PSYC 361 MT2: AROUSAL & GOAL-DIRECTED BEHAVIOUR (2) Theories & Experimental Evidence Flashcards
Activation Theory of Motivation
Activation (Arousal) = part of emotion
- as physiological response that accompanies emotional experience
- as dimension of emotions (dimensional theory of emotion)
Arousal (like drive) hypothesized to energize behaviour
- Duffy: energy mobilization, emphasizing autonomic system arousal
- provided physiological account of drive (drive as “state”)—> diverges from drive theory
Reticular Activation System in the Brain
**Reticular Formation* in midbrain
- receives all sensory inputs except olfactory (limbic)
- integrating & coordinating activities in CNS & PNS
Reticular Activating System (RAS)
- Ascending: cortical “preparation”
- Descending: motor/muscular tone-up
Highly neuromodulatory: DA, NE, 5-HT, HIS, acetylcholine, neuropeptides
Some brain stimulation & lesion studies support role for attention/consciousness/arousal
Pharmacological modulation of RAS activity also lends support
Reticular Activating System in the Brain- EEG ACTIVITY
Correlates with arousal states
- Alpha wave: awake, relaxed
- Beta wave: awake, activated
Optimal Arousal Level
Motivational POV: needs to be optimal level of arousal for behaviour
Inverted-U function of arousal; optimum stress = area of best performance
The Yerkes-Dodson Law
Brightness discrimination tasks (BvsW) + levels of shock as punishment
- Easy task: large contrast, best performance with high level of shocks (high arousal)
- Medium task: intermediate contrast, best performance with medium level of shocks
- Hard task: minimal contrast, best performance with low level of shocks (low arousal)
Cognitively difficult/intellectually demanding tasks, may require lower level of arousal for optimal performance to facilitate concentration; tasks demanding stamina/persistence may be performed better with high levels of arousal, presumably to increase & maintain motivation for “boring” tasks
Caffeine Increases Arousal & Affects Performance
Activates adenosine receptors (GPCRs) in NS
Anderson: gave undergrads different levels of caffeine & observed performance on easy & difficult language tasks
- found performance of easy task enhanced by higher levels of caffeine & higher caffeine levels impaired performance of difficult task
Support inverted-u function
The Easterbrook Hypothesis
Hypothesized arousal levels alter attentional/perceptual processes & affect performance
- attention works like “spotlight”; increased arousal decreases range of attention
- relevant (R) & irrelevant (IR) cues coexist & are simultaneously processed
Performance modulated by arousal levels but also relative to task itself
Research into eyewitness reporting in criminology/forensics
Evidence for the Easterbrook Hypothesis
(Anderson & Revelle): undergrads asked to proof-read articles while provided varying caffeine amounts
- 2 types of errors: intra-word (typo/misspell) & inter-word (wrong syntax/grammar)
- test sensitivity to different types of errors with different arousal levels
Aroused individuals = lower detection rate of inter-word errors, required wider range of cue utilization
- detection rate of intra-word errors unaffected by caffeine
Drive Theory vs Activation Theory
Both theories attempt to address an intensity dimension of motivation but
Drive Theory: argues that it is optimal to maintain minimal level of drive, since deviation from homeostasis is smallest
Activation Theory: argues that it is optimal to maintain a somewhat intermediate level of arousal, since performance is more reliable at this optimal level & is affected at lower/higher arousal levels
Drive Reduction focuses on meetings biological need; however, arousal may not always be relevant to biological need
Suggests animals under certain circumstances will seek out stimulation to maintain such an optimal level of arousal
Environmental Stimulation & Arousal
Lucid Behaviour: activates that we call “recreation, entertainment/idle curiosity—art, philosophy, pure science”; does not have biological function we can clearly recognize
Seeking the following quilting’s in stimuli:
1) Novelty: surprise, incongruity, unfulfilled expectations
2) Uncertainty: amount of info carried by stimulus, ambiguity
3) Conflict: multiple responses aroused at same time
4) Complexity: # of distinguishable elements, dissimilarity of elements
Environmental Load: high vs low; amount of qualities present in these environments
Individual Differences: screeners vs non-screeners
Motivated Behaviour & Reinforcement by Arousal
Berlyne: hypothesized different arousal levels due different affects
- Positive affect aroused by stimuli that produce medium level of arousal
- Animals seek out medium arousal stimuli
- Stimuli too far above/below optimal level are aversive
- Motivated approach & avoidance behaviour to stimuli that do not restore homeostasis
- Positive affect also reinforces behaviour without having to restore homeostasis
Aesthetics & Arousal
Smith & Dorfman: complexity of visual patterns leads to different dynamic changes in the liking upon repeated exposure (shifts in arousal levels of stimuli produced)
Vitz: aesthetic appreciation of different tone sequences changes with raters’ expertise
Humour & comedy have pleasant arousal-eliciting qualities—why we enjoy them
Instrumental Behaviour & Neural Representations
Instrumental behaviour more sophisticated & flexible than SR learning would allow
Goal-Directed Action involved Multiple Processes
Purpose of goal-directed behaviour is to achieve desired outcome through performing chosen behaviour, animals must be able to:
- form direct SR associations (instrumental conditioning through reinforcement)
- evaluate value of outcome as an instrumental goal (incentive motivation)
- evaluate hedonic value of outcome (dissociable from incentive motivation)
- decipher & encode action-outcome contingency
- process physiological & environmental cues
2 Value-Processing Systems
Hedonic Value System: how much animal is willing to consume the reward
- Hedonic value can be changed by satiation/devaluation etc.
