Understanding communicative cues of infants with down syndrome: Effects of mothers' experience and infants' age

JOURNAL OF APPLIED DEVELOPMENTAL PSYCHOLOGY 13, 1-16 (1992)

Understanding Communicative Cues of Infants With Down Syndrome: Effects of Mothers' Experience and Infants' Age JAMES K. HYCHE, JR. ROGER BAKEMAN LAUREN B. ADAMSON

Georgia State University

Eighty mothers, half with Down syndrome (DS) infants and half with non-handicapped (NH) infants, were asked to watch videotaped segments of infants, half of whom were DS and half of whom were NH. Infants were matched far mental ages (MA) of 7, 10, and 16 months. Mothers were instructed to push a button whenever infants acted in a way they found salient, a measure which we believe reflects infant readability. Conh'oUing far maternal education, mothers of DS infants noted more acts overall than mothers of NH infants. Only at 7 months/CA were DS infants seen as less readable than NH infants. All mothers found infants, both DS and NH, more readable with age. These results provide iustification far intervening early with parents of DS infants, helping parents identify the more subtle nature of the preverbal cuing of their young infants.

The past 20 years o f developmental research concerning infants have been marked by the discovery of the young infant's adaptive competencies in preverbal communication (Adamson & Bakeman, 1991; Ainsworth, Bell, & Slayton, 1974; Brazelton, Koslowski, & Main, 1974; Richards, 1974; Stern, 1974). From this research has emerged the concept of an infant's "readability" (Goldberg, 1977), which refers to the extent to which an infant's behaviors are clearly defined and thus provide distinctive communicative signals for adults. Reading an infant's communicative signals can be regarded as a multistep process consisting of: (a) awareness of the infant's signaling behavior (Ainsworth et al., 1974; Crawley & Spiker, 1983); (b) selection from the ongoing stream of

The present report is based on a dissertation submitted to Georgia State University by the f'wst author. We thank Angie Richardson of the Atlanta Chapter of the Down SyndromeAssociationfor her assistance in recruiting subjects and Charles Hopperfor technical assistance with instntmentatlon. Correspondence and requests for reprints should be sent to Roger Bakeman or Lauren B. Adamson, Department of Psychology,Georgia State University, Atlanta, GA 30303, or James K. Hyche, North Fulton Early Intervention Program, 5025 Roswell Road, Atlanta, GA 30342.

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HYCHE,BAKEMAN,AND ADAMSON

infant behavior the particular signals to be interpreted (Adamson, Bakeman, Smith, & Waiters, 1987); (c) attribution of intention and meaning to the cues selected (Brazelton et al., 1974; Bmner, 1982; Fraiberg, 1974; Richards, 1974; Shorter, 1974); (d) decision-making regarding the caregiving or communicative response called for (Goldberg, 1977; Sorce & Emde, 1982); and (e) delivery of the chosen parental response (Crawley & Spiker, 1983): The research reported here focuses on factors that we believe influence the second step in the process, the selection of behaviors that the recipient interprets as signals. In order to examine the process by which adults segment infants' behavior, a method is needed that allows the recording of the subjects' selection of acts without requiring them to interrupt their observation of ongoing behavior. In addition, the recording of several adults' readings of several infants is needed if the effect of variables such as infant age and developmental status is to be probed. A research paradigm meeting these requirements was developed in an earlier study by Adamson et al. (1987). Inspired by the work of Newtson (Newtson, 1973; Newtson & Enquist, 1976; Newtson, Enquist, & Bois, 1977), who investigated how adults segment streams of behavior into meaningful units, Adamson et al. (1987) showed videotapes of infants in various situations and instructed subjects to press a button whenever an infant was observed behaving in a manner the adults found salient. The timing and occurrence of each button press was automatically recorded, with the result that the number of button presses became a measure of how clearly defined, textured, or readable an infant's behavior seemed to the observer. Using this procedure, Adamson et al. (1987) investigated the effects of two infant factors, age (9, 15, and 21 months) and engagement state (attending to an object exclusively or attending to an object and mother jointly); one subject factor (parents versus nonparents); and a contextual factor (type of instruction given to observers) on how adults select acts from the preverbal communicative behavior streams of normally developing infants. The instruction manipulation consisted of instructing one half of the subjects to press the button each time a meaningful act was observed and the other half to press the button each time an intentionally communicative act was observed. This manipulation was designed specifically to investigate the distinction (Lock, 1980) between "true communicative acts" (the sender intends to communicate) and "perceived communicative acts" (the recipient perceives a meaningful act that the sender does not necessarily intend). Adamson et al. (1987) found that adults pressed the button more when instructed to look for meaningful acts but agreed more when instructed to look for communicative acts and that the frequency of button presses increased systematically with the infants' ages. Parents were found to press the button more frequently than nonparents when given the "meaningful" instruction, but there were no differences between parents and nonparents when given the "communicative" instruction.

