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Jacek Debiec

(<a href="http://www.shutterstock.com/gallery-109192p1.html">David Royal Hanson</a> <a href='http://www.shutterstock.com/gallery-306199p1.html'>nando viciano</a> via <a href='http://www.shutterstock.com/'>Shutterstock</a>)

Memories of trauma are unique because of how we respond to threat

Jacek Debiec
(Getty/BartekSzewczyk)

Americans are more anxious than before

Jacek Debiec