Research figure: Mary Ainsworth · Written by Artificial Sapiens
Mary Ainsworth's secure-base concept explains how an infant uses an available, familiar caregiver as a point of support for exploring the environment and as a person to approach when tired, frightened, uncertain, or distressed. Its central observation is an organized relationship between outward exploration and access to protection. A child may move away, monitor the caregiver's location, return for contact, and resume investigating the world. Ainsworth made these patterns observable through naturalistic fieldwork, home visits, and structured laboratory research. Secure-base behavior is a relationship-specific developmental construct, not a personality label or a clinical diagnosis. Her original home-observation criteria and the coauthored Ainsworth and Bell (1970) study remain important primary sources.
What Is a Secure Base in Ainsworth's Attachment Research?
A secure base is a caregiver whose expected availability permits a child to engage with people, objects, and unfamiliar surroundings while retaining reliable access to support. This phrase identifies a function of a particular attachment relationship and the behaviors through which that function becomes visible. It does not imply that securely attached infants remain beside caregivers, never become upset, or acquire independence by abandoning attachment needs. Security is expressed through the flexible coordination of proximity and distance according to circumstances.
The idea concerns behavioral organization rather than one isolated action. A child who looks back, approaches briefly, leaves again, and explores may demonstrate secure-base use. Another child who stays near the caregiver because a room is overwhelming may be regulating attachment demands. Interpretation requires observing the situation, developmental level, caregiver availability, signs of distress, interaction quality, and the behavioral sequence. A single glance, separation protest, or interval of solitary play cannot establish attachment security.
Secure Base, Safe Haven, and Exploration
Secure-base use and safe-haven use identify complementary functions. A secure base supports movement outward toward learning, social engagement, and investigation. A safe haven provides refuge or comfort when distress is active. The same familiar adult may serve both functions, with transitions between them occurring repeatedly during ordinary activities. The distinction matters because comfort following distress and confidence to investigate an environment illuminate related but distinguishable aspects of the relationship.
Exploration is a developmental activity involving movement, attention, manipulation of objects, and encounters with new experiences. Attachment behavior may become more prominent when conditions signal fatigue, pain, illness, unfamiliarity, separation, or danger. As a child regains a sense of safety and access to support, exploratory attention may return to the environment. Ainsworth's explanatory advance was to study the changing coordination of these functions rather than equating attachment simply with prolonged physical closeness.
Historical Origins: Blatz, Bowlby, and Ainsworth
William Blatz and Early Security Theory
Mary Dinsmore Salter Ainsworth studied at the University of Toronto, where William E. Blatz's security theory influenced her intellectual formation. Blatz connected security and a person's capacity to engage with challenges beyond an immediate source of support. Ainsworth later brought questions about security, dependence, and confident activity into research on infancy. Historians have documented how she connected this earlier inheritance to the attachment framework that subsequently emerged. Van Rosmalen, van der Horst, and van der Veer (2016) examine this historical integration.
Bowlby's Attachment-Theoretical Framework
John Bowlby formulated the theoretical foundation of attachment theory. His work presented proximity seeking toward familiar protective figures as part of an organized behavioral system with evolutionary and developmental significance. Attachment behavior responds to conditions such as distress, threat, or separation, while the accessibility of a protective figure can support exploration. Bowlby's theoretical framework provided questions that Ainsworth investigated and refined through observation. Their intellectual relationship was collaborative, while their principal contributions remain distinguishable. Bretherton's historical study traces this history.
Ainsworth's Empirical Elaboration
Ainsworth's distinctive contribution was to describe secure-base use as a sequence of observable behaviors. She examined an infant moving away from the caregiver, orienting back across distance, returning for contact, playing nearby, and modifying activity as access to the caregiver changed. This permitted security to be studied as a behavioral organization embedded in a particular relationship. Her work helped researchers distinguish having an attachment relationship from the manner in which the relationship supports regulation and exploration.
