Memory for speech and speech for memory.

MEMORY FOR SPEECH AND SPEECH FOR MEMORY JOHN L. LOCKE

Yale University, New Haven, Connecticut KATHRYN J. KUTZ

Children's Research Center, Champaign, Illinois Thirty kindergarteners, 15 who substituted/w/for/r/ and 15 with correct articulation, received two perception tests and a memory test that included /w/ and /r/ in minimally contrastive syllables. Although both groups had nearly perfect perception of the experimenter's productions of /w/ and /r/, misarticulating subiects perceived their own tape-recorded w/r productions as/w/. In the memory task these same misarticulating subjects committed significantly more/w/-/r/confusions in unspoken recall. The discussion considers why people subvocally rehearse; a developmental ~.eriod in which children do not rehearse; ways subvocalization may aid recall, including motor and acoustic encoding; an echoic store that provides additional recall support if subjects rehearse vocally, and perception of self- and otherproduced phonemes by misarticulating children-including its relevance to a motor theory of perception. Evidence is presented that speech for memory can be sufficiently impaired to cause memory disorder. Conceptions that restrict speech disorder to an impairment of communication are challenged. The learning of speech requires that one be able to remember phonetic information long enough to use it in reproducing speech. It is not clear, though, whether the memory subsystem necessary for speech learning can be deficient enough to account for articulatory disorders. In question is auditory memory, which is used to hold short stretches of connected speech briefly. Assuming that item and time demands are relatively low, why do some memory studies (see review in Winitz, 1969, pp. 178-180) show reduced short-term recall on the part of misarticulating children? This paper examines the prospect that misarticulated speech may indirectly cause poor memory. While speech learning requires memory, memory also often depends on speech. Speech serves memory, in part, when the memorizer generates or reproduces stimulus names in subvocal articulation (Murray, 1967; Locke, 1970; Locke and Fehr, 1970a; Glassman, 1972). Evidence for the use of speech in memorizing is diverse. Subjects may be seen mouthing speech silently (Flaveil, Beach, and Chinsky, 1966; Kenney, Cannizzo, and Flavell, 1967); subvocal speech may be heard as whispering or vocal speech and, therefore, is not literally below the voice (Murray and Roberts, 1968); where speech rehearsal is not apparent to the unaided senses of an observer, it still may be 176

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identified via electromyography (Locke and Fehr, 1970a, b), skin conductance, and digital vasoconstriction (Wozniak, 1973) or subject report (Sperling and Speelman, 1970). One can also infer the existence of speech recording, which may or may not be roughly equivalent to speech rehearsal, from analyses of short-term forgetting ( Conrad, 1962). Spontaneous speech rehearsal often enhances memory performance and produces identifiable phonetic effects in recall. Evidence that subvocal rehearsal facilitates recall comes from studies of children who do and do not spontaneously rehearse (Keeney et al., 1967; Daehler, Horowitz, Wynns, and Flavell, 1969), experiments in which subjects are instructed to rehearse quietly or aloud (Murray, 1966), and tasks in which subjects' natural inclination to rehearse is tolerated, blocked, or disrupted (Barlow, 1928; Underwood, 1964; Murray, 1968). In all cases spontaneous or instructed rehearsal is associated with greater recall than is reduced rehearsal. These recall advantages typically obtain for the first few list positions in serial recall (Rundus, 1971; Meunier, Stanners, and Meunier, 1971), the well-known primacy effect. The phonetic effects of speech rehearsal can be observed in subjects' recall of stimuli whose phonetic forms are similar or different (Conrad, 1971; Locke, 1971; Locke, 1973). For example, if subjects are asked to learn lists of rhyming letters, words, or pictures, their recall of them will differ from their recall of similar lists of items whose names do not rhyme (Conrad, 1972b). Generally, free recall of homophonous items is better and ordered recall worse than the free and serial recall of nonhomophonous items (Conrad, 1971; Locke, 1971). But this occurs only for people whose mental age is or exceeds about five years, which is approximately when subvocal rehearsal first is observed (Conrad, 1971; Locke, 1973). That language mediation is a general phenomenon is apparent from deaf children's recall of letters they have rehearsed dactylically. Here there is a tendency for letters that would feel alike to the hand of a finger spelling rehearser to be recalled better than letters whose dactylic representations are not kinesthetically similar (Locke and Locke, 1971). The deaf demonstrate dramatically that underdeveloped speech is associated with a short-term forgetting quite unlike that of speech-sophisticated hearing persons. As a population, deaf children (Conrad and Rush, 1965) and adults (Conrad, 1973) can be distinguished from the hearing on the basis of memory test results alone. If recall is bolstered by subvocal rehearsal, it should be impaired if rehearsal opportunity is taken away. In fact one of the several paradigms through which rehearsaI's value was discovered involved precisely this restriction (Cole, Sales, and Haber, 1969). Of course there are other strategies by which people attempt to recall verbal items, and there are various stimuli which, by their nature elude verbal rehearsal. But a spontaneously rehearsing subject, if denied his preferred strategy, is likely to experience reduced recall (a conclusion tempered by the fact that any restriction may reduce recall). More broadly, it is known that recall suffers when the subject (1) cannot or LOCKE, KUTZ: Memory [or Speech 177


