Classifying by dimensions and reading: A comparison of the auditory and visual modalities

OURNAL.

OF EXPERIMENTAL

CHILD

PSYCHOLOGY

139-169

51,

(1991)

Classifying by Dimensions and Reading: A Comparison of the Auditory and Visual Modalities BEA

LINDA

GATTLJSO

B.

SMITH

AND

REBECCA

Children

have

because children objects.

difficulty

visual reading visual

adults

attend to the in kindergarten

(Experiment

7) classified

alphabetic

writing

spoken language to the individual in reading may parts of any perceptual through fourth grade triads

systems,

3). However, classification modalities when the children

constituent tasks did selectively Preparation

(Experiment not usually to phonemes of this

article

4). Regardless relate to reading

of spoken

seems was

to be a “special”

supported

to Rebecca Treiman and NSF Grant acknowledge the help of the principals. School in Stinesville. IN, St. Charles’ Elementary School in Pompano. FL. for

reprints Salem,

should be sent OR 97301.

was more consistent were told to classify of instructions. and spelling

wholes. (Experiments

in part

by NlCHD

To

syllables

part,

and

explore 1. 3. and triads

of

related to classifying (Experiments

to

across the visual and based on a shared

performance skill. The skill--one

in

into phonemes. Young dimensions of visual be one sign of a general

objects. Classifying speech by common parts was positively and spelling ability (Experiments I and 41, but usually not stimuli by common parts under free classification instructions

I through auditory

Requests University.

to read

they have difficulty segmenting also have difficulty attending Thus, children’s early difficulty

inability to selectively this notion, children 4) and

learning

TREIMAN

ability

which Grants

on the visual to attend may

require

HDl838?

and

30276

BNS 81-09888 to Linda B. Smith. We gratefully teachers. and students at Stinesville Elementary Elementary School in Bloomington, IN. Broadview and several daycare centers in Bloomington. IN.

to Bea

Gattuso.

Department

of Psychology.

Willamette

002?-0965/91

$3.00

CopyrIght SC’ IV91 hy Academic Pres,. Inc. All rights of rcproductmn m any form rc~crved.

140

GATTUSO,

SMITH.

AND TREIMAN

specific experiences with language. such ah those involved in learning to read an alphabetic writing system. c’ I’WI Acxlem~c PI-C\\. Inc.

Learning to read an alphabetic writing system involves the learning of letter-sound rules. The simplest of these rules involves knowing, for instance, that hall, hnr. and ho?: are all written with an initial letter h because they all begin with the same sound. Learning such letter-sound rules appears to be difficult for young children, in part, because they have difficulty segmenting speech into phonemes (see. e.g., Bruce, 1964: Fox & Routh, 1975; Liberman. Shankweiler, Fischer, & Carter, 1974: Rosner & Simon. 1971; Treiman & Baron, 1981). Moreover, children’s phonemic segmentation skills are related to reading and spelling in general. and to knowledge of letter-sound rules in particular (Calfee. Lindamood, & Lindamood. 1973; Fox & Routh. 1975; Liberman. Shankweiler. Liberman, Fowler, & Fischer. 1977: Lundberg, Olofsson, & Wall. 1980; Treiman & Baron, 198 I 1. Several researchers (Treiman 61 Baron, 1981; Walley. 1,. B. Smith. & Jusczyk. 1986; Wolford & Fowler. 1984) have suggested that the young child’s difficulty in segmenting speech into phonemes is one manifestation of a general perceptual difficulty. The notion is that learning letter-sound correspondences requires the child to attend to the parts of speech (i.e.. phonemes) and that young children have difficulty doing this just as they have difficulty attending selectively to the parts of any perceptual wholes. Other investigators (Ehri, 1983: Morais. Bertelson. Cary, & Alegria. 1986; Morais. Cary. Alegria. & Bertelson. 1979; Read. Zhang. Nie. & Ding, 1986; Rozin & Gleitman. 1977). however, have suggested that phonemic segmentation ability depends on specific experiences with language, such as learning to read an alphabetic writing system. The present work sought to distinguish between these two views. If phonemic segmentation skill is one instance of a more general developmental trend in perception, then performance in phonemic segmentation tasks should relate to performance in other selective attention tasks, and selective attention tasks in general should predict knowledge of letter-sound rules. However, if segmentation ability depends on reading instruction, then performance in phonemic segmentation tasks should not necessarily relate to performance in other selective attention tasks. The particular selective attention task we employed was constrained classification. In one version of the task. subjects classify three stimulus objects like those shown in Fig. I. Three different classifications of the three objects are possible. First is a dimensional classification-A and B are classified together. These two objects are identical in one constituent. but are (due to their difference on dimension Y) not similar overall. Thus, this classification implicates selective attention to the common parts of perceptual wholes. Second is an overall similarity classi-

CLASSIFYING

BY DIMENSIONS

AND

141

READING

.C l B

t c 0 B 5 E i5

Dimension FIG.

I.

A stimulus

set that

pits

a dimensional

X relation

against

an

coverall

similarity

relation.

fication-B and C are classified together. These items are not identical on either dimension but are highly similar on both. This classification thus implicates attention to the whole object-to all the components. Third. and nondiagnostic of any obvious perceptual strategy, is a haphazard classification. Here, objects A and C, which neither share a constituent nor are particularly similar on both dimensions. are grouped together. Garner (1974) and others (e.g.. L. B. Smith & Kemler, 1978; L. B. Smith & Kilroy, 1979) have shown that the constrained classification task is diagnostic of adults’ difficulty in selectively attending to one integral dimension and their ease in selectively attending to one separable dimension. L. B. Smith and Kemler (1977). Shepp (1978). and others (Shepp & Swartz, 1976; Ward. 1980) have found a consistent developmental trend in this task with visual stimuli, for example objects varying in color and shape. Children seven years and younger are more likely than older children to produce overall similarity classifications-a result consistent with the limitations on selective attention ascribed to young children (Gibson, 1969; Pick & Frankel, 1973, 1974). The constrained classification task also diagnoses phonemic segmentation skills. Treiman and Baron ( 1981) asked kindergarten and first grade children to classify triads of spoken syllables such as /bI/. /ve/, and /bo/. Younger children tended to construct overall similarity classifications-grouping /br/ and /vc/ together. These syllables share no phonemes but are, by adult ratings of perceptual similarity (Singh & Woods. 1971; Singh, Woods, & Becker. 1972). similar overall. Older children, in contrast, were relatively more likely to construct “dimensional” classifications-grouping the syllables /bo/ and /bl/. These syllables share their initial phoneme but are (again by adult perceptual similarity ratings) different overall. Treiman and Baron (1981) further showed that ease of learning to classify by phonemes instead of overall similarity relates to reading skill.

