The field of psychology is vast, and there are many ways to carve it up. For example, one possible difference is between animal and human psychology. Another division is between science and practice.

How old do you feel? Experts explain how subjective age works, and why it matters. (Getty Images) Your heart tells you you're 27, but your birth certificate says 42. For many of us, there’s a big ...

1 Centre for Exercise and Sport Science, Deakin University, School of Exercise and Nutrition Sciences, Burwood, Victoria, Australia 2 Centre for Physical Activity and Nutrition Research, Deakin ...