" McDougall does not dispute the thesis as to
the collective inhibition of intelligence in groups
(p. 41). He says that the minds of lower intelligence
bring down those of a higher order to their own
level. The latter are obstructed in their activity,
because in general an intensification of emotion
creates unfavourable conditions for sound intellectual
work, and further because the individuals are intimidated
by the group and their mental activity is
not free, and because there is a lowering in each
individual of his sense of responsibility for his own
performances. "

― Sigmund Freud , Group Psychology and the Analysis of the Ego