Escape and avoidance

Question 1

What are escape and avoidance?

Answer 1

• Escape: getting away from an aversive stimulus in progress
―Escape behaviour results in the termination of an aversive stimulus.
• Avoidance: behaviour occurs before aversive stimulus preventing the delivery of it
― Negative contingency between response and aversive stimulus
― Results in an increase in operant responding (behaviour) that is maintained by negative reinforcement

Question 2

What are the 4 steps to escape?

Answer 2

• In presence of aversive stimulus
• Make a response
• Aversive event terminates
• Action is negatively reinforced

Question 3

What are the 3 steps to neurosis, learned helplessness?

Answer 3

Uncontrollable bad events –> Perceived lack of control –> Generalised helpless behaviour

Question 4

What if there is an escape?

Answer 4

• Better still, you can anticipate the aversive event before it affects you and evade it?
• Avoidance Learning!

Question 5

What are the 2 types of avoidance?

Answer 5

• Active avoidance: Actively making a response to avoid event
• Passive avoidance: Learning NOT to make response in order to avoid the event

Question 6

How do we conduct an active avoidance experiment?

Answer 6

Rat is trained in a shuttle box with a hurdle in the middle.
A tone is presented for 10 seconds à electric shock delivered through the floor of the cage.
If the rat jumps over the hurdle while the shock is on, the shock is immediately terminated.
If the rat jumps before the shock comes on, then the tone is turned off and the scheduled shock is cancelled.
Thus, depending on when the rat jumps over the barrier, it can either escape from the shock once it is on or avoid it altogether.
This procedure is called signalled avoidance because the experimenter provides a signal to indicate when the shock is imminent.

Question 7

How do we measure avoidance learning?

Answer 7

Avoidance learning is measured in latency to respond to the signal

Question 8

How do we conduct a passive avoidance experiment?

Answer 8

Passive avoidance using shuttle-box procedure
It is a form of operant conditioning where the person/animal must abstain from an act or reaction– which will otherwise à a negative outcome
The animals learn to suppress their normal dark-seeking reflex because their entry into a dark chamber is paired with a foot shock.
Learn to stay in bright side of box (avoid shock)

Question 9

OCCD vs phobia

Answer 9

• OCD typically involves an active avoidance response
• Phobic behaviour typically involves a passive avoidance response.

Question 10

What is the avoidance paradox?

Answer 10

• A response/behaviour is made before the aversive stimulus occurs
• Behaviour clearly increases, so is reinforced
• But what is taken away (or delivered) to reinforce it?
• Mowrer and Lamoreaux (1942)― “Therefore, not getting something can hardly, in and of itself, qualify as rewarding.”
§ Bit of a problem for behaviourists who need to be able to specify a stimulus!
• Not getting “punished” or “injured”, is rewarding only if punishment is expected, i.e. only if the subject is anxious or fearful, and if this expectation in some ways gets reduced

Question 11

What is the 2 process theory of avoidance?

Answer 11

• Two process theory: classical and operant learning experiences are involved in avoidance learning
Explains avoidance learning in terms of two necessary processes:
1. First the subject learns to associate the warning stimulus with the aversive stimulus
This is a classical conditioning process:
The warning stimulus of the light is the CS, the aversive stimulus (shock) is the US
2. Now the subject can be negatively reinforced during the warning stimulus; this is the second, operant conditioning process
Thus the two-process theory reduces avoidance learning to escape learning! The organism learns to escape from the CS and the fear it elicits.

Question 12

What is the link between avoidance conditioning and phobias?

Answer 12

• Phobia
– Irrational fear of specific object or situation
– Fear is disproportionate to real threat
–Acquisition –classical conditioning Elevator(CS) :
Feeling Trapped (US) –> Fear (UR) Elevator(CS) –> Fear (CR)
– Maintenance –Avoidance (negative reinforcement)
Elevator (SD): Avoid Elevator (RR) à Reduced Fear (SR)

Question 13

What is some support for the 2 factor theory?

