Matevia, M., Fritz, J., Nankivell, B. 1991. Effect of increased space on behaviors of captive chimpanzees. American Journal of Primatology 24, 120-121 (Abstract).

The results suggest that increased space may reduce some social interactions. It is not clear if levels of social activity [in general] in smaller spaces are 'abnormally' high, and are reduced to more 'normal' levels following an increase in available space.