142

GATTUSO.SMITH,ANDTKEIMAN

Given its use with both visual and speech stimuli, the constrained classification task is well suited to test the notion that children’s phonemic segmentation skills are closely related to their general ability to selectively attend to the common parts of distinct perceptual wholes. Accordingly, Experiment 1 asked prereaders and beginning readers to classify triads of spoken syllables and triads of visual objects that varied in color and size or length and orientation. We were unsure whether success in classifying by common parts with the visual stimuli would predict success with the speech stimuli since Mann, Tobin, and Wilson (1987) did not find a positive correlation between kindergartner’s performance on speech and visual classification tasks similar to those used here. However, J. D. Smith and Baron (1981) found that adults’ performance on visual tasks (similar to those used here and by Mann, Tobin, & Wilson) did correlate significantly with a speech task. We also examined children’s ability to read and spell regular words (e.g.. dome) that conform to letter-sound rules of English orthography, exception words (e.g., come) that do not conform to English lettersound rules, and nonsense words (e.g., gome). Our question was whether the ability to selectively attend to single visual dimensions and single phonemes related more closely to reading by letter-sound rules-rules which require attention to phonemic segments of speech-than to other aspects of reading ability. EXPERIMENT

1

Method Eighteen kindergartners (mean age 5 years, 8 months; range: 5,3-6,3), IX first graders (mean age: 6 years, 9 months: range: 6.3-7,4), and 18 second graders (mean age: 7 years, 11 months; range: 7,4-c). I) attending a rural elementary school served as subjects. All subjects in this and subsequent experiments were native speakers of English. Stimuli Visd stinzdi. The ~010~ and .size stimuli were circles varying in diameter and shade of green mounted on 4 by 6 in. white cards. The five diameter values were 3.5. 4.1, 4.7. 5.7. and 6.6 cm. The five shades of green ranged from a light yellow green to a dark green (Coloraid notation: YG-T4, YG-T2, GYG-Tl. GYG Hue. and G-S3). The length and orientution stimuli were arrows varying in length and orientation mounted on 3 by 5 in. white cards. The length values were 1.9, 2.5, 3.1. 3.8. and 4.4 cm. The orientation values were 5, 20. 40. 60, and 80” counterclockwise from horizontal. Each visual stimulus in a triad was on a separate card.

CLASSIFYING

BY DIMENSIONS AND READING

143

For both sets of visual stimuli, the specific values on the dimensions were chosen from similarity-scaling data generated by four adults using the method of magnitude estimation, such that all one step estimated differences were approximately equivalent and such that the range of similarities on the dimensions were comparable. The discriminability of the smallest differences employed was examined via a same-different oddity task with IO preschoolers. All one step differences in the color and size stimuli were highly discriminable for the children. Although all one step differences in orientation were discriminable in the length and orientation stimuli, the results of the same-different oddity task suggested that two of the length differences were not discriminable for some of of these differences was not the children. The “nondiscriminability” considered to be a serious problem because perception of stimuli such as these are subject to optical illusions (such as the Muller-Lyer). In addition, none of the differences were smaller than the smallest differences employed in the color and size task. Twelve unique triads structured as shown in Fig. 1 were constructed from the color-size values and I?. were constructed from the lengthorientation values. Each dimension served equally often as the dimension by which a dimensional classification was possible. To limit the possibility that the results would reflect local (nonsystematic) perturbations of the children’s multidimensional similarity space, triads were selected from all regions of the space. In addition. six practice triads were constructed for each set. For two practice triads, two of the stimuli were identical and one was different. For the remaining four practice triads, the three items were nonidentical, but either a dimensional or a similarity relation produced the same classification. Thus, for each practice triad, unlike the experimental triads, there was one correct classification. Speeclz stirnrrfi. Twelve experimental triads were constructed from consonant-vowel-consonant syllables. One pair of syllables in each triad shared a phoneme (always the first consonant), while another pair was more similar overall. For example, in the test triad /v&g/, /vol/, and /brk/, /v&g/ and /vol/ share a phoneme, but /v&g/ and /brk/ are most similar overall. /vol/ and /btk/ are the haphazard pair. Published similarity ratings of pairs of phonemes (Singh & Woods, 1971; Singh et al., 1972) were used to construct the triads. Six practice triads were constructed analogously to those for the visual stimuli. The speech stimuli are listed in Appendix A. Reuding clnd spelling tests. The reading and spelling tests consisted of lists of 32 regular. 32 exception, and 32 nonsense words from Treiman ( 1984). For the reading test, these words were printed in large uppercase letters on 4 by 6 in. white cards. For the spelling test. the words were read by the experimenter. The regular words (e.g., dome. gum) con-

I44

GATTUSO,SMITH.ANDTKEIMAN

formed to standard letter-sound rules of English. The exception words (e.g.. come, some) violated the rules. The nonsense words (e.g.. gome. woot) could be read or spelled analogously to either a reguIar or exception word.

Visrral stimrrli. The experimenter and subject sat facing each other across a table. Thl-e stimuli were set out in a row in front of the subject and he/she was asked to put together the two that went together. Following the procedure of L. B. Smith and Kemler (1977). the words “most similar” or “most alike” were not used. For half of the subjects. the color and size stimuli were presented before the length and orientation stimuli. The other subjects received the reverse order. The triads were presented in one of two random orders. On the practice trials. the child was corrected if he/she gave the wrong answer. Criterion for participation in the test phase was a correct response on each of the six triads within a maximum of two repetitions through the practice list. During the test phase, the children were encouraged, but given no specific feedback. Speech stittrrrli. The classification task with the spoken stimuli necessarily differed from the visual task since the three auditory stimuli could not be presented simultaneously. Following the procedure of Treiman and Baron (1981). the child was first shown three identical animals drawn on the vertices of an equilateral triangle. The child was told that he/she would hear the names of the three animals and that the animals whose names sounded alike were friends. (These instructions differ somewhat from those used with the visual stimuli. Our intent was to replicate the procedures used by L. B. Smith and Kemler (1977) with visual stimuli and by Treiman and Baron (1981) with speech stimuli.) The “names” were presented with a UHER 4200 tape recorder. (The tape in this and subsequent experiments was prepared by a female speaker who did not know the purpose of the experiment.) The experimenter pointed to each animal as the tape said the name. (The animals were always pointed to in the same order.) The child was then asked to repeat the names. Ii the child did not repeat the syllables correctly. the experimenter corrected him/her. A!! three names were presented a second time and the child was asked to point to the two animals whose names sounded alike. During the practice trials. children’s classifications were corrected. No specific feedback was given during the test phase. Criterion for participation in the test phase was a correct response on each of the six triads within a maximum of three repetitions through the practice list. Half the subjects received the speech stimuli before the visual stimuli. The remaining subjects had the reverse order. The auditory triads were presented in a single random order.

