AN INVESTIGATION OF THE POSITIVE AND NEGATIVE EFFECTS OF FREQUENCY TRAJECTORY

Abstract

Age-dependent learning refers to the notion that earlier learnt items are processed faster than later learnt items. In the lexical acquisition domain, age-dependent learning was initially operationalised as age-of-acquisition (the age at which a word is first learnt). This changed when frequency trajectory (the distribution of a word across one's lifetime) was proposed to replace age-of-acquisition. However, studies showed that frequency trajectory effects do not always support age-dependent learning and may sometimes challenge it. The type of frequency trajectory effects observed is dependent on whether the link between the presented item and the subsequent given response is arbitrary (arbitrary mapping task) or systematic (non-arbitrary mapping task). The present research extends previous work by analysing the contrasting frequency trajectory effects in two empirical experiments via the megastudy approach. Results showed that frequency trajectory effects were congruent with age-dependent learning in the arbitrary mapping tasks but non-significant in the non-arbitrary mapping tasks. This suggests that frequency trajectory is only suited to test for age-dependent learning in arbitrary mapping tasks. On the other hand, to reconcile with the literature, lexical access was found to be an important variable in explaining the non-significant frequency trajectory effects in the non-arbitrary mapping tasks.