"St Andrews University and US scientists said they had established that too much analysis made the golfer's game worse. They said thinking too much about the previous shot can disrupt performance. ... The researchers think the loss of performance was due to an effect called verbal overshadowing, which makes the brain focus more on language centres rather than on brain systems that support the skills in question. The study, which also involved the University of Michigan, marks the first time researchers have claimed to demonstrate that verbal overshadowing can adversely affect motor skills." - Overthinking 'disrupts golf putt', BBC website, 30 January 2009.