The secure-base construct emerged through a series of inquiries that spanned everyday observation, longitudinal research, and experimental variation of the caregiving environment. It therefore belongs to a larger scientific program rather than a single brief definition or a solitary laboratory experiment.
Secure-Base Behavior in Ainsworth's Uganda Study
Ainsworth undertook fieldwork in Uganda during the 1950s to investigate infant care, social behavior, and relationships with familiar caregivers in ordinary contexts. Her book Infancy in Uganda: Infant Care and the Growth of Love (1967) describes an observational study involving 28 infants across 23 households. The ethnographic setting helped her see infants venture away from caregivers, explore their social and physical surroundings, and return to familiar adults.
Repeated observations made the organization of these excursions especially informative. The investigator could attend to the timing of movement away, visual orientation toward the caregiver, the response to interruption, and brief returns to contact. These sequences connected exploration to a relationship whose availability mattered to the infant. Ainsworth recognized that sustained closeness alone was an insufficient description of attachment. The presence of an accessible caregiver could facilitate the very movement away from that caregiver.
Naturalistic fieldwork offered a major advantage: infants were observed amid ordinary household activities, caregiving arrangements, other people, and customary ways of interacting. Its limitations also deserve explicit recognition. The sample was small and situated in a specific historical and cultural context, and observations were shaped by opportunities available within families. The study generated and grounded a construct that later work examined in other settings. It did not establish identical visible expressions of secure-base behavior in every society.
The historical term mother refers to the particular relationships examined in many of Ainsworth's original studies. Modern attachment research investigates mothers, fathers, adoptive parents, grandparents, and other consistent caregivers. The relevant question is whether a familiar figure is accessible and responsive within a particular relationship, not whether the caregiver conforms to the household pattern represented in the earliest samples.
The Baltimore Longitudinal Program: Secure Base at Home
Ainsworth developed longitudinal observational research with families in Baltimore after her Uganda work. Repeated home visits documented interaction during feeding, play, caregiving, departures, returns, and responses to infant signals. This made it possible to describe variation in the everyday relationship before examining the same children in more structured settings. The Baltimore program joined questions about sensitive caregiving, the organization of infant behavior, and the developmental meaning of security.
What the Home-Observation Criteria Looked For
In methodological criteria revised in July 1970, Ainsworth described classifying the balance between exploratory and attachment behavior at home. Her original research document centered on whether the child could use the caregiver as a base for excursions, monitor the caregiver from a distance, return voluntarily, establish brief contact, and subsequently move off to explore. These actions have meaning as coordinated sequences.
The home setting also introduces interpretive challenges. Available floor space, household hazards, mobility, sleep, feeding schedules, unfamiliar visitors, and the availability of toys change the opportunity for exploration. Age, physical development, sensory characteristics, temperament, and current illness can affect a child's observed behavior. Thus secure-base use cannot be equated with total minutes spent away from the caregiver. A sound assessment asks how the child manages access to support under the conditions actually present.
Caregiver Sensitivity and Responsiveness
Ainsworth's Baltimore studies helped develop the concept of caregiver sensitivity. In its classical formulation, sensitivity concerns noticing infant signals, interpreting them appropriately, and responding promptly and suitably to the infant's needs. Repeated effective interactions may foster an expectation that seeking support is useful. Caregiving quality is therefore investigated across patterns of exchanges, rather than through a demand that adults respond perfectly to every signal.
Caregiver sensitivity deserves its own methodological treatment because observational scales, coding approaches, and explanatory models differ. In the secure-base context, the key theoretical connection is that expectations of caregiver accessibility can facilitate the child's movement between seeking comfort and investigating the environment. The concept concerns reciprocal interaction, not a universal formula for one exact parenting behavior.
How Attachment and Exploration Change With Circumstances
Attachment theory describes behavioral systems whose relative activation changes with the child's perception of safety, fatigue, unfamiliarity, and support. In manageable conditions, an infant may engage with a toy or approach another person while checking that the caregiver remains accessible. When uncertainty or distress rises, the child may interrupt activity, vocalize, return, seek contact, or remain nearby. After effective reassurance, exploratory engagement may resume.
