Chapter 10- Avoidance Flashcards
Avoidance:
- Responding removes aversive outcome
- i.e. open umbrella so you don’t get wet
- Negative contingency between instrumental response and aversive stimulus
Active Avoidance:
- Avoidance conditioning
* Safety is achieved by responding
Discriminated Avoidance Procedure:
- Signaled avoidance
- Involves discrete trails, each trial initiated by warning stimulus or CS
- If participant makes target response before shock is delivered, CS is turned off and US is omitted on that trial (successful avoidance trial)
- If participant fails to response during CS-US interval, shock delivered and remains on until the response occurs, and both CS and US are terminated (escape trial)
- At beginning of training, most trials are escape trials, avoidance trials become more prominent as training progresses
Shuttle Avoidance:
- Animal placed in shuttle box (box with 2 compartments with an opening seperating them)
- Start on left side of box, CS presented, if animal crosses over to right side, no shock delivered (1 way shuttle avoidance)
- Procedure repeats with animal starting on right side (2 way shuttle avoidance)
- 2 way harder to learn because it involves animal returning to side that was dangerous on previous trial
Two Process Theory of Avoidance:
- Classical conditioning of fear to CS- Classical conditioning pairs warning stimulus (CS) with aversive event (US) on trials where animal fails to make avoidance response
- CS comes to elicit fear
- Instrumental reinforcement of avoidance response through fear reduction- avoidance response is learned because response terminates CS, reduces conditioned fear elicited by CS
- 2 processes depend on each other
Escape From Fear Experiments (EFF):
- First condition fear to CS regardless of response
- Animal periodically exposed to fear eliciting CS and allowed to respond to turn off CS (no shocks scheduled in this phase)
Independent Measurement of Fear During Acquisition of Avoidance Behaviour:
- If fear motivates avoidance response, and if fear reduction is reinforcing, then conditioning of fear and conditioning of instrumental avoidance behaviour should be correlated
- Wrong- correlated only in early training. After that, responding may persist without fear when CS or warning signal occurs
Response Blocking:
- Participants can’t terminate CS (need extensive CS exposure without US)
- In shuttle box, barrier inserted to prevent participant from going to safe side when CS comes on
Flooding:
Blocking avoidance response results in participants being exposed to CS for a long time
Nondiscriminated (Free-Operant) Avoidance:
- Avoidance conditioning procedure without a warning stimulus
- Aversive stimulus (i.e. shock) occurs periodically without warning (i.e. every 10 seconds)
- Each time participant makes avoidance response, it obtains a period of safety (i.e 20 seconds) during which no shock is delivered
- Repetition of avoidance response before end of shock free period restarts safe period
S-S Interval:
- Shock- shock interval
* Interval between shocks in absence of a response
R-S Interval:
- Response- shock interval
- Period of safety created by each response
- Avoidance response always sets R-S interval
Safety Signals:
- Stimulus that signals absence of an aversive event
* i.e. tactile feedback, light produced after each avoidance response
Safety-Signal Hypothesis:
- Safety signals that accompany avoidance responses may provide positive reinforcement for avoidance behaviour
- Introducing feedback stimuli will facilitate learning of avoidance response by becoming a conditioned inhibitor of fear
Shock-Frequency Reduction:
- Alternative to 2 process theory
- Reduction of shocks critical to reinforcement of avoidance behaviour
- Not necessary for avoidance theory (animals can still learn to make an avoidance response even if response does not reduce frequency of shocks delivered)
Avoidance and Species-Specific Defense Reactions (SSDRs):
- Aversive stimuli elicit strong unconditioned, innate responses
- i.e. in rats, SSDRs include flight and freezing
- Environmental context dictates which SSDR predominates (if escape if possible, then flight SSDR kicks in)
- Instrumental responses similar to SSDRs more easily learned in avoidance experiments
Predatory Imminence Continuum:
- Different defensive responses occur depending on the level of danger faced by an animal
- i.e. freezing if rat is close, jumping if snake attacks
- Response can be conditioned to be elicited by a CS if CS becomes associated with an aversive event
- If CS presented before US, then response will be one level lower
- i.e. US-> jumping, CS-> freezing
- If CS and US presented at same time, response will be more similar to response to US
Expectancy Theory:
- Encounters with aversive events trigger a conscious process of threat appraisal that generates expectations of future threat based on cues and responses
- Cue paired with shock elicit expectations of shock, responses that turn off cues and prevent shock elicit expectations of no shock
Time Out:
Removal of opportunity to obtain positive reinforcement