attachment and cognitive skills: an investigation of mediating mechanisms

Journal of Applied Developmental Psychology 28 (2007) 458–476

Attachment and cognitive skills: An investigationof mediating mechanisms☆

Erin O'Connor a,⁎, Kathleen McCartney b

a New York University Steinhardt School of Education, 239 Greene Street, East Building 200A, New York, NY 10003, USAb Harvard University, USA

Available online 20 July 2007

Abstract

Associations between maternal attachment patterns and cognitive skills at first grade were examined, and mediators of identifiedassociations tested using Phase I and II data from the National Institute of Child Health and Human Development Study of EarlyCare and Youth Development, a prospective study of 1364 children and families from birth through sixth grade. There were threemain findings. First, ambivalent and insecure/other attachment patterns were negative predictors of cognitive skills. Second, theassociation between ambivalent attachment and cognitive skills was mediated by children's behaviors related to testing. Third, theassociation between insecure/other attachment and cognitive skills was mediated by children's exploration, maternal instruction,children's social relationships, and children's behaviors related to testing. Implications for attachment theory and education arediscussed.© 2007 Elsevier Inc. All rights reserved.

Keywords: Attachment; Cognitive skills; Mediators

1. Introduction

The heuristic value of attachment theory for developmental psychology has been great. Research on attachment andsocial development is particularly robust, with multiple large scale studies demonstrating associations between specificinsecure attachment patterns and social skill difficulties (Greenberg, 1999). Furthermore, the mechanisms responsiblefor associations between attachment and social skills are well understood. A smaller literature demonstrates anassociation between maternal attachment and cognitive skills (e.g., Van IJzendoorn, Dijkstra, & Bus, 1995). Theliterature on maternal attachment and cognitive development, however, is limited in two ways. First, researchers havegenerally studied the effects of maternal attachment security versus insecurity on cognitive skills. Little research hasbeen conducted on the influence of specific patterns of insecure attachment on cognitive skills (De Ruiter & Van

☆ This project was funded by a grant from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care andYouth Development to the second author (HD25451). We thank the investigators in the NICHD Early Child Care Research Network for the data set,the site coordinators and research assistants for their data collection efforts, and the families and teachers for their participation in this longitudinalstudy. This project was presented in part at the Society for Research in Child Development biennial meeting, Tampa, FL, April 24, 2003.⁎ Corresponding author.E-mail address: [email protected] (E. O'Connor).

0193-3973/$ - see front matter © 2007 Elsevier Inc. All rights reserved.doi:10.1016/j.appdev.2007.06.007

mailto:[email protected]

http://dx.doi.org/10.1016/j.appdev.2007.06.007

459E. O'Connor, K. McCartney / Journal of Applied Developmental Psychology 28 (2007) 458–476

IJzendoorn, 1993). This is a concern, as the behavioral profiles of children with different insecure attachment patternsvary greatly. Second, there are no large scale empirical studies of the multiple mediating mechanisms believed to beresponsible for associations between attachment and cognitive skills. The purpose of the current study is to addresseach of these limitations.

1.1. Attachment theory

According to attachment theory, children develop attachment relationships with primary caregivers, usuallymothers, during the first years of life. Within these relationships, children seek feelings of safety and security.Attachment relationships compose a motivational control system that regulates children's wishes to maintain proximityto caregivers and to explore the environment. When children are anxious, their attachment systems are activated, andtheir exploratory systems, which encourage children to interact with their environments, are deactivated, leading totheir engagement in behaviors that bring them close to their attachment figures. On the other hand, when children arecomfortable, their attachment systems are deactivated and their exploratory systems activated, leading to their use ofattachment figures as secure bases from which to explore the environment. In other words, the attachment system actsin concert with the exploratory system to control children's interactions with their environments and to influence theirdevelopment.

All children, except those who experience severe neglect, develop attachments to their primary caregivers; however,children demonstrate varying patterns of attachment that reflect differences in caregiver sensitivity and responsivity(Ainsworth, Blehar, Waters, & Wall, 1978). At the most basic level, children develop either secure or insecureattachments. Secure attachment is associated with high levels of caregiver sensitivity and responsivity. Secure childrentrust that they will be attended to in times of need and, thus, effectively use caregivers as secure bases from which toexplore their surroundings. Insecure attachment is associated with relatively low levels of caregiver sensitivity and/orresponsivity. Insecure children do not trust that they will receive support when threatened. As such, insecure children'sattachment systems are more frequently activated and exploratory systems deactivated than those of secure children.Thus, insecure children are not as effective as secure children in their use of caregivers as secure bases. Variations existthough among the behaviors of insecure children's caregivers and in insecure children's attachment strategies. Basedon these variations, several subcategories of insecure attachment have been identified among children: ambivalent,avoidant, controlling, and insecure/other (Cassidy, Marvin, & the MacArthur Working Group on Attachment, 1992).

Ambivalent attachment correlates with inconsistent caregiver availability. Ambivalent children are hypervigilant tosigns of impending caregiver unavailability and are dependent and clingy with caregivers to ensure their caregivers'physical proximity in times of stress and/or danger (Ainsworth et al., 1978; Cassidy & Berlin, 1994; Magai, 1999;Weinfield, Sroufe, Egeland, & Carlson, 1999). Avoidant attachment is associated with caregiver unavailability.Avoidant children do not expect to receive caregiver support when mildly stressed. They thus often inhibit affect, avoidextensive contact with caregivers when mildly stressed, and focus on the immediate environment to prevent feelingrejected by caregivers (Magai, 1999; Weinfield et al., 1999).

Controlling and insecure/other attachment styles are associated with fearful caregiver behaviors (Main & Hesse,1990). Controlling children manage this fearful behavior by controlling their caregivers. These children take chargeover caregivers by assuming either a punitive or a caregiving role (Teti, 1999). Through controlling behaviors, they arecapable of regulating their caregivers' fearful actions. Controlling children, like ambivalent and avoidant children, haveorganized behaviors to get some of their attachment needs met and are thus somewhat able to use their caregivers assecure bases (Teti, 1999; Main & Cassidy, 1988). Insecure/other children, on the other hand, exhibit anomalous andunorganized attachment behaviors, which appear to prevent them from using caregivers as secure bases (Cassidy et al.,1992; Humber & Moss, 2005).

1.2. Attachment and cognitive skill development

Research on attachment and cognitive skills, including ability, intelligence, memory, and reasoning, indicates thatsecure children have more advanced skills than insecure children (e.g. De Ruiter & Van IJzendoorn, 1993; Main, 1983;Spieker, Nelson, Petras, Jolley, & Barnard, 2003; Van IJzendoorn et al., 1995; Van IJzendoorn & Vliet-Visser, 1988;Van IJzendoorn, Sagi, & Lambermon, 1992). Limited research on specific attachment patterns and cognitive skillsindicates variation in skills among insecure children. For example, in one study, ambivalent children demonstrated

460 E. O'Connor, K. McCartney / Journal of Applied Developmental Psychology 28 (2007) 458–476

fewer correct solutions than their peers on a measure of cognitive competence (Fagot, Gauvain, & Kavanagh, 1996).Furthermore, in a meta-analysis of 25 studies of attachment and cognitive skills, Van IJzendoorn et al. (1995) found thatthe magnitude of the effect of insecure attachment on cognitive skills is larger in studies with higher percentages ofambivalently attached children.