does not subvocally repeat stimulus names (Keeney et al., 1967; Cole et al., 1969), (2) is in doubt about which subvocal responses best fit the stimuli or has difficulty in executing appropriate subvocal responses (Blanton and Odom, 1968; Meunier et al., 1971), or (3) makes subvocal responses but cannot recover the original stimuli from them, presumably because his responses are insufficiently distinctive (Conrad, 1972a). One would think, from this list of particulars, that the pioneering work on speech-disordered children has already been done, but these observations were made on normal-speaking adults under contrived experimental conditions. It is conceivable that these types of rehearsal failure could occur in misarticulating children whose subvocal speech would be constrained by the same factors that disturb their intelligibility and speaking ease (that is, there is no obvious reason why subvocal speech should be more precise and dependable than vocal speech). Rehearsal failure has been linked to two specific memory phenomena: (1) a "release" from the usual primacy effect and (2) phonetic mediation patterns that drift toward the learner's speech rehearsal capabilities. This paper reports an experiment, which shows that children who speak with a phonemic substitution display at least the latter characteristic. We will argue from these data that in some children disordered articulation may present a cognitive as well as a communicative problem because it can cause, via disordered rehearsal or recoding, reduced recall from short-term memory. METHODS

Subiects The subjects were 30 kindergarteners seen either in a mobile laboratory or quiet school room. The experimental group of eight males and seven females had a mean age of 5.7 years (range: 5.3-5.10). Each of these children substituted /w/ for /r/ but had perfect perception of these two phonemes according to task procedures to be reported. A group of 15 children who correctly spoke and perceived/w/ a n d / r / were matched for sex and age (-+- 1 month). No speakers of the so-called bilabial /r/ were permitted to serve in either group. All children served voluntarily and without formal reward in three sessions. Since this experiment sought to examine recall confusions, it was especially important at the outset to ensure veridicaI perception. It also was minimally requisite that experimental subjects' production of ring in rehearsal be functionally identical to their production of wing. Otherwise, disturbed production would not inevitably yield disturbed recall; a "ring-like" wing would be distinguishable in memory from a "true" wing. Thus, a speech production task and two speech perception tasks were required. It was assumed these tasks might also provide some interesting information on production-perception relationships that have long intrigued clinicians, including the case where a child insists that his error productions are correct: 178 1ouraal of Speech and Hearing Research


18 176-191 1975

Child: "I want a wabbit." Adult: "A wabbit?" Child: "No, a wabbitl"

Speech Production Task This task was supposed to perform, and as it turned out, did perform, three functions: (1) to train subjects to use in their rehearsal efforts the labels intended for them to use (2) to ensure that initial screening results including group assignment were valid, and (3) to provide a tape that subsequently would be played to determine each child's perception of his own speech. Pictures of a ring, wing, king, shack, sack, and tack were displayed before each subject, who was asked to name them. When a child correctly named the complete display on two successive attempts, the experimenter began a formal 30-item sequence in which she pointed to each picture five times in a predetermined randomized order. Subjects were to name each picture as the experimenter pointed to it. Their naming response was recorded with a Sony ECM-22P lavalier-held microphone and a Sony TC-106A recorder. Rate of subject-naming ranged from one every two seconds to one every seven seconds.

Other-Voiced Speech Perception Tasks The subject heard a tape prepared by the experimenter under laboratory conditions in which she spoke the names of each of the six pictures five times in another randomized sequence. Rate of naming was one word every two seconds. The subject, who heard these items through earphones, was to point to a picture as soon as he heard it named. As in the production task sequence, each label appeared once in every subset of six items with randomizations upon each of the five distinct subsets.

