The term anal retentive, commonly abbreviated to anal, is used to describe a person who pays such attention to detail that the obsession becomes an annoyance to others, potentially to the detriment of the anal retentive person. The term derives from Freudian psychoanalysis. In Freudian psychology, the anal stage is said to follow the oral stage of infant or early-childhood development. This is a time when an infant's attention moves from oral stimulation to anal stimulation (usually the bowels but occasionally the bladder), usually synchronous with learning to control his or her excretory functions — in other words, toilet training. Freud theorized that children who experience conflicts during this period of time may develop "anal" personality traits, namely those associated with a child's efforts at excretory control: orderliness, stubbornness, a compulsion for control. If these qualities continue into later life, the person is said to be "anal retentive". Conversely, those who reject anal retentive characteristics are said to have "anal expulsive" personality types. Although Freud's theories on early childhood have been influential on the psychological community and the term anal retentive survives in common usage, the concept is largely regarded as unscientific "pop-psychology" and therefore discredited by the majority of psychologists of the late 20th and early 21st centuries. Research suggests that the overall pattern of parental attitudes has a much more concrete effect on how an infant will grow up. There is no conclusive research linking anal stage conflicts with "anal" personality types.