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 ...

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.

A criticism of happiness research is that it often relies on what a person says about his or her own happiness. Calling a self-report measure of happiness "subjective well-being" seems not to help ...