A child at the nursery door who charms you, then rages, then crumples is running through the whole repertoire in ninety seconds. Nothing has gone wrong yet.

What the research says

A meta analysis of the standard laboratory social stress test found it reliably raises cortisol in most healthy people, and that the size of the rise depends heavily on the details of how the test is run. Responding physically to social pressure is normal machinery, and the setting shapes how big the response is. That work used adults in a laboratory, so read the nursery door as an illustration rather than as the thing measured.

Strength of evidence: one line of research. A single study, or a theoretical account.