This process is not a mechanical sequence. One child may require sustained proximity in a new environment; another may monitor from a distance; a third may become deeply absorbed in a familiar activity. Developmental and situational differences affect the visible expression of attachment behavior. The scientific question is how the caregiver's availability shapes the organization of the child's response across situations.
Monitoring, Returning, and Re-Engaging
Visual checking, vocal exchange, brief approaches, physical contact, renewed play, and reactions to a caregiver's departure can contribute to the observed picture. Each has meaning in relation to what happened before and afterward. A child who returns for reassurance and resumes exploration may illustrate effective secure-base use. Yet researchers cannot require one identical checking gesture from all children. Motor, sensory, language, social, and cultural conditions affect how orientation and access are communicated.
The Importance of Separation and Reunion
When a familiar caregiver leaves, the child loses immediate access to a particular source of support. Exploration may decline, while calling, searching, crying, or other proximity-seeking behaviors become more prominent. The caregiver's return gives researchers an opportunity to observe how proximity, comfort, recovery, and exploration are coordinated. Separation distress alone does not determine attachment security. Low visible distress alone does not prove security. The broader behavioral pattern and context are essential.
The Strange Situation as an Investigation of the Secure Base
The Strange Situation Procedure emerged from the Baltimore program as a structured way to observe infant behavior under changing conditions of unfamiliarity, separation, and reunion. Its historical development includes Mary Ainsworth and Barbara A. Wittig's 1969 publication, followed by Mary Ainsworth and Silvia M. Bell's 1970 article. The two collaborators retain separate credit for their coauthored original works.
The 1970 Ainsworth and Bell study examined 56 white, middle-class infants approximately one year old. It reported that the caregiver's presence generally encouraged exploration, whereas separation often reduced exploratory behavior and heightened attachment-related responses. The pattern demonstrated the theoretical importance of changing caregiver accessibility within a controlled setting. Its historically specific sample and laboratory conditions establish important constraints on generalization.
The procedure involved a succession of encounters with an unfamiliar room, toys, a stranger, brief separations, and reunions. Each condition changed the demands placed upon the infant's regulation of attachment and exploration. The full chronology and coding instructions belong to the distinct history of the Strange Situation method. For the secure-base concept, its contribution is the demonstration that behavior can be organized in relation to changing availability of the attachment figure.
Secure-Base Organization and Ainsworth's A/B/C Classifications
Ainsworth's original research program distinguished organized avoidant (A), secure (B), and resistant or ambivalent (C) infant attachment patterns. The secure pattern involves effective use of the caregiver for support and the ability, in suitable circumstances, to resume exploration. Other patterns involve different organizations of proximity seeking, avoidance, contact, and distress during the procedure. These categories characterize a relationship under defined observational conditions; they are not general personality diagnoses.
The major collaborative account is Patterns of Attachment: A Psychological Study of the Strange Situation, first published in 1978 and authored by Mary D. Salter Ainsworth, Mary C. Blehar, Everett Waters, and Sally Wall. Later disorganized/disoriented attachment classification D was developed through the work of Mary Main and Judith Solomon. Historical descriptions should not attribute that later category to Ainsworth's original A/B/C classification system.
What Secure-Base Behavior Measures
Secure-base behavior is an observable expression of how a child organizes exploration and access to support in a specific attachment relationship. It can illuminate attachment security, but it is not synonymous with the intensity of affection, the frequency of physical contact, or the caregiver's own reports of love. Nor is it equivalent to a lifelong trait, an adult romantic style, or the total quality of all the child's relationships.
A child may form several attachment relationships with different caregivers, and their organization can differ. The child's age and capacities also matter. A toddler's movement and visual checking may later be replaced in part by verbal reassurance, social reference, negotiated separations, or different forms of contact. Developmental continuity concerns the organization and function of relationships; it does not require identical behaviors at every age.