Research on the cognitive sequelae of controlling and insecure/other attachment is limited. Recently, Moss and hercolleagues conducted several studies to examine the effects of controlling attachment on academic performance (Moss,Rousseau, Parent, St-Laurent, & Saintong, 1998; Moss, St-Laurent, & Parent, 1999). Controlling children performedlower than their peers on academic performance measures (Moss et al., 1999; Moss & St-Laurent, 2001). One studywas conducted in which the cognitive skills of insecure/other children were observed. Results from this study indicatethat insecure/other children score lower than peers on tests of IQ at 6 and 8 years of age (Moss & St-Laurent, 2001). Thesample size for insecure/other children, however, was too small to allow for inferential statistics (Moss & St-Laurent,2001).

Although a limited amount of empirical work has been conducted to investigate associations between attachmentand cognitive skills, theorists have developed hypotheses that may explain associations between attachment andcognitive skills (Bretherton et al., 1979; Bell, 1970; Belsky, Garduque, & Hrncir, 1984; De Ruiter & Van IJzendoorn,1993; Jacobsen, Edlestein, & Hofmann, 1994; Lieberman & Pawl, 1990; Van IJzendoorn et al., 1995). Thesehypotheses involve pathways or mediating mechanisms through which attachment may influence cognitive skills (DeRuiter & Van IJzendoorn, 1993; Van IJzendoorn et al., 1995). According to Van IJzendoorn and colleagues, several ofthese pathways or mechanisms are: children's exploration, parental instruction, children's social relationships, andchildren's behaviors related to testing. A brief review of relevant research on each of these mechanisms follows.

1.2.1. Children's explorationExploration involves investigation of the environment and engagement in tasks. Individual differences in

investigation and task engagement are associated with cognitive skills and maternal attachment (Jacobsen et al., 1994).Investigation enhances cognitive skills as children learn from interactions with people and objects (Carpenter, Nagell,& Tomasello, 1998; Matas, Arend, & Sroufe, 1978; Schunk, 1985; White, 1959). Task engagement involves anindividual's agency and persistence in tasks (Yarrow, Morgan, Jennings, Harmon, & Gaiter, 1982). Children whoengage in tasks seek out challenges and persist even when frustrated. Engagement is associated with greater cognitiveskills as agency, attention, and persistence are necessary for learning processing and understanding concepts (e.g.,Choudhury & Gorman, 2000; Pianta, 1999; Soares, Lemos, & Almeida, 2005; Yarrow et al., 1982).

The literature on the association between children's exploration and attachment patterns is fairly extensive (e.g.,Bowlby, 1969/1982; Bretherton et al., 1979; Cassidy, 1990; Van IJzendoorn et al., 1995). Secure children take part inmuch higher levels of investigation and gain more cognitive stimulation from their investigations than insecurechildren (Bowlby, 1988; Bretherton, 1985). Secure children also evidence higher levels of task exploration andengagement than insecure children (e.g. Bretherton, 1985; Bus & Van IJzendoorn, 1988). The extent and quality ofchildren's investigations and task engagement vary among insecure children. Avoidant children often investigate theenvironment and engage in tasks at the expense of interacting with caregivers. The extent of avoidant children'sinvestigations and task engagement, though, tends to be lower than that of secure children, as they are not as effectiveas secure children in using caregivers as secure bases. Ambivalent children, because of their anxiety over caregiveravailability and their clingy behaviors with caregivers, exhibit limited investigation and task engagement (Ainsworth &Bell, 1970; Bretherton, 1985; Bowlby, 1988; Cassidy & Berlin, 1994; Main, 1983; Matas et al., 1978; Moss & St-Laurent, 2001). Results from one study indicate lower levels of task engagement among ambivalent than avoidantchildren (Frosch, Cox, & Goldman, 2001). Little research has been conducted on investigation and task engagementamong controlling and insecure/other children. It is likely that because of their controlling behaviors, which requireextensive contact with caregivers, controlling children exhibit significantly lower levels of investigation and taskengagement than their secure peers. Insecure/other children would also be expected to engage in extremely low levelsof investigation and engagement, as they are unable to use caregivers as secure bases.

1.2.2. Maternal instructionParental instruction, or the extent to which parents encourage children's comprehension of information and

acquisition of knowledge, is associated with children's cognitive skills and attachment patterns (Isabella & Belsky,1991; Rogoff, 1998; Van IJzendoorn et al., 1995). High-quality instruction results in children gaining new knowledge


and learning cognitive strategies (Molfese, DiLalla, & Lovelace, 1996; Saltaris et al., 2004; Snow, Barnes, Chandler,Goodman, & Hemphill, 1991). Because children tend to spend a greater amount of time with mothers than fathers, theassociation observed between maternal instruction and cognitive skills is often stronger than that between paternalinstruction and cognitive skills. Associations exist between quality of maternal instruction and children's cognitiveskills both concurrently and over time (e.g. Moss & St-Laurent, 2001).

Mothers of secure children are more contingently responsive; give more task-relevant, appropriate instruction totheir children; and encourage more academic skill development, in both formal and informal instructional interactions,than mothers of insecure children (e.g. Isabella & Belsky, 1991; Van IJzendoorn et al., 1995; Weinfield et al., 1999).Variations are found among mothers of insecure children in their specific instructional behaviors. The interactions ofambivalent children and their mothers are characterized by an intense interpersonal focus and maternal disapproval andintrusiveness (Ainsworth & Bell, 1970; Cassidy & Berlin, 1994; Fagot et al., 1996; Isabella & Belsky, 1991). Resultsfrom several studies suggest that mothers of ambivalent children are less warm toward and supportive of their childrenduring instructional tasks, and provide lower levels of cognitive stimulation than mothers of secure and avoidantchildren (Fagot et al., 1996; Frosch et al., 2001). Inconsistencies exist in the literature on avoidant attachment andmother–child interactions. Several studies demonstrate that mothers of avoidant children are insensitive in theirinstruction and provide lower quality assistance in problem solving tasks than mothers of secure children (Ainsworthet al., 1978; Frankel & Bates, 1990; Lewis & Feiring, 1989a; Matas et al., 1978). Other studies, however, indicate nodifferences in maternal behaviors within avoidant and secure dyads (Crittenden, 1992; Fagot et al., 1996; Frosch et al.,2001). Some researchers have suggested that as their children become more independent, mothers of avoidant childrenare better able to provide appropriate instruction (Crittenden, 1992; Fagot et al., 1996; Frosch et al., 2001). Theinteractions of controlling dyads are defined by low levels of maternal affirmation of child behaviors, responsivity, andmaternal provision of help and encouragement (Moss & St-Laurent, 2001; Stevenson-Hinde & Shouldice, 1995). Littleresearch exists on insecure/other dyads. Results from one study, however, indicate that mothers of insecure/otherchildren demonstrate lower levels of sensitivity and warmth and higher levels of disengagement and flatness of affectduring instruction than mothers of secure, avoidant, and ambivalent children (Teti, Gelfand, Messinger, & Isabella,1995). Similarly, Teti (1999), in a study of behaviorally disorganized (e.g. children who evidence no coherentattachment behaviors) and controlling preschool children, found lower quality mother–child interactive competenceamong the behaviorally disorganized dyads.

1.2.3. Children's social relationshipsRelationships with peers and teachers are central to child development and strongly influenced by maternal

attachment (e.g. Van IJzendoorn et al., 1995). Both the number of friends children have and the quality of theirfriendships are predictive of cognitive skills (Cauce, 1986). Children with higher quality relationships gain morecognitive stimulation from their friends than those with lower quality relationships (Van IJzendoorn et al., 1995).Specifically, children have more dynamic conversations, engage in more mutual problem solving during tasks, andremember more about tasks completed with friends than acquaintances (Azmitia & Montgomery, 1993; Hartup, 1996;Newcomb & Brady, 1982). Consequently, children with more friends and with higher quality relationships demonstrategreater cognitive skills than children with fewer friends and lower quality relationships.

