There are innumerable forms of meditation. Only some come with long traditions, and even fewer have been carefully scientifically studied.
Of the ones that have been studied, we’ll take a look at the differences between these two: Focused-Attention and Mindfulness (aka Open Monitoring).
Focused-Attention Meditation (FAM) is exactly what it sounds like, participants are asked to bring their full attention to a particular stimuli, sometimes an external image, sometimes an internal sensation.