Well-developed auditory, gross motor, and fine motor development in five-month-olds generally signifies intelligence.
In terms of hearing, they can initially distinguish the voices of their parents, can differentiate the voices of family members from those of strangers, and have responded to their own names.
In terms of gross motor development, infants can lift their heads, and some can roll over or sit for a while holding onto something.
In fine motor skills, infants can reach for objects and follow objects with their eyes.
There are individual differences among infants, and it is important not to expect every infant to behave in the same way. Some infants are not able to roll over well by 5 months of age, but this does not necessarily indicate that they are unintelligent. The development of each infant is not only related to his/her own condition, but also related to the training in the later stage of life.
If they do not meet the standard for a long time, in terms of movement, language or vision, you can go to the hospital for relevant examinations to see if there is a developmental delay.