Using rats in a shuttlebox avoidance study concluded "(a) Avoidance response strength is greater if the change in CS energy is greater, irrespective of the rate or direction of the change. (b) The response required of S and the training procedure are probably of greater importance in determining performance differences than are differences due to the direction of change in CS energy. (c) In a shuttlebox, avoidance response strength is greater with a 6-sec. CS-UCS interval than with a 3-sec. interval." (PsycINFO Database Record (c) 2006 APA, all rights reserved)