COMMUNICATIVE CUESOF INFANTSWITH DOWN SYNDROME

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Based on these findings, Adamson et al. (1987) concluded that "the emergence of consensual communication depends both on developmental changes in infants' behavior and the interpretative skill of their social partners" (p. 386). What happens, however, when the infants being observed have a diagnosed developmental disorder such as Down syndrome (DS) and when some of the observers are mothers with a child diagnosed with DS? Is the emergence of consensual communication for these infants tied to development in the same manner as it is for nonhandicapped (NH) infants? Are mothers of children with DS, by virtue of their experience with these infants, better at reading the preverhal signals of infants with DS than mothers of NH children? A review of the research conducted over the past 20 years has yielded very little direct information on the clarity or "readability" of DS infants' preverbal communicative cues. However, when compared with NH infants, infants with DS have been found to exhibit lower vocal output during the fLrSt 3 months following birth (Berger & Cunningham, 1983), to smile and vocalize less frequently (Buckhalt, Rutherford, & Goldberg, 1978; Rothbart & Hanson, 1983), to be chronologically delayed in the establishment of adequate levels of communicative eye contact (Berger & Cunningham, 1981), and to exhibit, overall, less intensity in expressions of affect (Cicchetti & Pogge-Hesse, 1982; Cicchetti & Serafica, 1981; Cicchetti & Sroufe, 1976; Thompson, Cicchetti, Lamb, & Malkin, 1985). With respect to the sensitivity or "reading" skills of mothers of DS infants, Sorce and Emde (1982) reported that mothers of DS infants were much more likely to select stimulating activities in response to photographs depicting low intensity emotional expressions of their infants than were mothers of normal infants. Similarly, mothers of children with DS have been found to be more responsive to their child's signals than the mothers of the NH, developmentalage-matched children and to exhibit higher levels of contingent responsiveness (Fischer, 1987). Conflicting findings have been repotted regarding such maternal-style behaviors as directiveness, sensitivity, and intrusiveness (Crawley & Spiker, 1983; Fischer, 1987; Jones, 1977, 1979, 1980; Maurer & Sherrod, 1987). The present research utilized methodology developed by Adamson et al. (1987). Mothers observed DS and NH infants who were matched for developmental age (i.e., mental age [MA]). Half the mothers had had experience with DS infants and half the mothers had not. Specifically, we predicted that: 1.

2.

Infants with DS, even when matched for developmental level with their NH peers, will be perceived as exhibiting less clear communicative signals. Although DS infants are quite heterogeneous, the majority of the findings reviewed here point toward predictions of reduced clarity in the communicative cues presented by DS infants (see also recent reviews by Pruess, Vadasay, & Fewell,'1987; Richard, 1986), Mothers of DS infants will perform differently on the experimental task than

HYCHE,BAKEMAN,AND ADAMSON

4

.

4.

mothers of NH children. Because of their prior experience with DS infants, we predict they will note more acts when observing DS infants than will mothers of NH infants--analogous to the parents in the Adamson et al. (1987) study who noted more acts for infants in general than did nonparents. Replicating Adamson et al. (1987), mothers of both groups of infants will note more meaningful than intentionally communicative acts. Again replicating Adamson et al. (1987), more acts will be noted for developmentally older infants.

METHOD Subjects Subjects in this study were 80 mothers of children under the age of 18 years. One half of the subjects were mothers of children with a confn-med diagnosis of DS. The remaining 40 subjects were mothers of children with no diagnosed or suspected developmental problems. All subjects were recruited individually by telephone and were informed that the research involved infant-parent interaction. The mothers of the children with DS (DS sample) were recruited from the local chapter of the Down Syndrome Association, Inc. The mothers of the NH children (NH sample) were volunteers recruited from the PTA membership and the immediate neighborhood of a local public elementary school. The mothers ranged in age from 28 to 53 years. Mean ages for mothers of DS children and mothers of NH children were 38.7 and 36.3 years, respectively. The average number of years of education for the DS sample was 15.25 with 78% having had at least 2 years of college. The NH sample averaged 16.25 years of education and 93% had completed at least 2 years of college. All subjects reported annual incomes above $30,000 with 82% of the DS sample and 95% of the NH sample reporting incomes above $40,000. The subjects' children ranged in age from 1 month to 17 years, with 73% of the total sample having at least one child 5 years of age or younger at the time of participation. Subjects averaged 2.20 children (M = 2.33 for DS, M = 2.08 for NH).

