Freud's Psychosexual Stages: Part 1

ORAL STAGE
During the oral stage, the infant’s primary source of interaction occurs through the mouth, so the rooting and sucking reflex is especially important. The mouth is vital for eating, and the infant derives pleasure from oral stimulation through gratifying activities such as tasting and sucking. Because the infant is entirely dependent upon caretakers (who are responsible for feeding the child), the infant also develops a sense of trust and comfort through this oral stimulation.