When you leave your baby and return, proving that you always come back, you're helping him develop trust and the ability to form attachments to other people. When you leave your baby, kiss and hug him and tell him you'll be back. If he's frightened or just falls apart, take the extra time to calm and reassure him. It's hard not to cry when he starts crying, but your breaking down only prolongs the agony. If your baby gets anxious about nighttime separations, spend some extra cuddle time reading, snuggling, and softly singing together with him before you put him to bed.
Every child is different, as is the amount of reassurance each needs.
The idea that you do something to an object is beginning to emerge, so an activity center with lots of things your baby can bang, poke, twist, squeeze, shake, drop, and open will fascinate him. Your baby now understands how objects relate to one another, too. For example, he realizes that smaller things fit inside bigger ones. He'll easily find something you hide, and he'll point or look at the correct picture when an object is named. Remember, each baby is unique and meets physical milestones at his or her own pace.