Self-Voiced Speech Perception Task In this task the subject heard a tape recording of his picture-naming responses in the production task. With the other-voiced perception task interposed to ensure loss of item-order information, the subject was asked to point to each picture he heard himself naming, performing as in the othervoiced task. It may be helpful here to explain the presence in the stimulus list of two items that would not appear later in memory testing, king and tack. In an earlier study w/r children named the pictures wing and ring in a two-item, 10-trial set. When a tape of his naming was played, an experimental subject heard, presumably, 10 productions of wing, although he had attempted earlier to name five rings and five wings. In nearly all cases such children began the perception task by pointing to wing. Subsequently, at some midlist point, they switched and pointed to wing and ring haphazardly. Apparently the children LOCKE, KVTZ: Memory for Speech 179


knew they had named both pictures earlier and should be hearing both pictures named in the perception task. The inclusion of king and tack here, creating a six-item task, was to take the pressure off this tendency, to keep subjects from discovering they had not yet pointed to ring.

Memory Task Memory stimuli were 24 three-item lists drawn from the ring, wing, shack, and sack set. Lists were randomized within the constraints that 12 lists contain three different words, and 12 contain two different words with one item repeated. Repeated items occupied positions one and two, two and three, and one and three equally often (four times each). At least one item from the wing-ring set and the shack-sack set occurred in each of the 24 lists. Each word appeared 18 times, six times in each of the three positions. These distributional criteria were needed to control for possible interactions between list position and item memorability. Repeated items were necessary so an experimental subject, who might falsely think an item had been repeated in a list such as ring-shack-wing, would find it legitimate and acceptable to point to a single item twice. The stimulus tape for the memory task was recorded by the experimenter, who spoke the other-voiced perception tape, under identical conditions of recording and instrumentation. Words were heard by the child, over earphones, at a rate of one every two seconds. Following the third item in each list there was an eight-second delay ended by the command "Point." To defeat visual-space coding, six different response sets were used, each comprising a single page in a booklet containing a different randomized display of the four pictures (2N" • 2g" black-on-white line drawings). A response set was not displayed until the child heard "Point," a procedure that prevented attempts to respond earlier. It never was necessary to enforce a preset (approximate) 10-second limit on responding since all responses fell within that period. During pretraining on eight three-item lists, each subject was instructed to point, in correct order, to the pictures named; that a picture might" be named twice, once, or not at all in each list; and a thing named twice should be pointed to twice. In pretraining, accuracy feedback was given and subjects were informally reinstructed as needed. During the memory task, formal accuracy feedback was discontinued but verbal praise was offered when a list was recalled correctly.

Task Sequence Each subject was seen on three 20-minute occasions following his articulation screening. All tasks were completed within one week. The first session began with the speech production task followed by other-voiced and self180 1ournal of Speech and Hearing Research


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voiced perception tasks. The session was terminated with memory task pretraining. Session 2, usually begun on the following day, involved the presentation of the 24-list memory task (after some informal rediscussion of instructions) and an exact replay of the other-voiced perception task. The third and final session was a faithful replication of Session 2. In all, then each child attempted to recall 48 lists in all. Other-voiced perception testing was conducted at the end of Sessions 2 and 3 to ensure that perception was as accurate during the two memory sessions as it had been at the beginning of Session 1. RESULTS

Other-Voiced Perception Task Of the 1350 responses per group (30 items • 3 sessions • 15 subjects) only four errors were committed in total by each group. This exceedingly low percentage error rate assured us that most memory task errors probably would be just that, memory errors. Of the 225 possible wing~ring confusions, and an equal number of potential substitutions of ring for wing, three times control subjects heard/wi13/ and pointed to ring; twice experimental subjects heard /rIr3/ and pointed to wing. These findings rather forcefully speak to the issue of whether children who substitute one phoneme for another have any difficulty in distinguishing the two phonemes on this kind of task. Some implications of this for a motor theory of speech perception will be discussed later.

