Experimental evidence is presented which shows that the relative magnitude of galvanic reactions in palmar and in non-palmar regions is determined by the type of activity giving rise to the change. "It is shown that situations favoring an increase in the subject's anticipation, alertness, or apprehension (including arousal from sleep), are likely to be attended by marked increase in conductance of the palm, while situations involving various sorts of muscular activity are likely to be attended by large increases in the conductance of non-palmar areas. Activities designated roughly as mental work may effect marked changes in either type of reacting mechanism, the locus of greatest activity possibly depending upon the amount of muscular activity involved. These observations have been shown to be in agreement with certain findings of other investigators. They further have been shown to be consistent with the view that while perspiration on non-palmar, non-plantar areas is thermo-regulatory in function, that on the palms and soles is primarily to maintain the adhesiveness and pliability essential to tactual acuity and good grip upon objects, and is psychologically significant because it is normally called forth in situations demanding alertness in the mobilization of the energies of the organism for emergency adjustive response." (PsycINFO Database Record (c) 2006 APA, all rights reserved)