In 2004, I received my Ph.D. on research of person perception. In my dissertation, I connected attribution and spontaneous inferences to further develop understanding of cognitive social inferential judgment: the process of social inferences. My dissertation won the 2004 dissertation award of the Dutch Association of Social Psychologists.

In my research projects, I study other questions related to social cognition, social perception and judgment. For example, together with Roos Vonk, I investigated spontaneous ingratiation inferences: Spontaneous inference people draw about somebody acting on ulterior motivation. In many research project I study the role of automaticity and the unconscious. For example, I recently showed (Ham & Van den Bos, 2008) that when people are treated unfair themselves, they respond more strongly than when they witness something unfair happening to somebody else, but importantly, only at an automatic level, and not in their more controlled responses. In another line of research, I showed that unconscious thinking can lead to more accurate judgments about social judgment than conscious thinking (Ham, Van den Bos & Van Doorn, 2008).

One of my most important lines of research is Social Robotics. Here I investigated (Ham, Midden & Tak, 2008) that negative feedback from a robotic agent has stronger persuasive effects (changes behavior) than positive feedback. Related research studies Persuasive Technology, and more specifically Ambient Persuasive Technology.