 <p class="lead" id="first">Faces and voices are more likely to be judged as male when they are angry, and as female when they are happy, new University of Essex research has revealed.</p><p>The study led by Dr Sebastian Korb found that how we understand the emotional expression of a face or voice is heavily influenced by perceived sex, and vice versa.</p><p>The paper published in the journal<em> Emotion </em>reveals that both men and women subconsciously make the same mistakes.</p><p>Dr Korb, from the Department of Psychology, hopes the research will be expanded and could help make us more aware of our built-in biases.</p><p>He said: "This study shows how important it is not to rely too much on your first impressions, as they can easily be wrong.</p><p>"Next time you find yourself attributing happiness or sadness to a woman be aware of your bias and possible misinterpretation.</p><p>"Interestingly there wasn't a gender divide in the way the perceived sex of a face affected emotional judgements -- but women were slightly more sensitive to subtle changes in emotion overall."</p><p>The research used 121 avatar faces and 121 human voices created by modifying the emotional expression in degrees from happy to angry, and the sex on a sliding scale from male to female.</p><p>A total of 256 participants in three studies were shown the mock-ups or played the voices and asked to judge emotions and whether someone was male or female.</p><p>When comparing the size of the effects, it was found for both faces and voices that emotion influenced the perception of sex more than the other way around.</p><p>It is thought this may be due to an unconscious activation of the amygdala -- an important emotion centre in the brain.</p><p>This almond-shaped cluster of neurons located deep in the brain allows us to rapidly detect and react to threats, such as an angry attacker but is not involved in determining a person's sex.</p><p>It is also speculated that being biased to perceive males as angry is an evolutionary advantage as it prepares for a fight or flight response.</p>