CLASSIFYING

BY DIMENSIONS AND READING

145

Reading test. In a preliminary reading test, the child matched letters with pictures having names beginning with the letters. The test consisted of 10 items (10 letters with three pictures as possible choices for each letter). Only children who succeeded in this task (at least nine correct) took the primary reading task. During the primary reading test, the experimenter held up a card with a stimulus printed on it. The child was asked to read this “word” aloud. Before presenting the nonsense words, the experimenter told the child that they were not real, but to read them as well as he/she could. The reading list was divided into three parts, according to increasing difficulty. Within each part. all regular words were presented first, all exception words were presented second. and all nonsense words were presented last. A nonsense word was scored as “correct” if it was pronounced analogously to either a regular or an exception word. If a child could not read at least IO words correctly in one part, we did not proceed to the following part. In addition, if a child read none of the regular or exception words correctly, we did not proceed to the nonsense words. SpefIing test. This test was given only to children who were successful on the preliminary reading test. The experimenter pronounced each stimulus and used it in a phrase (if it was a real word). The child then spelled the stimulus. Before presenting the nonsense words, the experimenter told the child that they were not real, but to spell them as well as he/she could. The sheet of paper was turned over for the nonsense word section so that the child could not compare his/her spellings of the nonsense words to his/her spellings of the real words. The pattern of presentation and the scoring were the same as in the reading test. Half the subjects took the reading test first and the other half took the spelling test first. The letter-picture matching test always preceded the reading and spelling tests. The reading and spelling tests always followed the classification tasks. All testing began in the fall of the school year. Each child was tested during two or three sessions, each approximately 25 min long. Results

and Discussion

Table 1 shows the mean proportions of dimensional classifications at each grade level for the three classification tasks. These proportions were submitted to a one-way analysis of variance by grade, separately for each task. Neither of the analyses for the visual tasks revealed a significant grade effect. As expected from previous results (e.g., L. B. Smith & Kemler, 1977), dimensional classifications were relatively infrequent at all age levels and overall similarity classifications predominated. The lesser use of dimensions with the more integral (and less discriminable) combination of length and orientation than with the more

146

GATTUSO,

SMITH, TABLE

PRO~~K~ION

OF DIMENSIONAL

AND

TREIMAN

I

CI.ASSIEKATIONS ANI) TOTAL REAUING EXPERIMENT I

Color

ANU SPELLING

SWRES.

&

Length &

size

orientation

Speech

Kindergarten M

.37

.2s

.2:!

SD N

.I4 I8

.I4 IX

I?x

.?7

.2?

.3s

5.78

2.50

I?IX

.II IX

IO I6

6.S4 IX

2.41

.44

.:‘I

.47

41.43

22.94

.I9

.0x IX

.I’) I7

21 .07 IX

17.27 IX

Read”

Spell”

I I .so 21.02

.SO I .oo

4

4

First

M SD N

IX

Second

M SD N “ Maximum

IX possible

score

=

96.

separable combination of color and size (053) = 7.07, p < .001. onetailed) also fits with previous work (L. B. Smith & Kilroy. 1979). The analysis of variance for the speech task did reveal a significant grade effect (HZ, 38) = 6.65, p < .004). The tendency to classify syllables on the basis of a shared phoneme increased significantly (approximate Scheffe for unequal groups. p < .Ol) from kindergartners to second graders. This result extends the findings of previous investigators (e.g., Treiman & Baron, 1981) to a wider range of grade levels. Table I also presents the means obtained by averaging the total reading and spelling scores (i.e., regular + exception + nonsense) across all of the subjects at each grade level who scored at least 90% on the letterpicture matching test. There was a significant grade effect for reading (F(2, 37) = 23.08, p < .OOOl) and spelling scores (F(2, 37) = 14.96, p < .OOOl). Second graders outperformed first graders (approximate Scheffe. p < .Ol for both reading and spelling). The differences between the few kindergartners who contributed data and the first graders were not significant. (The high reading mean for kindergartners was due to one precocious child.) To examine the correlations between the classification tasks and the various subtests (regular, exception, and nonsense) of the reading and spelling tests. we converted scores for each of the reading and spelling subtests into z-scores. Following Treiman (1984), the reading z-score and the spelling z-score for each subtest were added. The three correlations between the speech classification scores and the reading and spelling of

CLASSIFYING

BY DIMENSIONS TABLE

CORRELATIONS Color

& size Color & size Length & orientation Speech Read Spell

AMONG

.31’

147

2

THE TASKS.

Length 82 orientation

AND READING

EXPERIMENT

I

Speech

Read

Spell

.25 .02

.?O .I8 .34*

.20 .I7 .36* .wl**

* ~1 < .05, one-tailed. ** p < ,001, one-tailed.

regular (~(35) = .35. p < .02), exception (r(3.5) = .37, p < .02) and nonsense (1.(35) = .41, p < .006) z-scores corroborate earlier findings of a link between common phoneme classifications and reading and spelling in general, and the learning of letter-sound rules in particular. Supporting this last point, the frequency of common phoneme classifications was more highly correlated with the number of correctly read and spelled nonsense words than with the number of correctly read and spelled regular words (t(34) = 2.01, p < .05, one-tailed, using Cohen and Cohen’s t 1975) test for dependent correlations). Table 2 shows the correlations among the three classification tasks. the reading task, and the spelling task for all three grade levels combined. (These correlations reflect the performance of children who completed all the tasks.) As found previously with adults (e.g., J. D. Smith & Baron, 1981), the correlation between the proportion of dimensional classihcations on the two visual tasks was small but significant. Also significant were the correlations between the speech and reading scores and the speech and spelling scores. However, consistent with work by Mann, Tobin, and Wilson (1987), neither of the visual tasks correlated significantly with the speech task. Moreover. the reading and spelling scores did not correlate significantly with the visual tasks. Although the low correlations involving the proportion of dimensional classifications in the length and orientation task may have been due to range restrictions in the values of this variable; such limited variability did not occur in the other tasks. Our results suggest that classifying speech by common parts is related to learning to read and spell, but that none of these linguistic tasks is closely related to classifying visual stimuli by common parts. Supporting this conclusion, performance on the speech task was more highly correlated with reading and spelling than was performance on either of the visual tasks (p < .OOl, one-tailed, for all, using the test for dependent

148

GATTUSO.SMITH,ANDTREIMAN

correlations recommended by Appelbaum and McCall. 1983). Perhaps. as some investigators have suggested, learning to read an alphabetic writing system is the critical factor in coming to selectively attend to the phonemes within speech. If alphabetic literacy promotes attention to phonemes, then skilled readers ought to be well able to classify speech sounds by common phonemes whatever their tendency to attend to the common parts of nonspeech stimuli. We explored this possibility in Experiment 2 by examining college undergraduates’ classification of speech and visual stimuli. Experiment 2 had two goals. The first was to demonstrate the sensitivity of our tasks to developmental differences in selective processing ability. The restricted age range in Experiment I precluded the possibility of demonstrating such differences in the visual tasks, but previous work with children (L. B. Smith. 1980, 1981, 1983) and adults (J. D. Smith & Baron, 1981: L. B. Smith. 1981; L. B. Smith & Kilroy. 1979; Ward, Foley, & Cole, 1986) suggests that developmental differences do emerge with a broader age range. The second goal was to examine the relationship between adults’ performance on visual and speech classification tasks like those of Experiment I. EXPERIMENT

2

Method

Thirty-eight college students randomly selected from a larger pool of subjects used in another study served as subjects. Stimuli Visuul stimuli. The two sets of visual stimuli varied in either size and brightness or length and orientation. The size and brightness stimuli were squares varying in length of side and shade of grey. The six side lengths were I .9, 2.5. 3.1, 3.8, 4.4, and 5 cm. The six shades of grey ranged from a light grey to a dark grey (Coloraid notation: Greyl, Grey2, Grey3, Grey4, Grey6. and GreyS). The size and brightness stimuli were assumed to be comparable to the color and size stimuli in Experiment I. (This assumption is supported in Experiments 3 and 4). The length and orientution stimuli were arrows varying in length and orientation. The length and orientation values were the same as in Experiment I and were chosen in the same way. Each square or arrow in a triad was mounted on a separate 3 by 5 in. white card. Twenty triads structured like those in Experiment I were constructed from the size-brightness values and 20 were constructed from the length-orientation values. Speech stimuli. Fifteen experimental triads structured like those in Experiment I were constructed from consonant-vowel-consonant syllables. In addition, five practice triads were constructed. The three items

CLASSIFYING

BY DIMENSIONS

AND

KEADING

149

in each practice triad were nonidentical, but use of either a dimensional or similarity relation produced the same classification. The specific practice and experimental speech stimuli included those in Appendix A, with the exception of the first two practice stimuli. In addition, the four triads listed in Appendix B were used.

