One-year-olds don't grasp the concept of "good" versus "bad" behavior. You'll have more luck conveying right and wrong by the tone of your voice -- and by setting achievable limits.
"Bad" and "Good" Behavior, p.1
From time to time, you will hear people saying to their children (and perhaps even to yours), "Be a good girl" or "Good boys don't do that." It is important to understand, however, that being good doesn't mean very much to a 1-year-old. Right and wrong are abstract concepts that a child this age isn't ready to grasp. And the individual behaviors that fall under these headings are too many and too varied for him to remember.
The 1-year-old who grins as he drops Cheerios off his highchair tray, or who runs from you, naked and shrieking with glee, as you try to dress him after his evening bath, or who pulls the cat's tail until the poor creature runs and hides under your bed is not being bad. His love of and delight in experimenting with the world, his joy in being free of clothing and capturing your undivided attention, and his inability to take the cat's point of view are behind these mischievous behaviors.
"Bad" and "Good" Behavior, p.2
To classify them as naughty or bad is to misunderstand your child's view of the world. Furthermore, such a response does nothing to clarify to your child that it's the behavior, and not something fundamental about the child herself, that has displeased you. This is not to say that your child's mental health depends on your giving up clean floors and neat clothes or condemning the cat to a life of torment. Far from it -- this is the time to begin to set limits for your child and to arrange her world so that the limits can be met. It is far better to explain to her, "I don't like that behavior" or "I don't like it when you pull the cat's tail" than to declare, "You are a bad girl when you do that." Although your child may not, at this young age, completely understand what you are saying to her, the tone of your voice will have an impact, and in the meantime, you'll be helping her to learn language.
Give your child a head start on desirable behavior by structuring his world in ways that help him to meet your expectations. For example, it's smarter to pack away your prized collection of Victorian teacups than to leave them within his reach and hover over him, or to discipline him later for their inevitable destruction. For motor and intellectual development, it's important that curious and fast-moving 1-year-olds intent on exploration be able to move about relatively freely in their own homes. You should take steps to ensure the safety of both your child and your most treasured possessions as soon as your little one begins to crawl about the house. By the time he's walking, you should have all breakables well out of your child's reach, sharp corners padded, electric outlets plugged, poisons locked up, and stairs securely gated off.
All content here, including advice from doctors and other health professionals, should be considered as opinion only. Always seek the direct advice of your own doctor in connection with any questions or issues you may have regarding your own health or the health of others.