On the other hand there are often certain influences at work, which tend to make the child unlike his parents in just these qualities of energy and self-reliance. Thus a high degree of initiative, self-confidence or masterfulness in the predominating parent may easily cause the child--unless himself endowed with these characteristics to the same or to an even greater degree--to abandon himself habitually to the supremacy and initiative of the parent and thus in time to develop a lack of those qualities which distinguished the personality of the latter. Conversely, a lack of energy or authority in the parents may compel a child to fall back constantly upon his own power of decision and resource, thus developing in him, to some degree at least, those character qualities in which his parents were defective. For these reasons it may often happen that strong and masterful parents have children who are relatively weak as regards initiative and power of self-assertion, while these in turn may be followed by a generation more resembling their grandparents with respect to these qualities than their immediate predecessors. This "alternation of generations" as regards certain important mental powers and characteristics has attracted some attention among students of heredity and some attempts have been made to give a biological explanation of the problem, but as there would seem to be no known laws of heredity which easily fit the case, it is probable that we must regard the psychological influences here indicated as the sole, or at least the chief, causes of the phenomenon. [Sidenote: Children may identify themselves with their parents]