- Changes in hedonic value directly affect consumption of reward
- Reflects how much animal likes reward
Instrumental Incentive Value System: how much animal is willing to work for reward (ie. to what extent outcome of action is a desirable goal)
- Reflects how much animal wants reward
- Animals must learn through experience that a change in hedonic value of food changes its incentive value (ie. food is not worth working for when they are not hungry)
Devaluation Changes Goal-Directed Action Performance
In Devaluation, defaulted group expected to associate sugar with illness, devaluing sugar
In Test 1, groups (1&2) not expecting sugar pressed lever equally frequently; Group 3 expecting sugar pressed lever less frequently
In Test 2, re-exposure to sugar led devalued groups (2&3) to press lever less frequently (ie. learned that sugar is not as nice & not worth working for)
Result suggests that during relearning, animals experienced discomfort associated with sugar & that this experience reduced incentive value of the outcome & hence, performance
Habitual Responding NOT Affected by Devaluation
Holland: repeated instrumental conditioning reduces impact of devaluation (ie. animal will keep pressing lever for food reward even after it has been associated with illness)
- Devaluation still leads to decreased incentive value but performance unaffected
- Suggests no role for incentive learning
- Repeated instrumental conditioning procedure leads to strong SR connections
- Habit & goal-directed action operate differently
2 Systems Also Present in Humans
Devaluation lesions studies in rodent models: instrumental conditioning involve 2 systems distinct neural substrates
- Incentive learning (goal-directed system): PFC + dorsomedial striatum
- SR learning (habits): dorsolateral striatum
Valentin: examined neural substrates of goal-directed component in humans
- Trained participants to acquire food reward with higher probability, then “devalued” reward by satiation
- Participants self-reported less pleasant less for devalued food (hedonic value change) & reduced choice for high-probability reward (incentive value change)
- fMRI found areas of the orbitofrontal cortex showed increase activity before devaluation & decreased activity after devaluation—suggests role for encoding incentive value
Liking vs Wanting (Revisited)
2 dissociable constructs
- Stereotyped consumptive behaviour for liking
- Brain damage/manipulation to differentiate the 2
- Animals still “like/dislike” reward following damage to DAergic system, they are no longer motivated to earn reward— no longer goal-directed
Intracranial self-stimulation in rats (ICSS)
- Mesocorticolimbic DA system: VTA DA neurons projecting to frontal cortex & NAcc
- ICSS causes dramatic DA increases within NAcc— key site for reward-related learning & addiction
- DA agonists increase ICSS whereas DA antagonists suppress it
- Lesions of mesocorticolimbic DA system disrupt ICSS
What Signals do DAergic Signalling Carry?
Electric recording from DA neurons (monkeys)
- before learning: DA neurons fire when reward (US) occurs
- US unsignalled, therefore unexpected at this point
Once CS-US association established, DA neurons now fire to CS, DA neurons do not fire to reward anymore
If expected award missed, DA neurons pause firing
Da neurons also ram up firing after CS presentation if US delivery is less certain— maximal “ramping” seen when p = 0.5 (maximal uncertainty)
What Signals do DAergic Signalling Carry?
DA transmission comes in different timescales that mediate different functions of the brain
- Fast (subsec): DA transmission typically observed in VTA & substantia nigra— shows prediction-error responses to rewards
- Slow (sec-min) & Tonic (continuous): DA transmission modulates many other brain functions & appears to be unrelated to reward processing
Animals must understand their actions result in outcome (ie. detection of causal contingency between pressing lever & food delivered) & outcome is goal that is desired by animal
Fast DA transmission hypothesized to underly brain’s ability to decipher & encode action-outcome contingency
The Prelimbic Cortex
In rats: known to receive DA input from VTA
The dorsolateral PFC in humans involved in planning, response selection, control of purposive actions— knowledge of action-outcome contingencies
Damage = reduced ability of animals to detect contingency changes
- rats failed to discriminate between actions & outcomes— if 1 reward presented non-contingently, reduced responding for both rewards
- generalized disruption in task performance = responses not truly goal-oriented
Previous Learning can Affect Goal-Directed Action
Pavlovian CC’d stimuli can modulate instrumental performance
In conditioned reinforcement, rat 1st learns light predicts food, then test whether rat will work for light (indicator)
In PIT, rat learns separately light predicts food & lever press = food. Then rat presented with both l ever & light—> rat will press lever more in presence of light even if light has not been previously paired with lever pressing
Goal-Directed Behaviour is Complex
Involves:
- form direct SR habits
- value of outcome as instrumental goal (incentive motivation)
- hedonic value of outcome (dissociable from incentive motivation)
- encode of the action-outcome contingency
Influenced by Pavlovian processing including conditioned reinforcement (CRf) & Pavlovian-to-Instrumental Transfer (PIT)
Summary of Arousal & Goal-Directed Behaviour
Activation (arousal) can affect range of cognitive (physiological) processes that affect performance
Optimal level of arousal is a somewhat medium level of arousal but also task-dependent
Goal-direction behaviour is complex & involves multiple processes
DA transmission in different brain areas mediate goal-directed learning
