Just in case you don't already know, the New York Times did release a nice piece on the life and death of Robert Zajonc. In it you'll see a more extensive coverage of his research, than just the mere exposure effect and social facilitation. It's pretty good, plus there's a lot of interesting facts about Zajonc that I did not know. For instance, here's a little snippet on his life during WWII:
"Robert Boleslaw Zajonc, an only child, was born in Lodz, Poland, on Nov. 23, 1923. In 1939, after the Nazis invaded Poland and headed toward Lodz, he and his parents fled to Warsaw. There, the building in which they were staying was bombed, and Robert’s parents were killed. Robert woke up in a hospital, seriously injured.Wow. If you have time, you should really read the full article. It's good. Zajonc was a remarkable man.
He attended an underground university in Warsaw before being dispatched to a labor camp in Germany. He escaped and, recaptured, was sent to a political prison in France. Escaping again, he joined the French Resistance and studied at the University of Paris. Reaching England in 1944, he worked as a translator for American forces in the European campaign."