Stimulus Dyads In order to provide a stimulus videotape similar in design to that developed by Adamson et al. (1987), infant-mother dyads in which the infant had a confirmed diagnosis of the trisomy 21 form of DS and infant-mother dyads in which the infant had no known developmental problems were contacted for possible videotaping. We selected physically healthy infants who were between chronological ages 8 and 30 months for DS infants and 6 and 15 months for NH infants. The Mental Scale portion of the Bayley Scales of Infant Development (Bayley, 1969) was administered during scheduled home visits. Fifteen infants with mental age equivalents in the range of 6 to 16 months were videotaped for a minimum of 10 consecutive minutes using a hand-held color camera (Panasonic PV 200). The

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TABLE 1 Characteristics of Infants Selected for Videotaping DS Infants

NH Infants

Sex

CA

MA

Sex

CA

MA

F M M M F F

9 8 15 15 26 23

6.5 7.0 11.5 10.5 16.5 17.0

F M F M F M

7 6 9 8 14 13

7.5 7.5 9.5 9.0 15.5 15.0

Note. DS = Down s y n d r o m e ; NH = nonhandicapped; CA = chronological age (in months); M A = mental age (in months; Bayley 1969); F = female; M = male.

same set of age-appropriate toys was provided to all participants. Mothers were instructed to "Play with your baby as you normally would." During most of the taping, the camera was positioned behind the mother and aimed face-on at the infant. Twelve mother-infant dyads were selected from the 15 videotaped and were used in preparing the stimulus tape. Our sampling design specified three developmental levels--7, 10, and 16 months MA. These ages were chosen to cover the developmental age span surrounding the emergence of spoken language. In addition, the design specified that the 7 and 10 month (MA) DS infants should be as close to 10 and 16 months chronological age (CA) as possible so that, in addition to comparing DS and NH infants at 7, 10, and 16 months MA, DS and NH infants of approximately 10 and 16 months CA could also be compared. The actual MAs and CAs of selected infants are presented in Table 1. Stimulus Tapes A 1-min segment of videotape was selected for each of the 12 dyads. These segments were the first 60 consecutive s in which: (a) the infant was engaged in play with, or was in the immediate presence of, his or her mother; (b) no observable disruptions to either the infant's or the mother's attentional focus occurred as a function of external sights or sounds, for example, telephone, doorbell, entry of another person and so forth; (c) the infant was not preoccupied with the camera in that no more than three brief glances nor a single glance longer than 5 s toward the camera occurred; (d) the infant did not exhibit sustained crying (i.e., 15+ s); and (e) the infant's face, profile, or full body did not disappear from view for longer than 5 s and shorter disappearances did not total more than 2 s. The stimulus tape consisted of twenty-eight 1-min segments, each separated by 12 s of blank tape. Each segment was presented twice in succession so that

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HYCHE,BAKEMAN,AND ADAMSON

observers could f'wst look and then react; thus, segments 1 and 2, 3 and 4, 5 and 6, and so forth, were identical. The first pair depicted an NH infant, the second a DS infant; these four segments were used for practice only. The final 24 segments, used for data collection, depicted the 12 dyads described in the previous paragraph. In order to control for possible order effects, two versions of the stimulus tape were prepared (order 1 and order 2). They differed only in the randomly determined order of presentation for the final 12 pairs. Instructions Two different sets of instructions were developed for use in guiding subjects' responses to the stimulus tapes. In the communicative instruction, subjects were told that we were interested specifically in how adults know when infants have intended to express something. These subjects were asked to press the button whenever they saw infants trying to communicate with their mothers. In the meaningful instruction, subjects were told that we were interested specifically in how adults know when infants have done something understandable; that is, how adults decide when infants have acted in a meaningful way. These subjects were asked to press the button each and every time they saw infants behaving in a way that was meaningful or made sense to them. Procedure The study took place in a small room containing a VCR (Akai VS-603U/UM), a 13-in. color television (Emerson ECT 1300A), an audiocasette recorder (Panasonic RQ-2104), and a cylindrical-shaped, hand-held relay switch. The relay was connected to an event recorder display manufactured by Lafayette Instruments and located in an adjacent room. Subjects were run individually. Upon arrival, subjects completed a demographic background questionnaire. Instructions were played for each subject from audiotape with a printed copy also being provided. Subjects were instructed to preview the first segment of each pair by watching "as if you were in the mothers place." This gave subjects ample opportunity to become familiar with the segment and to make preliminary decisions about the behaviors they observed. During the presentation of the second segment for each pair, they were instructed to press the button each and every time they observed infants behaving in the manner specified in the instructions they received. of instruction was balanced across both maternal status groups. The total number of button presses for each infant was recorded. RESULTS The number of infants' acts selected (i.e., the number of times subjects in each experimental condition pressed the button) was analyzed with a mixed design analysis of covariance. Two factors were used as covariates, maternal age and

