These findings buttress those of a prior study reporting stable within-individual consistency of CSF AVP concentration in a modest sample of N = 10 monkeys [41], and add to growing evidence linking individual differences in CSF AVP concentration to individual differences in primate social functioning, including grooming behavior in macaques [41] and Autism Diagnostic Observation Schedule Calibrated Severity Scores in people with ASD [42]. Here, AVP is linked to autism.