Visud stimuli. The procedure for the visual stimuli in Experiment 2 was identical to that in Experiment I except that there were no practice trials. All subjects had previously participated in a similar visual task with different stimuli. Therefore. they understood what was required. Spwch stimuli. Each adult was told that on each trial he/she would hear three syllables. He/she was to decide which two went together. The three syllables were presented from a prerecorded tape on a UHER 4300 tape recorder. After hearing the three syllables, the adult was asked to repeat them. All three syllables were then presented a second time. The adult was asked to decide which two sounded most alike and to circle the letters corresponding to his/her choice on an answer sheet. Adults’ classifications were corrected during the practice trials but not during the test phase. Half the subjects received the speech stimuli before the visual stimuli. The remaining subjects had the reverse order. The speech triads were presented in one of two random orders.

Results and Discussion The mean proportions of dimensional classifications for each task were .68, .43, and .64 for the size and brightness, length and orientation, and speech tasks, respectively. Dimensional classifications were frequent and significantly more common than for the second graders in Experiment I (t(54) = 3.49, p < .OOl, t(54) = 2.81, p < .OOZ, and t(53) = 2.58. p < .Ol, for the color and size/size and brightness, length and orientation, and speech tasks, respectively. all one-tailed). Consistent with previous results (e.g., L. B. Smith & Kilroy, 1979), classification by common parts was more frequent for the size and brightness stimuli than for the length and orientation stimuli (t(37) = 8.49, p < .OOl, one-tailed). The correlation between the two visual tasks was significant (r(36) = .77, p < .OOl, one-tailed), as in previous studies with adults (J. D. Smith & Baron, 1981; Ward et al.. 1986) and with the children in Experiment I. However, in a failure to replicate J. D. Smith and Baron, neither of the visual tasks correlated significantly with the speech task (r(36) = .12 for size and brightness and r(36) = .04 for length and orientation). (The low correlations involving the speech task were not due to range restrictions in any of the variables.) Thus, classifying speech by common parts does not appear to be closely related to classifying visual stimuli

150

GATTUSO, SMITH. ANDTKEIMAN

by common parts for the adults in this experiment or for the children in Experiment 1. The results of Experiments I and 2 corrld be taken to suggest that a strong association between classification performance with visual dimensions emerges with development. However, the low correlation between the two combinations of visual dimensions for children (Experiment 1) and the strong correlation between combinations of visual dimensions for adults (Experiment 3) may alternatively reflect the severe integrality of length and orientation for children. It is possible that this dimensional combination was so integral for the children that there was a virtual “floor effect” and they could not show their greater or lesser abilities to selectively attend to single dimensions. The results of Experiments I and 2 further suggest that the visual classification tasks used here are sensitive to developmental differences in selective processing ability. Experiment 3 asked whether there are additional developmental trends in classification performance in the period between second grade and adulthood by using second and fourth graders as sub.jects. To further examine the sensitivity of different tasks to differences in selective processing ability, Experiment 3 used two additional visual tasks. One was the size and brightness task used with the adults in Experiment 2. This particular dimensional combination is highly separable for adults (Ward et al., 1986) and is one for which developmental trends in classification performance have been demonstrated (L. B. Smith &r Kemler, 1977). The second additional dimensional combination was length and density. This dimensional combination is moderately separable for adults and, once again. is sensitive to developmental differences in classification performance (Ward. 1980). Experiment 3, therefore, employed four sets of visual stimuli and one set of speech stimuli. EXPERIMENT

3

Method Sixteen second graders (mean age 8 years, 0 months; range: 7.0-9.3) and 16 fourth graders (mean age: IO years, 0 months; range: 9,4-10.6) attending elementary schools, afterschool programs at daycare centers. and a girls’ club served as subjects. Some of the subjects (most of them fourth graders) were paid $3.00 for their participation in the experiment. Stirmtli Visud stimuli. The specific values of each dimension for the color and size, length and orientation, and size and brightness stimuli were identical to those used in Experiments I and 2. The lerlgth and density stimuli

CLASSIFYING

BY DIMENSIONS AND READING

151

were rows of dots (periods) varying in length and density typed with a Smith-Corona typewriter on 3 by 5 in. white cards. The seven length values were 1, 1.5, 2, 3, 4, 6, and 8 cm. The seven density values corresponded to seven interdot distances: .12.5. .25. .37, .50, .75, 1, and 1.5 cm. The three lines of each triad were typed in horiz.ontal rows, centered one above the other on the same card. As with the color and size and length and orientation values, the discriminability of the smallest differences employed was examined via a same-different oddity task with 10 preschoolers. All one step differences in the size and brightness stimuli were highly discriminable for the children. The values on the length and density set were the same ones used by Ward et al. (1986). Ten triads structured like those in Experiments I and 2 were constructed for each of the four dimensional combinations. In addition, four practice triads were constructed for each set. For two practice triads. two of the stimulus items were identical and one was different. For the remaining two practice triads, the three items were nonidentical but either a dimensional or a similarity relation produced the same classification. Sprc~h stimuli. Ten experimental triads structured like those in Experiments I and 2 were constructed from consonant-vowel-consonant syllables. These 10 triads were randomly chosen from those used in Experiment I. In addition. the six practice triads of Experiment I were used.

Visucrl arzd speeds stimuli. The procedures were identical to those in Experiment 1. Half of the subjects received the speech stimuli before the visual stimuli; the remaining subjects had the reverse order. The four different visual tasks were presented in four different orders such that each task was the first, second, third, and fourth task approximately equally often. The triads within each task were presented to the subjects in one of two random orders. The auditory triads were presented in a single random order. All testing occurred in the spring of the school year. Each child was tested in one session, approximately 15 min in length.

Results and Discussion Table 3 shows the mean proportions of dimensional classifications at each grade level for the five classification tasks. Also included in Table 3, for comparison. are the mean proportions of dimensional responses for the second graders and adults in Experiments I and 2. Dimensional responding was more frequent in the color and size and size and brightness tasks than in the length and orientation and length and density tasks (r(93) = 9.43, p < .0005, one-tailed. using the method

153

GATTUSO.

Color

SMITH,

AND

I .ength

TREIMAN

Size

& Gzr

K: orientation

K:

Length B

brightness

denvty

II4 SD

.43 .Ih

.I4 .I5

.43 .I7

.?(I I3

.5h

Fourth A4

Speech

Second .2

.17

.72

..w

.Y

.h’

SD Second”

.I7

.I5

.I9

.75

.71

hl SD

.‘u .I9

.?‘I .0x

-

.33 .2X

.47 .I9

A&Ilk?”

n-I .)‘!I NOIE. ” From ” From

N

=

I6 for

Experiment Experiment

all

tasks

in

Experiment

.6X .3h

.hJ .2-l

3.

