A series of cancellation and reaction-time tests showed that the simple sensory reactions were slower and more regular than those of the average person, but the motor reactions were much quicker. This accords with previous indications as to Poincaré's general motor type. The most significant thing about the reactions is said to be the wandering and unstable attention which they disclosed. It was difficult to keep Poincaré's mind on the tests, because his attention constantly wandered to the apparatus. In receiving instructions for such experiments he did not seem to comprehend what was being said, but appeared distracted and uninterested. This is the same impression he is said to have given to those whom he met in his daily relations. He was restless, could not remain in one position or stay by one task, had no patience and abandoned his work whenever it seemed to require any voluntary effort. Tests of reverie associations and of free paired associates showed absence of voluntary attention and predominance of purely verbal association tendencies. Binet's "cigarette description" test was used, and Poincaré was found to belong to Binet's first type of observer (simple description, with no evidence of reflection or judgment, no display of erudition, no expression of fancy or sentiment). His description was remarkably lucid and clear. Poincaré spoke correctly, never learned his addresses by heart, and made few corrections either in writing or in speaking. Indications of his temperament and type are said to be suggested by his handwriting.
Poincaré's opinions on various topics are given, and several peculiar habits of daily life are recorded, chiefly for the sake of emphasizing his constant air of distraction, his impatience and restlessness. He loved music; sketched a little; did not sleep soundly; and often began to work on a problem only to abandon it in the faith that it would in some way solve itself unconsciously or that the right idea would come spontaneously on some later occasion. He often began a memoir without having any conclusion in mind. He often wrote formulae automatically for the sake of the chance associations which they might bring.
These tests of Poincaré showed him to present a striking contrast to Zola, the novelist. Zola's type was found to be characterized by prominent voluntary intellectual activity, clearly conscious and intense, concentrated effort, with no tendency to perseveration of ideas after cessation of work. His thought, as disclosed by the tests, was logical, methodical, and seemed preëminently fitted for the work of mathematical deduction. His method of work was quite the opposite of that of Poincaré, who, when he met with a difficulty or with a point requiring voluntary effort, abandoned his work or proceeded to another part of it which would develop more spontaneously. The surprising thing was that a methodical, logical and persistent worker, such as Zola, should have become the prince of romance that he was. One might have expected that the mental processes of Poincaré, which were shown to be flighty, uncontrolled, spontaneous, unstable and spasmodic, would have particularly fitted him for the activity of the romancer. Instead, they found their outlet in severe mathematical and philosophical creation. Poincaré's genius is thus said to be incapable of explanation on the basis of his sensori-motor equipment, his imagination and memory, and the speed or control of his psychic activity. If his case is taken as typical, it suggests the quite unexpected result that tendency to distraction, automatisms, oscillating attention, restlessness, uncontrolled association and reliance on chance syntheses and spontaneous ideas are significant for the type of genius required in mathematics and philosophical speculation. Certainly in Poincaré's case they seem to have constituted a definite method of research.