I came across two interesting papers published relatively recently when researching penalty kicks. Both consider psychological variables that influence one party, either the goalkeeper or the kicker in a penalty shoot-out.
1. The first finding comes from a paper published in Psychological Science in 2011 by Roskes, Sligte, Shalvi, and De Dreu. This one relates to goalkeepers. The researchers collected data from World Cup penalty shootouts and show that Goalkeepers are more likely to dive to the right when in a losing position in a penalty shoot-out. This is attributed to psychological bias towards choosing 'right' when forced to act quickly.
2. The second paper comes from 2009 and was published in Psychology of Sport and Exercise. This time the application is to the penalty taker. The researchers, Jordet, Hartman and Sigmundstad show that there is a link between a penalty takers success and the length of time taken between the referee’s whistle to signal a player can proceed and when the kick is actually taken. Taking a longer time to respond to a referee’s 'ready signal' was positively correlated to successful conversions. John Considine has since told me that the book Scorecasting (reviewed by John in the book section of this website) has a short chapter on the 'myth' that the opposition should delay (or ice) the kicker in American Football. The data does not support the strategy for soccer.
So, when it comes to penalties maybe goalkeepers should jump to the left more and kickers should try to leave nations hold their breath a little longer!