Most people tend to be good at extrapolating in incomplete info games, and depending on the risk aversion culture of whatever situation you're in, this means that most people will react defensively.

You learn this so vividly in Silicon Valley particularly with VCs, where staying mum is almost always the best strategy. VCs act as little reactive microprocessors dealing with too many signals, and the less information you give them the easier it is for them to arrive at a decision or strategy. Instead, there's a bias for founders to do the opposite when raising (or salesmen when closing), which is to overshare information thinking there's just one more bit of data that they can provide which will unlock the magical outcome they want. It's a habit of smart but otherwise inexperienced people fall into a trap of in negotiations.

There's tons of other competing externalities too like emotion and market signalling and stuff (eg repeated n-person incomplete games), but if you removed all of that just boiled it down to strategic decision making, this is what game theory teaches us.