"This study was designed to test the effects of both interaction distance and the quality of the interaction upon attraction. It was found that close interaction distances amplified the quality of the interaction so that for a positive interaction there was more liking for a close rather than a far partner, while for a negative interaction a close partner was liked less. "

Physical distance and attraction: An intensification effect by Allen Schiffenbauer in the Journal of Experimental Social Psychology

(sorry I don't have a free pdf link)

http://www.sciencedirect.com/science/article/pii/0022103176900573

http://psycnet.apa.org/?&fa=main.doiLanding&uid=1976-26057-001