Self-Voiced Perception Task On the self-voiced perception task there were 30 subjects listening to 30 different recordings of a single list, rather than one recording of one list as in the other-voiced perception task. However, these 30 recordings, allophonic and suprasegmental variations aside, essentially comprised two separate lists. Control subjects received their own productions of /s, f, t, k, w, r/-five of e a c h - i n this once-administered task. As far as the normal-speaking experimenters were concerned, however, each experimental subject heard five /s/'s, five /f/'s, five /t/'s, five /k/'s and 10 /w/'s since he had said five /w/'s for the five /r/'s in the production task. The question is whether these 15 experimental subjects would be as convinced of the /w/-ness of t h e i r / w / ' s f o r / r / as we were. Would they respond differently to the /w/'s said in place o f / r / than to the /w/'s said where /w/ was the correct phoneme? If so, one could not look to rehearsal for a cue-collapsing function, as our logic and design require. The production and self-perception errors of both groups are shown in Figure 1. Of the control subjects, 13 correctly produced and perceived the five instances o f / w / and /r/. Two children made one error each for a total LOCKE, KUTZ: Memory for


Speech 181

CONTROL SAW

SAID

SUBJECTS (r/r) HEARD

POINTED

TO

074 075

-

-

,II~ 7 5 -

-

Ir,rJI75

'/r,rj/75

01 EXPERIMENTAL SAW

SAID

SUBJECTS (w/r) HEARD

POINTED

~ 07s~/w,,]/7S

~75 -

TO

014

--/w,rj/75~ 4~61

-

0 7 FIGOXaE1. Subjects' production of the picture names wing and ring and their identification of those names when heard on a tape recording several minutes later. Numbers in subscript refer to the number of times the behavior occurred in each group (15 subjects per group • five instances per subject = 75 possible ).

of 2/150 errors. This group kept Irl and lwl distinct both in production and perception. Therefore, there was no reason to believe their subvocal rehearsal would fold / r / into / w / any more than it would equate /s/ and / f / (the error rate f o r / s , f, t, k / w a s less than 1~ for both groups ). Experimental subjects , correctly, said /wn3/ each of the 75 times wing was pointed to by the experimenter. Hearing these 75 /wnj/'s on the tape, the children pointed to wing 68 times, to ring seven. The same subjects incorrectly said /wn3/ each of the 75 times the experimenter pointed to ring. On 182 ]ournal of Speech and Hearing Research


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61 of those 75 tape-recorded /wir3/'s , the children pointed to wing, on the remaining 14, to ring. In 90~ of the cases where the experimenter pointed to wing, these subjects said / w / and subsequently pointed to the wing in the self-voiced perception task. However, when the experimenter pointed to the ring, in 81% of the cases subjects said / w / and pointed to wing after hearing a tape of these productions. So, ring "became" wing with nearly the same frequency with which wing was realized as wing. There was, then, considerable reason to suspect that subvocal rehearsal could c o l l a p s e / r / a n d / w / in these experimental subjects. And, of course, there also was reason to doubt the longheld belief that children who substitute one phoneme for another necessarily classify their error productions differently than others do.

Memory Task As in the study by Conrad (1962), the confusions analysis was based on only those lists in which one error occurred, avoiding the otherwise arbitrary resolution of what was confused with, or intruded upon, what. The confusion matrix in Table 1 shows the frequency of intrusion errors for each group. It is obvious from the disparity in row totals that direct comparisons between T~L~ 1. Confusion matrix showing the number of recall confusions.

Controls" Responses Stimuli wing ring sack shack Total

wing

ring

Experimentals" Responses s a c k shack Total wing ring s a c k shack Total

72 59 25 17 101

44 22

21 24 117

42 108

47 21 50 118

163 102 96 83 444

101 85 19 20 124

29 17 147

36 27

38 20 54

41 104

112

175 132 102 78 487

rows are not possible from these data. To correct this, the frequency of each intrusion was divided by its row's total. These calculations produced a new matrix, Table 2, which reveals the conditional probability of a particular intrusion, given that the correct response to a specific stimulus was replaced by any incorrect response from the four-item set. The left half of Table 2 shows TABLE 2. Confusion matrix showing the conditional probability of recall confusions. ( Row totals = 1.00. )

