New research suggests that three and four-year-olds are more physically aggressive than most adults; anyone subjected to the wrath of an indignant pre-schooler will not argue with that.
The researchers from Montreal University say aggressive behaviour is natural in young children and those who are not are more likely to become aggressive adults.
Child expert Professor Richard Tremblay says children must learn to regulate their use of violence in the early years as they mature, and whether or not they manage to do so depends on a range of environmental and genetic factors; he says those who do not are more likely to become aggressive adults.
Professor Tremblay says most children quickly learn that a physical attack on a peer will be responded to by a physical attack on them.
Tremblay who is a Professor of paediatrics, psychiatry and psychology at the University warns that physical aggression in children is a "major public problem" because it is an indicator of aggression in adulthood.
Tremblay also says such aggression can lead to other serious behavioural problems such as drug and alcohol abuse, violent crime and continues the cycle of abusive parenting.
Professor Tremblay believes if toddlers are surrounded by adults and other children who are physically aggressive, they will learn that physical aggression is part of everyday social interactions.
Tremblay says the factors which influence whether a child's aggressive tendencies remain uncheck range from the type of parental care a child received to whether its mother smoked when pregnant.
He says research has shown that nicotine affects the development of areas of the baby's brain which are responsible for emotional control, and physical aggression increased the most in the early years when human development was on "fast forward".
It is during this time, says Tremblay that environment plays a very important role in the extent to which physical aggression develops or is controlled.
Recent studies have shown that most children substantially increase the frequency of physical aggressions between nine months and the age of four, a time when they are exploring social interactions with their newly acquired skills in walking, talking, running, grasping, pushing, kicking and throwing.