s come into sharp relief. But let
us understand clearly what such an experiment means. When the
psychologist goes to work in his laboratory, his aim is to study those
thoughts and emotions and feelings and deeds which move our social
world. But his aim is not simply to imitate or to repeat the social
scenes of the community. He must simplify them and bring them down to
the most elementary situations, in which only the characteristic
mental actions are left. Is this not the way in which the
experimenters proceed in every field? The physicist or the chemist
does not study the great events as they occur in nature on a large
scale and with bewildering complexity of conditions, but he brings
down every special fact which interests him to a neat, miniature copy
on his laboratory table. There he mixes a few chemical solutions in
his retorts and his test-tubes, or produces the rays or sparks or
currents with his subtle laboratory instruments, and he feels sure
that whatever he finds there must hold true everywhere in the gigantic
universe. If the waters move in a certain way in the little tank on
his table, he knows that they must move according to the same laws in
the midst of the ocean. In this spirit the psychologist arranges his
experiments too. He does not carry them on in the turmoil of social
life, but prepares artificial situations in which the persons will
show the laws of mental behaviour. An experiment on memory or
attention or imagination or feeling may bring out in a few minutes
mental facts which the ordinary observer would discover only if he
were to watch the behaviour and life attitudes of the man for years.
Everything depends upon the degree with which the characteristic
mental states are brought into play under experimental conditions. The
great advantage of the experimental method is, here as everywhere,
that everything can be varied and changed at will and that the
conditions and the effects can be exactly measured.

If we apply these principles to the question of the jury, the task is
clear. We want to find out whether the cooeperation, the discussion,
and the repeated voting of a number of individuals are helping or
hindering them in the effort to judge correctly upon a complex
situation. We must therefore artificially create a situation which
brings into action the judgment, the discussion, and the vote, but if
we are loyal to the idea of experimenting we must keep the experiment
free from all those fea