Studies from the Harvard Psychological Laboratory: Involuntary Motor Reaction to Pleasant and Unpleasant Stimuli.

Study of the emotions, in one way or another, has had a conspicuous place in the work carried on in the Harvard Psychological Laboratory.In this field of all others, perhaps, the investigator gains easiest access to the goal of physiological psychology-the determination, namely, of the quantitative and qualitative relations obtaining between those wonderful correlates, mind and body.That elementary organism, the amceba, when jarred by its environment or more directly stimulated, contracts and tends to take the spherical form.On the other hand, all its movements of self-gratification are processes of expansion or extension.This observable double tendency seems to be the type, almost symbolically expressed, of a deep biologic law which science has shown to exist with almost infinite adaptation to circumstances and habit, in every organism.Experiment proves that, like other impulses of the lower animals, it exists persistently in man.Professor Miinsterberg has advanced the hypothesis that stimuli which cause action of the extensor muscles are as a rule agreeable, while stimuli which cause action of the flexor muscles are as a rule disagreeable.This tendency we should nat-