As your little one reaches the age of 4-5 months, his sensory development would be quite significant. Your toddler will now blink in response to changes around him. You can swap objects or places so as to test your baby's responses.
What you need to know You shouldn't push your baby when it comes to learning visual skills. It is with age that such growth traits will surge in your toddler. You can use toys and swinging objects to check your baby's blinking responses.