Examined the fact that the degree of attention of any individual at a given time depends upon certain factors that remain constant for that individual, in spite of endless variations in the specific form or content of the mental processes involved. The degree of attention of 12 Ss were measured in each of the following 4 cases: Reactions to touch, sound, light and choice reactions to an increase or decrease in the intensity of light. The degree of attention was measured by the use of irregularly mixed preparatory intervals of 2 secs. Results show that the mode of stimulus was a condition of attention. In case of choice reactions, the degree of attention was lower than in the case of simple reactions. There were marked individual differences in the degree of attention. There were general individual conditions of attention, which were operative as a constant in all cases of attention of a given individual. (PsycINFO Database Record (c) 2006 APA, all rights reserved)