When an infant is capable of sitting and is hungry (hunger motive is yellow), there is a high chair available, and you click on the infant and choose Get Fed By..., the chosen caretaker sim will choose a baby food to explore at random, and may choose a baby food that is known to be disliked by the infant. This results in a mess on the floor, an unsuccessful feeding (infant still hungry), and the infant getting the Betrayed angry moodlet. I have never seen the infant being given finger food autonomously, nor a never tried baby food (though the latter may be because I have generally already explored most if not all baby foods.)
Version 1.116.202.1030
