Obj. 2:  Further, when, as a result of contraction, the vital spirits and heat are accumulated in the interior parts, man cries out, as may be seen in those who are in pain.  But those who fear utter nothing:  on the contrary they lose their speech.  Therefore fear does not cause contraction.

Obj. 3:  Further, shame is a kind of fear, as stated above (Q. 41, A. 4).  But “those who are ashamed blush,” as Cicero (De Quaest.  Tusc. iv, 8), and the Philosopher (Ethic. iv, 9) observe.  But blushing is an indication, not of contraction, but of the reverse.  Therefore contraction is not an effect of fear.

On the contrary, Damascene says (De Fide Orth. ii, 23) that “fear is a power according to systole,” i.e. contraction.

I answer that, As stated above (Q. 28, A. 5), in the passions of the soul, the formal element is the movement of the appetitive power, while the bodily transmutation is the material element.  Both of these are mutually proportionate; and consequently the bodily transmutation assumes a resemblance to and the very nature of the appetitive movement.  Now, as to the appetitive movement of the soul, fear implies a certain contraction:  the reason of which is that fear arises from the imagination of some threatening evil which is difficult to repel, as stated above (Q. 41, A. 2).  But that a thing be difficult to repel is due to lack of power, as stated above (Q. 43, A. 2):  and the weaker a power is, the fewer the things to which it extends.  Wherefore from the very imagination that causes fear there ensues a certain contraction in the appetite.  Thus we observe in one who is dying that nature withdraws inwardly, on account of the lack of power:  and again we see the inhabitants of a city, when seized with fear, leave the outskirts, and, as far as possible, make for the inner quarters.  It is in resemblance to this contraction, which pertains to the appetite of the soul, that in fear a similar contraction of heat and vital spirits towards the inner parts takes place in regard to the body.

Reply Obj. 1:  As the Philosopher says (De Problem. xxvii, 3), although in those who fear, the vital spirits recede from outer to the inner parts of the body, yet the movement of vital spirits is not the same in those who are angry and those who are afraid.  For in those who are angry, by reason of the heat and subtlety of the vital spirits, which result from the craving for vengeance, the inward movement has an upward direction:  wherefore the vital spirits and heat concentrate around the heart:  the result being that an angry man is quick and brave in attacking.  But in those who are afraid, on account of the condensation caused by cold, the vital spirits have a downward movement; the said cold being due to the imagined lack of power.  Consequently the heat and vital spirits abandon the heart instead of concentrating around it:  the result being that a man who is afraid is not quick to attack, but is more inclined to run away.