On the eve of the second anniversary of the World Trade Center tragedy, research has confirmed the cliche that the world is a changed place. It shows that people's personalities have changed markedly since September 11.
Christopher Peterson and Martin Seligman, from the universities of Michigan and Pennsylvania, set up an online experiment about positive emotion. Web surfers were asked to rate themselves on 24 positive psychological traits including bravery, gratitude, kindness, spirituality, hope and industry.
The questionnaire was put on the web in spring 2001, so the researchers were able to compare the responses before and after September 11.
More than 900 people completed the survey before September 11 and more than 3,000 after, most of whom were from the US.
It found that people who responded after September 11 regarded themselves as significantly more grateful, hopeful, kind, loving and spiritual than those who responded before September 11.
The respondents also declared a greater sense of leadership and emphasised the importance of teamwork.
The academics suggest that these traits are similar to St Paul's virtues of "faith, hope and charity". They note that the secular traits in their survey showed little significant increase.
The authors conclude in an article in Psychological Science that these findings provide food for thought. "Our data direct the attention of positive psychology to the role of crisis as a possible crucible for what is best about people," they write.