Deindividuation
A loss of individual self-awareness and accountability in group settings, especially when anonymous. The modern view is that people do not lose themselves; they swap personal norms for the group's norms, so anonymity amplifies whatever the group already values.
What drives it
It relieves people of personal accountability and lets them act on impulses or group norms they would not own individually. Identifying it correctly matters: the question is not 'is this person in a crowd?' but 'what norm does this crowd make salient?'.
How it shows
Work
Anonymous engagement surveys and Glassdoor reviews that are far harsher than anything said in person. Pile-ons in large group chats or all-hands Q&As where questions get more aggressive as they go. Teams in matching kit or under a strong brand who take risks or cut corners together they would not take alone. Equally, anonymous peer giving or crowdfunding where the salient norm is generosity.
Relationships
A family at a wedding or funeral where old behaviours erupt that no one would show at a quiet dinner. Online, someone who is mild in person posts cruelly under a pseudonym, or joins a pile-on against an ex.
Self
Afterwards you hardly recognise what you said or did in the group and feel a small shock reading it back. In the moment there was a pleasant loss of self-consciousness, the feeling of being carried.
What tells it apart
Conformity: Conformity can happen with full self-awareness and identifiability; deindividuation shows when identifiability is removed. Ask people to sign their names and see if behaviour changes.
Emotional contagion: Emotional contagion is the spread of a feeling between people; deindividuation is the loss of personal accountability. A crowd can share calm (contagion) without anyone acting outside their norms.
Moral disengagement: Moral disengagement comes with justifications the person will state; deindividuated behaviour often comes with no story at all, and embarrassment once the person is identified.
A test
Make people identifiable (names on comments, faces on camera, roles stated) and watch whether behaviour changes; if it shifts towards personal norms, deindividuation was in play.
Questions to carry
- When names and faces became visible, how did the behaviour change, and which norm had the crowd been following?
- What have I written or done when no one knew it was me that I would not sign my name to?
How strong the research is
mixed. The classic idea that anonymity in crowds releases antisocial behaviour is not well supported; a meta-analysis (Postmes and Spears, 1998) found anonymity makes people follow whatever norms are salient in the group, good or bad, which is what the SIDE model predicts, and the Stanford Prison Experiment often cited here is now seriously discredited.
Where it comes from
Gustave Le Bon, 1895 (crowd psychology); Leon Festinger, Albert Pepitone and Theodore Newcomb, 1952; Philip Zimbardo, 1969; Stephen Reicher, Russell Spears and Tom Postmes, 1995 (SIDE model)