Most people agree that emotions can be caused by a specific event and that the person experiencing it is aware of the cause, such as a child’s excitement at the sound of an ice cream truck. But recent research suggests emotions also can be unconsciously evoked and manipulated.

Psychologists Kirsten Ruys and Diedrick Stapel of the Tilburg Institute for Behavioral Economics Research at Tillburg University in The Netherlands have uncovered the first empirical evidence to suggest humans do not need to be aware of the event that caused their mood or feelings in order to be affected by it. The scientists hypothesized that, since humans have evolved to respond quickly and unconsciously to stimuli, they should be able to react to an emotional event without full awareness: “You are likely to live longer if you immediately stop moving at the sight of a growling grizzly bear and do not need full awareness for such a response to be instigated,” explained Ruys and Stapel.