Answer 13

• Two-factor theory predicts that the avoidance responding will be learned only to the extent that the warning signal terminates when a response is made.
• Kamin (1957)–trained four groups of rats in a two-chamber avoidance apparatus
― Terminate signal; avoids shock
― No termination of signal; avoid shock
― Terminates signal; does not avoid shock
― Control
• A significant amount of avoidance responding occurred in the first group only (response terminates the signal and enables animal to avoid shock)
• As predicted by two-factor theory, avoidance responding was poor in the group that was able to avoid shock but could not terminate the signal
• We know that delaying the onset of reinforcement reduces the effectiveness of reward so it should be possible to reduce the level of reinforcement by introducing a delay between the avoidance response and termination of the feared stimulus.
• After the avoidance response, the CS was terminated: (1) immediately (2) 2.5 seconds after the response (3) 5 seconds after the response (4) or 10 seconds after the response
• As predicted, the animals in the zero delay condition successfully avoided shock on over 80% of the trials.
• Animals in the 10-second delay condition avoided shock on fewer than 10% of the trials.
• Effectiveness of CS termination to support avoidance was decreased by increasing delay
• Results suggest that the source of reinforcement in avoidance conditioning was the reduction of fear generated by the termination of the CS

Question 14

What is Sidman free operant avoidance?

Answer 14

Avoidance can be learned without a warning CS
• Shocks at random intervals
• Response gives safe time
• Extensive training, but rats learn avoidance (errors, high variability across subjects)
- bit of a problem for Two Factor theory but
1. Rescorla and LoLordo (1965) trained dogs using the Sidman avoidance procedure (no warning stimulus and shock is programmed to occur at fixed time intervals)
2. In this study shocks were programmed to occur every 10 seconds but every time the dogs jumped over the hurdle in the shuttle box they ensured a shock-free period of 30 seconds
3. By jumping at least once every 30 seconds the dogs therefore could ensure they would never receive a shock
• Once dogs learned the avoidance response, they were confined to one half of the shuttle box and given discriminative fear conditioning trials:
―one tone (CS+) was followed by shock and
―another tone (CS-) was not. indicates absence of shock
• Sidman avoidance training was resumed and once dogs were responding reliably, CS+ and CS- were occasionally presented for five seconds.
• When the CS+ was presented the rate of jumping doubled
• When the CS- was presented the rate of responding fell to almost zero

Question 15

How do CS+ and CS- affect avoidance?

Answer 15

• CS+ can amplify avoidance
• CS-can reduce avoidance
• Evidence that the conditioned stimuli have acquired drive properties
Supports the Two Factor Theory’s position that it is the CS that drives the avoidance response

Question 16

What is some evidence against the 2 factor theory?

Answer 16

• Conditioned avoidance responding in dogs
― Light (CS) : Shock (UCS) –> Fear (UR)
―Light (CS) –> Fear (CR) (fear response elicited by the CS)
―Light (SD ) : Cross Barrier (R) –> Reduced Fear (SR )
• Shock then disconnected― Dogs jump barrier for 100s of trials to avoid shock
― But…(R) should extinguish because CS occurred without the US

• Rats placed in Skinner box
―Electric shock delivered randomly (probability = .3 for every 2-second period that elapsed)
―Probability of shock reduced from .3 to .1
• Rats could not avoid or escape shock…just reduce number of shocks received
―Most rats learned the task and kept lower rate of shock probability
• Problem for two-factor theory: avoidance learning in absence of CS
• Avoidance learning can be explained by one factor – reduction in shock rate (operant conditioning)

Question 17

What is the one factor theory of avoidance?

Answer 17

• Avoidance is negatively reinforced by the lower rate of aversive stimulation to which it is associated
― Reduction of aversive stimulation accompanying avoidance maintains avoidance

Question 18

What are 2 problems for theories of avoidance?

Answer 18

• Fear is a necessary component
• But fear reduces with experience

Question 19

What is the fearlessness problem?