The Strange Situation is a research assessment of infant–caregiver attachment organization. It is not a psychiatric diagnostic instrument or a test for reactive attachment disorder, disinhibited social engagement disorder, or a child's overall mental health. Professional clinical assessments address different questions and require a broader developmental, caregiving, and clinical evaluation.
Later Measurement: The Attachment Q-Sort
Subsequent researchers developed naturalistic tools to assess the organization of secure-base behavior beyond a short laboratory setting. Everett Waters and Kathleen E. Deane (1985) described the Attachment Q-Sort, in which behavioral descriptions are arranged according to their fit with an observed child. The procedure can capture patterns of everyday security-related behavior across age ranges and contexts not identical to those of Ainsworth's original laboratory sample.
The Q-Sort and Strange Situation provide related but distinct operational definitions. One emphasizes the organization of behavior in naturalistic contexts; the other uses structured episodes that manipulate unfamiliarity and caregiver accessibility. Results depend on observer training, reliability, observation length, and developmental appropriateness. Investigators must not equate their scores as though they were interchangeable measurements.
Modern Empirical Evidence
Sensitivity and Attachment Security
A 2024 meta-analysis by Madigan and colleagues combined 174 studies, 230 effect sizes, and 22,914 parent–child dyads. Across caregivers, sensitivity was positively associated with attachment security, yielding a pooled correlation of r = .25 with a 95% confidence interval from .22 to .28. The reported estimates were r = .26 for maternal sensitivity and r = .21 for paternal sensitivity; the estimates were broadly comparable in magnitude.
This association is statistically reliable in the pooled literature and substantively relevant to attachment theory. It also leaves substantial individual variation unexplained. Sensitive responsiveness is one contributor among several; family circumstances, stability, caregiver stress, child characteristics, measurement, and historical context all warrant investigation. Correlation does not establish that any isolated parental action caused an individual attachment classification.
The 2024 analysis found variation in estimates according to observational instruments, length of assessment, measurement reliability, and timing between sensitivity and attachment measures. These methodological findings are especially important for the secure-base construct. They show why a naturalistic estimate and an estimate based on the Strange Situation should be interpreted according to their actual measurement procedures.
The First 20,000 Strange Situation Procedures
The Madigan and colleagues (2023) meta-analytic review synthesized more than 285 Strange Situation studies involving 20,720 dyads. It provided large-scale evidence concerning classification distributions across different populations, periods, and regions. The synthesis demonstrates that Ainsworth's observational program became a durable research tradition. It also provides a framework for investigating how historical and population differences affect classification outcomes.
An accumulation of many assessments strengthens the evidence base but does not erase the limits of each setting or automatically validate every interpretation. The strongest conclusions distinguish replication of a procedure, consistency of measured patterns, and agreement about the psychological meaning of those patterns.
Evidence From Nine Countries
In a cross-cultural study by Posada and colleagues (2013), trained observers in nine countries used an Attachment Q-Set to examine 547 children aged 10–72 months; 81 child-development experts also described optimal secure-base use. Secure-base behavior was observed across the studied settings, and experts' descriptions showed substantial similarities. The observed organization of behavior showed more modest similarities across contexts.
The finding supports the relevance of a general secure-base function across multiple cultural settings while recognizing variation in its expression. A child might investigate an environment independently within the caregiver's view, or explore amid continuous physical proximity and interaction with familiar people. Caregiving practices, household organization, expectations about independence, and the meaning of unfamiliar encounters all affect what an observer sees. No finite sample establishes the same visible behavior as a universal requirement.
Research Validity and Methodological Limitations
Construct Validity
Construct validity asks whether observed behavior captures a theoretically meaningful relationship between caregiver accessibility and exploration. The interpretation is inferential: researchers cannot directly see an internal state called security. They observe actions, their sequencing, responses to contextual change, and relations with caregiving history. Evidence drawn from independent settings and appropriately aligned measures can strengthen the construct, while discrepancies between methods require explanation.
