Abnormal behaviour

Some babies may do it cz they just discovered tt they can do it and will keep repeating it. My nephew did tt ard 8 mths, my sis went PD to check but he's alright. He gradually stopped doing it aft a week. PD said to just monitor his food/milk intake if there's any change and if there's any body jerks accompanying those eye rolls which may indicate infantile spasms. If not, it's just developmental. But visit ur PD just to have a peace of mind.