This is another contribution to the symposium on 'The Concept of Aggression' held by the British Psychological Society in 1938. In it Dr. Stephen discusses infantile aggression as the result of anxiety arising from an accumulation of undischarged instinctual tension. Such aggressive feelings, she thinks, perform a useful function in so far as they enable the child, firstly, to discharge its emotions to some extent, secondly, to force the people about it to gratify its needs, and thirdly, to attack and destroy the source from which the unpleasure it is experiencing comes; but they are harmful in so far as they make the child afraid of giving way to such a violent outburst of rage and hatred that it will destroy both those it loves and its own self. This fear leads to stronger measures of frustration, which in their turn increase instinctual tension and consequent aggression; and thus a vicious circle is set up, until the possibility of the child's finding any emotional outlet whatever is in the end completely blocked. The best