Jean Piaget, a Swiss psychologist, profoundly impacted educational theory with his comprehensive theory of cognitive development. His work was developed in the mid-20th century, but it remains highly ...

Citation: O'Connor, C. & Miko, I. (2008) Developing the chromosome theory. Nature Education 1(1):44. Scientists were able to identify chromosomes under the microscope as early as the 19th century.

If a fully developed theory of mind is the benchmark, for instance, then “consciousness” is potentially only available to humans above the age of five or so.