & Weight
    BMI Chart

    In US roughly 40% of adult population is overweight and over 28% are obese

    Weight US
    Why? Factors in Obesity in US

    A. Genetic Predisposition

    obseity gene loci

    B. Excessive Eating & Inadequate Exercise

            Cola Sugar

    C. Inadequate Sleep

    D. The Notion of a "Set Point"

            point metabolism 

    This page was originally posted on 10/16/03 and last updated on October 12, 2020