COMMUNICATIVE CUES OF INFANTSWITH DOWN SYNDROME

7

maternal education. As reported earlier, mothers of DS infants were older and had fewer years of schooling than moflmrs of NH infants (the point biserial correlations of age and education with mammal status were .24 and - . 2 8 , p < .02 and p < .01, respectively), thus, it made sense to control these two factors statistically. Moreover, although mammal age did not correlate with the number of acts selected (r = - . 0 7 , N.S.), maternal education did (r = .19, p < .05). Thus, replicating Adamson et al. (1987), we also found a positive correlation between education and number of acts selected. Three factors were between subjects: maternal status, which indicated whether the subject was a mother of a D S infant or an N H infant;instruction, which indicated whether the subject was given the meaningful or the intentionallycommunicative instruction;and order, a methodological control variable which indicatedwhether the subjectsaw order I or order 2 of the stimulus tape. A n additional two factors were within subjects: infant status (DS or N H ) and developmental age (7, 10, or 16 months). The resultsof thisanalysisare summarized in Table 2. The hypothesized main effect for maternal status, controlling for maternal age and education, was significant. The hypothesized main effects for instruction and developmental age were also significant although each was qualified, but not changed substantially, by two-way interactions that were qualified in turn by two significant three-way interactions (Instruction x Infant Status × Developmental Age and Maternal Status x Order x Developmental Age). The hypothesized main effectfor infantstatuswas not significant.However, both infantstatusand TABLE 2 Summery of Analysis of Variance Source of Variation

d/r

F

All Main Effects (both Between and Within) Covariates (Age and Education) Maternal Status Instruction Order Infant Status Developmental Age

2,70 1,70 1,70 1,70 1,72 2,144

2.99 4.37* 9.12"* 0.51 1.94 86.12"**

Significant Two-Way Interactions Maternal Status x Order Instruction x Age Infant Status x Age

1,70 2,144 2,144

10.61"* 20.49*** 60.01"**

Significant Three-Way ~ n = Maternal Status x Order x Age Instruction x Infant Status x Age

2,144 2,144

86.73** 10.34"**

*p < .05; * * p < .01; * * * p < .001.

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HYCHE, BAKEMAN, AND ADAMSON

maternal status appeared in two-way interactions that were qualified in turn by the same two significant three-way interactions that qualified instruction and developmental age. The two significant three-way interactions are described in the next two sections.

Instruction, Infant Status, and Developmental Age Subjects instructed to note meaningful communicative acts pressed the button more (M = 7.8 and 5.4/min for meaningful and intentionally communicative instructions, respectively) and developmentally older infants received more button presses (M = 5.0, 6.8, and 7.9/rain for 7, 10, and 16 months MA, respectively). These main effects were qualified by Instruction x Age and by Infant Status x Age interactions that were qualified in turn by an Instruction x Infant Status x Developmental Age interaction (see Table 3). The instruction effect was pervasive. For all six of the groups defined by infant status and age, more acts were selected when subjects were instructed to note meaningful acts than when instructed to note intentionally communicative ones (in Figure 1, the two dotted lines representing meaningful and communicative instructions when viewing DS infants do not cross nor do the two solid lines representing meaningful and communicative instructions when viewing NH infants). The age effect was almost as pervasive. For three of the four groups defined by instruction and infant status, the number of acts selected either increased or remained the same for the next developmental age. The exception was the NH infant group viewed by subjects who received the intentionally communicative instruction. For this group, the number of acts selected per minute actually declined (from 6.1 at 10 months to 4.9 at 16 months), whereas for both DS and TABLE 3 Mean Number of Acts per Minute Noted by Subjects Given Different Instructions and Viewing Infants Differing in Status and Developmental Age Developmental Age (Months) 7

10

16

Meaningful Act Down Syndrome

5.4bc

Nonhandicapped

6.5de

7.5f 7.4ef

10.20 9.5g

Communicative Act Down Syndrome Non handicapped

2.9a 5.3bc

6.0ca 6.1ca

Instruction/Infant Status

6.9def 4.9b

Note. Scores are means based on the 2 min of videotape viewed by each subject for each age, instruction, and infant status combination (N = 40). Means sharing a common subscript are not significantly different (p < .05) by the Tukey post-hoc test.