I. 2.

of planned comparisons). as in previous work (I,. B. Smith & Kilroy. 1979; Ward et al., 19%). Also. performance on the color and size task was nearly identical to performance on the size and brightness task. supporting our assumption that these two tasks are comparable in ease of selectively attending to one dimension. Finally. the mean proportion of dimensional responses made by the second graders in Experiment 3 was nearly identical to the mean proportion of such responses made by the second graders in Experiment 1 for the color and size task, but not for the length and orientation task. No differences in classification performance between second and fourth grade were significant by t tests for independent groups. The absence of grade level differences in the visual tasks suggests that the transition from similarity based to dimensionally based classification of visual objects is not complete by the fourth grade. Indeed, even for the fourth graders, dimensional classifications did not predominate in any task. . The lack of a significant grade effect in the speech task has a different explanation. Here, the mean proportion of common phoneme classifications made by the fourth graders was almost identical to that made by the adults in Experiment 2. Thus, the fourth graders were at “ceiling” (in terms of adultlike responding) on the speech task. Tables 4 and 5 show the correlations among the five classification tasks for the second and fourth graders, respectively. For the second graders. all the correlations among the visual tasks were small and nonsignificant.

CLASSIFYING

153

BY DIMENSIONS AND READING TABLE4

CORRELATIONS

AMONG

THE TASKS FOR THE SECOND

Color & size Color & size Length & orientation Size & brightness Length & density Speech

Length & orientation

EXPERIMENT

Size & brightness

.I4

” This correlation is significant by a one-tailed is at the wrong tail of the distribution.

GRADERS,

.20 IO

test,

but the direction

Length & density -.I5 -.I9 ~ .?2

3

Speech .09 .I4 .27 ~ .48”

of the difference

For the fourth graders, all of the correlations among the visual tasks were strong and all but one was significant, consistent with results with adults in Experiment 2 and in J. D. Smith and Baron (1981). Interpretation of these data are complicated by the presence of a very large number of “preferrers” on the color and size and size and brightness tasks. These children appear to have attended to a single dimension across trials. For example, the color and size stimuli were constructed such that a dimensional classification was possible on the basis of color for half of the trials and on the basis of size for the remaining half. A child who selectively attended to color, for example, would have made dimensional classifications on half of the stimuli (i.e., the half in which the shared dimension MVZScolor) but overall similarity classifications on the other half-putting together the two objects that were closest in color. Table 6 presents the number of children “preferring” on each task for the two grade levels. Also presented in this table are the number of preferrers for each task in Experiment 1. For Experiment I, we defined a “preferrer” as a child who made dimensional classifications on at least four of the six triads in which the relevant dimension was dimension X (e.g., size), but who did not dimensionally classify more than two of the six triads in which the relevant dimension was dimension Y(e.g., color: see Fig. I). For Experiment 3, we defined a “preferrer” as a child who made dimensional classifications on at least four of the five triads in which the relevant dimension was dimension X, but who did not dimensionally classify more than one of the five triads in which the relevant dimension was dimension Y. In Experiment 3, over halJ’the children at each grade level preferred a particular dimension on the color and size and size and brightness tasks--selectively attending to and basing their classifications on one (usually size) of the two dimensions for each of these tasks. However. the fourth grade children. like the second graders in Experiment 1. more

1.54

GATTUSO.

SMITH.

AND

TABLE COKKELA~WNS

AMONG

THY TASKS

Color & Gzr Color & size Length & orientation Size & brightness Length & density Speech

KIR

Length &! orientation ..ss*

TREIMAN

5 IHE

FOURIH

GRADERS,

EYPERIMENI

Size & hrightnesa

Length ‘UC demity

.5l’ .w*

.?l .7J**’ .M*”

3

Speech .Oh ~~ .06 .27 .24

preferred than did the second graders in Experiment 3. Among the fourth graders, eight of the nine color and size preferrers were also size and brightness preferrers. Such consistency was not observed among the second grade preferrers in Experiment 3. At neither age level did the visual tasks correlate significantly with the speech task. The one exception to this was the strong, negative correlation between the length and density and speech tasks for the second graders. It is not clear why this particular correlation was less than zero. In sum. the children in Experiment 3. like the children and adults in Experiments I and 1, did not classify consistently across sensory modalities. Classifying speech stimuli by common parts did not appear to be positively related to classifying visual objects by common parts for either second or fourth graders. However, consistency in classification within the visual modality differed for the two grade levels in this experiment. These results are like those of Experiments I and 2 in that the relation between classifying different visual combinations of dimensions appears to increase with age. However. the present results differ somewhat from those of Experiment I in that the second graders in Experiment 3 showed no correlation among the visual tasks whereas those in Experiment I showed a weak but reliable one. This discrepancy suggests that young children’s tendencies in responding (and preferences for particular dimensions) are malleable and dependent on the task context. Thus. the correlations and means presented here may index children’s tendency to respond on the basis of a shared dimension or phoneme. rather than their crbifity to do so. The notion that tendencies in responding are reflected in the data is supported by the correlations among the three language related tasks in Experiment I. Although the correlation between performance in the cwzsistently

CLASSIFYING

NUMBER

BY

DIMENSIONS TABLE IN VISUAL

OF “PREFERRWS” Color

EXPERIMENTS

I ,AND 3

Size

orientation

& brightness

IO Y

2 9

IO

5 II Y

1

Y

I

Kindergarten First Second Note,.

READING

3

Fourth Experiment

Experiment

6 TASKS.

Length &

& size Experiment Second

AND

N

=

I6 for

each

grade

3 -

3 level

in

Experiment

3. N

IX for

each

grade

level

in

I,

speech classification task and reading ability was significant, this relationship was not as strong as that found in previous studies in which children were specifically told that classifications based on a shared sound were correct (e.g., Stanovich. Cunningham, & Cramer, 1984: Treiman & Baron. 1981). Thus, any age changes observed in the present work may be due to changes in prefi~ttcr rather than changes in ~&lit?. Perhaps the ability to classify visual objects on the basis of a shared dimension is related to the ability to classify spoken syllables on the basis of a shared phoneme, even though preference to classify by shared dimensions and preference to classify by shared phonemes are not related. Experiment 4 pursued this possibility. Children in Experiment 4 were given reading and spelling tests and were asked to classify on the basis of a shared dimension or phoneme. For the visual tasks, the children were presented with triads of stimuli identical to those in Experiment 3 and were explicitly asked to choose the one of the three that differed on a specified dimension from the rest. For the speech task, two of the syllables shared an irziriLll consonant in half the triads while two of the syllables in each of the remaining triads shared a.final consonant. Children were asked to choose the one of the three “words” that had a different beginning (or ending) sound from the rest. The introduction of a second potentially relevant dimension into the speech task made it more directly comparable to the visual tasks. EXPERIMENT Method

4

Sixteen kindergartners (mean age: 5 years, 9 months; range: 5.4-6.4). IS first graders (mean age: 6 years. I I months: range: 6,2-7,6), 16 second

156

GATTUSO.SMITH,ANDTKEIMAN

graders (mean age: 8 years, 5 months: range: 7.6-9.3) and 15 fourth graders (mean age: 10 years, 5 months; range: 9.4-12, I) attending elementary schools and daycare centers served as subjects. Two of the subjects (one first grader and one fourth grader) were each paid $3.00 per session for participating in the experiment. Stirnrrli Visd

.stirnzl/i. The four sets of visual stimuli

of Experiment

were identical

to those

3.

