The cause was complications of prostate cancer, a family spokeswoman said.
Dr. Rimland’s interest in autism, the puzzling social-skills disorder, and his work on behalf of families touched by it grew out of his intuition as an experimental psychologist and his experience as a father.
When his young son Mark received a diagnosis of autism, doctors generally blamed the disorder on cold, distant mothering. In his book “Infantile Autism: The Syndrome and Its Implications for a Neural Theory of Behavior,” Dr. Rimland demolished the cold-mother theory by presenting lucid evidence that the disorder was rooted in biology.
“He was tremendously important to the field, in that he reoriented research from a focus on the parents to a focus on the brain,” Dr. Fred R. Volkmar, director of the Child Study Center at Yale, said. “He also developed the first checklist for diagnosing autism. He was a pathfinder and tireless advocate for families dealing with autism.”
Early on, his judgment was prescient. He was among the first scientists to recognize that a brand of systematic rewards and punishments, pioneered the University of Californiapsychologist O. Ivar Lovaas, could lead to significant improvements in autistic children. The treatment is widely used today.
Dr. Rimland also quickly saw through the spurious claims of a therapy called “facilitated communication,” in which therapists claimed to help channel the thoughts of autistic children and heal them.
He wrote articles, pushed for more research and founded advocacy organizations, including what is now the Autism Society of America, in Bethesda, Md., and the Autism Research Institute in San Diego, where he was director.
In 1985, after retiring from his day job as