Between three and 12 months, a baby undergoes a period of rapid development that coincides with her fast growing brain. Researchers believe baby’s brains aren’t just adult brains in miniature: as well as being smaller they lack all kinds of connections between areas of the brain. Making these connections is the key to development of a baby’s physical, intellectual, emotional and social functions.

Not all areas of the brain develop at the same time and different babies develop at different rates. This means that particular behaviours appear in different babies at different times.
Between 2-6 months, a baby’s eyesight improves enormously. She begins to connect what she sees with what she hears, tastes and feels. Understanding your baby and what on earth she wants is a big job and it is quite normal for parents to experience some pretty exhausting emotions during this time.
Between 6-9 months, your baby is developing ideas about who she is and working out the difference between parents, caregivers, strangers, adults and children. She has positive and negative emotions and is beginning to express them. She can tell you when she wants help.
She’s getting more attached to people she spends most time with, and her memory is getting better and better, so she may protest when separated from familiar caregivers and be wary of unfamiliar humans. This is called separation anxiety. See more about separation anxiety.
Taste becomes the next best thing (after seeing) to work out what something is about.
You may be getting to know your baby’s personality and temperament, including when and how she tries to communicate. You might also be coming to grips with adapting things such as bath or bed time in her routine.
Between 9-12 months, your baby will be getting ready to crawl and walk. She will deliberately use her hands to pick up things and drop them. She can work out what is upside down and what is the right way around. During this time she may hang off your leg to steady herself. She will begin to understand simple expressions such as ‘Where is the dog?’, ‘Pass it to me’ and ‘How did that fit in your nose?’
You’ll be spending more and more time on activities to help your baby comprehend and communicate. Everyday moments like changing nappies, feeding and bath time can still form some of the most important times for you to talk, play and get to know each other. Whether you’re singing a song or talking about what’s for dinner tonight, the way you interact during these times helps baby learn and develop and helps your relationship grow. Understanding your child’s needs and responding appropriately are the keys to developing a good relationship with your child.
Babies develop at different rates. Child development experts expect skills and abilities to appear in an overall time frame, rather than at specific ages. Some skills do not appear until later in infancy or during childhood. If you are concerned about your child’s development, seek advice from a health professional.
Bornstein, M.H. (2002). Parenting infants. In M.H. Bornstein (ed), The handbook of parenting, vol 1, 3-44. NJ: Lawrence Erlbaum.