Spc~c~ch ,stimrr/i. Ten unique triads structured as shown in Fig. I were constructed from consonant-vowel-consonant syllables. For half the triads, the initial phoneme served as dimension X, the dimension by which a dimensional classification was possible. The final phoneme served as dimension X on the remaining five triads. All triads were constructed on the basis of similarity ratings of pairs of phonemes (Singh & Woods. 1971: Singh et al., 1972). The triads in which the initial phoneme was the relevant dimension were randomly chosen from the triads used in Experiment 3. The triads in which the final phoneme was the relevant dimension were constructed from the five triads in Experiment 3 not chosen for the “initial consonant relevant” portion of the task by reversing the initial and final phonemes of each syllable. The six practice triads were constructed analogously. The “final consonant relevant” triads are listed in Appendix C. Re(zdi)zg (rrld spelling tests. The reading and spelling tests were identical to those used in Experiment 1.

Visd stinzufi. The procedure used with the visual stimuli was identical to the procedure used in Experiments 1 and 3 except that children were asked to classify on the basis of a shared dimension. For the color- and six task, the children were asked to choose the circle that was a different color (or size) than the other two. For the lengtlz and orictztntion stimuli, the children were asked to choose the arrow that was a different length than the other two. To explore children’s knowledge of orientation as a dimension, they were asked to choose the arrow that was pointing in a slightly different direction from the rest. In the size and briglztness task, children were asked to choose the square that was a different size (or lightness or darkness) than the rest. In the length relevant trials of the length and drlzsity task. children were asked to point to the row that was a different length than the other two. Finally, on the density relevant trials. the child was asked to point to the row in which the dots were spaced differently than in the other two rows. Before the practice triads for the length and orientation and length and density tasks, the child was trained on the meaning of “length” if necessary.

CLASSIFYING

BY DIMENSIONS AND READING

1.57

Criterion for participation in the test phase was the same as in Experiments I and 3. Speech stimuli. The procedure for the speech stimuli was identical to that of Experiments I and 3 except that children were asked to classify on the basis of a shared phoneme. For example, the child was asked to point to the animal who had a name beginning (or ending) with a different sound than the other two. Criterion for participation in the test phase was the same as in Experiments I and 3. Reading and spelling tests. The procedure used with the reading and spelling stimuli was identical to the procedure used in Experiment 1. Half the subjects were given the reading test first and the other half were given the spelling test first. If a child was given the reading test first and read none of the words correctly. we did not proceed to the spelling test since children’s spelling ability on this test typically falls behind their reading ability. The letter-picture matching test of Experiment I always preceded the reading and spelling tests. The reading and spelling tests always followed the classification tasks. All testing took place in the spring of the school year. Most children were tested during two sessions, each approximately 30 min long. Results and Discussion Table 7 shows the mean proportion of dimensional classifications at each grade level for the five classification tasks. Dimensional responding was more frequent in the color and size and size and brightness tasks than in the length and orientation and length and density tasks for all grade levels (t(183) = 12.71, p < .0005, one-tailed, using the method of planned comparisons), consistent with findings of Experiment 3 and previous work (L. 9. Smith & Kilroy. 1979: Ward et al.. 19%). The proportions in Table 7 were submitted to one-way analyses of variance by grade, separately for each task. The analyses for the visual tasks revealed significant grade effects (F(3, 58) = 3.38, p < .05; F(3, 58) = 10.94, p < .OOl; F(3, 58) = 7.27. p < .OOl; and E’(3, 58) = 7.44, p < .OOl. for the color and size, length and orientation, size and brightness, and length and density tasks. respectively). For the color and size and length and orientation tasks, the tendency to classify on the basis of a shared dimension increased significantly from kindergarten to first grade (p < .05 and p < .Ol for color and size and length and orientation. respectively. An approximate Scheffe post hoc test for unequal groups was used here and in all that follows.). For all tasks except the color and size task, the proportion of dimensional classifications increased significantly from kindergarten to fourth grade (p < .Ol for all) and from second to fourth grade (p < .Ol for size and brightness and length and

I58

GATTUSO.SMITH,

PROPOR-II~N

ANDTKEIMAN

ok DIM~NSIONAI

'FABLE 7 CI ASSI~-ICA~I~NS.

EXP~RIMEN

I 3

Color

Length

Size

Length

& size

& orientation

& brightness

& density

.75

.36

.70

.43

.1x 16

.I?4 I6

.IX Ih

.72 I6

.37 .I7 I3

M

.91

.hl

.x.5

.57

.h7

SD N

IO IS

.32 I5

.I

.22 IS

.I% I.‘,

.x1

.>I

.73

.3x

.$I)

.I7 I6

.N I6

.IX Ih

.-‘I Ih

.‘3 Ih

Fourth M

.XX

.77

SD I\’

.I3 I5

.IX IS

.Y2 .07

.7h .I7

.71 .I6

I5

Ii

IS

Speech

Kindergarten

M SD N First

IS

Second

M SD N

density, p < ,025 for length and orientation). None of the smaller differences were significant. The analysis of variance for the speech task also revealed a significant grade effect (F(3. 55) = X.76. p <: .OOl). Shared phoneme classifications increased significantly from kindergarten to first grade (p < .Ol), from kindergarten to second grade (p < .05). and from kindergarten to fourth grade (p < .()I). with none of the smaller differences significant. In this experiment. dimensional classifications were frequent at (111age levels. This result is quite different from those of Experiments I and 3 and of L. B. Smith and Kemler (1977). where overall similarity classifications predominated in the early grades. However. the predominance of dimensional classifications fits with more recent work (e.g., L. B. Smith, 1989) showing that young children can selectively attend to single dimensions. To compare performance with explicit versus nonexplicit instructions, Figs. 2-5 show the mean proportions of dimensional classifications at each grade level for explicit and nonexplicit tasks. These data were submitted to four instruction by task repeated measures analyses of variance, one for each grade level. Dimensional responding was more frequent with explicit instructions at all grade levels (I;(I. 19) = 24.34. p < ,001: F(1, 29) = 196.46, p < ,001; t;(l. 30) = 39.45, p < .OOl: and F( I, 29) = 69.82; p < .OOl for kindergartners. first, second, and fourth graders, respectively. Included in these analyses were data from subjects

CLASSIFYING

BY

DIMENSIONS

AND

159

READING

111 Nonexplicit

C&X L Size FIG. explicit

2.

