Final answer:
The description of Peter's behavior suggests he has impaired social skills, which align with characteristics of Autism Spectrum Disorder.
Step-by-step explanation:
The passage provides a description that matches symptoms often associated with a pervasive developmental disorder such as an Autism Spectrum Disorder (ASD). People with ASD might have impaired social skills, exhibit repetitive motor behaviors, have strict adherence to certain rituals, and have a preoccupation with specific subjects. Peter's difficulty in changing conversation topics and continuing to speak on the same topic despite the social cues to move on is indicative of such social impairments often seen in ASD.