Edward Thorndike (1874–1949) supported the scientific movement in education. He based teaching practices on empirical evidence and measurement.  Thorndike developed the theory of instrumental conditioning or the law of effect. The law of effect states that associations are strengthened when it is followed by something pleasing and associations are weakened when followed by something not pleasing. He also found that learning is done a little at a time or in increments, learning is an automatic process and all the principles of learning apply to all mammals. Thorndike's research with Robert Woodworth on the theory of transfer found that learning one subject will only influence your ability to learn another subject if the subjects are similar.  This discovery led to less emphasis on learning the classics because they found that studying the classics does not contribute to overall general intelligence.  Thorndike was one of the first to say that individual differences in cognitive tasks were due to how many stimulus response patterns a person had rather than a general intellectual ability.  He contributed word dictionaries that were scientifically based to determine the words and definitions used.  The dictionaries were the first to take into consideration the users maturity level.  He also integrated pictures and easier pronunciation guide into each of the definitions.  Thorndike contributed arithmetic books based on learning theory . He made all the problems more realistic and relevant to what was being studied, not just to improve the general intelligence .  He developed tests that were standardized to measure performance in school related subjects.  His biggest contribution to testing was the CAVD intelligence test which used a multidimensional approach to intelligence and the first to use a ratio scale.  His later work was on programmed instruction, mastery learning and computer-based learning:
Critical theorists, like social reconstructionists, believe that systems must be changed to overcome oppression and improve human conditions. Paulo Freire (1921-1997) was a Brazilian whose experiences living in poverty led him to champion education and literacy as the vehicle for social change. In his view, humans must learn to resist oppression and not become its victims, nor oppress others. To do so requires dialog and critical consciousness, the development of awareness to overcome domination and oppression. Rather than "teaching as banking," in which the educator deposits information into students' heads, Freire saw teaching and learning as a process of inquiry in which the child must invent and reinvent the world.