Teachers also serve an important function in children's development of cognitive skills. Teachers provide childrenwith cognitive stimulation and formal and informal instruction that is necessary for optimal cognitive development.Children are more comfortable during and subsequently better able to obtain cognitive stimulation from didacticinteractions with teachers with whom they have harmonious relationships (Pianta, 1999). Additionally, children withhigh-quality relationships express their understandings of concepts more readily to their teachers than children withlow-quality relationships, as they trust that teachers will respond sensitively (Pianta, 1999). Teachers are thus betterable to modify their instruction to meet the needs of children with whom they have high-quality relationships. Notsurprisingly, children with higher quality relationships with teachers evidence greater cognitive skills in elementaryschool than those with lower quality relationships (Birch & Ladd, 1997; Hamre & Pianta, 2001).

Extensive research demonstrates associations between maternal attachment and children's relationships withfriends, playmates, and teachers. Secure children have more friends than insecure children and develop higher qualitypeer relationships (Elicker, Englund, & Sroufe, 1992; Grossmann & Grossmann, 1991; Kerns, 1994; Lewis & Feiring,1989b; Pierrehumbert, Iannotti, Cummings, & Zahn-Waxler, 1989; Sroufe, 1983a). Ambivalent children tend toevidence the lowest quality interactions with playmates (Jacobson & Wille, 1986; Pastor, 1981). Secure children also


develop higher quality relationships with teachers than insecure children (Howes &Matheson, 1992; Pianta, Nimetz, &Bennett, 1997; Sroufe, Fox, & Pancake, 1983). Limited research indicates that ambivalent and insecure/other childrenhave the lowest quality relationships with teachers (O'Connor & McCartney, 2006; Sroufe, 1983b).

1.2.4. Children's behaviors related to testingChildren's cognitive performance often reflects not only their cognitive skill level, but also their behaviors during

test administration. Specifically, many tests of cognitive skill require children to communicate with the testadministrator and to attend to the task at hand (Van IJzendoorn et al., 1995). Consequently, children's performance on astandardized test of cognitive skill may demonstrate variation in socioemotional rather than in cognitive development(Van IJzendoorn et al., 1995).

Associations exist between attachment patterns and behaviors related to testing. Secure children are better able tocommunicate than are insecure children (Gersten, Coster, Schneider-Rosen, Carlson, & Cicchetti, 1986; VanIJzendoorn et al., 1995). Among at-risk children ambivalent children evidence the lowest quality expressive languageskills (Belsky & Fearon, 2002). Research suggests that insecure/other children communicate the least effectively withadults (e.g. Cassidy et al., 1992; Goldberg, 1997). Secure children tend to evidence higher levels of attention thaninsecure children, especially when stressed and during structured tasks (e.g. Gersten et al., 1986; Matas et al., 1978).Research suggests that among insecure children, ambivalent and behaviorally disorganized children evidence thelowest levels of attention (e.g. Clarke, Ungerer, Chahoud, Johnson, & Stiefel, 2002; Moss, Cyr, & Dubois-Comtois,2004; Van IJzendoorn et al., 1995). Secure children may therefore perform higher on tests of cognitive skill thaninsecure children, regardless of actual differences in ability, due to variation in behaviors during tests of cognitive skill(Matas et al., 1978; Van IJzendoorn et al., 1995).

1.3. The present study

We investigated relationships between maternal attachment patterns and cognitive skills with data from the first twophases of the National Institute of Child Health and Human Development Study of Early Child Care and YouthDevelopment (NICHD SECCYD), a prospective study of 1364 children from birth through first grade. Specifically, weused regression analyses to examine associations between avoidant, ambivalent, controlling, and insecure/otherattachment patterns and cognitive skills, and to test whether children's exploration, maternal instruction, children'ssocial relationships, and children's behaviors related to testing mediated identified associations.

This study extends the literature on attachment and cognitive skills in at least three ways. First, associations betweenspecific insecure attachment patterns, including controlling and insecure/other attachment, and cognitive skills wereexamined. Second, the mediating mechanisms theorized to explain the association between attachment and cognitiveskills were tested empirically. Third, the comprehensive nature of the data used in this study allowed for the inclusion ofextensive controls to account for potential omitted variable biases.

2. Method

2.1. Participants

Participants in the NICHD SECCYD were recruited through 1991 from 24 hospitals near the following sites: LittleRock, AK; Irvine, CA; Lawrence and Topeka, KS; Boston, MA; Philadelphia, PA; Pittsburgh, PA; Charlottesville, VA;Morganton and Hickory, NC; Seattle, WA; and Madison, WI. Potential participants were selected from 8986 mothersgiving birth during selected 24-h sampling periods. Participants were selected in accordance with a conditional randomsampling plan that was designed to ensure that the recruited families reflected the demographic diversity (economic,educational, and ethnic) of the catchment area at each site. A total of 1364 families enrolled in the study. Thedemographic distribution of the sample is 24% ethnic minority (13% African-American, 6% Latino-American, 1.4%Asian-American, and 3.4% of ethnic or racial backgrounds classified as other); 11% of the mothers did not have a highschool education and 14% were single at the birth of the child (NICHD Early Child Care Research Network [ECCRN],2001).

The current sample consisted of 1000 children who had completed the assessment of maternal attachment patterns at36 months and remained in the study at first grade. The children included in the current analyses were compared with


children from the original sample who were not included. Mothers in the current sample were more likely to havecompleted high school (χ2 = 12.08, p b .001) and children were more likely to be white (χ2 = 15.57, p b .001).

Missing values for continuous variables were imputed using a Markov chain Monte Carlo (MCMC) method(Schafer, 1997). This was appropriate, as the data were normally distributed (Graham & Donaldson, 1993; Kellum,Rebok, Ialongo, & Mayer, 1994) and appeared to be missing at random. Data were determined to be missing at randombecause the probability of missing data at one time point, on variables collected at multiple time points, was unrelatedto their values at other time points. The MCMC method uses simulation from a Bayseian prediction distribution. Fiveimputations were performed with a burn-in period of 500. This burn-in period was used to prevent starting values forthe imputation from affecting final parameter estimates (Pederson et al., 2003). SAS PROC MIANALYZE was thenused to calculate final parameter estimates (Schafer, 1997). SAS PROC MIANALYZE aggregates the results of theanalyses performed on the data sets to arrive at precise parameter estimates. Descriptive statistics and regressionmodels estimated using only the original values were similar to those with the imputed values.

