The Autistic Brain: Malfunction or Human Evolution?

Are you aware that Autism prevalence figures are growing rapidly? According to recent statistics, Autism now affects 1 in 54 male children. More young people will be diagnosed with Autism this year (male and female) than with AIDS, diabetes and cancer combined.

Autism is the fastest growing “developmental disability” in the U.S. – and the only disorder dramatically on the rise (with mental retardation, Down syndrome, and cystic fibrosis remaining roughly the same). Earlier Autism prevalence figures were much lower, centering at about 0.5 per 1,000 during the 1960s and 1970s, and about 1 per 1,000 in the 1980s.

The reported spike in the prevalence of Autism raises questions about whether this dramatic increase is factual, or a byproduct of greater awareness that has led moms and dads, educators, and professionals to see symptoms of Autism in kids who would not have received the diagnosis 20 years ago.

The increase in Autism prevalence figures suggests several possibilities (here are just a few):

• some relatively recent changes in the environment may be responsible
• the diagnosis may be applied more broadly than before as a result of the changing definition of the disorder
• there may be more complete pickup of autism (i.e., case finding) as a result of increased awareness and funding (e.g., attempts to sue vaccine companies may have increased case-reporting).
• this is the way the human brain is developing

Human evolution is characterized by a rapid increase in brain size and complexity. Decades of research have made important strides in identifying the unique features of the human brain. But it has become possible only very recently to examine the genetic basis of human brain evolution. Through “genomics” (i.e., the study of the genomes of organisms), tantalizing insights regarding human brain evolution have emerged.

Metabolic changes responsible for the evolution of the human brain’s unique cognitive abilities indicate that it may have been pushed to the limit of its capabilities. Research adds weight to the theory that some neurological disorders are a costly by-product of human brain evolution.

The idea that certain neurological disorders are by-products of increases in metabolic capacity and brain size, which occur during human evolution, has been suggested before, but now researchers have access to new technical approaches to really put the theory to the test.



The human brain is unique among all species in its enormous metabolic demand. If researchers can explain how the human brain sustains such a tremendous metabolic flow, they will have a much better chance to understand how the brain works – and why it sometimes “malfunctions.” But is it truly a “malfunction” (i.e., functions badly)? Or is the human brain on its evolutionary path to “hyper-functioning” (i.e., functioning above and beyond the norm)?