Benjamin Bloom (1903–1999) spent over 50 years at the University of Chicago, where he worked in the department of education. He believed that all students can learn. He developed taxonomy of educational objectives. The objectives were divided into three domains: cognitive, affective, and psychomotor. The cognitive domain deals with how we think. It is divided into categories that are on a continuum from easiest to more complex. The categories are knowledge or recall, comprehension, application, analysis, synthesis and evaluation. The affective domain deals with emotions and has 5 categories. The categories are receiving phenomenon, responding to that phenomenon, valuing, organization, and internalizing values. The psychomotor domain deals with the development of motor skills, movement and coordination and has 7 categories, that also goes from simplest to complex. The 7 categories of the psychomotor domain are perception, set, guided response, mechanism, complex overt response, adaptation, and origination. The taxonomy provided broad educational objectives that could be used to help expand the curriculum to match the ideas in the taxonomy. The taxonomy is considered to have a greater influence internationally than in the United States. Internationally, the taxonomy is used in every aspect of education from training of the teachers to the development of testing material. Bloom believed in communicating clear learning goals and promoting an active student. He thought that teachers should provide feedback to the students on their strengths and weaknesses. Bloom also did research on college students and their problem solving processes. He found that they differ in understanding the basis of the problem and the ideas in the problem. He also found that students differ in process of problem solving in their approach and attitude toward the problem.