He is most well known for his research on what is now called applied behavior analysis (ABA) to teach autistic children through prompts, modeling, and positive reinforcement.
His application of the science was also noted for its use of aversives (punishment) to reduce undesired behavior, which are no longer supported as a part of most ABA treatment plans.
He is also considered a pioneer of ABA due to his development of discrete trial training and early intensive behavioral intervention for autistic children.
Løvaas began teaching at UCLA in 1961 in the Department of Psychology, where he performed research on children with autism spectrum disorder at the school's Neuropsychiatric Institute.
[6][9] Løvaas taught now prominent behaviorists, such as Robert Koegel, Laura Schreibman, Tristram Smith, Doreen Granpeesheh, John McEachin, Ron Leaf, Jacquie Wynn, and thousands of UCLA students who took his "Behavior Modification" course during his 50 years of teaching.
[9][10][11][12] Løvaas established the Young Autism Project clinic at UCLA in 1962, where he began his research, authored training manuals, and recorded tapes of him and his graduate students implementing errorless learning—based on operant conditioning and what was then referred to as behavior modification—to instruct autistic children.
He later coined the term "discrete trial training" to describe the procedure, which was used to teach listener responding, eye contact, fine and gross motor imitation, receptive and expressive language, academic, and a variety of other skills.
[1][11][13] In 1987, Løvaas published a study[14] which demonstrated that, following forty hours a week of treatment, 9 of the 19 autistic children developed typical spoken language, increased IQs by 30 points on average, and were placed in regular classrooms.
A 1993 follow-up study[15] found that 8 maintained their gains and were "indistinguishable from their typically developing peers", scoring in the normal range of social and emotional functioning.
However, the study also recommended to later generalize the child's skills with more naturalistic ABA-based procedures, such as incidental teaching and pivotal response treatment, so their progress is maintained.
[20] Another review in 2008 described DTT as a "'well-established' psychosocial intervention for improving the intellectual performance of young children with autism spectrum disorders..."[21] In 2011, it was found that the intervention is effective for some, but "the literature is limited by methodological concerns" due to there being small sample sizes and very few studies that used random assignment,[22] and a 2018 Cochrane review subsequently indicated low-quality evidence to support this method.
[24] Løvaas co-authored a study with George Rekers in 1974 where they attempted to modify the behavior of feminine male children through the use of rewards and punishment with the goal of preventing them from becoming adult transsexuals.
Despite the follow-up study (which Løvaas was not involved in) writing that the therapy successfully converted his homosexuality, his sister expressed concerns that it was overly biased as "he was conditioned to say that", and she read his journal, which described how he feared disclosing his sexual orientation due to his father spanking him as a child as punishment for engaging in feminine behavior, such as playing with dolls.
[38] Eventually, Løvaas abandoned these tactics, telling CBS in a 1994 interview, "These people are so used to pain that they can adapt to almost any kind of aversive you give them.