Southwick, C. H. 1967. An experimental study of intragroup agonistic behaviour in rhesus monkeys (Macaca mulatta). Behaviour 28, 182-209.

A significant increase in agonistic behavior occurred when the distribution of the food was restricted, but the amount of food remained normal. Highly significant increases in the frequency of agonistic behavior occurred with the introduction of new monkeys who were social strangers. ... A significant increase in agonistic behavior also occurred with a [50%] space reduction.