This paper considers how intersubjective co-ordination is integral to human forms of interpersonal engagement, sharing experiences with others, and acquiring knowledge about persons with minds. It dwells on three studies involving children and adolescents with autism, each concerned with different aspects of non-verbal communication in greetings and farewells, conversation, and imitation, respectively. Other researchers’ reactions to these studies illustrate how scientists tend to be sceptical of measures (however reliable) intended to capture the intersubjective dimension of personal relatedness. On a more theoretical note, it is suggested that intersubjectivity acquires the structure that it does, and has the developmental implications that it does, in virtue of human beings’ propensity to identify with others’ attitudes.