PSY 402

1. PSY 402 Theories of Learning Chapter 9 – Motivation

2. Evidence of Motivation • Behavior is variable. • Rate of responding changes even in the presence of the same stimuli (the same environment). • Behavior is persistent. • Behavior continues once started, even when not rewarded immediately. • Motivation translates knowledge into action – Tolman’s distinction between learning and performance.

3. Early Studies of Motivation • Deprivation leads to behavior that can be quantified (measured, counted). • Deprivation increases motivation. • Specific deprivation leads to specific hungers. • Animals and people are more motivated to work for what they need. • Homeostasis – behavior helps the body defend an equilibrium of nutrients.

4. Hull’s Drive Theory • Hull’s drive theory started simple but added parameters to account for observed behavior. • The first version included just drive (D) and habit (H). • Habit is Hull’s term for learning. • Drive is motivation • Behavior strength = D X H • The terms do not interact.

5. Problems with Drive Theory • Drive was hypothesized to increase general activity levels, but did so inconsistently. • Hungry and thirsty animals don’t necessarily show more activity of different kinds, than satiated ones. • Deprivation affected different species differently. • Hunger and thirst seem to motivate increases in behaviors related to seeking food or water, not all behavior.

6. Incentive Learning • Simple behaviors show a direct connection to deprivation, but more complex behaviors have a more complicated relationship with reward. • Dickinson & Balleine argued that in order for an incentive to be motivating, the animal must know that it will satisfy a state of deprivation. • The thirsty rat must drink water and feel better in order for water to become an incentive.

7. Examples • Baby rats learn that water satisfies thirst and food pellets satisfy hunger. • Rats learn that a heat lamp is uncomfortable in a warm room, then learn that it feels good in a cold room. • Tolman emphasized cathexes – the relationship between a goal and its motivational state (e.g., food and hunger).

8. Anticipation of Need • Motivated behavior is organized to anticipate need, instead of waiting until there is deprivation. • Rats on a high protein diet, over time, drink water before they need to. • With 3 meals, when meal 2 is eliminated, rats eat more at meal 3, but gradually shift to eating more at meal 1. • Rat stomachs are never empty during free-feeding

9. Children’s Eating • Newborn babies initially cry to nurse when hungry. • By 6 weeks (not months), they learn to eat more when they recognize cues to approaching night, so they begin sleeping through the night. • Preschool kids eat more snacks in rooms associated with food (ice cream), even though satiated. • Room cues are CS’s that elicit digestive CR’s.

10. Food Preferences • Children prefer the foods they eat when they are hungry. • Children can be taught to pay attention to both internal and external cues. • Internal = hunger, external = environmental signals such as time of day, signals for food. • Specific hungers for certain foods may be learned too -- the food is associated with feeling better after a deprivation state.

11. Anticipation of Reward • Acquired motivation – expectation of reward based on prior experience. • Bait and Switch – animals show disappointment when the expected reward is not there. • Monkeys who expect banana but get lettuce are mad. • Rats who expect mash but get sunflower seeds run slower.

12. Contrast Effects • Crespi switched incentives halfway through an experiment. • Negative contrast – rats switched from 245 to 16 were slower than those receiving 16 all along. • Positive contrast – rats switched from 1 to 16 ran faster than rats receiving 16 all along. • Crespi called these “elation” and “depression” effects because he thought the rats were emotional about the change.

13. Frustration • Flaherty reduced a 32% sucrose solution to 4% and observed negative contrast in behavior. • No stress response occurred until the second day. • On the first day, rats licked less but explored their environment, looking for the 32% solution. • On the second day, rats became frustrated and upset (judging by corticosteroids). • Tranquilizers abolished the contrast on day 2.

14. Hull’s Response • Spence modified Hull’s drive theory to include findings of incentive motivation. • K was added to account for incentive. • Behavior strength = D x H x K • Drive is innate and internal, incentive is learned and external. • Drive pushes behavior, incentive pulls it.