2.2. Measures

2.2.1. Cognitive skillsChildren's cognitive skills at first grade were assessed using cognitive ability subscales of the Woodcock Johnson

Psycho-Educational Battery–Revised (WJR) (Woodcock & Johnson, 1990). In the NICHD SECCYD, cognitive abilitywas evaluated with four subscales from the WJR: Memory for Names, Memory for Sentences, Incomplete Words, andPicture Vocabulary. The Memory for Names test measures long-term retrieval by evaluating the ability to learnassociations between unfamiliar auditory and visual stimuli. The Memory for Sentences test assesses short-termmemory and comprehension/knowledge through the ability to remember and repeat simple words, phrases, andsentences presented auditorily. The Incomplete Words test evaluates auditory processing. The participant is asked toname the complete word after hearing a recorded word with one or more phonemes missing. The Picture Vocabularytest measures verbal comprehension and crystallized intelligence through the participant's ability to recognize or namepictured objects. These scales are normed to have a mean of 100 and a standard deviation of 15. Values above 100indicate that the raw score was above the mean in the norming sample. Scores for cognitive skills were computed as themean of the four ability subscale scores. Mean scores were used, as previous studies indicate that these four subscalesmeasure varying aspects of cognitive ability that when combined provide a general measure of ability (see Woodcock& Johnson, 1990). Furthermore, items on the subscales have high internal reliability (Cronbach's α = .91). The WJRhas excellent test–retest reliability and predictive validity across the life span (McGrew & Kopnick, 1993).

2.2.2. Child and family controls

2.2.2.1. Child sex. Sex was dummy coded such that males were assigned a value of 0 and females a value of 1.

2.2.2.2. Race/ethnicity. Two dummy variables for race/ethnicity were created: African-American versus white andLatino-American versus white.

2.2.2.3. Early cognitive skills. At 15 months, the Bayley Mental Development Index was used to assess children'scognitive skills (Bayley, 1969). This index measures infants' sensory–perceptual, memory, and problem solving abilities.Higher scores indicate greater skills. The Bayley has very good reliability and predictive validity (Gagnon&Nagle, 2000).

2.2.2.4. Hours in child care. Number of hours in nonmaternal care was obtained from maternal reports at 6, 15, 24,and 36 months. A variable for average number of hours in nonmaternal care from 6 through 36 months was created.

2.2.2.5. Quality of child care. The Observational Record of the Caregiving Environment (ORCE; 1996, 2000) wasdeveloped to assess characteristics of child care quality generally and nonmaternal caregiving specifically (NICHDECCRN, 1996). Behaviors were coded during observations of primary child care settings for two 44-min cycles whenthe children were 54 months old. Then four qualitative ratings of child care setting (chaos, overcontrol, positiveemotional climate, and negative emotional climate) were made on a scale of 1 to 4, with 1 = “not at all characteristic” and4 = “highly characteristic.” Overall quality is an a priori composite computed as the sum of the four setting ratings after


reflecting values for chaos, overcontrol, and negative emotional climate. The raw items used to create this composite hadmodest internal reliability (Cronbach'sα = .68), and the composite had low to moderate levels of skewness and kurtosis.

2.2.2.6. Episodes of family poverty. At 6, 15, 24, 36, and 54 months, kindergarten, and first grade, the ratio of familyincome to needs was computed by dividing total family income by the poverty threshold for the appropriate family size(U.S. Bureau of the Census, 1999). Income-to-needs ratios less than 2 indicate poverty status. The number of episodesof income-to-needs below 2 from 6 months through first grade was calculated to obtain an index of episodes of poverty.

2.2.2.7. Maternal education. Level of maternal education was obtained during interviews and scored as: b 12 = numberof years in school, 12 = high school graduate orGED, 14= some college, 16 = a bachelor's degree, 17 = some graduate schoolexperience, 18 = amaster's degree, 19 = a law school graduate, and 21 =more than onemaster's degree or a doctoral degree.

2.2.3. Attachment statusBased on recommendations by Cassidy et al. (1992), a modified strange situation was used to assess children's

attachment styles at 36 months. In this procedure, designed to be moderately stressful for the child, the mother and childwere separated from each other for two brief periods. After 3 min together in the laboratory, the mother was signaled toleave. The first separation lasted 3 min, unless the child was overly distressed. After a 3-min reunion, the mother leftagain. The second separation lasted 5 min. The children's behaviors during the assessment were classified according tothe system developed by the MacArthur Working Group on Attachment (Cassidy et al., 1992). With the MacArthurcoding system, preschoolers are classified as secure, ambivalent, avoidant, controlling, or insecure/other on the basis oftheir reunion behaviors with their mothers. Secure children resume calm, comfortable interactions with their motherson reunion. Avoidant children maintain extreme neutrality toward their mothers and rarely express positive or negativeemotion toward their mothers, even after reunion. Ambivalent children exhibit fussy, helpless, whiny, and/or resistantbehavior toward their mothers when reunited with them. They may seek contact but find it unsatisfactory. Controllingchildren take charge of the reunion, usually in either a caregiving (role-reversal) or punitive manner. Insecure/otherchildren do not demonstrate a coherent attachment behavioral strategy during reunion. Intercoder agreement (beforeconferencing) was 75.7% (κ = .58) (McCartney, Owen, Booth, Vandell, & Clarke-Stewart, 2004). In the currentanalyses, four dichotomous variables, with secure serving as the comparison group, for attachment style were created.Specifically, one variable represented avoidant versus secure attachment. A second variable represented ambivalentversus secure attachment. A third variable represented insecure/other versus secure attachment. Lastly, a fourth variablerepresented controlling versus secure attachment.

2.2.4. Measures of children's exploration

2.2.4.1. Task engagement. Mother–child interactions were videotaped in semistructured 15-min observations at54 months and first grade. Interaction activities included two tasks that were too difficult for the child to carry outindependently. In addition, a third activity was included that encouraged play between mother and child. In the 54-month visit, the first activity consisted of completing a maze using an Etch-A-Sketch that had been altered by attachinga maze to the screen. The second activity was to form a series of same-sized rectangular cube “towers” from variouslyshaped wooden blocks. The third activity was play with a set of six hand puppets. For first graders, the first mother–child interaction activity involved mother and child operating the Etch-A-Sketch together to draw a specified picture ofa house and tree on the screen. The task was challenging because one was to control the vertical knob and the other thehorizontal knob and thereby coordinate how they worked together to draw. The second activity involved the child usingdifferent shaped parquet pattern blocks to fill in three geometric cutout frames. The third activity was a card gameinvented for the procedure called “one-up/one-down,” whereby the mother and child were to successively lay cardsface up on a growing pile between them and to race to slap and claim the pile of cards when the card laid on the pile waseither one higher or one lower than the previous card. Mother–child interactions were rated using 7-point global ratingscales modified from Egeland and Heister (1995). Task orientation/engagement is the sum of two behaviors: agencyand persistence. Agency measures the child's self-initiated participation in the activity and active exploration of theactivity. Persistence assesses the child's engagement in the activity even when frustrated. The range of values for thiscomposite is 2 to 14, with higher scores indicating higher levels of engagement. Intercoder reliability was calculatedusing an intraclass correlation (Winer, 1971). Reliability was .89 at 54 months and .87 at first grade. Chronbach's α for


child exploration was .88 at 54 months and .81 at first grade. In the current analyses, scores at 54 months and first gradewere averaged to create a mean task engagement score.

2.2.4.2. Investigation/engagement in classroom. Child behaviors in the classroom were measured at first gradethrough observational ratings from the Classroom Observational System (COS) (NICHD ECCRN, 1996, 2000).During the COS, the study child was observed in the classroom for two 44-min cycles. In each cycle, observers madetime-sampled recordings for three 10-min periods of 30-s “observe” and 30-s “record” intervals. Thus, there were 30different minutes in which discrete behaviors were sampled across each of the two observation cycles for a total of 60different minutes (e.g. 60 intervals) in which codes were completed. Child investigation and engagement is the sum oftwo individual behavior scales: active engagement and passive engagement. Active engagement is coded when thechild investigates the classroom, interacts with others, seeks out activities, and is attentive to activities during theinterval. Passive engagement is coded when the child does not seek out activities in the classroom on his or her own butis engaged in them. Scores range from 0 to 60, with higher scores indicating higher levels of investigation andengagement. All observers had to pass a videotaped reliability test involving six 44-min cycles for behavioral coding.Criteria for passing were at least 60% match with a master coder on time-sampled codes. All coders passed at this levelon a reliability test before being certified to conduct observations in the field. Average exact agreement with the gold-standard videotape test for the time-sampled codes was .70. Observers also conducted paired visits for the purposes ofestimating live reliability. Correlations between observers exceeded .60.

