Evolution and Revolution in Child
ADHD as a Disorder of Adaptation
by Peter S. Jensen, M.D., David Mrazek, M.D.
Penelope K Knapp, M.D., Laurence Steinberg, Ph.D., Dynthia Pfeffer, M.D., John Schowalter,
M.D., and Theodore Shapiro, M.D., Journal of American Child & Adolescent Psychiatry,
Summary by Teresa Gallagher:
The many authors of this article echo Thom Hartmann's
"Hunter in a Farmer's world" concept. They look at ADHD behavior through
an evolutionary lens and describe how ADHD behavior may have been life-saving in earlier
the current estimated frequency of ADHD (3% to 5%), it is unlikely that such a
"disorder" could be as prevalent in the human species if not maintained within
the species by selection forces that conveyed certain advantages to some ADHD
characteristics or other associated traits."
The three major diagnostic criteria of
hyperactivity, impulsivity and attention differences were examined to see if these traits
might actually have helped our ancestors to survive.
Organisms which are exploratory (on the lookout for
threats and opportunities) may be more adaptive, especially in environments in which food
is scarce and dangerous predators lurk. Increased motor activity and the
exploratory behavior associated with ADHD may have been useful within this context.
I have always identified most with the "explorer" concept, and find it
interesting that the authors linked exploratory behavior with hyperactivity in animals.
An exploratory temperament would quite naturally lead to increased creativity,
which may explain why ADDers tend to be so inventive.
Incidentally, Bill Allsopp of Project
Lab has found that kids who do best in his hands-on science & technology class
have very high levels of curiosity compared with their classmates. They display exploratory
behavior by readily taking apart old appliances and trying out new things when directions
are lacking. "Normal" kids, the ones who do well in most classrooms,
falter under this environment as they wait to be told exactly what to do. Bill found
a very complete description of his best students when he read a list of ADD traits.
The authors note that animals which live in harsher or
changing environments are in fact more hyperactive as they forage and search. The young of
such animals are also hyperactive even though they are playing and not foraging or hunting
yet. When hyperactive fox pups play in a frenetic manner they are gaining experience
and sharpening their survival skills for later use. Interestingly, juvenile animals
are hyperactive only when they are in the presence of a caregiver. If they are
away from safety or experiencing novel stimuli the hyperactivity ceases. Anyone with
an ADHD child should recognize this behavior.
Attention Processes (scanning
and rapidly shifting attention): Animals which live in environments where
they are preyed upon and in which food is scarce must be vigilant. Otherwise they
may be caught by a predator or miss a meal. A scanning type of attention might be
quite adaptive for such an environment. Moreover, when young animals (or
humans) are raised in a dangerous environment, or an environment with a lot of novel
stimuli, they may develop even more of a scanning attention type. Although the
authors don't elaborate, this could mean that ADHD kids raised in fast-paced modern times
might become more ADHD than they otherwise would be. An endless stream of large busy
classrooms, fast-paced TV shows, amusement parks, malls and tight schedules may
present an environment which encourages the young plastic brain to mold itself towards a
scanning form of attention.
authors define this term as "an organism's quick response to environmental cues
while not considering alternative responses to the cues." Impulsivity was
also found to have advantages.
that does not quickly pounce on a potential prey or dodge a potential predator may not get
another chance. The relative danger of false-positive responses could easily be
outweighed by the 'downsides' of missing a critical cue in dangerous or resource-scarce
Environments: Humans evolved as hunter/gatherers for a few million years,
and as agricultural beings for only 10,000 years, so it makes sense that much of our
behavior still reflects our hunter/gatherer heritage. The authors believe that
earlier environments ranged from gentle and stable to harsh and changing. ADHD
traits would have been most adaptive in harsh or changing environments such as a frozen
steppe. Kinder, more stable environments may have been more amenable to other
types of personalities, perhaps including "Farmers" of the future. In
other words, Hartmann's "Farmers" Diversity of personality traits would
have been important. In such kinder regions individuals with ADHD traits would
likely have become "successful warriors on a primitive battlefield."
Clinical Implications: The
authors believe that modern school environments are the exact opposite of what ADHD
children need and that alternative schools designed for the ADHD learning style be
employed. I whole-heartedly agree and have a page on alternative
|"Alterations in the environment may
reduce the adaptive strain on a child's nervous system whose set-point may be at the other
pole from the environment in which he or she finds himself or herself."
They also believe that clinicians should
reframe their views of ADHD when counseling patients. A child seen as
"response-ready" may be viewed in a more positive light than one labeled
with a disorder.
Researchers, clinicians and parents should be open-minded to the idea of ADD being
perfectly normal but different: an exploratory temperament held by our hunter/gatherer
ancestors. Russell Barkley, a noted researcher in the field of ADD, recently
hypothesized that ADD is caused by genetic mutations. But his idea is inconsistent
with modern theories of evolution. Genetic mutations are not passed down from
generation to generation on a large scale unless they provide some advantage to the
population. If anything, the reverse is more likely to be true.
Hunter-gatherer genes may have been the original genes, and "normal" or
"Farmer" genes may have appeared later as a result of random mutations.
(Barkley's paper on ADHD appeared in Scientific American and can be viewed at http://www.scientificamerican.com/1998/0998issue/0998barkley.html.)
Resources: The full version of this
paper is currently available at http://www.hypies.de/add/evolutio.html
(this is on someone else's website).
Anyone who would like to read more about ADD as an
evolutionary trait can either obtain the paper at a library or read some of Thom
Hartmann's books (below). In addition, the original "Born to
Explore!The Evolution of ADD and Creativity" article was also along these same
Thom Hartmann books: Reader reviews
Deficit Disorder - A Different Perspective, by Thom Hartmann, $12.00. The original
"Hunters in a Farmer's World" book.
ADD -- Hunting For Reasons
In The Past & Present, by Thom Hartmann, $10.36 Mythical
Intelligence Inc., 1996. My favorite Hartmann book.
Stories - A Guide to Fulfillment for Families with ADD, by Thom
Hartmann, $17.47 Mythical Intelligence Inc, 1995.
The ADD Experience, Edited by Thom Hartmann & Janie Bowman
with Susan Burgess, $10.36 Underwood Books, 1996.