The keys are in the ignition. The gearshifts are in drive. But babies still need to develop their motor skills before they can run on all four cylinders.
In the first three months of life, babies' actions are driven by reflex reactions to their environment. From 4 to 7 months, babies begin to choose their actions, according to the <a href="[BASEDOMAIN]/healthinfo/bouncelink.aspx?shortcut=aap" target="_blank">American Academy of Pediatrics</a>. 
Movin' on up 
During this time, babies will be working toward a major accomplishment: sitting up. They will start by lifting their heads when placed on their stomachs. You can encourage this by placing them on their stomach and extending their arms forward, then holding a rattle or other toy out in front of them while coaxing them to look. 
Sitting on top of the world 
Once they have mastered raising themselves up on their arms, you can help babies develop their balance by propping them up on pillows or a couch corner. Encourage them to lean forward while extending their arms to balance. Placing favorite toys just in front of them will help them focus as they learn to balance. 
Rock 'n' roll 
At 5 months, you may notice that when babies are on their stomachs, they start to push up with their arms, rock on their stomachs or kick with their legs. These skills will help them learn to roll over, another accomplishment of this period. 
Vision update
Babies generally have good color vision around 5 months. They are also seeing in three dimensions and developing depth perception.
Born to babble 
Babies begin to babble more frequently, using many of the rhythms and intonations of their native language. Encourage their speech by talking to them throughout the day. When they repeat a syllable like "bah" over and over, reinforce the sound by introducing words that start with it like "box" or "bottle." 
The social butterfly 
Babies are often very social during this time, showing off, smiling and playing with other people they meet. You will begin to see their unique character traits emerge. 
Play away 
As babies interact with their environment they grow interested in more complex objects. Appropriate toys for babies at this age are: 
<ul>
 <li>An unbreakable mirror attached to a crib or playpen. </li>
 <li>Soft balls or textured toys that make sounds. </li>
 <li>Musical toys such as bells and maracas with no loose parts. </li>
 <li>See-through rattles that show the pieces making the noise. </li>
 <li>Cloth and board books. </li>
</ul>
Reviewed 11/2/2023

Babies from 4 to 7 months

Babies' motor skills and personalities emerge at this age, bringing a new set of abilities.