Cognition

Quite simply, cognition refers to thinking. There are the obvious applications of conscious reasoning—doing taxes, playing chess, deconstructing Macbeth—but thought takes many subtler forms, such as interpreting sensory input, guiding physical actions, and empathizing with others. The old metaphor for human cognition was the computer—a logical information-processing machine.

Relationships

Love is the most profound emotion known to human beings. For most people, romantic relationships are the most meaningful element in their lives. But the ability to have a healthy, loving relationship is not innate. Almost all of us have experienced a failed relationship, and most of us have to work consciously to master the skills necessary to make them flourish.

Stress

Stress is simply a reaction to a stimulus that disturbs our physical or mental equilibrium. In other words, it's an omnipresent part of life. A stressful event can trigger the “fight-or-flight” response, causing hormones such as adrenaline and cortisol to surge through the body.