Abstract
Background and Objectives: Many studies have been done to understand the nature and mechanisms of verbal short term memory. These studies have led to linguistic and non-linguistic approaches to it. Phonological similarity effect as an important finding of these studies increased the conflict between both approaches. Regarding differences between languages, cross- language investigations may be helpful. The aim of this study is to investigate the effect of phonological similarity on span of verbal short term memory in Persian language.
Material and Methods: In this descriptive analytic study, 16 graduate and postgraduate students (mean age 20 years, SD= 2.03) participated (4 males, remaining females). All participants were native Persian (monolingual) without any speech or hearing disorders. Stimuli were 450 words categorized in 3 different lists, namely rhyming words list, alliterative words list and dissimilar words list. Each list consisted of twenty five 6-words sequences (150 words in each list). Stimuli were presented via a speaker. There was a 1 second interval between words in each sequence. Three seconds after presenting each sequence a signal was heard as a sign to start the recall.
Results: A one-way ANOVA test showed significant difference between rhyming, alliterative and dissimilar words (p= 0.000).Post hoc Tukey test showed significant difference between rhyming list and dissimilar list (0.000). Also a significant difference was shown between alliterative and dissimilar list (0.006). There was no difference between rhyming and alliterative lists.
Conclusion: These data suggests that in rhyming and alliterative words, vowel, because of higher sonority (rather than other phonemes) enhances the memory span as a cueing feature. Cross-language differences, especially in phonemes sonority level may cause different phonological similarity effects among languages. Since verbal short term memory is sensitive to vowel in words, it seems that the verbal short term memory has a linguistic nature.