Disturbing experiences don't actually heighten our perceptions. In fact, according to new Weizmann research, in adverse conditions we're more likely to experience slightly different sights or sounds as being the same. The scientists think that this lumping together of similar sensory stimuli may be behind post-traumatic stress syndrome. The experiments showed that volunteers learning to distinguish between similar tones had much more trouble telling them apart when these were associated with a shockingly bad smell. Dr. Rony Paz explains that this blurring of our perceptions may have helped…