Abstract: It is frequently believed that autism is characterized by a lack of social or emotional reciprocity. In this article, I question that assumption by demonstrating how many professionals—researchers and clinicians—and likewise many parents, have neglected the true meaning of reciprocity. Reciprocity is “a relation of mutual dependence or action or influence,” or “a mode of exchange in which transactions take place between individuals who are symmetrically placed.” Assumptions by clinicians and researchers suggest that they have forgotten that reciprocity needs to be mutual and symmetrical—that reciprocity is a two-way street. Research is reviewed to illustrate that when professionals, peers, and parents are taught to act reciprocally, autistic children become more responsive. In one randomized clinical trial of “reciprocity training” to parents, their autistic children’s language developed rapidly and their social engagement increased markedly. Other demonstrations of how parents and professionals can increase their behavior of reciprocity are provided.

— Morton Ann Gernsbacher, "Towards a Behavior of Reciprocity"

The paper cites several examples of improvements to autistic children's social development when non-autistic peers, parents, or teachers are trained to behave reciprocally towards them. This one particularly caught my eye (emphases added):

In 1986 researchers taught four typically developing preschoolers to either initiate interaction with three autistic preschoolers or to respond to the interaction that the three autistic preschoolers initiated, in other words, to be reciprocal (Odom & Strain, 1986). Which intervention had the more lasting influence on the autistic preschoolers’ social interaction? When the typically developing preschoolers were taught to respond to the interaction that the autistic preschoolers initiated, the autistic preschoolers responded more frequently. In other words, when the typically developing preschoolers behaved reciprocally, the autistic preschoolers responded more positively.