In The Crowd, Le Bon examines the various characteristics of crowd psychology: impulsiveness, irritability, incapacity to reason, the absence of judgment of the critical spirit, the exaggeration of sentiments, and others… He believes that an individual immersed for some length of time in a crowd soon finds himself - either in consequence of magnetic influence given out by the crowd or from some other cause of which we are ignorant - in a special state, which much resembles the state of fascination in which the hypnotized individual finds himself in the hands of the hypnotizer. . This Crowd Psychology has been applied to modern investing, product development and social media development. Gustave Le Bon was a French social psychologist, sociologist, anthropologist, inventor, and amateur physicist. His writings incorporate theories of national traits, herd behavior and crowd psychology. He is best known for this work, The Crowd: A Study of the Popular Mind.