Barnum effect
Overview
The Barnum effect is a cognitive bias where you take vague, general personality descriptions as accurate portraits of you specifically. It's also called the Forer effect, after an experiment Bertram Forer reported in a 1949 paper. The name comes from showman P.T. Barnum, who is said to have claimed that "if you say something that fits everyone, everyone will think it's about them."
In Forer's experiment, all of the students were given the same personality description and told it was "an analysis of you personally," and they rated the description highly as accurate. "You want other people to like you." "At times, you doubt your own decisions." Statements like these tend to fit almost anyone.
Question boxes and the Barnum effect
The Barnum effect shows up in question box answers when the person answering responds with vague generalities. "I think you're actually a really kind person." "The fact that you're worried shows how seriously you're thinking about it." Answers like these could be said to anyone. Yet the sender may feel "they really get me."
This isn't necessarily a bad thing. If the sender comes away feeling reassured, that has value in itself. The problem is when the person answering, unaware of the Barnum effect, keeps answering every question with generalities. Senders may be moved at first, but they can eventually notice that "this person always says pretty much the same thing." The Barnum effect wears off fast.
Answers that go beyond the Barnum effect
The key to writing answers that don't rely on the Barnum effect is being specific. Not "you're kind," but "the part of your question where you say [X] shows that you care about the other person." Not "being worried shows you're serious," but "if you're torn between [X] and [Y], how about laying out the pros of each?"
A specific answer fits only that one sender. That's why it can have the power to make them feel "they really thought about me." Not the fake empathy of the Barnum effect, but real empathy based on specifics. That difference shows in the quality of question box answers. It takes effort, but specific answers that stick in senders' memories can lead them to come back again.