There is a direct correlation between how angry a teenager gets and the size and structure of the amygdala, which is a part of the brain that is involved with emotions and memory. The research was conducted by the ORYGEN Research Centre, University of Melbourne, Australia and the Oregon Research Institute, USA and was published by the Proceedings of the National Academy of Sciences. The research indicates that an increase in the size of the amygdalas has a direct correlation with the length and intensity of tantrums.