Emotions can be “caught” from other people. This might make intuitive sense - for example you might notice you are drawn to cheerful people.
We tend to unconsciously mimic those around us. We mimic facial expressions, vocal expressions, and postures of those around us. This causes us to “catch” others emotions.
How does this happen?
Scientists have captured the attunement of emotions in the laboratory by measuring the physiology — such as heart rate — of two people in conversation. As the interaction begins, their bodies operate at different rhythms. But after 15 minutes, the physiological profiles of their bodies look remarkably similar.
Scientists describe the open loop as “interpersonal limbic regulation”; one person transmits signals that can alter hormone levels, cardiovascular functions, sleep rhythms, even immune functions, inside the body of another. …in all aspects of social life, our physiologies intermingle. Our limbic system’s open-loop design lets other people change our very physiology and hence, our emotions.
Emotions can even be caught without a single word being uttered:
Psychologists found that even completely nonverbal expressiveness can affect other people. For example, when three strangers sit facing one another in silence for a minute or two, the most emotionally expressive of the three transmits his or her mood to the other two — without a single word being spoken.