Some Effects of Thiamin on the Winning of Social Contacts in Mice

Abstract

Adult, black S mice (C57, Jackson Memorial Laboratory) caged separately, except when brought together in staged pair contacts at appropriate intervals, establish an order of rank somewhat comparable with that known in man for tennis players. Controlled amts. of Merck''s thiamin hydro-chloride, added to an already adequate diet, produced no increase in aggressiveness or in the ability to win fights. Mice returned to a full diet after being deprived of thiamin for 15 days or more soon show a strong upswing in social rank whether they are (a) meeting other mice that they have fought only a few times, or (b) meeting individuals in a long continued series of pair contacts. Mice that have maintained a rank for some time have a marked tendency to remain dominant and, mice in the w position tend to submit passively when meeting another mouse. Changes occur in the rank order for unknown reasons. They occur more frequently in intermediate ranks than among those in a or w position. a mice usually retain that status after being completely deprived of thiamin until they are in an advanced stage of B1 avitaminosis. The span of retention of dominant rank by such mice approx. equalled that shown by control animals on full diet. Thiamin de-ficiency, in most instances, did not effect aggressive behavior until the mice were so physically weakened that their ability to be actively aggressive was almost completely impaired. Social status among these mice, as measured by results from staged pair contacts, until avitaminosis becomes too extreme, seems to be influenced more strongly by so-called psychological factors than by any other physiological considerations under our control.