Bernard Rimland studied autism in children in the United States in the second half of the twentieth century. His early research in the 1950s and into the 1960s led him to assert that infantile autism was a neurodevelopmental disorder, or one that is caused by impairments in the growth and development of the brain or central nervous system. Rimland's assertion that infantile autism was a neurodevelopmental disorder contradicted another theory at that time that the condition resulted from emotionally cold parenting. Rimland spent much of his career as a psychology researcher for the United States Navy in Point Loma, California, but in his spare time he researched and wrote about autism, and he advocated for children with autism and their families.

Infantile Autism: The Syndrome and Its Implications for a Neural Theory of Behavior (hereafter Infantile Autism) is a book written by Bernard Rimland, published in 1964. The book proposed a theory to explain the causes of autism. The book also synthesized research into autism and used Rimland's neural theory, described in the book, as a theory to explain some aspects of behavior, intelligence, and abnormality. Moreover, Infantile Autism contributed to a debate between Rimland and child psychologist Bruno Bettelheim in the 1960s over whether autism was caused by upbringing (see refrigerator mother theory) or by impaired brain development. Rimland's book convinced many autism researchers to look for abnormal psychological development.

In 1943, child psychiatrist Leo Kanner in the US gave the first account of Early Infantile Autism that encouraged psychiatrists to investigate what they called emotionally cold mothers, or refrigerator mothers. In 1949, Kanner published Problems of Nosology and Psychodynamics of Early Infantile Autism. In that article, Kanner described autistic children as reared in emotional refrigerators. US child psychiatrists claimed that some psychological or behavioral conditions might have origins in emotional or mental stress, meaning that they might be psychogenic. Kanner described autism's cause in terms of emotional refrigeration from parents into the early 1960s, often attributing autism to the lack of parental warmth. In the 1960s, Bernard Rimland in the US and Bruno Bettelheim in Austria disagreed on the role of psychogenesis in autism. Rimland suggested that autism's cause was rooted in neurological development, while Bettelheim continued to emphasize the role of nurturing during early childhood. Nevertheless, many mothers reported that they felt a deep sense of anguish and resentment toward child psychiatrists who often made them feel as if they were to blame for their children's autism.

In 2011, Sonja Vernes and Simon Fisher performed a series of experiments to determine which developmental processes are controlled by the mouse protein Foxp2. Previous research showed that altering the Foxp2 protein changed how neurons grew, so Vernes and Fisher hypothesized that Foxp2 would affect gene networks that involved in the development of neurons, or nerve cells. Their results confirmed that Foxp2 affected the development of gene networks involved in the growth of neurons, as well as networks that are involved in cell specialization and cell communication. The researchers determined that Foxp2 is important for a variety of developmental processes such as motor control, language acquisition, and cognition.

Paul Eugen Bleuler studied autism and schizophrenia, among other psychiatric disorders, throughout continental Europe in the early twentieth century. Bleuler worked as a psychiatrist caring for patients with psychiatric disorders at a variety of facilities in Europe. In 1908, Bleuler coined the term schizophrenia to describe a group of diseases that cause changes in thought processes and behavior in humans as well as difficulties relating to the world. Bleuler also introduced the concepts of autism, which he defined as a disconnect from the outside world, and ambivalence, which he defined as the coexistence of conflicting ideas in one’s mind. Bleuler’s concepts enabled later researchers, such as Bernard Rimland, to study the causes of those disorders, and to suggest that abnormal development of fetal brains potentially caused those disorders.