The phonological similarity effect in serial recognition

An experiment is reported examining the effect of consistent phonemic similarity among list items on memory retention in a task that is independent of overt speech production, the serial recognition task. Lists of consonant-vowel-consonant (CVC) words and nonwords were constructed such that although phoneme overlap was manipulated (i.e., shared vowel and final consonant [_VC], initial consonant and vowel [CV_], or the two consonants [C_C]), similarity remained constant. The results show that the influence of sub-syllabic mechanisms on STM performance is independent of speech production processes, and similarity in the pattern of results suggests that the same mechanisms subserve the recall of words and nonwords in STM. It is argued that the results are more consistent with psycholinguistic models than nonlinguistic models of STM, and implications for current STM models are discussed.     

The phonological similarity effect in serial recognition

An experiment is reported examining the effect of consistent phonemic similarity among list items on memory retention in a task that is independent of overt speech production, the serial recognition task. Lists of consonant-vowel-consonant (CVC) words and nonwords were constructed such that although phoneme overlap was manipulated (i.e., shared vowel and final consonant [_VC], initial consonant and vowel [CV_], or the two consonants [C_C]), similarity remained constant. The results show that the influence of sub-syllabic mechanisms on STM performance is independent of speech production processes, and similarity in the pattern of results suggests that the same mechanisms subserve the recall of words and nonwords in STM. It is argued that the results are more consistent with psycholinguistic models than nonlinguistic models of STM, and implications for current STM models are discussed.     

Modulating the phonological similarity effect: The contribution of interlist similarity and lexicality

The classical phonological similarity effect (PSE) was studied with words and nonwords in two immediate serial recall (ISR) tasks. The relative contributions of intralist and interlist interference were compared, and differential effects on item and order memory were observed. PSE occurred with words and was reversed with nonwords. In addition, PSE was modulated by interlist similarity, which enhanced recall of rhyme items and impaired recall of distinct items. Finally, interlist similarity reduced item recall of words, whereas it improved serial recall of nonwords. The latter finding rules out the hypothesis that the reverse PSE for nonwords is due to interlist interference. It is concluded that two opposing effects of phonological intralist similarity cause the interaction between PSE and lexicality in ISR. With words, the positive effect on item recall is usually masked by a much more disruptive effect on position accuracy. With nonwords, however, the positive effect often masks the negative one. These findings are discussed in relation to current models of verbal short-term memory.     

The Stroop effect in English-Japanese bilinguals: the effect of phonological similarity

English-Japanese bilinguals performed a Stroop color-word interference task with both English and Japanese stimuli and responded in both English and Japanese. The Japanese stimuli were either the traditional color terms (TCTs) written in Hiragana or loanwords (LWs) from English written in Katakana. Both within-language and between-language interference were found for all combinations of stimuli and responses. The between-language interference was larger for Katakana LWs (phonologically similar to English) than for Hiragana TCTs, especially with Japanese responses. The magnitude of this phonological effect increased with self-rated reading fluency in Japanese. Overall responding was slower and the Stroop effect larger with English than with Japanese stimuli. These results suggest that unintentional lexical access elicits automatic phonological processing even with intermediate-level reading proficiency.     

Overlap of phonetic features as a determinant of the between-stream phonological similarity effect

Serial recall from working memory is known to be impaired by the presence of irrelevant background speech, but several prior studies have concluded that the magnitude of the impairment is independent of the phonological relationship between to-be-remembered (TBR) and to-be-ignored (TBI) sources of information. In the present study, we examined the influence of between-stream phonological similarity in serial recall while attending to a heretofore uncontrolled variable, the phonetic feature. We found that TBI items sharing many phonetic features with TBR items produced significantly stronger working-memory impairments than TBI items with minimal phonetic feature overlap. In addition, participants were more likely to report remembering incorrect items that incorporated phonological characteristics of the TBI stream in the high-overlap condition. These findings provide evidence for subphonemic between-stream interactions and suggest that multiple parallel processes contribute to the irrelevant speech effect. We propose that a 2-component model, which combines the assumptions of process- and content-based accounts for the irrelevant speech effect, offers the best explanation for these findings.     

The phonological similarity effect in immediate recall: Positions of shared phonemes

Earlier literature proposes two ways phonological similarity could harm immediate recall: (1) It could increase the degradation of the representations of items in memory, or (2) it could decrease the probability that a degraded representation is correctly reconstructed. A multinomial processing tree model for each hypothesis was used to analyze an immediate recall experiment. Both gave a good account of the data, but, of the two, results favor the hypothesis that the effect of phonological similarity is to impair reconstruction of degraded representations. A second issue is whether positions of repeated phonemes in phonologically similar items matter. We found that mere repetition of phonemes produced a phonological similarity effect. Repeated phonemes in the same positions appeared to produce a greater effect. A final finding is that when reading rate was preequated, phonological similarity affected memory span by changing the time taken to recall a list of span length.     