2.2.5. Measures of maternal instruction

2.2.5.1. Cognitive stimulation. At 54 months, the HOME Inventory (Caldwell & Bradley, 1984) was completed. TheHOME Inventory consists of direct observation and a semistructured interview with the mother, and is designed tomeasure the quality and quantity of stimulation and support available to a child at home. The focus is on the child in theenvironment, as a recipient of inputs from objects, events, and interactions. The HOME consists of 46 items scored as 1if the behavior is observed during the visit or if the parent reports that the conditions or events are characteristic of thehome environment. A score of 0 is recorded if the behavior is not observed or reported. The information needed tocomplete the inventories is obtained during a 90-minute home visit. In the current study, three subscales of the HOMEwere summed to create a cumulative cognitive stimulation score. The three subscales used were: Language Stimulation,Academic Stimulation, and Responsivity. Language Stimulation is measured on seven items that assess positive parentalverbal exchanges with the child (e.g., parent answers child's questions or requests verbally). Academic Stimulation isevaluated on five items that measure parental behaviors that encourage the acquisition of cognitive skills (e.g., child isencouraged to learn colors). Responsivity is assessed on seven items and measures maternal behaviors that encourageacademic skill development (e.g., “child is encouraged to learn numbers”). The Language Stimulation and Responsivityscores were recomputed on a 0 to 5 scale so that each subscale of the HOME contributed equally to the final score. OnlyHOME inventories completed with mothers were used in the current study. Total scores range from 0 to 15, with highervalues indicating greater stimulation. A centrally located system of training was used for data collectors. Every4 months, each observer coded videotaped visits, and the coding was compared with global standard codes. Allobservers were required to maintain a criterion of scoring like the master coder on 90% of the items.

2.2.5.2. Quality of assistance. Maternal assistance was assessed at 54 months and first grade in the samesemistructured interaction task in which child task engagement was evaluated. Maternal assistance was rated on a 7-point global rating scale. Higher scores indicate higher levels of maternal assistance at a level appropriate for the child'sability. Scores at 54 months and first grade were averaged to create a mean maternal assistance score. Reliability formaternal assistance was .85 at 54 months and .87 at first grade.

2.2.6. Measures of children's social relationships

2.2.6.1. Number of friends. At 54 months and first grade, mothers were asked to report on a scale the number offriends/playmates with whom the child currently interacts. Values range from 1 = “my child has no regular playmates"to 5 = “my child has several playmates and a close friend." Values for the 54-month and first grade assessments wereaveraged to create a mean number of friends score.


2.2.6.2. Friendship quality. At 54months and first grade, mothers completed an adaptation of the Quality of ClassroomFriends (Clark & Ladd, 2000) questionnaire. This questionnaire assesses the quality of their child's friendship with onefriend. Scale items assess how well the study child and his or her friend interact with each other. At 54 months and firstgrade, the questionnaire includes 11 statements about peer relationships (e.g., “when these two children are playingtogether they take turns during conversations”) scored on a 5-point Likert scale, where 1 = definitely does not apply and to5 = definitely applies. Proportional weighting is used to create a total score (see NICHD ECCRN, 1997). Items computedusing this method range from 1.00 to 4.00, with higher values denoting a higher quality relationship. Total scores from the54-month and first grade assessments were averaged to create amean friendship quality score. The estimatedCronbach'sαin the NICHD SECCYD sample was .80 at 54 months and .81 at first grade.

2.2.6.3. Quality of teacher–child relationship. A 15 item subscale of the Student Teacher Relationship Scale (STRS)(Pianta, 1992) was used to assess teacher perceptions of the teacher–child relationship in child care at 54 months and infirst grade. The items are based on attachment theory and the Attachment Q-Set (Waters & Deane, 1985). The STRSevaluates the teacher's feelings and beliefs about the student's actions toward him or her. Using a 5-point Likert scalethat ranges from 1 = “definitely does not apply” to 5 = “definitely applies,” teachers rate how applicable each statementis to their current relationship with a particular child. Two features of the relationship are studied: conflict andcloseness. The conflict subscale taps the extent to which the teacher–child relationship is marked by antagonistic,disharmonious interactions (e.g., “This child and I always seem to be struggling with each other”; α = .94 at all threetime points). The closeness subscale is an index of the amount of warmth and open communication present in therelationship (e.g., “I share an affectionate, warm relationship with this child”; α values ranged from .88 to .91). Theoverall quality of the relationship is determined by the amount of closeness and conflict (reflected) in the relationship.Higher scores indicate more positive teacher–child relationships. In the current study, teachers completed the STRS inthe spring of each year. The STRS has been widely used in studies with preschool and elementary school children. It isassociated with children's and teachers' classroom behaviors, and correlates with observational measures of quality ofthe teacher–child relationship (e.g., Birch & Ladd, 1997; Howes & Hamilton, 1992; Howes & Ritchie, 1999).Additionally, STRS scores correlate with Attachment Q-Set ratings of teachers and students such that higher STRSscores are associated with more secure relationships (Howes & Ritchie, 1999). Scores at 54 months and first grade wereaveraged to create a mean score for quality of the teacher–child relationship.

2.2.7. Measures of children's behaviors related to testing

2.2.7.1. Child communication with adults. At 54 months, teachers completed the Child's Adaptive LanguageInventory (Feagans & Farran, 1979). Eleven items that assess communication with adults (e.g., when the adult asks himor her a question, he or she responds appropriately) were used in the current study. Items are rated on a 5-point Likertscale that ranges from 1 = “well below average” to 5 = “well above average.” Scores range from 11 to 55, with higherscores indicating better quality communication. The items used have high internal reliability (Chronbach's α = .89).

2.2.7.2. Child attention in laboratory. At 54 months and first grade, children completed the Continuous PerformanceTask (CPT) (Rosvold, Mirsky, Sarason, Bransome, & Beck, 1956). This task was administered to each childindividually toward the end of a 21/2-h laboratory visit. With an experimenter in the room, the child sat at a table infront of a 2-inch square screen and a red button. Dot-matrix pictures of 10 familiar objects (e.g., flower) were producedby a computer and presented on the screen. The child was asked to press the button “as fast as you can” each time atarget stimulus (a chair) appeared on the screen. A total of 220 stimuli were presented in 22 blocks. The target stimuluswas randomly presented twice within each block, for a total of 44 presentations. Each stimulus appeared on the screenfor 500 ms. The child was required to: (1) press the red button as soon as he or she saw the image of the chair on thescreen, and (2) refrain from pressing the button at the appearance of other nontarget stimuli. The task took 7 min 20 s.Attention was assessed by the number of errors of omission and commission. Errors of omission occurred when thechild did not press the button in response to the appearance of the target stimulus. Therefore, children with greaterability to sustain attention had fewer lapses in attention and made fewer errors of omission. Lower scores indicatehigher levels of attention. Errors of commission occurred when the child pressed the button in response to nontargetstimuli. This is a reflection of impulsivity. Lower scores indicate less impulsivity. These measures of attention derivedfrom the CPT have adequate test–retest reliability (r = .65–.74) (Halperin, Sharma, Greenblatt, & Schwartz, 1991).


