Lecture 16: Motivation Flashcards
Define motivation
- Motivation is an internal state that
explains why we behave or why we
learn to behave
-The science of motivation is
understanding behavioural causation.
What tools do we use to study motivation
Skinner boxes
Skinner believed that trying to understand any internal states that make an animal interact with a reinforcer distracts from
understanding the effect of the reinforcer on behaviour.
By contrast, Thorndike (e.g. Law
of Readiness) proposed that learning is motivated by an internal state.
Define the drive reduction theory
Hull proposed that a reinforcer supports learning because it alleviates an internal state of deprivation.
– e.g., food is reinforcing to an organism if and because it alleviates hunger state.
Clark Hull
What was the emphasis of drive reduction theories of motivation
Emphasis of drive reduction theories of
motivation was on Homeostasis = a tendency
by physiological systems towards
equilibrium/balance.
*Imbalance in homeostasis creates ‘arousal’
that initiates action.
*The goal of homeostasis is to decrease the
‘arousal’
*Can achieve this goal by minimising the
difference between an optimum ‘set-point’ and
an ‘actual point’ of a physiological system.
What is involved in the physiological systems based on homeostatic processes
A number of physiological variables in our
body must be maintained within narrow
limits for the body to function properly:
Temperature, Hydration, Nutrients
e.g. Take jacket off.
e.g. Initiate drinking behaviour
e.g. Initiate feeding behaviour
Optimum set points for:
If actual point deviates from set point, homeostatic
processes will become active to minimize the
effect:
Define negative feedback
We minimise the difference between a ‘set point’ and an ‘actual point’ of a physiological system.
* Negative feedback = a process whereby
the effect produced by an action serves to
diminish or terminate that action
Describe the components of homeostatic system
1.System variable: variable controlled by system (e.g., temp, hydration, nutrients)
2. Set-point: the desired level of a variable
3. Sensor/receptor: a mechanism for measuring the variable.
4. Effector system: behavioural /physiological
mechanism(s) to change variable and restore
homeostasis.
5. Control center
Why do we need water and why is thirst needed in homeostasis
- Water comprises 70% of our lean body
mass - As water is lost, cellular processes become
inefficient, & eventually excessive water
loss is fatal - Fluid loss through evaporation, respiration
(H2O), urine and sweating (H2O + salt). - Drinking behaviour is the primary means of
replenishing water.
About 2/3 of body water is inside cells, the remaining 1/3 is extracellular. - Direct water loss occurs primarily from
this extracellular compartment.
Explain why water is needed for intracellular and intravascular fluid volume and composition
Intracellular and intravascular (plasma) fluid volume and composition must be kept in precise limits.
Intracellular - relative concentration solutes between
intracellular and interstitial compartments (isotonic)
Water moves from intracellular to intrastitial (through semi-permeable membranes) to intravascular.
Explain osmometric thirst/cellular dehydration
Extracellular fluid consists mainly of water
and salts (particularly sodium chloride)
* Water loss causes the concentration of salts
to increase
* This increase in salt causes an osmotic
imbalance between the extra- and intra-
cellular compartments, & water leaves cells
to restore balance (by osmosis).
Artificial increasing extracellular salt (NaCl)
content stimulates drinking (Gilman, 1937)
* Drinking is directly proportional to additional
salt load
* Microinjection of small amounts of NaCl into
certain brain areas induces drinking.
* Changes in osmolarity are monitored by cells
(osmoreceptors) in the Organum Vasculosum
of the Lamina Terminalis (OVLT).