A re-evaluation of the phonological similarity effect in adults' short-term memory of words and nonwords

The phonological similarity effect (PSE) was studied in two tasks of serial recall, in one task of serial recognition and one item identification task. PSE occurred only in the former three tasks involving memory of order when study items were words and nonwords with an associative connectedness to long-term memory. Nonwords that, according to a reaction time assessment of associative value, were less well connected to long-term memory mechanisms, were not sensitive to phonological similarity. These results are discussed in relation to contemporary models of short-term memory that explain the PSE as a result of confusions of items that are similarly encoded in a phonological layer. This layer is identified as a higher-level phonological space that is accessed by words and nonwords of high associative value and not by nonwords of low associative value.     

Reexamining the phonological similarity effect in immediate serial recall: The roles of type of similarity,category cuing,and item recall

Study of the phonological similarity effect (PSE) in immediate serial recall (ISR) has produced a conflicting body of results. Five experiments tested various theoretical ideas that together may help integrate these results. Experiments 1 and 2 tested alternative accounts that explain the effect of phonological similarity on item recall in terms of feature overlap, linguistic structure, or serial order. In each experiment, the participants' ISR was assessed for rhyming, alliterative, and similar nonrhyming/nonalliterative lists. The results were consistent with the predictions of the serial order account, with item recall being higher for rhyming than for alliterative lists and higher for alliterative than for similar nonrhyming/nonalliterative lists. Experiments 3 and 4 showed that these item recall differences are reduced when list items repeat across lists. Experiment 5 employed rhyming and dissimilar one-syllable and two-syllable lists to demonstrate that recall for similar (rhyming) lists can be better than that for dissimilar lists even in a typical ISR task in which words are used, providing a direct reversal of the classic PSE. These and other previously published results are interpreted and integrated within a proposed theoretical framework that offers an account of the PSE.     

Dissimilar items benefit from phonological similarity in serial recall

In short-term serial recall, similar sounding items are remembered less well than items that do not sound alike. This phonological similarity effect has been observed with lists composed only of similar items, and also with lists that mix together similar and dissimilar items. An additional consistent finding has been what the authors call dissimilar immunity, the finding that ordered recall of dissimilar items is the same whether these items occur in pure dissimilar or mixed lists. The authors present 3 experiments that disconfirm these previous findings by showing that dissimilar items on mixed lists are recalled better than their counterparts on pure lists if order errors are considered separately from intrusion errors (Experiment 1), or if intrusion errors are experimentally controlled (Experiments 2 and 3). The memory benefit for dissimilar items on mixed lists poses a challenge for current models of short-term serial recall.     

Phonological awareness and the use of phonological similarity in letter-sound learning

The effects of the phonological similarity between a letter sound and the sound in a spoken word, and phonological awareness on letter-sound learning were examined. Two groups of 41 kindergartners were taught four letter sounds. First, both groups had to learn the associations between four symbols and four familiar words. Next, both groups were taught the letter sounds that were paired to these same symbols. Each letter sound corresponded to the first sound of the word that was previously associated with that symbol in the phonological similarity group, whereas such a relation was absent in the other group. In addition, measures of vocabulary, letter knowledge, and phonological awareness were administered. Phonological similarity facilitated letter-sound learning. Individual differences in phonological awareness had a strong effect on letter-sound learning even after current letter knowledge was controlled. Unexpectedly, the effects of phonological awareness and the ability to use phonological similarity on letter-sound learning were found to be independent.     

Reduced phonological similarity effects in patients with damage to the cerebellum

Ten cerebellar patients were compared to 10 control subjects on a verbal working memory task in which the phonological similarity of the words to be remembered and their modality of presentation were manipulated. Cerebellar patients demonstrated a reduction of the phonological similarity effect relative to controls. Further, this reduction did not depend systematically upon the presentation modality. These results first document that qualitative differences in verbal working memory may be observed following cerebellar damage, indicating altered cognitive processing, even though behavioral output as measured by the digit span may be within normal limits. However, the results also present problems for the hypothesis that the cerebellar role is specifically associated with articulatory rehearsal as conceptualized in the Baddeley-Hitch model of working memory.     

The influence of phonological similarity neighborhoods on speech production

The influence of phonological similarity neighborhoods on the speed and accuracy of speech production was investigated with speech-error elicitation and picture-naming tasks. The results from 2 speech-error elicitation techniques-the spoonerisms of laboratory induced predisposition technique (B. J. Baars, 1992; B. J. Baars & M. T. Motley, 1974; M. T. Motley & B. J. Baars, 1976) and tongue twisters-showed that more errors were elicited for words with few similar sounding words (i.e., a sparse neighborhood) than for words with many similar sounding words (i.e., a dense neighborhood). The results from 3 picture-naming tasks showed that words with sparse neighborhoods were also named more slowly than words with dense neighborhoods. These findings demonstrate that multiple word forms are activated simultaneously and influence the speed and accuracy of speech production. The implications of these findings for current models of speech production are discussed.     