COMMUNICATIVECUESOF INFANTSWITH DOWN SYNDROME 12-

.~D6. Mn

10-

H. Mn

O) t°o°°°°°°" o.°°°°°°'°°°'°°°°" O..

<

6$ JO E "I Z ¢- 4-

~

0)

x,o o"

N

H

,

Cm

2-

' 7 mo

10'=o Developmental Age (in months)

16'm o

Figure 1. Effect of instructions given mothers, infant's diagnostic status, and infant's develop mental age on number of acts selected. Squares and triangles represent the meaningful instruction, +'s and x's represent the intentionally communicative instruction; dotted lines indicate DS infants, solid lines NH infants.

NH infants viewed with the meaningful instruction and DS infants viewed with the communicative instruction the number of acts selected increased from 10 to 16 months MA. The predicted effect of infant status was present only at the youngest age examined. More acts were selected for 7-month NH infants than for 7-month DS infants both by subjects who received the meaningful and by subjects who received the communicative instruction. No differences were noted for 10-month infants, no matter what the instruction. However, as described in the previous paragraph, subjects given the intentionally communicative instruction distinguished between 16-month DS and NH infants--and, contrary to our hypothesis, selected more acts for the 16-month DS infants.

Maternal Status, O r d e r , and Developmental Age Mothers of DS infants noted 7.0 acts/min whereas mothers of NH infants noted 6.1 (the means, adjusted for the covariates, were 7.4 and 5.7, respectively). The number of acts selected did not differ for subjects who viewed order 1 and those

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HYCHE,BAKEMAN,AND ADAMSON

who viewed order 2 of the stimulus tape. The Maternal Status × Order effect was significant, however, and was further qualified by a Maternal Status × Order × Developmental Age interaction. The age effect was again pervasive. For all four groups defined by maternal status and order, the number of acts selected either increased or remained the same for the next developmental age. Thus, age is included in the interaction because the pattern of the increase (from 7 to 10, 10 to 16, or 7 to 16 months) varies for the different groups. Otherwise, and in a way that defies easy explanation, when viewing the order 1 stimulus tape, mothers of DS infants selected more acts than mothers of NH infants (M = 8.0 and 4.8/min, respectively) whereas when viewing the order 2 stimulus tape, mothers of NII infants selected more acts than mothers of DS infants (M = 7.4 and 6.0/rain, respectively). Chronological Age In addition to the developmental age (MA) comparisons described in the preceding paragraphs, infants in this study were sampled so that two CA comparisons could be made. Specifically, the youngest MA group of DS infants was the same CA as the middle group of NH infants (8.5 months), whereas the middle DS group was the same CA as the developmentally oldest NH group (15 months). This allows us to reinterpret the Instruction × Infant Status x Age interaction in terms of chronological, not developmental, age. When subjects who received either instruction viewed 8.5-month CA infants and when subjects who received the meaningful instruction viewed 15-month CA infants, more acts were selected for NH infants than for DS infants. However, when subjects who received the intentionally communicative instruction viewed 15-month CA infants, more acts were selected for DS infants than for NH infants (see Table 4). In summary, the analysis of covariance revealed: (a) significant main effects for the between-subjects factors of maternal status and instruction and the withinsubjects factor of infant age; (b) the absence of main effects for the withinsubjects factor of infant status and the between-subjects factor of stimulus tape order; (c) interactions that qualified but did not change substantially the instruction and infant age main effect; and (d) the unexpected and undesired finding of Maternal Status × Order and Maternal Status × Order × Age interactions. In general, mothers of DS infants selected more acts than mothers of NH infants and both groups of mothers pressed the button more when instructed to look for meaningful rather than communicative acts and when looking at older infants. For the youngest ages sampled, NH infants received more button presses than children with DS and this remained the case even when infants were matched for developmental level. For the oldest MA groups, however, NH infants were perceived as exhibiting fewer communicative acts than their counterparts with DS, Interestingly, this last finding remained tree even when CA, rather than MA, was the basis for comparison.

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TABLE 4 Mean Number of Acts per Minute Noted by Subjects Given Different Instructions and Viewing Infants Differing in Status and Chronol~ieal Age Chronological Age

(montfm) Instruction/Infant Status

8.5

15

Meaningful Act Down Syndrome Nonhandicapped

5.4bc 7.4el

7.5f 9.60

Communicative Act Down Syndrome Nonhendicapped

2.9a 6.1cd

6.0cd 4.9b

Note. Scores are means based on the 2 min of videotape viewed by each subject for each instruction, chronological age, and infant status combination (N = 40). Means sharing a common subscript are not significantly different (p < .05) by the Tukey post-hoc test.

