Birth to Six Months
Physical Development - At birth, infants cannot control their body movements. Most of their movements are reflexes as their nervous system is not fully developed. During the first months, infants can clearly see objects that are about 10 inches away from their faces.
Social and Emotional Development - Infants begin to develop trust as their parents readily attentive to changing their diapers when needed, feeding them when they are hungry, holding them when they cry, etc. When frightened, infants cry, may look surprised and/or afraid. They also cry to express anger, pain and hunger as it is their way of communicating. With infants being so easily excited or upset, they need to be cradled and comforted. There is NO SUCH THING as a "spoiled" infant. What society has deemed as spoiling is actually the way in which infants learn to cope early on in life. It can be a positive or negative experience - but it is an experience nonetheless.
Intellectual Development - Infants babble, coo and gurgle. They study their hands and feet as well as will turn to locate the source of sounds. Infants begin tracking at an early age - which is focusing and/or follow moving objects with their eyes. The 5 senses are developing and with that, infants will constantly explore things with their mouths.
https://extension.illinois.edu/babysitting/age-infant.cfm