Mean

proportion

dimensional

Length L Orientation responses

Speech

for

kindergwtners

on

nonexplicit

vs.

task\.

who completed all the classification tasks.). In addition. the interaction between task and instruction was marginally significant for kindergartners (F(2, 38) = 3.17, p < .053) and significant for the remaining grade levels (FE 5X) = 4.42, p < .02; F(4, 120) = 6.60, p < .OOl; and F(4. 116) = 9.32, p < .OOl for first, second. and fourth graders, respectively). For kindergartners and first graders, the interaction reflected the very large difference between performance with and without explicit instructions

Ii .$= 0.8 E g 0.6 E ‘Z f 0.4 2 Ii c I

0.2

Color a Size FIG. explicit

3. Mean tasks.

proportion

dimensional

Length & Orientation

Speech

responses

for

first

graders

on

nnnexplicit

vs.

160

GATTUSO.

SMITH.

A&D

TREIMAN

Nonexplicit

z.o_

I

0.8

2 E 5

0.6

s ‘S ‘,::

0.4

ri 5 %

0.2

Color & Size

FIG. explicit

4.

Mean

proportion

dimensional

Length & Orientation

Explicit

Size a Brightness

reaponseh

for

Length IL Density second

graders

Speech

on

nonexplicit

vs.

tasks.

in the color and size task @ < .01. for both ages). This difference confirms that the kindergartners and first graders in Experiment I MYW preferring and basing their judgments on one dimension in the color and size task. despite their ability to classify such stimuli on the basis of a shared dimension when told to do so. The smaller increases in dimensional responding in the speech task with explicit instructions supports the Nonexplicit

n

Color L Size FIG. explicit

5. Mean tasks.

proportion

dimensional

Length & Orientation

Explicit

Size & Brightness

responses

for

Length 8 Density fourth

graders

Speech

on

nonexplici~

vs.

