What is beautiful is usable

Tractinsky, N., Katz, A.S., and Ikar, D. “What is beautiful is usable” in Interacting with Computers, 13 (2000), 127-145 says it all.

Perceptions were elicited before and after the participants used the system. Pre-experimental measures indicate strong correlations between system’s perceived aesthetics and perceived usability. Post-experimental measures indicated that the strong correlation remained intact.

The research was conducted with ATM machines but I would think it’s easily applicable for interfaces in general.