Most people recognized the amazing physical growth that the baby will have in the first year but they forget about the mental growth that takes place.  I believe the reason for this is because the baby starts out really doing nothing and the things he or she is able to do seems minute compared to what we have accomplished since the time we can remember.

However, the physical growth talked about in the Physical Development the first year article has to take place simultaneous with the mental growth that we are talking about in this article.  Some physical growth is innate.  Some mental growth is innate.  But they are both interdependent on each other.  The first article I wrote in this series, Baby Development of Trust, is the social factor which is important for reinforcing and interacting with both the physical and mental development.

Mental Development at 4 Months

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As much as parents do not like to see it, developmental psychologist loves it when the baby is starting to put things in their month.  This is called “mouthing” and it is very important step in the developmental milestones. 

My wife gets on to me when I am playing with my fingers, hands and toes, but if I was a baby, this would be exactly what she would want to see.  A baby that is playing with these body parts is becoming aware of their “space” within the universe.  They are starting to realize that the mind and the body are two separate things and these two things are interacting together to produce a desired result.  Yes, it is only playing with the toes, but to a baby it is like exploring a new planet.  Who knows what you will find there.

Babies this age will start to turn their heads toward colors, brighter lights, and sounds.  This is an ability that is required for survival.  Being able to see, hear, touch, smell, or taste danger can keep us alive once we learn and have the abilities to react. 

Parents report they can tell the difference between the cries of the infant for hunger, pain, or diaper change.  How do you think they can do that?  Well, it takes practice, but it also takes the baby being able to change the sounds they make to send that message.  Communication is a two way street even for an infant. 

Babies will come to love to be hugged, kissed, and held tightly.  This is satisfying to the adult because they want to take care of the baby, but not only is it satisfying to the baby, it is necessary for developing the Trust that Erik Erickson talks about in his psychosocial development stages.

Babies will start to babble and coo.  They will also start to return a smile that is actually a smile and not just gas.  This is the forming of expressive communication for the baby.  Parents love to hear the first word, but his is the precursor to that first word. 

Mental Development at 8 Months

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The baby has already mastered the crying for pain, hunger, and changing, but about this time, they will also add in the crying for attention.  They will cry when they get lonely or just want the parent to interact with them. If the parent responds, Trust in the parent and eventually others will be established.  If no response, the child will not develop and may be in time cold and harsh themselves. 

Communication through crying is getting better, but the baby learns a new form of communication around this time as well, the ability to communicate displeasure.  They may shake their head or make a sound to indicate they want something to stop or not to happen.  “No” could be their first word. 

As stated before communication is a two way street.  The baby has also learned to distinguish the voices of the important people around them and will start to search for that voice.  The parent can be in a different room and be talking and the child may be comforted by that voice. 

Babies at this age will learn that when things are out of sight, they are not out of mind.  They will look for a car or a ball that has rolled under a table or a chair.  To help with this they have been able to focus on small objects and will reach for them when it is placed near them.  They will also continue to reach for objects as they are pulled away.

I always tell the parents when I am testing a child; we are going to look to see if we have a future drummer here.  Children may get on their parents nerves taking a spoon and banging on a pan, but this is quite normal development and something we need to see happening. 

Babies will learn their names around this time.  They will respond either by looking or by smiling.  This is not just responding to the caregiver’s voice, as they should have already mastered that by this time, but they are responding specifically to their name. 

About this time, but sometimes a little later, the child will develop stranger anxiety.  This is quite normal.  They child used to go to anyone, including grandparents, but when stranger anxiety comes into play, they generally want to stay with the primary caregiver.  This hurts other people’s feelings, thinking the baby has become scared of them, but it is very normal.

Mental Development at 12 Months

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By this time, the baby should have already learned their first word or words.  Usually this is “mommy” or “daddy” or even “no.”  These are the words they have been hearing a lot.  Parents talk about themselves in reference to the role of mommy or daddy.  The baby might not fully understand who mommy and daddy are yet, but they know when they say those words, it cause some actions to happen.  They have probably heard “No” quite a bit since they started to be able to get around and get into things.  They know this is a negative word that is sometimes followed by punishment, so when they are unhappy, they will want to “punish” the parent and will say “no.”

They are starting to pay attention to conversation, but only for the words, but not the message right now.  However, they are learning that some words illicit different responses and will use them.  Prime example is the “No” word again. 

Babies may start to bounce and “dance” to music or even to sounds.  They may even do it to a rhythm they have in their heads.  I think we, adults still do this.  I know when I hear a good song; I might start tapping my foot.

Babies become interested in pictures.  You need to be reading to your baby.  They will take notice of pictures in the book.  The quality time you spend reading to and with your baby is one of the greatest things you can do to promote a love of reading.  Research has proven that a child that loves to read will enjoy and be more successful in school.

One last thing has more to do with learning, but babies at this age love to put things into other things.  Buy the toys will lets the child display this new found talent and enjoyment.  I believe they learn visual-spatial techniques and they learn to enjoy doing things with their hands. 


The mental development is sometimes overlooked and put on a back burner because of the great strides in physical development.  However, a parent’s role in allowing and encouraging the baby to developmental mentally will be the difference between Trust and Mistrust. 

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What to Expect the First Year, Second Edition
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