"Under conditions of stress, however, sometimes the person lose trust in her honed instincts, and the explicit system takes over. That is what it means to choke. Choking is different from panicking, when someone stops thinking under pressure. Panicking is thinking too little, choking is thinking too much."

http://stephencfchan.blogspot.com/2009/12/choking.html

Another related article, focus too causing tiring, pay more and get less - http://cn.wsj.com/big5/20111024/eoe082512.asp?source=rss