DISCUSSION One of the primary questions guiding this research centered around the readability of infants with DS. Specifically, the question was posed, "Are infants with Down syndrome, even when matched for developmental level, more difficult for mothers to read than NI-I infants?" The answer appears to depend both upon how mothers define their task and the specific MA of interest. The expectation that DS infants would compare unfavorably with NH infants in readability across all developmental ages (Hypothesis 1) clearly was not supported. Only at the youngest developmental age sampled, that is, 7 months, were infants with DS clearly more difficult for mothers to read regardless of the instruction given. When matched with NH infants, DS infants at this developmental level were perceived by mothers as either signaling less frequently, less clearly, or both. This finding was predicted from the review of previous research in which infants with DS in this age range were found to exhibit less preverbal social signaling behavior than developmental-age-matched NH peers (Buckhalt et al., 1978; MacTurk, Hunter, McCarthy, Vietze & McQuiston, 1985; Rothbart & Hanson, 1983). For the infants in the 10-month developmental age range, there were no differences in number of acts noted due either to child status or to type of instruction. In order to place this finding into perspective, a distinction should be made between nonspecific social-communicative signaling (smiling, preverbal vocalization plus eye contact, etc.) and specific communicative behaviors (e.g.,

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HYCHE,BAKEMAN,AND ADAMSON

requesting, referential looking, and turn-taking). On nonspecific measures, infants with DS in this general developmental age range have been found to compare favorably with NH infants with respect to frequency of interactive exchanges (Jones, 1977), nonverbal social interaction skills (Mundy, Sigman, Kasari & Yirmiya, 1988), and preverbal social signaling (Fischer, 1987). In contrast, these same researchers have found deficiencies in the communicative repertoire of DS infants with respect to the specific skills of referential looking and turn-taking (Jones, 1977) and nonverbal requesting (Mundy et al., 1988). Both sets of instructions used in this study allowed mothers to select a wide range of behaviors as meaningful or communicative, therefore approximating the more general type of sociocommunicative signaling that DS infants have been found to exhibit with a frequency similar to that of NH infants. Potential differences in readability across these two infant status groups as a function of instructional specificity should be investigated further. The finding that the developmentally oldest DS infants in this sample were perceived as exhibiting more communicative acts than their Nil developmental age mates was clearly unexpected. Infants with DS have been found previously to exhibit significant strength, relative to MA-matched normal infants, in nonverbal social interaction skills (Mundy et al., 1988). With regard to chronological age, the DS infants in this present study were much older (23 and 26 months vs. 13 and 14 months) than the NH infants. Although matched with respect to general cognitive ability, it is reasonable to assume that the older DS infants were more socially mature, if for no other reason than that they have had 10 to 12 more months of life experience. Because communication is by definition social in nature it is logical to assume, especially if communicative form and content are not specified, as was true in this study, that more socially interactive infants would be perceived as more communicative. Furthermore, a number of mothers described temperament or personality style differences among the children which influenced their responses. Differences in temperament were not controlled for in this study. Obviously, further research with these additional methodological controls is needed before a def'mitive explanation of this unexpected and apparent relative strength in nonverbal communicative behavior of these older children with DS can be advanced. The finding that mothers of children with DS and mothers of NH children differed from one another in the manner in which they responded to the experimental task (Hypothesis 2) was supported, although not with the specificity predicted. Maternal experience with DS infants does appear to lead to greater willingness to attribute meaning to infant behavior, but this effect was not limited to DS infants. In a finding similar to that reported by Sorce and Erode (1982), it rather appears that mothers of DS infants may be sensitized to respond to less salient behaviors in all infants. Indeed, the first author has noted that during a county health department sponsored intervention mothers whose second child

