Interpersonal Effects

Interpersonal effects describe how we think, feel, and behave in social interactions based on our interpretation of the other person's likely thoughts, feelings, and intentions. This is an umbrella topic covering several specific interpersonal mechanisms including the halo effect, projection, assumed reciprocity, and self-fulfilling prophecy — not a single universally defined cognitive bias.

Social interactions involve a constant, often automatic process of modelling what the other person is thinking and feeling. These mental models are quick, intuitive, and often inaccurate. They can create self-fulfilling cycles: if we expect someone to be hostile, we act defensively, which provokes the hostility we expected.

• You assume a new colleague dislikes you because they did not greet you, so you act coldly, which makes them pull away — confirming your original impression.
• A customer enters a shop assuming the salesperson will be pushy, so they act dismissive, which the salesperson interprets as rude, leading to a genuinely poor interaction.
• You believe a friend is upset with you, so you avoid them, which they interpret as you being distant, creating the very distance you feared.

• Ask: 'Is my interpretation the only possible one?'
• Notice when your behaviour is creating the reaction you expected.
• Check your assumptions before acting on them.
• Most people are not thinking about you as much as you think.