Chapter 16 Suggested Answers
REVIEW 16.1
1
Behaviour and consequence:
Scenario
1
2
3
Behaviour
Consequence
Dog stops at the edge of the
pavement
Attempts
to
pronounce
‘hospital’ correctly
Buy special card for sixmonth anniversary
Blind friend crosses road safely
(reward)
Encouragement from big sister
(reward)
Huge, loving hug (reward)
Work hard to get an A+
Get $50 (reward)
4
5
Swimming training more than Get into the AIS swimming squad
four hours each day
(reward)
Speeding
Incurred a fine and lost one demerit
point (punishment) so now have
become a careful and observant
driver
6
2
Student’s own examples.
REVIEW 16.2
Discriminative Stimulus (D), Behaviour (B) and Consequence (C):
Example
D
B
C
1
Traffic light is red
Stop the car
Avoid an accident
2
Feel cold
Put on a jumper
Feel warm
3
Mobile phone rings Press receive button
Talk to friend
4
Johnny: shopping Johnny: scream
(supermarket)
Mother: screaming Mother: give chocolate
from Johnny
Johnny: get chocolate
Oxford Psychology Units 3 & 4
Mother: feel relieved;
no
longer
embarrassed
by
Johnny screaming
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REVIEW16.3
1
A reinforcer is any stimulus (action or event) that strengthens likelihood of
behaviour. A punisher is any stimulus that weakens or decreases the likelihood of
behaviour.
2
Positive reinforcement occurs when a behaviour causes a reward to be given
(pleasant consequence) that strengthens the response. Negative reinforcement occurs
when an unpleasant stimulus is removed, which strengthens the response in the
likelihood it will happen again.
3
a
Positive reinforcement
b
Positive reinforcement
c
Response cost
d
Negative reinforcement
e
Punishment
REVIEW 16.4
1
Partial reinforcement schedules are hardest to extinguish.
2
‘Ratio’ refers to number of responses. ‘Interval’ refers to the length of time.
3
A ‘fixed’ partial reinforcement schedule refers to a response being rewarded on a
set basis (e.g. every tenth time it occurs, or every 10 seconds). A ‘variable’ reinforcement
schedule is when a response is rewarded without regular frequency, so it cannot be
predicted.
4
Variable ratio schedule (VR) is the most effective partial reinforcement schedule,
where a reward is given on an irregular basis. Due to its unpredictable nature, the animal
or person being rewarded in this way will be likely to keep performing the behaviour
over and over on the chance that it will be rewarded at some point (based upon the
average number of correct responses).
5
Fixed interval schedule (FI) is the least effective partial reinforcement schedule,
where a reward is given after a specified amount of time has elapsed regardless of the
number of responses. Due to its predictable nature, the animal or person being rewarded
in this way will be likely to only perform the behaviour when the time interval has
elapsed and a reward is about to be given. This can lead to extinction of the behaviour
once the reward ceases.
6
Variable ratio reinforcement leads to the fastest acquisition of behaviour. If an
animal or a person is rewarded irregularly after an unpredicted number of responses, the
more responses they make, the faster they are likely to receive the next reward.
7
Student’s own examples.
8
Schedules of reinforcement:
a
Variable ratio (varied (variable) number of games (ratio) leads to reward (win)
b
Fixed interval (set (fixed) time lapse (interval) leads to reward (cross road)
c
Fixed ratio (every (fixed) 10 bracelets (ratio) leads to reward (pay)
d
Fixed ratio (every (fixed) occasion he sits (ratio) leads to reward (treat)
e
Variable interval (good waves are unpredictable (variable) so can wait different
lengths of time (interval) for reward (ride on wave)
Oxford Psychology Units 3 & 4
ISBN 978 0 19 556717 5 © Oxford University Press Australia
REVIEW 16.5
Situation
Discriminative
stimulus
Behaviour
Consequence
a
Cricket team
Bowling practice
Make it into team as
master leg-spinner
b
School play
Learning lines
Lead role in school play
c
Psychology exam
Learn psychology
Perform well in exam
INVESTIGATE 16.1
Student’s own responses.
TEST YOUR UNDERSTANDING
1
a
2
b
3
c
4
c
5
b (relating to operant learning)
6
a
7
c
8
d
9
d
10
a
11
d
12
b
13
c
14
Comparing negative reinforcement and punishment:
a
Differences:
Punishment decreases the likelihood of a response, whereas negative reinforcement
increases the likelihood of a response.
With punishment, an unpleasant stimulus follows the response, whereas with negative
reinforcement the behaviour removes an unpleasant stimulus.
Examples:
b
Negative reinforcement: A toddler doesn’t like being confined to his highchair.
A parent allows the toddler to get out of its highchair when breakfast is eaten to
encourage him to eat all food on his plate next time
Oxford Psychology Units 3 & 4
ISBN 978 0 19 556717 5 © Oxford University Press Australia
Punishment: smack your dog when it digs up the garden in an attempt to reduce the
likelihood of digging behaviour in future
15
Dorothy is training Toto:
a
Dorothy is using operant conditioning.
b
She is using continuous reinforcement.
c
She may start rewarding Toto on a variable basis to encourage him to sit longer.
For example, rewarding him after 1 minute has elapsed, then after 2 minutes, then 30
seconds, then 1 minute. The unpredictable schedule of rewarding Toto should lead to a
longer lasting response.
16
A variable ratio of reinforcement occurs when a person or animal is rewarded on
the basis of an irregular but set average number of correct responses occurring. This
means the reward cannot be predicted with certainty.
17
Extinction occurs when the conditioned response disappears over time after
reinforcement has ceased. For example: a dog may no longer sit and wait at the door if it
has not been rewarded with a treat for a period of time.
18
Shaping may be used to teach a child to tie their shoelaces by using
encouragement as a reward for successive approximations leading to the target behaviour
of tying laces. The first step may be giving a positive response to the child looping two
laces together, then again once they are able to perform the next step … and only giving
the reward when the behaviour was showing an accomplishment of each subsequent step.
Rewards are no longer given for the initial behaviours once each step is accomplished.
Oxford Psychology Units 3 & 4
ISBN 978 0 19 556717 5 © Oxford University Press Australia