Faces and voices are more likely to be judged as male when they are angry, and as female when they are happy, new research has revealed. The study found that how we understand the emotional expression of a face or voice is heavily influenced by perceived sex, and vice versa. He said: "This study shows how important it is not to rely too much on your first impressions, as they can easily be wrong. "Next time you find yourself attributing happiness or sadness to a woman be aware of your bias and possible misinterpretation."