* SENSITIVITY TO REWARD IN CHILDREN WITH ADHD:
IMPLICATIONS FOR BEHAVIORAL MANAGEMENT
Among the different ideas that have been proposed for
factors contributing to the symptoms of ADHD, abnormal
responsivity to behavioral rewards has a long history.
Some researchers have suggested that children with ADHD
have a reduced sensitivity to reward, which requires that
they be rewarded more often to maintain good behavior.
Others suggest that they actually have a heightened
sensitivity to reward - specifically that they show an
increased tendency to seek immediate rewards. As a result,
they become more easily distracted and pulled off tasks
that require long-term effort before any reward is obtained.
In this interesting experimental study the authors tried
to test these competing ideas about sensitivity to reward
in children with ADHD (Tripp, G., & Alsop, B. (1999).
Sensitivity to reward frequency in boys with ADHD. Journal
of Clinical Child Psychology, 28, 366-375.) This is very
much a laboratory-type experiment rather than a more "real
world" type study, but is one that seems to have important
applications for the day to day management of children with
ADHD.
Fifteen boys with ADHD and 15 matched control children with
an average age of 10 served as participants. All the ADHD
children were probably of the Combined Type - i.e. they had
both inattentive and hyperactive/impulsive symptoms.
As in many studies of ADHD, girls were unfortunately not
included.
The task for participants in the study was to sit in front
of a computer screen on which either of 2 highly similar
stimuli were repeatedly displayed for a very brief instant.
After each presentation, children were required to press a
button to indicate which stimulus they had seen. Correct
responses were signaled by the computer and children knew
that they would be awarded points that they could later
use to purchase a desirable prize.
Not every correct response was rewarded, however. Instead,
the computer was programmed so that a correct response for one
of the two stimuli would be rewarded 3 times as often as the
other. Thus, during the task, the children learned that a
correct response for one of the stimuli was more likely to
produce a reward than a correct response for the other.
RESULTS
Because of this differential rate of reward for correct
identifications of the 2 stimuli, a bias developed to select
the stimuli that was most likely to be rewarded. This simply
means that children developed a tendency to select the more-
frequently rewarded stimulus more often, even though the two
were presented an equal number of times.
What was interesting, however, is that for children with and
without ADHD, the strength of this bias was found to depend
heavily on which stimulus had been most recently rewarded.
Consider the situation in which the child was just rewarded
for correctly identifying the stimulus that had been consistently
rewarded more often throughout the test session. In this
scenario, children with and without ADHD showed a similar
tendency to select this stimulus on the next trial, even if
this was the incorrect choice.
What about when the most-recently rewarded choice was for the
stimulus that had been rewarded less often? For children
without ADHD, the "bias" they displayed on the very next trial
was still heavily in favor of the more-frequently rewarded
stimulus. In other words, they did allow their most-recently
rewarded choice to alter what they had learned was more likely
to be the "best bet". For children with ADHD, however, the results
were quite different and the strong bias in favor of the more
consistently rewarded choice disappeared on the next trial.
In other words, the behavior of the children with ADHD was
influenced less by their overall experience of reward on the
task and more by the very last reward that they had obtained.
What's more, this same tendency was evident - although to a
slightly lesser degree - even when the children with ADHD
were tested while on medication.
IMPLICATIONS
What are the implications of these results for understanding
the day-to-day, moment-to-moment behavior of children with
ADHD? To me, it seems that these results underscore the
extent to which children with ADHD live much more "in the
moment" than do other children. As demonstrated in this
experiment, their behavior is much more likely to be influenced
by their most recent experience with being "rewarded", even
when this recently rewarded behavior is inconsistent with a
more long-standing learning history. Thus, when a behavior
meets with some success (i.e. it results in obtaining some type
of desired response) they may tend to forget that this is not
what has typically occurred before and back away from behaviors
that have been more consistently rewarded.
It is not difficult to imagine how this could play itself out in
"real life". Based on these findings, a parent could be doing
a really excellent job of consistently praising and rewarding
behaviors that they are working to promote in their child and
ignoring or even punishing a particular unwanted behavior like
whining. As a result, their child is learning that the desired
behaviors are more likely to result in the kinds of social and
even tangible outcomes they desire, and begin to display this
behavior with greater frequency.
Consistently standing firm in response to a child's whining is
difficulty for anyone, however, and there are bound to be instances
when a parent "gives in" to their child's demands in an attempt
to obtain some quick relief and needed peace. Unfortunately, as
the data from this study indicate, the result for many children
with ADHD is that when this whining behavior has been "rewarded"
by the parent's giving in, it becomes increasingly likely that
they will engage in this behavior again soon.
In other words, unlike other children who would be more likely to
recognize that this was an isolated and unlikely-to-be-repeated
event (i.e. based on the history of what has been rewarded in the
past), the child with ADHD may tend to disregard the history
and base their next "behavioral choice" on what has been
most recently successful. Unfortunately, this "choice" may
often reflect behavior you are trying to discourage that has
been inadvertently rewarded.
This "heightened sensitivity" to the most-recently rewarded
behavior underscores the important need for consistency in
behavioral interventions designed for a child with ADHD. It
also helps in understanding why behavioral interventions for
a child with ADHD can be, at times, so difficult and frustrating
to implement effectively.
On the positive side, the sensitivity that children with ADHD
show to recently rewarded behavior suggests it may be possible
to alter long-standing patterns of negative behavior by being
consistent and vigilant about rewarding the new types of behavior
you are trying to promote. You just have to be really careful
to reward the new behavior consistently, and do your best to
avoid the "slip ups" noted above.
In my experience, and corroborated in a variety of studies on this
topic, it can be difficult for parents to do this when they are
under undue stress themselves, and when they do not have the
necessary supports in place to help in following through on a
well -designed behavioral treatment plan. This is where consulting
with an experienced child mental health professional, and enlisting
the support of other parents struggling with similar issues, can
be so helpful. This is hard work, but can make a substantial
difference in children's ability to be successful both at home
and at school.
Reprint requests to:
I hope the above information was of interest to you and potentially helpful. Staying informed about the latest research findings on ADD/ADHD will enable you to make better informed decisions about the best ways to promote your child's healthy development. That is my objective in publishing a monthly newsletter, ADHD RESEARCH UPDATE, and I invite you to become a regular subscriber. If you work with children who have ADHD in a professional capacity, I also think you will find that ADHD RESEARCH UPDATE is a convenient way to stay on top of important new research information. You can find information about subscribing by going to: Best wishes, David Rabiner, PhD
Gail Tripp
Dept. of Psychology
University of Otago
P.O. Box 56
Dunedin, New Zealand
A note from Dr. Rabiner:
Licensed Psychologist
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