Controls" Responses Stimuli wing ring sack shack

Experimentals" Responses

wing

ring

sack

shack

wing

ring

sack

shack

0.58 0.26 0.20

0.44 0.22 0.29

0.27 0.21 0.51

0.29 0.21 0.52 -

0.64 0.19 0.25

0.58 0.28 0.22

0.20 0.21 0.53

0.22 0.15 0.53 -

LOCKE, Kva-z: Memory for Speech 183


the probability of intraclass errors in the control group: w / r occurred more frequently than r/w (0.58 to 0.44), and the other intraclass confusions, f/s and s/f, (0.52 and 0.51, respectively). Interclass confusions, which should be much less frequent, averaged at 0.24. The probability of an intraclass confusion among experimental subjects may at first look similar to control performance-both f/s and s/f are 0.53. However, the probability of w/r a n d r/w intrusions (0.64 and 0.58 respectively) not only are larger than ~s-f~ confusions, they exceed / w - r / errors in the controls. The probability of an interclass error, averaging across the eight cases, was 0.22. The greater probability of intraclass errors, relative to between-class ones, was expected (Wickelgren, 1965, 1966) and indicates that considerable forgetting was partial. In other words, instead of forgetting /s~ek/, for example, subjects were inclined to forget/s/. Had we included pack, tack, and so forth, it would appear that not e v e n / s / was forgotten but certain featural subcomponents such as voicing or manner cues. Analyses of variance were performed on intrusion scores in the four major categories: (1) wing for ring and vice-versa, (2) sack for shack and vice-versa, (3) wing and ring for sack and shack, and (4) sack and shack for wing and ring. Individual subject means in the third and fourth categories were halved to correct for their twice-greater statistical probability (there being four instead of two sources of error). These tests showed a significant error effect (F = 40.348; df = 1, 112; p < 0.01), group effect, (F = 5.999; df = 1, 112; p < 0.05) and group-by-error interaction (F = 3.217; df = 3, 112; p < 0.05). The significant error effect confirms that certain intrusions occurred more commonly than others. Subsequent tests of simple effects (Ferguson, 1966, p. 296) showed that both within-class confusions significantly exceeded (p < 0.05) both between-class confusions in each group. The significant group effect-confirmation that the two groups of subjects committed an unequal number of errors-is theoretically meaningless since the scoring system ignored all lists in which three, two, or no responses were incorrect. In other words, the number of correct responses is unknown, and for this design, irrelevant. The significant group-by-error interaction, however, is central to this experiment. From the data in Table 1, it appears that most of this interaction is due to the different number of wing-ring confusions made by the two groups. This was confirmed by follow-up tests that showed that experimental subjects made significantly more wing-ring confusions than control subjects (p < 0.01), all other between-group comparisons being nonsignificant (p < 0.05). DISCUSSION The central finding of this experiment was that children who correctly perceived / w / and /r/ but consistently spoke one in place of the other experienced significantly more /w - r/ confusions in recall than children who char184 1ournalof Speech and Hearing Research


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acteristically produced a correct /w/ and /r/. If these experimental children heard / r - w s/ and tried to reproduce them privately (mouthing, whispering, and vocalizing of stimulus names commonly were observed), they would end up with /w/, /w/, and /s/ in their sensory or conceptual heads. If / ri13/ or / wirj / were not additionally "tagged" in some distinctive way (for example, wedding wing.., bird's wing), the child still might conclude that he heard both if he recalls that there were, in this case, three different words. But which was first or second would be unknown to him. He would, accordingly, get both r/w and w/r errors. Many of the / r - w / confusions probably had a common genesis in the two groups, for example, partial decay of the stimuli in sensory memory, failures of visual imagery, and inattention. It is the large number of / w - r / confusions in experimental subiects that we attribute to an extra source of information loss. The / w - r / confusions of rehearsing control subjects must, in part, reflect the incomplete forgetting of their articulatory responses to the stimuli they heard. Rehearsing experimental subiects also would lose information in this way, but additionally subiects could "forget" by correctly recalling misarticulated responses. Children with disordered articulation may have perfectly efficient memory, if by memory we mean the ability to retain and retrieve sensory input in sensory form, but if they translate verbal stimuli into their disordered code, they could end up efficiently retaining and retrieving the wrong information.

Why Speech Recoding? Nearly every normal speaker with a mental age above five years is likely to recode verbal stimuli into their phonetic form (Conrad, 1971), regardless of their mode or code at input (Locke and Fehr, 1972). From a biological point of view, we may assume that phonemic coding of nonspeech stimuli ensures a more efficient storage than would otherwise be likely. A good look at the options confirms this; iconic storage probably holds too few items for too short a time (Sperling, 1960; Averbach and Coriell, 1961) and aftercoming stimuli overwrite or push out the contents of acoustic storage (Crowder and Morton, 1969). Nonphonetic strategies, of which semantic coding and visual imagery are leading contenders, call for more scheming and encoding time than is available in many input circumstances. Such strategies as weaving coherent anecdotes and forming arrays of ordered visual images may work well with concrete stimuli, but we must also handle information less meaningful and spaced. Speech recoding appears almost as biologically natural as speech itself, and having looked at the nonspeech alternatives its popularity seems rather unremarkable.