Children's performance on the CPT has high construct validity as a measure of attention (Halperin et al., 1991) andadequate predictive validity (e.g., Barkley, 1994; Barkley, Grodzinsky, & DuPaul, 1992). Scores were transformedusing a log transformation because of the skewed distribution of the scores (NICHD ECCRN, 2003). Scores at54 months and first grade were averaged to create a mean score for attention during a structured and stressful task.

2.3. Data analysis plan

Associations between maternal attachment patterns and cognitive skills at first grade were examined in hierarchicalmultiple regression models. Control variables were entered first into the regression model predicting cognitive skills.Specifically, variables for child (sex, African-American status, Latino-American status, early cognitive skills, averagehours in child care, and child care quality) and family (maternal education and episodes of family poverty)characteristics were included. These particular controls were chosen because previous research has demonstratedassociations between these variables and cognitive skills (e.g., for associations with race/ethnicity see Brooks-Gunn,Klebanov, & Duncan, 1996; for associations with poverty see Bradley & Corwyn, 2002; for associations with maternaleducation, see Dollaghan et al., 1999; for associations with child care, see NICHD ECCRN, 2003) and/or because theirinclusion helped to control for the potential endogeneity of attachment (e.g., early cognitive ability may influence bothattachment and cognitive skills). Variables for attachment at 36 months were then entered into the model. Specifically,four dummy variables for avoidant, ambivalent, controlling, and insecure/other attachment were included. Secureattachment served as the comparison. Next, four blocks of variables, representing the mediating mechanisms throughwhich maternal attachment may affect cognitive skills, were entered individually into the model so that the separatecontribution of each block could be assessed. The children's exploration block consisted of two variables: taskengagement and investigation/engagement in the classroom. The maternal instruction block included two variables:cognitive stimulation and quality of assistance. The children's social relationships block was composed of threevariables: number of friends, friendship quality, and quality of teacher–child relationships. Lastly, the children'sbehaviors related to testing block included two variables: communication skills with adults and attention in a laboratorytesting situation. Multicollinearity was not a problem in any model (tolerance statistics ranged from .82 to .98).

Individually adding sets of variables for each of the potential mediating mechanisms allowed for examination of thestability of attachment variables across model specifications and investigation of whether mediation through aparticular mechanism was indicated. A decrease in the β value for a variable with the addition of a block of variablesindicates that the effect of the initial variable on the outcome is mediated through one or more of the added variables(Baron & Kenny, 1986). Complete mediation is suggested when the coefficient associated with the predictor decreasesto zero when the mediator is included in the model. Partial mediation is indicated when the magnitude of the associationbetween the predictor and the outcome decreases, but remains greater than zero, when the mediator is in the model. Formediation to occur, the hypothesized mediator must also be a significant predictor of the outcome.

In cases where mediation was suggested, because of a decrease in one or more of theβ coefficients for the attachmentvariables, formal tests of mediation were conducted to elucidate the relations among the variables. Sobel's z tests wereperformed with individual variables, which were significant predictors of cognitive skills, in the added block todetermine which variables significantly mediated the association between attachment and cognitive skills. The Sobel's ztest indicates whether the difference between the coefficient associated with the predictor variable of interest excludingand including the mediator is greater than zero. If this difference is greater than zero, mediation is indicated such that theeffect of the predictor on the outcome occurs through the relationship between the predictor and the mediator. TheSobel's z test was used to test for mediated effects as this test is less vulnerable to Type I errors than other tests ofmediation. Specifically, the error rates for Sobel's z tests are less than .05. Additionally, Sobel's z tests have adequatepower to identify small effects for sample sizes of 1000 or greater (MacKinnon, Lockwood, Hoffman, West, & Sheets,2002).

3. Results

3.1. Descriptive statistics

Means and standard deviations for all continuous variables and frequencies for dichotomous variables are presentedin Table 1. The children demonstrated average-level cognitive skills at 15 months on a standardized test of skill, and

Table 1Descriptive statistics (n = 1000)

M SD Minimum Maximum %

Woodcock Johnson Achievement score — first grade 100.56 10.14 51.00 132.00Female 50.10African-American 11.30Latino-American 5.80White 82.90Bayley Mental Development Index 109.20 13.90 63.00 150.00Average hours in child care 28.70 14.08 .00 57.75Quality of child care 13.85 1.90 6.00 16.00Years of maternal education 14.47 2.45 7.00 21.00Episodes of poverty 2.02 2.52 .00 7.00Avoidant attachment (modified Strange Situation) 4.90Ambivalent attachment (modified Strange Situation) 16.60Insecure/other attachment (modified Strange Situation) 7.10Controlling attachment (modified Strange Situation) 9.30Child task engagement (Structured Interaction Task) 8.21 1.24 3.50 11.46Child investigation/engagement in classroom (Classroom Observational System) 55.81 4.83 28.00 60.00Maternal cognitive stimulation (HOME) 11.49 2.45 3.00 15.00Quality of maternal assistance (Structured Interaction Task) 4.87 1.16 1.00 7.00Number of friends 4.30 .88 1.00 5.00Friendship quality (Quality of Classroom Friends) 2.70 .51 1.00 4.00Quality of teacher–child relationship (Student Teacher Relationship Scale) 65.33 6.39 28.00 75.00Child communication with adults (Adaptive Language Inventory) 27.28 5.78 11.00 46.14Child attention in lab (errors of omission and commission) 16.22 16.70 .00 120.00


attachment distributions were comparable to those found in other studies (Van IJzendoorn, Goldberg, Kroonenberg, &Frenkel, 1992). The distribution patterns of most predictor variables and the outcome variable were normal. CPT errorsof omission and commission, however, were not normally distributed and, thus, were log transformed for the analyses.

3.2. Regression models

Table 2 displays the regression results for child cognitive skills and includes zero-order correlations between thepredictors and the outcome, β values for each predictor, and▵R2 between the models. Several significant associationswere found between the control variables and cognitive skills at first grade.

Two attachment patterns were significantly associated with cognitive skills. Specifically, ambivalent and insecure/other attachment were negative predictors of cognitive skills. Several significant associations were also evidentbetween variables for each of the potential mediating mechanisms and cognitive skills. One of the two variablesrepresenting children's exploration was related to cognitive skills. Children with higher levels of task engagementevidenced greater cognitive skills. Both variables representing maternal instruction were related to cognitive skills.Children who received higher quality maternal assistance and more cognitive stimulation demonstrated greatercognitive skills. One of the three variables representing children's social relationships was associated with cognitiveskills. Children who had higher quality relationships with teachers demonstrated greater cognitive skills. Lastly, bothvariables for children's behaviors related to testing were associated with cognitive skills. Children with higher levelcommunication skills and attention evidenced greater cognitive skills.

Structure coefficients are listed in Table 3. Structure coefficients demonstrate the relative predictive strength of eachvariable in the model, as they do not account for shared variance among the variables (Courville & Thompson, 2001).The structure coefficient is the zero-order correlation between a predictor and the outcome divided by the square root ofthe multiple correlation. Coefficients are evaluated within a specific model (e.g. Model 3). As such, the structurecoefficients indicate the specific, unique strength of a predictor within a given model and provide accurate estimates ofeffect size.

