One explanation for the false consensus effect is that people use their own reaction as an "anchor" for predicting the attitudes and behaviors of others.

False Consensus Effect

The cognitive bias whereby people overestimate how much others share their beliefs, attitudes, and behaviors.

Anchor

A key piece of information used as a reference point for decision-making or assessment, often in negotiations or estimations.

Attitudes

A psychological tendency expressed by evaluating a particular entity with some degree of favor or disfavor.