Anxiety is only ever created by the body. I understand the experiment, but I don't understand what this headline is supposed to mean. I think somebody is letting their liberal arts leak into their science.
External things don't cause anxiety. Anxiety often occurs as a reaction to external things. Of course anxiety might be caused by a faster heartbeat; one of the symptoms of anxiety is a faster heartbeat. You can also cause it with injections of adrenaline, or amphetamines. Lack of oxygen works, too.
Maybe this seems profound because the mice can't explain their feelings?
External things don't cause anxiety. Anxiety often occurs as a reaction to external things. Of course anxiety might be caused by a faster heartbeat; one of the symptoms of anxiety is a faster heartbeat. You can also cause it with injections of adrenaline, or amphetamines. Lack of oxygen works, too.
Maybe this seems profound because the mice can't explain their feelings?