The structure coefficients indicate an analogous pattern of association between the predictor variables and cognitiveskills as the standardized coefficients. However, for most variables, the structure coefficients demonstrate a strongerassociation with cognitive skills than the standardized coefficients because of the variables' shared variance. The

Table 2Regression models predicting cognitive skills at first grade (n = 1000)

r Model 1 Model 2 Model 3 Model 4 Model 5 Model 6

Child and family controlsFemale − .05 − .10⁎⁎⁎ − .10⁎⁎⁎ − .09⁎⁎ − .11⁎⁎⁎ − .12⁎⁎⁎ − .11⁎⁎⁎

African-American − .27⁎⁎⁎ − .09⁎⁎⁎ − .10⁎⁎ − .11⁎⁎ − .08⁎⁎ − .10⁎⁎ − .10⁎⁎

Latino-American − .05 − .00+ − .01 − .01 − .00+ − .01 − .02Early cognitive skills(Bayley Mental Development Index)

.32⁎⁎⁎ .23⁎⁎⁎ .25⁎⁎⁎ .24⁎⁎⁎ .22⁎⁎⁎ .24⁎⁎⁎ .21⁎⁎⁎

Hours in child care .00+ .01 .01 .01 − .00+ .01 .00+Quality of child care (ORCE) .07⁎ .01 .01 .01 .00+ .00+ .00+Episodes of poverty 6 months-first grade − .39⁎⁎⁎ − .14⁎⁎⁎ − .13⁎⁎ − .12⁎ − .09⁎ − .12⁎⁎ − .11⁎⁎

Years of maternal education .40⁎⁎⁎ .26⁎⁎⁎ .26⁎⁎⁎ .24⁎⁎⁎ .20⁎⁎⁎ .25⁎⁎⁎ .24⁎⁎⁎

Attachment stylesAvoidant (modified Strange Situation) − .02 .01 .00 .01 .01 .01Ambivalent (modified Strange Situation) − .12⁎⁎⁎ − .10⁎⁎ − .09⁎⁎ − .09⁎⁎ − .09⁎⁎ − .08⁎

Insecure/other (modified Strange Situation) − .13⁎⁎⁎ − .08⁎⁎ − .07⁎ − .06⁎ − .07⁎ − .06⁎

Controlling (modified Strange Situation) − .00+ .00+ .01 .01 − .02 .02Children's exploration

Task engagement (Structured Interaction Task) .27⁎⁎⁎ .11⁎⁎⁎

Investigation/engagement in classroom(Classroom Observational System)

.07⁎ − .01

Maternal instructionCognitive stimulation (HOME) .35⁎⁎⁎ .17⁎⁎⁎

Quality of assistance (Structured Interaction Task) .34⁎⁎⁎ .09⁎⁎

Children's social relationshipsNumber of friends .15⁎⁎⁎ .04Friendship quality (Quality of Classroom Friends) − .09⁎⁎⁎ − .02Quality of teacher–child relationship(Student Teacher Relationship Scale)

.19⁎⁎⁎ .08⁎⁎

Children's behaviors related to testingCommunication with adults (Child Adaptive Language) .28⁎⁎⁎ .25⁎⁎⁎

Attention in lab (errors of omission and commission) − .23⁎⁎⁎ − .30⁎⁎

R2 .28⁎⁎⁎ .30⁎⁎⁎ .31⁎⁎⁎ .33⁎⁎⁎ .31⁎⁎⁎ .32⁎⁎⁎

▵R2 .02⁎⁎ .01⁎⁎ a .03⁎⁎⁎ a .01⁎⁎ a .02⁎⁎⁎ a

⁎p b .05. ⁎⁎p b .01. ⁎⁎⁎ p b .001.a Compared with Model 2.


structure coefficients for Model 2 indicate that ambivalent and insecure/other attachment were moderate predictors. Incontrast, avoidant attachment and controlling attachment were weak predictors. The structure coefficients in Model 3demonstrate that task engagement was a moderately strong predictor, and classroom investigation/engagement a weakpredictor, of cognitive skills. The structure coefficients in Model 4 indicate that quality of maternal assistance andmaternal cognitive stimulation were moderately strong predictors of cognitive skills. The structure coefficients inModel 5 show that number of friends and quality of teacher–child relationships were moderate predictors, andfriendship quality a weak predictor, of cognitive skills. Lastly, the structure coefficients in Model 6 indicate thatcommunication and attention were moderately strong predictors of cognitive skills.

3.3. Mediation analyses

Examination of the β values from the regression models suggested that the effects of ambivalent and insecure/otherattachment on cognitive skills weremediated through one ormore of the hypothesizedmechanisms. Note that theβ valuesfor ambivalent and insecure/other attachment decreased in several of the models with blocks of mediator variables. Inparticular, the magnitude of the effect for ambivalent attachment decreased and became nonsignificant in the model withthe block of variables for children's behaviors related to testing. Similarly, the magnitude of the effect and the significanceof insecure/other attachment decreased in models with blocks of variables for children's exploration, maternal instruction,children's social relationships, and children's behaviors related to testing. Sobel's z tests indicated several significantmediating mechanisms. The effect of ambivalent attachment on cognitive skills was statistically mediated by both

Table 3Structure coefficients for regression models predicting cognitive skills at first grade (n = 1000)

Model 1 Model 2 Model 3 Model 4 Model 5 Model 6

Predictors rs rs rs rs rs rsFemale .09 .09 .09 .09 .09 .09African-American .51 .49 .48 .47 .48 .47Latino-American .09 .09 .09 .09 .09 .09Early cognitive skills .60 .58 .57 .56 .57 .56Hours in child care .00+ .00+ .00+ .00+ .00+ .00+Quality of child care .13 .13 .13 .12 .13 .12Episodes of poverty .74 .71 .70 .68 .70 .68Years of maternal education .75 .73 .71 .70 .71 .70Avoidant .04 .04 .04 .04 .04Ambivalent .22 .21 .21 .21 .21Insecure/other .24 .23 .23 .23 .23Controlling .00+ .00+ .00+ .00+ .00+Child task engagement .48Child investigation/engagement in classroom .13Maternal cognitive stimulation .61Quality of maternal assistance .60Number of playmates .27Friendship quality .16Quality of teacher–child relationship .34Child communication with adults .49Child attention in lab .40


variables for children's behaviors related to testing: child communication with adults (z = − 2.57, p = .01) and childattention in the lab (z=− 2.03,pb .05). The effect of insecure/other attachment on cognitive skills was statisticallymediatedby one of the variables for children's exploration: task engagement (z =− 2.06, p b .05). Additionally, the effect of insecure/other attachment was mediated by both variables for maternal instruction: maternal assistance (z = − 2.22, p b .05) andmaternal cognitive stimulation (z = − 2.00, p b .05). Furthermore, the effect of insecure/other attachment was mediated byone variable for children's social relationships: quality of teacher–child relationships (z = − 1.99, p b .05). Lastly, the effectof insecure/other attachment was mediated by both variables for children's behaviors related to testing: communicationwith adults (z = − 2.87, p b .01) and attention in the lab (z = − 2.66, p b .01).

4. Discussion

There were two goals in the current study. The first was to examine associations between insecure attachmentpatterns and cognitive skills, and the second was to test mediators of identified associations. Attachment theorysuggests that variation in developmental outcomes exists among children with avoidant, ambivalent, controlling, andinsecure/other attachment patterns. The majority of research on attachment and cognitive development, however,examines only mean differences in cognitive skills between secure and insecure children. Additionally, attachmentresearchers have posited that maternal attachment influences children's cognitive skills through multiple mediatingmechanisms. No empirical studies of these mechanisms, however, have been conducted. Large-scale studies ofattachment and cognitive skills that allow for the examination of differences among insecure groups and permit the useof mediation statistics were needed. The NICHD SECCYD, a prospective study of children from birth through firstgrade, provided a data set to conduct such an investigation.