COMMUNICATIVE CUESOF INFANTSWlTH DOWN SYNDROME

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has DS frequently report that they are much more absorbed and attentive to the details of their DS.infant's development than they were to their fn'st NH infant's development. The finding that mothers of NH children and mothers of children with DS differed in the way they responded to the two random-ordered stimulus tapes was unexpected. As described in detail earlier, except for serial position of infants, the two stimulus tapes were identical in every respect. The procedure followed for both groups of subjects was, of course, identical and therefore an unlikely source for these differences. Moreover, all tapes began with exactly the same four practice segments. It may simply be that the Maternal Status × Order and Maternal Status × Order × Age interactions reflect chance findings and are not subject to rational interpretation. In an effort to place these findings into perspective, it should be noted that there was no main effect for order and order did not interact with instruction, which was the experimental variable of interest. Hypothesis 3 was supported. In confirmation of findings reported by Adamson et al. (1987), for all infant groups in this sample, mothers instructed to look for meaningful behavior noted significantly more acts than mothers instructed to look for communicative behavior. Clearly, mothers looking for communicative acts employed more narrow selection criteria and thus appear to have made a distinction between what previous researchers (Adamson et al., 1987; Lock, 1980) have described as perceived communication and true (or intentional) communication. Also confn'med was the general tendency for subjects to note more acts, with the one notable exception discussed earlier, for infants developmentally older (Hypothesis 4). This finding again is in line with developmental theory (Werner & Kaplan, 1963) and countless previous studies of developmental changes in infant behavior--both NH infants and infants with D S - - o v e r time (e.g., Bakeman & Adamson, 1984; Brooks-Gunn & Lewis, 1984). The results of this study have several implications for the delivery of early intervention services to families with infants and young children with the diagnosis of DS. First, the developmentally youngest DS infants in this sample, despite exhibiting general cognitive abilities comparable to the NH infants, were the most difficult for mothers to read. Therefore, parent-infant intervention services begun with infants in the 7-month developmental age range or younger and with a concentrated emphasis on helping parents identify the more subtle nature of the preverbal cuing of their infants may be especially helpful in bolstering parental feelings of competence. Second, the fact that the older DS infants were perceived as exhibiting comparable levels of meaningful/communicative behavior as their NH peers raises questions about the specific nature of the language delays of DS infants. It may be that their communicative delays are more related to communicative form than to deficits in cognitive ability, motivation to communicate, or communicative intent.

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I-fiCHE ~

,

AND ADAMSON

Systematic expansion and refinement of the criterion characteristics of the infants selected for videotaping, the segments selected for editing, and the subjects selected for viewing should allow researchers to attain deeper and more acctwate insights into how parents select significant acts from an infant's ongoing stream of preverbal behavior. Expansion and refinement of these methods and the research designs in which they are used may help us better understand whether subjects in this paradigm are selecting acts in the same manner as they would if actively interacting with the infants rather than watching them on videotape (Adamson et al., 1987), whether differences in caretaking responses to the cues selected would occur, and whether mothers would perceive and respond to their own infants in a similar manner. REFERENCES Adamson, L.B., & Bakeman, R. (1991). The development of shared attention in infancy. In R. Vasta (Ed.), Annals of child deve/opment (Vol. 8). London: Kingsley. Adamson, L.B., Bakeman, R., Smith, C.B., & Waiters, A.S. (1987). Adults' interpretation of infant acts. Developmental Psychology, 23, 383-387. Ainsworth, M.D., Bell, S.M., & Siayton, D.F. (1974). Infant-mother attachment and social development: SocialiT~tion as a product of reciprocal responsiveness to sjenal.~. In M.P.M. Richards (Ed.), The integrationof a child into a socialworld (pp. 99-135). London: Cambridge UniversityPress. Bakeman, R., & Adamson, L.B. (1984). Coordinating attentionto people and objectsin motherinfant and peer-infant interaction.Child Developmem, 55, 1278-1289. Bayley, N. (1969). Bayley scales of ir4am developmem. New York: PsychologicalCorporation. A~erger, J., & Cunningham, C.C. (1981). The development of eye contact between mothers and normal versus Down's syndrome infants. Developmental Psychology, 17, 678-689. Berger, J., & Cunningham, C.C. (1983). Development of early vocal behaviors and interactions in Down's syndrome and nonhandicapped infant-mother pe~rs. Developmental Psychology, 19, 322-331. Brazelton, T.B., Kosiowski, B., & Main, M. (1974). The origins of reciprocity: The early motherinfant interaction. In M. Lewis & L.A. Rosenblum (Eds.), The effect of the infant on its caregiver (pp. 49-76). New York: Wiley. Bmoks-Gunn, J., & Lewis, M. (1984). Maternal responsivity in interactions with handicapped infants. Child Development, 55, 782-793. Bnmer, J. (1982). The organization of action and the nature of the adult-infant transaction. In E.Z. Tmnick (Ed.), Social interchange in infancy: Affect, cognition and communication (pp. 2335). Baltimore: University Park Press. Buckhalt, J.A., Rutherford, R.B., & Goldberg, K.E. (1978). Verbal and nonverbal interaction of with their Down's syndrome and non-retarded infants. American Journal of Mental Deficiency, 82, 337-343. ~Acchetti, D., & Pogge-Hesse, P. (1982). Possible contributions of the study of organically retarded persons to development theory. In E. Zigler & D. Balla (Eds.), Mental retardation: The developmental-difference controversy (pp. 277-318). Hillsdale, NJ: Erlhaum. Ciccbetti, D., & Serafica, F.C. (1981). Interplay among behavioral systems: Illustrations from the study of attachment, affiliation, and wariness in young children with Down's syndrome. Developmental Psychology, 17, 36-49.

