A recent study published in Psychological Science shows that positive mood has been found to enhance creative problem solving and flexible yet careful thinking. Ruby Nadler at the University of Western Ontario and colleagues looked at a particular kind of learning that is improved by creative thinking. Volunteers were put into different moods and then given a category learning task to do, such as classifying sets of pictures with visually complex patterns. The researchers manipulated mood with help from music clips and video clips. After listening to the music and watching the video, people had to try to learn to recognize a pattern.