According to a competing hypothesis, words such as DECIDE and DECISION are learned, and produced as independent units. Under this Independent Unit Hypothesis (IH), speakers produce DECISION by direct read out from the internal lexicon, without applying derivational rules to DECIDE. Under IH, the fact that we so readily retrieve realated words such as DECIDE-DECISION suggests the possibility of associative connections between these otherwise independent word units.
- MacKay (2004), a pag.72