SARAH KENNEDY'S bestselling compilation of true stories, The Terrible Twos, shows the devastating candour of this age group.

"While working as a midwife delivered a baby in the morning at the mother's home and returned later for the evening visit," the passage goes. I was greeted at the door by the two year old, who said. Have you come to take it back again? We've had it all day."

According to Sheila Porter, senior clinical psychologist at the Lucena Clinic in Tallaght, Dublin, two year olds are at a wonderful age. They have so much to discover and they're very energetic. They delight in language and mastering words saying a nursery rhyme with their mother or father can be a real thrill.

Getting through to them does, however, require some thought. General commands like "tidy up" are too complicated for this age group, Porter says. Parents need to breakdown these general messages into more specific instructions.

Porter observes that many attractive toys for two year olds involve "sorting", because the children are at that stage of development so she advises would be persuasive parents to say something like "Now we need to tidy up. You pick up the red bricks and I'll pick up the jigsaw pieces."

Two year olds crave attention. If by behaving naughtily they get more attention, their poor behaviour becomes reinforced, Porter says. Instead, parents should reward good behaviour with attention. However, she stresses, parents must not ignore poor behaviour if the child's actions are a danger to him or herself or if other people or property are at risk.

She also suggests that parents "de-personalise" the rules. For instance, when intervening to stop a child from throwing stones, she advises parents to say something like "throwing stones is not allowed" rather than "you are not allowed to throw stones".

When the child is behaving well, she recommends, parents should set up a "time out" arrangement. This could involve a chair facing the corner, or an adjacent safe hallway. Explain that poor behaviour will result in having to sit on that chair or go out to the hall for between two and five minutes.

If the hall is chosen, it must be "safe but boring". There's little point in rewarding poor behaviour by letting them play with toys out there.

She calls this a strong form of ignoring, and suggests that parents enjoy this time with any other children so the erring child knows he or she is excluded. It should be time limited two minutes could be along enough. Sanctions should never be dependent on the child saying "sorry", she says, because that can needlessly lead to a stand off situation.

Tantrums in supermarkets can be among of the hardest things for parents to handle. As Porter says, parents invariably feel "somebody in the crowd is disapproving of whatever you do".

One piece of advice she offers parents is never to buy sweets for toys in front of the child, so he or she never associates what is seen with the chance of its purchase.

THE TWO YEAR OLD'S fondness for using that word "No" can hardly be overstated.

While this can drive parents to distraction, Porter sees toddlers' fascination with it as a good thing. "It shows that the child is beginning to have a sense of himself or herself as a separate being. Before their propensity for saying `No' develops, children aren't too sure who is doing what. Their growing capacity to say `No' allows them to experience a choice without necessarily getting into conflict.

"The child develops a sense of who is deciding and gains a sense of power over himself or herself."

Porter believes it's important for children to experience decision making, "but not to have control over his or her parent".

To avoid having to hold the line too often, she suggests parents look at how they're imposing the rules. She endorses the so called "grandmother's rule" of contingency behaviour that's where parents explain that when the child does X it will lead to Y. Two year olds can cope with cause and effect logic, and it gives them a certain control over themselves and their environment.