voluntary social interaction measurement difference between duration of physical contact or close proximity of test subject and social stimulus during sample phase and test phase 2015-12-03T13:41:08Z CMO:0002678 The difference in time spent in direct social interaction (that is, the amount of time within a specified period during which a test subject touches or voluntarily moves or remains close to, for example within one centimeter of, a social stimulus such as another animal of the same species) between the first introduction of a social stimulus and a subsequent reintroduction of the same stimulus. VT:0001360 clinical_measurement_ontology difference between time of physical contact/close proximity of test subject and social stimulus during sample phase and test phase jesmith