COMMUNICATIVE CUES OF INFANTSWITH DOWN SYNDROME

15

Cicchetti, D., & Sroufe, L.A. (1976). The relationship between affective and cognitive development in Down's syndrome infants. Child Development, 47, 920-929. Crawley, S.B., & Spiker, D. (1983). Mother-child interactions involving two-year-olds with Down's syndrome: A look at individual differences. Child Development, 54, 1312-1323. Fischer, M.A. (1987). Mother-child interaction in preverbal children with Down syndrome. Journal of Speech and Hearing Disorders, 52, 179-190. Fralberg, S. (1974). Blind infants and their mothers: An examination of the sign system. In M. Lewis & L.A. Rosenblum (Eds.), The effect of the infant on its caregiver (pp. 215-232). New York: Wiley. Goldberg, S. (1977). Social competence in infancy: A model of parent-infant interaction. MerriUPalmer Quarterly, 23, 163-177. Jones, O.H.M. (1977). Mother-child communication with prelingnistic Down's syndrome and normal infants. In H.R. Schaffer (Ed.), Studies in mother-infant interaction (pp. 205-225). London: Academic. Jones, O.H.M. (1979). A comparative study of mother-child communication with Down's syndrome and normal infants. In D. Shaffer & J. Duun (Eds.), Thefirst year of life: Psychological and medical implications of early experience (pp. 175-195). Chichester: Wiley. Jones, O.H.M. (1980). Prelingnistic communication skills in Down's syndrome and normal infants. In T.M. Field, S. Goldberg, D. Stem, & A.M. Sostek (Eds.), High-risk infants and children: Adult and peer interactions (pp. 205-285). New York: Academic. Lock, A. (1980). The guided reinvention of language. London: Academic. MacTurk, R.H., Hunter, F.T., McCarthy, M.E., Vietze, P.M., & McQuiston, S. (1985). Social mastery motivation in Down syndrome and nondelayed infants. Topics in Early Childhood Special Education, 4(4), 93-109. Maurer, H., & Sherrod, K. (1987). Context of directives given to young children with Down syndrome and nonretarded children: Development over two years. American Journal of Mental Deficiency, 91, 579-590. Mundy, P., Sigman, M., Kasari, C., & Yirmiya, N. (1988). Nonverbal communication skills in Down syndrome children. Child Development, 59, 235-249. Newtson, D. (1973). Attribution and the unit of perception of ongoing behavior. Journal of Personality and Social Psychology, 28, 28-33. Newtson, D., & Enquist, G. (1976). The perceptual organization of ongoing behavior. Journal of Experimental Social Psychology, 12, 436-450. Newtson, D., Enquist, G., & Bois, J. (1977). The objective basis of behavior units. Journal of Personality and Social Psychology, 35, 847-862. Pruess, J.B., Vadasay, P.F., & Fewell, R.R. (1987). Language development in children with Down syndrome: An overview of recent research. Education and Training in Mental Retardation, 22, 44-55. Richard, N.B. (1986). Interaction between mothers and infants with Down syndrome: Infant characteristics. Topics in Early Childhood Special Education, 6(3), 54-71. Richards, M.P.M. (1974). The development of psychological communication in the first year of life. In K.C. Conally & J.S. Bruner (Eds.), The growth of competence (pp. 119-131). New York: Academic. Rothbart, M.K., & Hanson, M.J. (1983). A caregiver report comparison of temperamental characteristics of Down syndrome and normal infants. Developmental Psychology, 19, 766-769. Shotter, J. (1974). The development of personal powers. In M.P.M. Richards (Ed.), The integration of a child into a social world (pp. 215-244). London: Cambridge University Press. Sorce, J.F., & Erode, R.N. (1982). The meaning of infant emotional expressions: Regularities in camgiving responses in normal and Down's syndrome infants. Journal of Child Psychology and Psychiatry, 23, 145-158.

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HYCHE,BAKEMAN,AND ADAMSON

Stem, D.H. (1974). Mother and infant at play: The dyadic interaction involving facial, vocal, and gaze behaviors. In M. Lewis & L.A. Rosenblum (Eds.), The effect of the infant on its caregiver (pp. 187-213). New York: Wiley. Thompson, R.A., Cicchetti, D., Lamb, M.E., & Malkin, C. (1985). Emotional responses of Down syndrome and normal infants in the Strange Situation: The organization of affective behavior in infants. Developmental Psychology, 21, 828-841. Wemer, H., & Kaplan, B. (1986). Symbol formation. New York: Wiley.