I imagine such behavior could happen if someone had a bad experience in the past, that they were disproportionally punished in some social situation. The punishment didn't even have to be a predictable logical consequence; maybe they just had a bad luck and met some psycho. Or maybe they were bullied at school, etc.

If their social skills are otherwise okay, they may intellectually understand what is usually the best response, but in real life they are overwhelmed by fear and their behavior is dominated by avoiding the thing that "caused" the bad response in the past. For example, if the bad thing happened after saying "hello" to a stranger, they may be unable to speak with strangers, even if they know from observing others that this is a good thing to do.

Then the framing of the test could make students think either about "what is generelly the right approach?" or "what would I do?"