Answer 19

Fear and avoidance are not as firmly linked as the theory believes:
• According to the theory, fear provides the motive to perform the avoidance response
• Early in experiments a dog would exhibit various signs of fear (whining, urination, shaking) when the tone was presented
• BUT once the avoidance response is well learned subjects respond without apparent fear

Question 20

What is alternation of behaviour?

Answer 20

•Every successful avoidance puts CS on extinction
•With extinction, fear drops, so motivation to avoid decreases
•Resulting in more shocks, strengthening CR again and increasing avoidance response
•But… we don’t really see this….

Question 21

What is persistence of avoidance? (cognitive explanation of avoidance learning)

Answer 21

• Cognitivists believe avoidance responding is based not on fear but on the subjects’ expectation that a response will avoid shock:
• During initial training, when the warning stimulus is followed by shock, it is assumed that subjects form an expectation that shock will occur when the stimulus is presented
• When the animal eventually jumps over the barrier to avoid shock, a new expectation forms (shock does not occur if the response is made)
• So the next time the warning stimulus is presented, the animal recalls both expectations (shock occurs if it doesn’t jump but not if it does) and because it prefers not to be shocked it will perform the response that produces this outcome
• Thus, fear has little role in this theory…it can therefore account for the shortcomings of two factor theory. First, regarding the disappearance of fear during training:
• Two factor theory assumes that once the avoidance response is learned and the warning stimulus is no longer followed by shock, the fear conditioned to this stimulus will extinguish
• But the animals continue to jump because it still expects shock to occur if it doesn’t jump, and prefers to avoid this outcome.
• Second, regarding the difficulty of extinguishing avoidance behaviour this also follows directly from a cognitive analysis:
• The theory says that avoidance depends on two expectations:
― in the absence of a response shock will occur; BUT
― if the response is made shock will not occur
• Early in extinction, the dog holds both of these expectations and therefore responds.
• And when shock doesn’t occur its expectation that responding will not be followed by shock is confirmed and it therefore continues to jump
• With each new trial this expectation receives further confirmation, so if anything the tendency to jump should be strengthened
• The fact that fear plays a minor role in this theory allows it to explain the continuation of avoidance responding in the absence of fear; but for the same reason it has difficulty explaining evidence that fear does influence avoidance.

Question 22

Does response prevention result in extinction?

Answer 22

• If this analysis is right then animals continue to respond during extinction because they never get a chance to learn what would happen if they didn’t respond…
• Katzev and Berman (1974) trained rats to avoid shock in a shuttle box and then gave them 50 extinction trials during which the CS was still presented but shock no longer followed.
― Control Group: was still allowed to jump over the barrier during this phase to terminate CS
― Response prevention/flooding group: had a barrier placed above the hurdle so that they could not jump.
• Rats that could control the termination of the CS during treatment (control) responded significantly more often during extinction than rats that could not.
• The probability of responding during extinction was also a decreasing function of the duration of CS exposure during treatment.

Question 23

What is the response problem?

Answer 23

• One difficulty arose when experimenters tried to teach rats to press a bar to avoid shock:
• We know that rats are very good at pressing bars to obtain food
• They can also learn to jump over a hurdle or run down an alley to avoid shock
• So if bar pressing is an easily learned response and avoidance of shock is a very powerful reinforcer then you might think that it would be easy to train rats to press a bar to avoid shock
• Yet hundreds of trials are needed to learn to press a bar to avoid shock, and many never do

Question 24

What are SSDRs?

Answer 24

• Because each species has somewhat different innate responses for coping with danger he called these Species Specific Defense Reactions.
• So the particular SSDR that occurs depends on:
1. The nature of the aversive stimulus
2. The response opportunities provided by the environment
Species-specific defense reactions
• Innate responses; evolved
― If an effective means of escape is available (e.g. an open field) the animal is most likely to flee for cover when it encounters the stimulus.
― Without a familiar escape route (e.g. a confined space) freezing will be the predominant defensive response.
• SSDRs predominate in initial stages of avoidance
• Hierarchy
―If first SSDR works, keep it
―If not, try next, etc.