Sampling, Reliability, and Context
Early Baltimore and laboratory studies were conducted with specific families in particular historical circumstances. Reliability depends on standardized coding and competent observers. Generalization to diverse cultural, socioeconomic, health, sensory, and developmental populations requires testing rather than assumption. Brief laboratory episodes and lengthy home observations provide different advantages. Neither can capture every aspect of a child's relationship with the caregiver.
Developmental Plasticity and Causation
Attachment behavior develops within changing social relationships and circumstances. A longitudinal association may indicate meaningful continuity, but later relationships, environmental changes, caregiving transitions, and supportive intervention can also influence developmental pathways. One infant classification is not a fixed forecast of adult personality, educational attainment, psychiatric disorder, or romantic relationships. Specific predictive claims need corresponding longitudinal evidence.
Caregiver Availability Beyond the Historical Mother–Infant Dyad
The core question concerns reliable access to a familiar caregiving figure. Modern studies have extended attachment research beyond mother–infant pairs, including father–child relationships. The 2024 sensitivity meta-analysis supports associations with both maternal and paternal responsiveness. Other caregivers may provide important attachment functions depending on a child's experience and caregiving arrangements.
Families vary in whether support is organized through parents, relatives, adoptive caregivers, or other established figures. Secure-base research must specify the actual relationship and care ecology under study. The term maternal remains appropriate when accurately naming Ainsworth's historical measures or the original sample. Contemporary conclusions should reflect the caregivers and populations covered by the evidence.
Exploration, Learning, and the Development of Agency
The secure-base concept provides a way to investigate how relational support may enable independent activity. Access to help under uncertainty may allow a child to direct attention toward movement, object manipulation, communication, social interaction, and new challenges. These connections are developmentally plausible and researchable. They are not guarantees that security produces a particular score, skill, or adult outcome.
In practical interactions, support can take different forms: remaining available while a child plays, joining an activity when invited, intervening when danger is real, helping regulate distress, or giving the child room to experiment. An adult's helpful action depends on the task and child. The relational function is more informative than any rigid rule about how often to touch, talk to, or direct the child.
Secure-Base Scripts and Adult Attachment: Later Research Traditions
Bowlby's concept of internal working models concerns developing expectations about the availability and effectiveness of support. Subsequent researchers, including Everett Waters and collaborators, developed the idea of a secure-base script, a representational sequence in which difficulty prompts a search for support, effective help, and renewed engagement. This cognitive-representational development extends the secure-base tradition beyond direct observation of infant movement and reunion.
Adult romantic attachment research investigates related questions about comfort, trust, dependence, anxiety, and avoidance, generally using different participants, scales, and theoretical models. Ainsworth's work influenced that intellectual tradition, but infant behavior in the Strange Situation cannot be translated mechanically into adult attachment categories. The connection is conceptual and historical; specific adult empirical claims require distinct evidence.
Scientific Interpretation and Legacy
Ainsworth's enduring insight is that a child's attachment relationship can be studied through the coordinated regulation of access to support and engagement with the environment. Her field observations, Baltimore home research, and collaborative Strange Situation studies converted a broad theoretical problem into identifiable research questions and methods. The evidence supporting an association between sensitive caregiving and security is established at the population level. Exact measurement equivalence across cultures, strong predictions for individuals, and the causal importance of particular caregiver actions require more qualified interpretation.
The scholarly history also illustrates collaboration. Blatz influenced Ainsworth's earlier security thinking; Bowlby developed attachment theory; Ainsworth elaborated secure-base observations and methods; Barbara Wittig and Silvia Bell coauthored major early methodological publications; Mary Blehar, Everett Waters, and Sally Wall coauthored the 1978 monograph. Mary Main and Judith Solomon developed the later disorganization extension. Their respective contributions form an intellectual genealogy in which each original publication retains its authorship.
Implications for Researchers and Caregivers
For researchers, the construct encourages study of how caregiver availability affects children's organized activity rather than measuring proximity and independent exploration as fixed opposing traits. Rigorous work identifies the caregiver–child dyad, observation context, developmental stage, coding system, reliability, comparison groups, and limits of inference. Cross-cultural work additionally examines whether particular behavioral indicators have equivalent meaning across settings.
