Imagine you're a researcher studying how sleep affects mood. To explore the connection, you would look at two key "variables": sleep (how much someone gets) and mood (how happy or irritable they feel) ...

Psychology is a relatively young science. The first person to call himself a psychologist, Wilhelm Maximilian Wundt, began his work in the 1860s in Germany and established the first-ever psychology ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. Credit: RichVintage/Getty Images Psychology is a relatively young science. The first person to ...