Effects of phonological similarity on priming in auditory lexical decision

Two auditory lexical decision experiments were conducted to determine whether facilitation can be obtained when a prime and a target share word-initial phonological information. Subjects responded “word” or “nonword” to monosyllabic words and nonwords controlled for frequency. Each target was preceded by the presentation of either a word or nonword prime that was identical to the target or shared three, two, or one phonemes from the beginning. The results showed that lexical decision times decreased when the prime and target were identical for both word and nonword targets. However, no facilitation was observed when the prime and target shared three, two, or one initial phonemes, These results were found when the interstimulus interval between the prime and target was 500 msec or 50 msec. In a second experiment, no differences were found between primes and targets that shared three, one, or zero phonemes, although facilitation was observed for identical prime-target pairs. The results are compared to recent findings obtained using a perceptual identification paradigm. Taken together, the findings suggest several important differences in the way lexical decision and perceptual identification tasks tap into the information-processing system during auditory word recognition.     

Irrelevant speech,articulatory suppression,and phonological similarity: A test of the phonological loop model and the feature model

Two experiments tested competing predictions about the nature of the irrelevant speech effect that were derived from Neath's (2000) feature model and from Salamé and Baddeley's (1982) phonological loop model. The first experiment examined the combined effects of irrelevant speech and articulatory suppression when target items were presented auditorily. Contrary to the suggestions of Neath, but consistent with the phonological loop model, the effects of articulatory suppression and irrelevant speech were additive even when the irrelevant speech was presented during the retention interval The second experiment examined the combined effects of irrelevant speech and phonological similarity when target items were presented visually. Consistent with the phonological loop model, the effects of phonological similarity and irrelevant speech were additive when participants were specifically instructed to use articulatory/phonological rehearsal to remember the list items. The results therefore contradicted Neath's claim that irrelevant speech abolishes the phonological similarity effect when list items are presented visually. However, the effect of phonological similarity was abolished in the irrelevant speech conditions when no instructions were given concerning rehearsal. It is argued that the phonological similarity effect disappears in some experiments because participants sometimes employ a semantic rehearsal strategy, consistent with the views of Salamé and Baddeley (1986).     

The phonological loop model of working memory: An ERP study of irrelevant speech and phonological similarity effects

The phonological loop model for retention of auditory verbal material in working memory, developed by Baddeley, assumes that irrelevant speech and phonological similarity influence only one and the same element of the system—that is, the phonological short-term store. We tested this idea by recording eventrelated potentials (ERPs) to auditorily presented letters that were phonologically similar or dissimilar and were to be memorized in the presence of more or less disturbing irrelevant speech. Irrelevant speech and phonological similarity caused ERP effects with clearly different scalp topographies, indicating that these factors influence different brain systems and hence probably different cognitive elements. Moreover, ERPs indicated that the phonological similarity effect might involve processes at the level of phonological analysis. Our data also support recent suggestions that the irrelevant speech effect is not based on the phonological similarity between relevant and irrelevant material, but on the phonological variability within the irrelevant stream.     

The word-superiority effect and phonological recoding

Previous work indicates that the locus of the word-superiority effect in letter detection is nonvisual and that letter names, but not letter shapes, are more accessible in words than in nonwords, that is, scrambled collections of letters (e.g., Krueger & Shapiro, 1979; Krueger & Stadtlander, 1991; Massaro, 1979). The nonvisual (verbal or lexical) coding may be phonological, or it may be more abstract. In the present study, a word advantage in the speed of letter detection was found even when the target letter was silent in the six-letter test word (e.g., s in island). Other test words varied in their frequency of occurrence in English and number of syllables (1, 2, or 3). The word advantage was larger for higher frequency words but was not affected by syllable length. The presence of unpronounceable nonwords and silent letters in the words discouraged reliance upon the phonological code but did not thereby eliminate the word advantage. Thus, the word-superiority effect with free viewing is not based entirely upon phonological recoding.     

Recalling pictures and words: Reversing the generation effect

Blind and sighted children’s memory for words and raised shape pictures was tested. The investigation compared performance with items when they were studied under neutral conditions (naming words and pictures) and when they were self-generated in response to cues (cue: hot ?: response: cold). The blind children could identify and name the raised shape pictures with the same apparent ease as blind-folded sighted children (as long as a cue was provided). The sighted children showed the generation effect (Slamecka and Graf, 1978) for both words and pictures, namely that self-generated items were far better recalled than neutral ones. The pattern of results for the blind children was markedly different. Although the level of memory performance overall was the same as that of the sighted controls, the congenitally blind children showed areverse generation effect. A stem completion study indicated that these results couldnot be accounted for by a relatively greater reliance on data-driven processing by the blind.     

The acoustic similarity effect

The latency of reading 5-word sequences of 3 levels of acoustic similarity was measured. Highly similar sequences were found to have longer latencies than sequences of low similarity or control sequences. The implications of this finding for the acoustic similarity effect in STM are discussed.