4.1. Attachment pattern classification and cognitive skills

Results from this investigation indicate variation among insecure children in their cognitive skills, as demonstratedon a standardized test of skill, at first grade. Avoidant children scored similarly to secure children. This finding suggeststhat avoidant attachment is not a risk factor for lower level cognitive skills. The attachment strategies that avoidantchildren develop appear to be sufficient to support their cognitive development. Contrary to expectations, controllingchildren also scored similarly to their secure peers. This finding warrants further investigation. It is possible that


through their efforts to manipulate their caregivers, controlling children develop age-appropriate cognitive skills. Onthe other hand, as anticipated, ambivalent and insecure/other children demonstrated significantly lower scores thantheir secure peers. Other studies have also found negative associations between ambivalent attachment and cognitiveskills (Ainsworth et al., 1978; Van IJzendoorn et al., 1995). The negative association between insecure/otherattachment and cognitive skills is consistent with descriptive findings from a previous study in which insecure/otherchildren demonstrated lower level cognitive skills than secure children (Moss & St-Laurent, 2001).

The significant negative associations between ambivalent and insecure/other attachment and cognitive skills areimportant findings with respect to the attachment literature. Because of the small magnitude of effect for attachment oncognitive skills in several previous studies, some researchers have speculated that maternal attachment is not ameaningful contributor to cognitive development (e.g., Sroufe, 1988; Van IJzendoorn et al., 1995). Results from thecurrent study, however, demonstrate that maternal attachment has an effect of statistical and practical significance oncognitive skills. Examination of the structure coefficients, which demonstrate the unique strength of a given predictorin a model, indicates that ambivalent and insecure/other attachment patterns are stronger predictors of cognitive skillsthan child sex, amount of child care, and quality of child care experiences. In other words, when the effects of specificattachment patterns on cognitive skills are examined in large, diverse samples, attachment appears to be an importantcontributor to cognitive skills.

4.2. Mediating mechanisms

Attachment theorists posit that the influence of attachment on cognitive skills is mediated through severalmechanisms: children's exploration, parental instruction, children's social relationships, and children's behaviorsrelated to testing. Specifically, attachment theorists speculate that insecure children engage in less exploration, receivelower quality maternal instruction, have less supportive social relationships, and demonstrate poorer test-taking skillsthan secure children. In other words, insecure children may not engage in the kind of behaviors, when alone and whenin relationships, that support the development of cognitive skills. Our findings provide some support for the role ofthese mechanisms in explaining the association between attachment patterns and cognitive skills.

The effect of ambivalent attachment on cognitive skills was mediated through poor-quality behaviors related totesting. Specifically, ambivalent children demonstrated lower level communication skills and less sustained attention ina structured and stressful task than their secure peers, which were in turn negatively associated with cognitive skills.These findings regarding ambivalent children's communication and attention skills are similar to those of other studies.Ambivalent children's reticence over caregiver availability appears to interfere with their abilities to engage withpeople and attend to objects in their immediate environments.

It is interesting that the effect of ambivalent attachment on cognitive skills could only be explained by behaviorsrelated to testing. Ambivalent children did not exhibit significantly lower levels of exploration, nor did they receivelower quality maternal instruction than secure children. Additionally, ambivalent children did not have lower qualitysocial relationships than secure children. It is therefore possible that ambivalent children's lower scores on a test ofcognitive skill that requires extensive communication with an examiner and sustained attention are related to behaviorsin the testing situation rather than deficits in cognitive skills per se. Additional research is necessary to determinewhether ambivalent children have lower level cognitive skills than secure children or are less able to demonstrate theiractual level of cognitive skill on standardized tests.

The effect of insecure/other attachment on cognitive skills was attributable to child exploration, maternalinstruction, social relationships, and behaviors related to testing. Specifically, insecure/other children evidenced lowlevels of task engagement, received low-quality maternal assistance, had low-quality relationships with teachers, anddemonstrated low-level communication and attention skills, which were in turn associated with lower level cognitiveskills. This finding that the influence of insecure/other attachment on cognitive skills was attributable to pervasivemaladjustment is consistent with findings from other studies in which insecure/other children demonstrated difficultiesin multiple developmental domains (Goldberg, 1997; Teti, 1999). Insecure/other children's inability to get theirattachment needs met and their continually activated attachment systems appear to impede their cognitive skilldevelopment. A continually activated attachment system may pose a special risk as children's exploratory systems,which encourage interactions with people and objects in the environment, are inactivated when their attachmentsystems are activated. Additionally, a continually activated attachment system leads to anxiety, which may interferewith children's abilities to attend during a test. The disjointed behaviors of insecure/other children may also inhibit


these children's interactions with others. In particular, because of insecure/other children's unorganized behaviors,mothers and teachers may have difficulty learning about these children's needs and how to respond appropriately,resulting in these children receiving low-quality instruction from their mothers and developing low-qualityrelationships with their teachers.

4.3. Future directions

These findings, at best, provide some indication that there are meaningful associations between attachment andcognitive skills. It should, however, be noted that attachment predicted only 2% of the variance in cognitive skillsbetween children with different attachment patterns, and thus, mediators of the relationship between attachment andcognitive skills pertain to mediation of a very small portion of variance in cognitive skills. Additional work is neededto better understand associations between attachment and cognitive skills. First, it is important to investigate theinterplay between the various mediating mechanisms through which insecure/other attachment affects cognitiveskills, and to examine additional mechanisms that may explain associations between attachment and cognitive skills(Van IJzendoorn et al., 1995). Second, it is necessary to conduct further studies to examine in more depth thedirection of effects between attachment and cognitive skills. It is possible that children with lower level cognitiveskills have more difficulty engendering sensitive and responsive caregiving from their mothers and are thus morelikely to develop ambivalent and insecure/other attachments. Third, it is essential to examine associations betweenattachment and cognitive skills among higher risk samples. The current sample is a product of the recruitment andenrollment methods of the NICHD SECCYD. Specifically, children with disabilities, children who lived indangerous areas, and children whose mothers did not speak English were excluded. The current sample may containrelatively few high-risk children, thus reducing the magnitude of association between insecure/other attachment andcognitive skills.

5. Conclusions

Results from the current study can inform research, as well as practice. With respect to research, these findingsdemonstrate the value of examining the effects of specific insecure attachment patterns on children's developmentaloutcomes, and of investigating the mechanisms through which attachment influences development. In relation topractice, this study has implications for interventions with children and families and for teacher education. Interventionefforts for both ambivalent and insecure/other children would be well served by helping these children become betterable to communicate with adults and sustain attention. Furthermore, intervention programs for mothers and insecure/other children could help support children's cognitive skill development by assisting mothers in providing high-qualitycognitive stimulation and formal and informal instruction to their children. In reference to teacher education, theseresults point to the value of helping teachers identify the quality of their relationships with students and of workingtoward improving low-quality relationships. Higher quality relationships with teachers are especially important forinsecure/other children, as these relationships mediate the negative effects of their maternal attachment patterns oncognitive skills. Informing teachers as to the influence of attachment on relationship quality may increase teachers'awareness and, in turn, prevent insecure/other children from reconstructing maladaptive maternal relationships withtheir teachers.

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