Researchers have found a general tendency for humans to fear things approaching, even if non-threatening.

In our long struggle for survival, we humans learned that something approaching us is far more of a threat than something that is moving away. This makes sense, since a tiger bounding toward a person is certainly more of a threat than one that is walking away.

According to University of Chicago Booth School of Business Professor Christopher K. Hsee, we still have negative feelings about things that approach us - even if they objectively are not threatening.

Hsee explains in order to survive, humans have developed a tendency to guard against animals, people and objects that come near them.

He said that this is true for things that are physically coming closer, but also for events that are approaching in time or increasing in likelihood.

Hsee, along with Chicago Booth doctoral student Yanping Tu, and Zoe Y. Lu and Bowen Ruan of the University of Wisconsin, conducted a battery of eight tests in support of their thesis and found that even nonthreatening objects and beings evoked negative feelings in participants as they came closer.

Even seemingly docile entities, such as deer, had a fear factor attached to them since participants could still attach some uncertainty to a wild animal's behavior.

These initial investigations into approach avoidance are of practical use in a number of areas.

The study has been published in the Journal of Personality and Social Psychology.