Recoding Deficiency As natural as phonetic recoding may be, there is a time in every child's life LOCKE, KUTZ: Memoryfor Speech 185


when it hasn't yet occurred to him, or in which he could not profit from it even if it did. By the age of two or three he can repeat stimuli but it will not be for a year or so hence that he will rehearse them. When he does, in the earliest instance such private communications may well be picture labeling (Appel et al., 1972) or sound echoing (Fay and Butler, 1971), which are of questionable aid to memory. The lag between verbal acquisition and verbal mediation has concerned many developmental psychologists, whose several hypotheses are relevant to this discussion (Reese, 1962, 1963; Youniss and Furth, 1963; Flavell et al., 1966; Keeney et al., 1967). The question is why children who can talk don't verbally mediate. One answer, the production deficiency hypothesis, suggests that children don't mediate in recall because they produce no potentially mediating terms in rehearsal (Flavell et al., 1966; Keeney et al., 1967; Moely et al., 1969; Daehler et al., 1969). Take the simple case of a four year old whose recall of rhyming and nonrhyming picture sets is equal. According to the production deficiency hypothesis, his recall shows no phonetic effects because he produced no relevant phonetic activity prior to recall; he did not silently name or experience the auditory representation of picture names in his head. Since the stimuli were not translated into their phonetic form, the child ne~;er discovered that some sets rhymed and others did not. The antithesis of this idea, the mediation deficiency hypothesis, suggests instead that the child subvocally spoke but this personal brand of speech had no mediating effects (Reese, 1962; Hagen and Kingsley, 1968; Potts, 1968). Perhaps he was unaware of movements in his mouth or sounds in his head, or detected them but never discovered the rhyming relationships (or was not capable of dealing with rhyme, conceptually or as an aid to recall). The production deficiency hypothesis ultimately was confirmed by Flavell (1970) and furthered by Ellis (1970), who specified a rehearsal deficiency as the locus of short- and long-term memory difficulties in the retarded. In addition to Ellis' recall evidence, this idea received support from a study that found no evidence that mentally retarded adults covertly spoke in a task which typically elicits subvocalization from children and adults alike (Locke and Fehr, in press). Production deficiency is an intriguing term. Clinical treatment is given to children with production deficiencies, that is, children with overt speaking behaviors considered unsuitable for the purpose of communication. But why should we suppose that they do any better talking when they serve as their own audience? Perhaps they have production deficiencies in memorizing as well as speaking.

Nature of Speech Recoding Some of the selective and general effects of speech mediation in short-term memory have already been discussed. Just how these effects are created from

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the subject's knowledge of speech is not clear. Probably, one can think about phonetic things without a corresponding speech-muscle excitation, and truly subvocal speech has no peripheral acoustic yield. However, we can generate auditory images, perhaps neuromotor images, and covert speech is described often by traceable muscle impulses (Locke and Fehr, 1970a, b). So if the learner is processing the feedback from rehearsing muscle groups, and attending to auditory images, such cues may be the basis of enhanced recall. He would have at his disposal not only information about the stimuli, in an albeit degraded or incomplete state, but correlated information about his subvocal responses to them. There has been substantial controversy as to whether the phonetic effects of speech rehearsal are motor-phonetic or acoustic-phonetic. Specifically, are items confused because they feel alike (Hintzman, 1967; Thomasson, 1970), sound alike (Conrad, 1962), both (Cheng, 1973), or neither (Wickelgren, 1969, posited an "abstract" similarity)? In this study, experimental subjects noted the perceptual differences between/w/ a n d / r / b u t didn't preserve that difference in their speech. If subvocalization furnishes the learner with kinesthetic information and correlated auditory images (such that he "hears in his head" roughly the same thing he would hear through his ears if he were to have rehearsed aloud), the storage and retrieval cues could be either motor or auditory. However, the actions of speech muscles would be crucial since l~hey could be traced directly as motor feedback, and indirectly through auditory imagery. Since our two groups of subjects differed in their production of phonemes-not their perception of phonelnes--it may be that their motor experience, directly or indirectly, provided the salient memory cues.

