Johnson and Downing - female ppts to give (fake) electric shocks to a confederate.
dressed in a KKK outfit;
nurses
control group they wore their own clothes.
KKK- gave most electric shocks ,'nurse' gave even fewer shocks than the control group.
it is not deindividuation itself, but the social role adopted after deindividuation which affects agg. If the adopted role is anti-social (e.g. KKK)=more agg
prosocial (e.g. nurses) = less aggression.
the mediating impact of social roles is unaccounted for, the theory can be considered incomplete.