The false consensus effect is the tendency to overestimate how widely our own beliefs, opinions, and behaviors are shared by others.

The Basic Pattern

People who eat meat estimate that most people eat meat. Vegetarians estimate that most people are vegetarians. Both groups inflate the prevalence of their own choice.

Why It Happens

• We mostly spend time with people like us — our social circles amplify perceived consensus
• Shared beliefs feel like objective truth rather than subjective preferences
• Motivated reasoning — widespread consensus makes our own views feel more valid

Real-World Consequences

• Product launches: Founders build for themselves, not the actual market — assuming others want what they want
• Politics: Both sides in a polarized debate are often shocked by how many people hold the opposing view
• Management: Assuming your team shares your enthusiasm for a project without checking

Antidote

Survey before you assume. Talk to people outside your existing network. Build feedback loops early.

Reference:

Wikipedia: False Consensus Effect

https://en.wikipedia.org/wiki/False_consensus_effect