Updated January 1, 2009
The Swedish Empathy Center recommends the following articles by David Aderman:
Aderman, D., & Berkowitz, L. (1970). Observational set, empathy, and helping. Journal of Personality and Social Psychology, 14, 141-148.
Aderman, D., Brehm, S., & Katz, L. B. (1974). Empathic observation of an innocent victim: The just world revisited. Journal of Personality and Social Psychology, 29, 342-347.
Brehm, S. S., & Aderman, D. (1977). On the relationship between empathy and the actor versus observer hypothesis. Journal of Research in Personality, 11, 340-346.