Short-Term Acoustic Storage A discussion of the contributions of speech to memory would be incomplete without some consideration of peripheral acoustic information. It is common, as readers' experience may confirm, for people to speak aloud things they wish to remember (for example, phone numbers and shopping lists). We increase the probability of correct recall through such "auditorizing." Imagine an experiment in which lists of single digits, letters, or words are presented in rapid succession for immediate serial recall. If presented aurally there will be near-perfect recall of the first and last thirds of the list. Presented to the eye there will be near-perfect recall of the first third but the last few items will be recalled no better than mid-list ones (Crowder and Morton, 1969; Craik, 1969). Crowder and Morton (1969) referred to this short-term store as precategorical acoustic storage (PAS), precategorical because it holds raw information, acoustic because it accepts input only from the ears. PAS may not hold stop consonants (Fujisaki and Kawashima, 1970; Pisoni, 1971; Crowder, 1973b), perhaps because they are perceived categorically (Liberman, Cooper, Shankweiler, and Studdert-Kennedy, 1967), though not necessarily for that

LOCKE, KUTZ: Memory for Speech 187


reason (Darwin, in press). However, it does accommodate other consonants (Crowder, 1973b), vowels (Crowder, 1973a), and suprasegmental features (Morton, Crowder, and Prussin, 1971 ). Although the longevity of ear-borne information is unspecified at present, its raw-form life has been clocked at six, eight (Cole, Coltheart, and Allard, 1974) and 10 seconds (Eriksen and Johnson, 1964). The shortest of these echoes exceeds by 30-fold the life span of Sperling's (1960) longest icons. This capacity to house aural input for such relatively long periods, pre- and postperceptually, probably is responsible for the marked recency effect observed commonly in the immediate recall of rapid speech. Particularly relevant to this discussion is the fact that PAS accepts one's own speech as well as the speech of other persons. For visual-verbal information, within certain limits, one can add to the benefits that ordinarily accrue from silent articulationrehearsal-simply by speaking aloud (Hagen and Kingsley, 1968; Crowder, 1970; McCarver and Ellis, 1972; Kappel, Harford, Burns, and Anderson, 1973). The question of whether misarticulating children forget, then, may be less important than where in the list the forgetting occurs. If memory for speech is impaired, the last third of the list should be affected primarily. On the other hand, if there is a reduction in early-list recall, the child may have failed to use speech effectively in the service of memory (Fischler, Rundus, and Atkinson, 1970; Meunier et al., 1971).

Speech Perception Although this paper is addressed to problems of speech and memory, some relationships between speech and perception were clearly isolated in this experiment. The term perception is used here with the understanding that it is not accessible to direct observation, must therefore be inferred, and is extremely sensitive to task structure. As detailed earlier, children who substituted /w/ f o r / r / showed near-perfect recognition o f / w / and /r/. On the surface, this would seem to contradict previous reports of poor perception in children with articulation disorders. However, the subiects in those earlier studies usually had to decide whether syllable pairs were sufficiently different, linguistically and psychologically, to say so. The task used here did not require a psycholinguistic decision, in the above sense, and found no recognition difficulties. In this experiment, 15 five year olds consistently perceived /r/ correctly but characteristically spoke in its place a /w/, the /w/-ness of which was as convincing to them as to us as experimenters. This is hard to explain with a theory which holds that phoneme perception is mediated by phoneme production (the motor theory of speech perception [Liberman et al., 1967]). However, the motor theory gets much of its best evidence from stop consonants, and its explanatory power may wane with excursions, along an acoustic/ linguistic continuum, from the stops into fricatives, liquids, and vowels. It also is possible t h a t / w / a n d / r / can be discriminated by recourse to a nonarticu188 Journal of Speech and Hearing Research


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latory process, one that matches acoustic patterns to stored templates, either naturally or as the result of the discovery by the child who s u b s t i t u t e s / w / f o r / r / t hat m o t o r consultation leaves him with insufficient advice. T h e misarticulating children's perception of their own t a p e d speech seems to say a / w / is a / w / is a / w / . T h e child's insistence th a t he has b e e n misp e r c e i v e d - a s in our earlier a n e c d o t e - p e r h a p s is the basis for the impression t hat misarticulators perceive their utterances differently th a n others do, or t hat their speech is described by acoustic p a r a m e t e r s missed b y normal-speaking adults. However, it seems iust as likely th a t the child is iudging his intent, not the phonetic p r o d u c t of his intent. In taping a 30-item list we effectively ablated the child's knowledge of his intent at the time he spoke any of the 10 wings. W h e n hearing wing, not knowing w h e t h e r he'd said it in response to a wing picture or a ring picture, he could only point to w h a t it s o u n d e d like:

wing. ACKNOWLEDGMENT This investigation was supported by Fellowship 1 F03 HD-53445-01 and Grant HD-05951 from the National Institute of Child Health and Human Development, and by a grant from the Biomedical Sciences Division of the National Institutes of Health. During the project Kathryn Kutz was C.I.C. traveling scholar from the graduate program at the University of Minnesota where the encouragement of Gerald Siegel was helpful. The authors wish to thank M. Bohnsak, G. Bourne, A. Conroy, and S. McDonald for serving as research assistants and the staff of Rantoul and Monticello, Illinois, schools for furnishing subjects and space. We are indebted to Robert Crowder and R. Conrad for their helpful comments on various portions of the manuscript and to Alvin Liberman for his remarks on the section that deals with speech perception. Requests for reprints should be addressed to John L. Locke, Speech and Hearing Laboratory, Children's Research Center, University of Illinois, Champaign, Illinois 61820. REFERENCES APPEL, L., COOPER, R., McCXnRELL, N., SIMS-KNXGnT,J., YUSSEN, S., and FLAVELL, J., The development of the distinction between perceiving and memorizing. Child Develpm., 43, 1365-1381 (1972). AVErmACH, E., and CORIELL, A., Short-term memory in vision. Bell Sys. tech J., 40, 309-328 ( 1961 ). BartLOW, M., The role of articulation in memorizing. J. exp. Psychol., 11, 306-312 (1928). BLANTON, R., and ODOM, P., Some possible interference and facilitation effects of pronunciability. 1. verb. Learn. verb. Behav., 7, 844-846 ( 1968 ). Cm~NG, C., Acoustic and articulatory coding functions in immediate memory. Doctoral dissertation, Yale Univ. ( 1973 ). COLE, R., SALES, B., and HABER, R., Mechanisms of aural encoding: II. The role of distinctive features in articulation and rehearsal. Percept. Psychophys., 6, 343-348 ( 1969 ). COLE, R., COLTHEXaT, M., and ALLARD, F., Memory of a speaker's voice: Reaction time to same or different-voiced letters. Quart. 1. exp. Psychol., 26, 1-7 ( 1974 ). CONnXD, R., An association between memory errors and errors due to acoustic masking of speech. Nature, 193, 1314-1315 (1962). CONRAD, R., The chronology of the development of covert speech in children. Develpm. Psychol., 5, 398-405 ( 1971 ). CONRAD, R., Short-term memory in the deaf: A test for speech coding. Brit. J. Psychol., 63, 173-180 (1972a). CONRAD, R., Speech and reading. In J. Kavanagh, and I. Mattingly (Eds.), Language by LOCKE, KUTZ: Memory for Speech


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Primary grade children's memory for parts of speech.

Effects of Age on Long Term Memory for Degraded Speech.

Noise reduction improves memory for target language speech in competing native but not foreign language speech.

Recognition memory in noise for speech of varying intelligibility.

Irrelevant speech and serial recall: implications for theories of attention and working memory.

Time-intensity trade for speech: a temporal speech-Stenger effect.

A Danish open-set speech corpus for competing-speech studies.

VERBAL AND SPATIAL WORKING MEMORY LOAD HAVE SIMILARLY MINIMAL EFFECTS ON SPEECH PRODUCTION.

Effects of hearing loss on speech recognition under distracting conditions and working memory in the elderly.

Abstract versus modality-specific memory representations in processing auditory and visual speech.

Working Memory Training and Speech in Noise Comprehension in Older Adults.

Updating working memory in aircraft noise and speech noise causes different fMRI activations.

On The (Un)importance of Working Memory in Speech-in-Noise Processing for Listeners with Normal Hearing Thresholds.

VoiceBak--speech for the speechless.

Participation of the classical speech areas in auditory long-term memory.

The Auditory-Visual Speech Benefit on Working Memory in Older Adults with Hearing Impairment.

Contribution of auditory working memory to speech understanding in mandarin-speaking cochlear implant users.

Habituation to irrelevant speech: effects on a visual short-term memory task.

Comparing the information conveyed by envelope modulation for speech intelligibility, speech quality, and music quality.

Neural Encoding of Speech and Music: Implications for Hearing Speech in Noise.

Automatic Speech Recognition Predicts Speech Intelligibility and Comprehension for Listeners With Simulated Age-Related Hearing Loss.

Music expertise shapes audiovisual temporal integration windows for speech, sinewave speech, and music.

The Role of Slow Speech Amplitude Envelope for Speech Processing and Reading Development.

Speech Training for Backward and Defective Children: Article III Nasal Speech.