Because of the wide variation of structures used in the treatment of autistic children, a study was designed in which structure was changed from relative structure to relative unstructure over two repeated cycles of two weeks each. Both children and therapists were rated on their reactions. The findings indicated that autistic children tended to react more favorably to structure than to unstructure. Individual differences showed that autistic children on a higher developmental level were better able to utilize relative unstructure than those functioning on a lower developmental level.
Schopler E, Brehm SS, Kinsbourne M, Reichler RJ. Effect of Treatment Structure on Development in Autistic Children. Arch Gen Psychiatry. 1971;24(5):415-421. doi:10.1001/archpsyc.1971.01750110027005