The relation between discriminability and memory for vowels, consonants, and silent-center vowels

Abstract

People remember lists of vowel-contrasting syllables better than lists that vary only in stop consonant identity. Most views suggest that this difference is due to the structure of immediate memory and the greater discriminability of vowels compared with consonants. In all of these views, there is a presumed systematic relationship between discriminability and recall so that the more discriminable an item, the better that item should be recalled. The 11 experiments reported here measured the relative discriminability of and compared serial recall for (1) intact syllables that varied only in the medial vowel, (2) intact syllables that varied only in the initial consonant, and (3) syllables with the center vowel replaced by silence (so-called silent-center vowels). Whenitem discriminability, as measured by identification, was equated for consonant-contrasting and silent-center lists, serial recall performance was also equal. However, even when the vowels were less discriminable than the consonants or silentcenter vowels, serial recall performance for the vowels.was still better. These results are problematic for theories based on acoustic discriminability but can be explained parsimoniously by Nairne's (1990) feature model.Theories detailing how people briefly retain the auditory characteristics of sound have been deeply influenced by research on memory for vowels and consonants. A number ofdifferent paradigms, including categorical perception, imagery, and serial list recall, have all demonstrated impoverished performance for stop consonants compared to that for vowels (see Surprenant, 1992, for a review). Most of the explanations of these results rely on an interaction between the structure of immediate memory and the relative discriminability of the items in the stimulus set.Several experiments have revealed differences in memory for vowels and stop consonants with a serial list recall task. In this paradigm, subjects are asked to recall a list of items in the order in which they were presented. When auditory-or vocalized-presentation is used, people generally recall the first few items well (the primacy effect) and the last few items well (the recency effect) relative to the middle items (Crowder, 1976). When visual presentation is used, there is no recency effect (LeCompte, 1992),and this difference between auditory and visual presentation is known as the modality effect (see Penney, 1989, for a review). When the to-be-remembered items are syllables that differ only in the vowel sounds, there is a particularly large and robust recency effect compared with when the Some of this research was supported by an NIDCD Individual National Research Service Award to A.M.S., and portions of these data were presented at the 35th Annual Meeting of the Psychonomic Society, St. Louis, November 1994. We thank J. S. Nairne for comments on an earlier version of this manuscript. Correspondence should be addressed to A. M. Surprenant, 1364 Psychological Sciences Building, Purdue University, West Lafayette, IN 47907-1364 (e-mail:...

Effects of Lexical Competition on Immediate Memory Span for Spoken Words

“…For both experiments, one-way within-subjects ANOVAs performed separately for the "easy" and "hard" word sets revealed no significant differences among the recall probabilities of each of the "easy" and "hard" words, all Fs < 1. This result demonstrates that there is no compelling evidence to suggest that recall rates are associated with the number of words sharing the same vowel.One difference between the present study and previous studies showing differential recall rates for vowels and consonants (e.g., Darwin & Baddeley, 1974;Surprenant & Neath, 1996) is that the previous studies used mostly nonsense syllables or a mixture of word and nonwords, whereas the present study used only real words. It is entirely possible that when nonword stimuli are used, sublexical properties such as phonotactics and consonant and vowel features are more salient and are recruited in redintegration and recall (for a detailed discussion of sublexical and lexical influences, see Gathercole et al, 1999;Vitevitch & Luce, 1998).…”

Advantages and disadvantages of phonological similarity in serial recall and serial recognition of nonwords

“…Consonant frame lists had better item recall scores and position accuracy than did rhyme lists. It seems as if vowel variation causes greater distinctiveness than consonant variation does (see Surprenant & Neath, 1996), but it is not entirely clear why this is so. In any case, vowel variation is associated with higher position accuracy than consonant variation is.…”

“…These investigators focused on vowel and consonant sounds in relation to such specific effects as recency effects, suffix effects, and modality effects, as well as the relative discriminability of the two speech categories. The differences between vowel and consonant sounds with respect to categorical perception were discussed by Pisoni (1973), whereas Surprenant and Neath (1996) discussed the relation between discriminabilityand memory of speech sounds.…”

“…But the fact that there are more consonants than vowels in most languages cannot explain why the serial position of items with differing vowels is recalled more accurately than is the serial position of items with differing consonants. Surprenant and Neath (1996) made use of a serial reconstruction task and found that memory performance for vowel-contrasting syllables was better than that for consonant-contrasting syllables, even when vowels were made less discriminable than consonants were. This result agrees with the present finding that positionaccuracy of vowels is better than position accuracy of consonants.…”

“…If there were an inverse relationship between position accuracy and the number of shared phonemes, one would expect no difference between the position accuracies of rhyme and consonant frame lists. Surprenant and Neath (1996) found that serial recall performance for vowel-contrasting lists (consonant frame trigrams), as measured by the correct-in-positionscore, was better than recall performance for consonant-contrasting lists (rhyme trigrams). However, a strict examination of their procedures shows that they did not run a serial recall experiment; rather, they inferred recall on the basis of data from a serial reconstruction task, and they did not compute a position accuracy score for these lists.…”