Three stereotypic behavioral responses to threat, sometimes simply called F3. The physiological responses concomitant to these behaviors are the same, namely mobilizing bodily resources for an expenditure of energy, and narrowing attentional focus to the features of the threat. This preparation activity of the body has been used as a rudimentary explanation for the pattern of arousal responses that are recorded during PDD. Handler and Honts (2007; 2008) offered an alternative based on the Behavioral Inhibition System theory proposed by Gray and Mc Naughton (2003).