All of us are taught from a young age about the importance of having a firm handshake and looking people in the eye. There is plenty of folklore out there about how important it is too shake hands properly, and most of us notice when someone is awkward about it, does it weakly, or has sweaty palms. Nonetheless, I always am intrigued by how clever researchers can be about studying such mundane things, and how they often generate insights about things in life that we all take for granted. A great example is a 2008 study of handshakes conducted by Greg Stewart and his colleagues at the University of Iowa, which was published in the Journal of Applied Psychology in 2008. They had local managers and executives give mock interviews to 98 undergraduate (50 women, 48 men) job seekers, and then the interviewers give the students feedback about how they might improve their interviewing style, and also give the researchers a rating of how likely they were to hire the student. The interesting twist -- which makes this study strong from a methodological standpoint -- was that neither the student interviewees or corporate interviewers knew that Stewart and his colleagues were doing a study of handshakes. The ratings of the students' handshakes were measured completely independent of the interviewer's ratings of whether or not they would hire the candidate -- although doing a handshake with the candidate was part of 45 minute or so mock interview.
The researchers somehow set things up so that, in the course of meeting the interview and going through the mock interviewer, the undergraduate shook hands with five different "raters" (and the job interviewer). I can't describe this as well as the researchers, so let me show you the paragraph from page 1141:
"The raters shook hands while greeting each participant, either before or after the mock interview, so both interviewees and interviewers were unaware that handshakes were being evaluated. None of the handshake evaluators served as an interviewer. Two raters greeted and shook hands when a participant arrived for the mock interview. Participants were then introduced to a third rater, who shook hands. After the mock interview, a fourth rater greeted participants, shook hands, and introduced them to the fifth rater, who shook hands. Within 5–10 s of shaking hands, raters excused themselves from participants and completed an evaluation form. To avoid priming interviewers to pay undue attention to the handshake, we did not ask them to provide explicit assessments of the handshake."
Each of these five hand shakers was trained to rate the quality of the handshake on 1. completeness of grip; 2. vigor; 3. strength; 4. duration, and 5. eye contact during the handshake. There was much agreement (inter-correlations between .68 and .85 among the raters). The researchers then (after using introducing fairly extensive statistical controls) looked for the link between the handshakes and the interviewers ratings of whether they would hire the candidate (and remember that the interviewer didn't know it was a handshake study and had a lot of other kinds of interaction with the undergraduate).
Despite all these other factors, the researchers found a significant (if modest) independent effect of handshake quality on whether the interviewer would be inclined to hire the student. To me, the most interesting finding pertains to women. The researchers found that, on average, women had weaker handshakes than men. Probably because their are different expectations for men and women, women's weaker handshakes did not lead to weaker hiring recommendations (In fact, overall, the interviewers were more positively disposed to hire women than men). BUT those women who had firmer and stronger handshakes, and used more complete grips, benefited more than men who had firm handshakes and complete grips -- the researchers suggest that this effect may have been seen because men are expected to have firm shakes, and because it is more unusual among women, those women with firm handshakes were more memorable. In other words, having a weaker handshake didn't seem to hurt women, but having a stronger handshake seemed to help them.
I like this study because it confirms common sense and business lore, and adds an interesting twist -- if you are a woman, make sure you've got a great handshake. it may help you gain an advantage over both male and female candidates.
P.S. Go here to see the complete reference and abstract.