CLASSIFYING

BY DIMENSIONS TABLE

TOTAL READING

-Kindergarten M SD N First M SD N Second M Sfj N Fourth M SL) N

AND READING

161

8

AND SPELLING

SCORES, EXPERIMENT

4 Spell

Read 1.80 7.49 5

1.20 .4s 5

47.53 75.76 I5

35.40 20.94 15

54.12 22.69 16

32.00 21.70 I6

85.13 6.28 I5 ~~ ~ .~~ -~ __~ _~ Ncjrc~. The maximum total reading or spelling score was 96.

~~~ ~~~

69.00 13.36 I5

notion that ability-rather than preference-is a limiting factor here. This idea is even more compelling upon consideration of the second and fourth grade data. Explicit instructions to classify on the basis of a shared sound did not significantly increase the proportion of common phoneme classifications made. However, explicit instructions to classify on the basis of a shared dimension did increase dimensional responding in the visual tasks. Thus, explicit instructions to classify on the basis of a shared dimension or a shared phoneme bring even the youngest children up to adult “nonexplicit” levels in the visual tasks. The same is not true in the speech task. In fact, only the first graders benefitted significantly (p < .Ol) from explicit instructions in the speech task. Explicit instructions were ineffective with the younger children and unnecessary for the older children. Thus, preference in responding may be the source of young children’s overall similarity responses in the visual tasks, but not in the speech task. Rather, an inability to segment the speech stream into phonemes may be the limiting factor. Reuciing rind Spelling Tests Table 8 presents the means obtained by averaging the total reading and spelling scores across all the subjects at each grade level who scored at least 90% on the letter-picture matching test and read or spelled at least one word correctly. An analysis of the total reading scores revealed

162

GATTUSO.SMITH.ANDTREIMAN

a significant main effect (F(3, 47) = 26.82. p < .OOl), as did an analysis of the total spelling scores (F(3, 47) = 34.72, p < .OOl). First graders outperformed kindergartners tp < .Ol, for both reading and spelling), and fourth graders outperformed second graders (I, < .Ol , for both reading and spelling). The differences between the first and second graders were not significant. To examine the correlations between the speech classification task and the various subtests (regular. exception, and nonsense) of the reading and spelling tests, we computed z-scores for each of the reading and spelling subtests as in Experiment I. The three correlations between the speech classification scores and the reading and spelling of regular (I’(49) = .54, p < .OOl), exception (~(49) = .5l. p < .OOl), and nonsense (~(49) = .52, p < .OOl) z-scores corroborate earlier findings of a link between common phoneme classifications and reading and spelling in general. However. they do not provide strong support for the link between segmentation ability and the learning of letter-sound rules in particular, since the differences between the correlations were small and nonsignificant.

It is difficult to interpret the correlations for each grade level separately because of the many range restrictions in the values of the variables. It is. in this case, perhaps more meaningful to look at the correlations for some of the grades combined. Specifically. we examined the correlations for the kindergarten, first, and second graders combined. The correlations involving the reading and spelling tests would be difficult to interpret if we combined all four grades because the mean reading and spelling scores for the fourth graders are considerably higher than those for the other children. The fourth graders represent what McCall ( 1986) calls an “extreme” group. (One could argue that the kindergartners also represent an “extreme” group because they have extremely low reading and spelling scores. However, given the small number of kindergartners whose scores contribute to the reading and spelling correlations. the pattern of correlations remains essentially the same whether or not they are included, Including them does, however. allow more direct comparison with the results from Experiment I. 1 Accordingly. Table 9 presents the correlations among the tasks for the kindergartners. first. and second graders. The correlations involving the proportions of dimensional classifications on the visual tasks were all significant, as in Experiments I and 2. and in Ward et al. (1986). Inconsistent with the findings of Experiments I and 2 are the sizeable correlations between the speech and color and size, length and orientation, and length and density tasks. Thus, giving explicit instructions on structurally similar tasks can result in performance on one task being

CLASSIFYING

BY

DIMENSIONS TABLE

CORR~LAIIONS

Color Length

8.~ size & orient.

Size & bright. Length & density Speech Read Spell

AND Y

AMONG THE TASKS FOR THE KINDERGARTNERS. EXPERIMENT 4 Color

Length

& size

& orient. .2x*

163

READING

FIRSI..

AND SECOND GRADERS,

Size &

Length &

bright.

density

Speech

Read

.50**** .52****

.37** .47****

.37** .53****

-.II .29*

.59****

.?I .37_”

.04 .?I .>I***

Spell ~ .I0 .31* .OY .75 .44*** ,xX*“**

predictive of performance on another task-even across sensory modalities. Whereas the correlations between speech and reading and speech and spelling were moderately large and significant. most of the correlations between the visual tasks and reading and spelling were small and only a few were significant. Thus, classifying speech stimuli by common phonemes appears to be more related to reading and spelling than does classifying visual stimuli by common parts. Supporting this conclusion, performance on the speech task was more highly correlated with reading and spelling than was performance on any of the visual tasks (p < .OOl, one-tailed, for all, using the test for dependent correlations recommended by Appelbaum and McCall, 1983). The total pattern of correlations is similar to that of Experiment 1 in that classifying one set of visual stimuli by dimensions was predictive of classifying other visual stimuli by common parts. In addition. reading and spelling ability was closely related to classifying speech stimuli by common parts, but not to classifying most visual stimuli by common parts. However, unlike in the previous experiments. the children in Experiment 4 often classified consistently across sensory modalities. GENERAL DISCUSSION Our results suggest that phonemic segmentation skill may be only weakly related to the more general ability to selectively attend to the parts of whole objects. The children and adults in Experiments I. 2, and 3 did not classify consistently across the visual and auditory modalities. despite the structural similarity of the tasks. Further, performance rt-ithin

164

GATTUSO.

SMITH.

AND

TREIMAN

the visual modality was not always consistent. Although the fourth graders in Experiment 3 and the children and adults in Experiments I and 2 classified consistently across the different visual tasks, the second graders in Experiment 3 did not. This inconsistency is difficult to interpret because of the large number of children who “preferred” in some of the visual tasks-selectively attending to and basing their judgments on OIZ~ of the two relevant dimensions. In contrast, the combined data from the children in Experiment 4 suggest that performance in the two modalities can be consistent if the tasks are structurally similar ad if explicit instructions are given to classify on the basis of a particular shared dimension or phoneme. Indeed. explicit instructions resulted in a dramatic increase in dimensional responding, although the magnitude of this increase varied with the age of the child and the modality. For instance. explicit instructions increased the dimensional responding of even the kindergartners to adult “nonexplicit” levels in the visual tasks. but tzot in the speech task. Thus. preference in responding does not explain younger children’s overall similarity responses in all the tasks. Preference can limit performance only when the ability to classify by dimensions is already present. Although preferences in responding may serve as limiting factors in the visual tasks, they seem to play a lesser role in the speech task. Rather, responding in the speech task may the major obstacle to “dimensional” be an inability to segment the speech stream into distinct components. That the limiting factors in the two modalities are different is even more reasonable when we consider that the preference/ability distinction does not appear to affect the relation between performance on the classification tasks and reading and spelling. Regardless of whether the task is explicit or nonexplicit, the conclusion is the same: classifying spoken syllables by shared phonemes is more related to reading and spelling ability than is classifying visual objects by shared constituents. Thus. some general perceptual limit (whether based in preference or ability) is probably rzof the source of differences in reading and spelling performance. Rather. young children’s dehcient phonemic segmentation skills may be specific to reading or language use. Such a conclusion is inconsistent with the suggestion of Wolford and Fowler (1984) that the deficit of poor readers is not specific to reading. Wolford and Fowler tested good and poor beginning readers on memory for letters using two different tasks-one which promoted visual encoding of the stimuli and one which promoted phonetic encoding. Finding comparable deficits in poor readers’ use of both phonetic and visual information, Wolford and Fowler suggested that good and poor readers differ in general ability to use stimulus attributes. However. since the stimuli (letters) used in the “visual” and “auditory” tasks were the same. the results may be specific to the alpizahetic~ visual stimuli used-stimuli

CLASSIFYING

BY DIMENSIONS AND READING

165

which are “linguistic” in that naming letters is clearly related to later reading skill (see Stevenson, Parker, Wilkinson, Hegion, & Fish. 1976). visual stimuli suggest that consistency in These results with “linguistic” performance across modalities may be stimulus-specific. Additional evidence consistent with the view that specific learningrather than general skill development-is needed for the development of phonemic segmentation skills comes from studies of adult illiterates. Morais et al. (1979), for example, administered a phonemic segmentation test to Portuguese literate and illiterate adults. Literate, but not illiterate, adults succeeded, leading Morais et al. to suggest that phonemic analysis skills are, at least in part, a consequence of learning to read. Additional support for this conclusion comes from Read et al. (1986), who compared Chinese alphabetic and logographic literates. Like the Portuguese illiterates studied by Morais, the nonalphabetic literates performed significantly worse than the alphabetic literates. The evidence from illiterate adults supports the view that special experiences with language, such as those involved in learning to read an alphabetic writing system. are required for the development of phonemic segmentation skills. The present results are certainly compatible with this view. Classifying by phonemes was more closely related to reading and spelling ability than was classifying by visual constituents, irrespective of whether explicit instructions were given. Moreover. reading and spelling skill did not generally correlate with children’s ability to selectively attend to the parts of visual wholes. Indeed, classification by dimensions in the visual modality appeared to differ fundamentally from classification by phonemes in the auditory modality. Our results imply that dyslexics’ difficulty in learning and using lettersound rules (Boder, 1973; Kochnower. Richardson. & DiBenedetto, 1983: Olson. Kliegl. Davidson, & Foltz, 1984; Snowling, 1980, 1981) stems from specific reading-related deficits rather than visual (or general perceptual) deficits (see also Vellutino, 1977, 1987). Training in phonemic analysis may be helpful or even necessary for learning to read (Treiman & Baron, 1983; Walley et al., 1986; Wolford & Fowler, 1984). Likewise. attention to the parts of perceptual wholes other than speech may also require specific learning about dimensions (see, e.g., L. B. Smith, 1979). Children may attend to the parts of objects and language only when they gain experience with the “units” that make up the “wholes” within that particular area.

166

GATTUSO. SMITH. AND TREIMAN APPENDIX SPEECH

STIMULI,

A EXPERIMENT

I

Position

Prcrctice

rAf prrg laz wis zeisut

siS pq 1~6 Eog zrS suk

rAf Ire m3k wet3 hub nip

OAC fud v/zn PEC dek zed sot too exk prm diz

vol biv oub beo ta3 dep seb f&m p3f f&p pus bun

brk zlb ois vif tAb dol sok fup tiz HOT ten brs

phoneme

Similarity

l&2 l&2 2&3 l&3 3&? I&I Z&3 3&3 I&? l&3 l&2 2&i

I&3 2&? l&Z 2&3 l&7 l&2 I&2 l&3 l&t2 I&:! I&3 I&3

APPENDIX ADDITIONAI

pair

l&3 l&2 I&:! l&3 I&? I&2 Common

Test vcg

of correct

SPEECH

Haphazard 2&? l&3 l&3 I&2 l&1 2&3 l&3 l&1 ?&? 7 ‘% 3 2&L.? l&l

B

STIMUI.I,

EXPEKIMEN

I 2

Position of correct pair

Pmcticr

yawl

kib

klv

1&3 Common

Tcj.st

Seb cld tls pee do.7 def

corn tur bcs

phoneme

Z&3 I&? I &2

Similarity

Haphazard

I&1 I&2 Z&3

l&3 1&3 l&3

CLASSIFYING

BY

DIMENSIONS

AND

APPENDIX FINAL

C

SPEECH STIMULI,

PHONEME

167

READING

4

EXPERIMENT

Position of correct pair f9xc.tic.c

zzel

be1

ksm

tus

kos

pin

l&2 l&2 Common

gev Ld

lov vi6 ked pe6 dez bes tus m2ef

Test

klb blz lod kos puf

phoneme

Similarity

Haphazard

l&3 Z&3 I &2 l&3 I&?

Z&3

l&2 l&2 I813 1.&3

Z&3

l&3

3&3 l&3 l&2

REFERENCES Appelbaum.

M.

chology. Wiley

I.,

&

McCall.

R.

In P. H. and Sons.

Mussen

(Ed.).

Buder.

E. t 1973). reading-spelling 687.

Bruce.

D. J. t 1964). The Edrfc~rrtiotfu/ P.~ddog~.

Calfee.

R.

C..

Developmental patterns.

Lindamood.

learning Springer Fox,

R..

to read Verlag.

P.,

&

Routh,

B

D.

Apphtl

spell. K.

alters

(1975).

E.

J. ( 1969).

Prirrc,ip/r.t

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