For caregivers and educators, the broad implication is that accessible support, appropriate responsiveness, and opportunities to explore can operate together. Ainsworth's construct provides a framework for understanding these interactions. It is not a home diagnostic checklist or a universal prescription for an individual family. Persistent developmental concerns, severe distress, possible maltreatment, or clinical questions require qualified professional assessment in context.
Frequently Asked Questions
Did Mary Ainsworth Invent the Secure Base?
Ainsworth developed and empirically refined the construct of secure-base behavior through detailed observations of infants and caregivers. Her work drew upon earlier security thinking associated with William Blatz and the attachment-theoretical framework formulated by John Bowlby. The broad theory and her distinctive observational elaboration have different historical attributions.
Is a Secure Base the Same as a Safe Haven?
They are linked functions. The secure base supports exploration while help remains accessible. The safe haven provides refuge and comfort when help is needed. The same caregiver can fulfill both roles repeatedly.
Can a Securely Attached Infant Cry During Separation?
Yes. Separation protest depends on many situational and developmental factors. Researchers examine the broader organization of behavior, including reunion, comfort, recovery, and exploration. Neither crying nor the absence of crying alone establishes an attachment classification.
Does Secure-Base Behavior Predict Adult Attachment Style?
The construct informed later work on relational expectations, but infant and adult attachment studies use distinct measures and research traditions. An individual infant classification does not map directly onto an adult romantic attachment style. Long-term claims require specific longitudinal evidence.
Does the Strange Situation Diagnose an Attachment Disorder?
No. It is a research procedure assessing attachment organization in an observed infant–caregiver relationship. Clinical attachment disorders require a separate professional evaluation using appropriate diagnostic criteria.
Is Secure-Base Behavior Expressed Identically Across Cultures?
Research across multiple countries supports the relevance of the secure-base phenomenon, alongside variation in observable behavior and caregiving arrangements. Cross-cultural interpretation requires attention to local practices and the validity of particular measurement indicators.
Related Articles
Mary Ainsworth — the central published scientific account of Ainsworth's life, original research, methods, collaborations, and intellectual legacy.
Attachment in Infancy and Early Childhood: Research and Evidence — the broader developmental science of early attachment, security, and caregiver relationships.
Adult Attachment Theory: How Anxiety and Avoidance Shape Relationships — the separate adult relational research tradition and its contemporary measurement.
Mary Ainsworth's Caregiver Sensitivity Scales: Observation and Evidence
Mary Ainsworth's Attachment Classifications: Secure, Avoidant, and Resistant
Mary Ainsworth and John Bowlby: Collaboration and Distinct Contributions
References
Ainsworth, M. D. S. (1967). Infancy in Uganda: Infant care and the growth of love. Johns Hopkins Press. Yale eHRAF publication record.
Ainsworth, M. D. S. (1970, revised). Criteria for classification of one-year-olds in terms of the balance between exploratory and attachment behavior at home. Stony Brook attachment archive.
Ainsworth, M. D. S. (1989). Attachments beyond infancy. American Psychologist, 44(4), 709–716. PubMed.
Ainsworth, M. D. S., and Bell, S. M. (1970). Attachment, exploration, and separation: Illustrated by the behavior of one-year-olds in a strange situation. Child Development, 41(1), 49–67. https://doi.org/10.2307/1127388.
Ainsworth, M. D. S., Blehar, M. C., Waters, E., and Wall, S. (1978). Patterns of attachment: A psychological study of the Strange Situation. Lawrence Erlbaum Associates. https://doi.org/10.4324/9781315802428.
Ainsworth, M. D. S., and Wittig, B. A. (1969). Attachment and exploratory behavior of one-year-olds in a strange situation. In B. M. Foss (Ed.), Determinants of infant behaviour (Vol. 4). Methuen. Wellcome Collection archive.
Bretherton, I. (1992). The origins of attachment theory: John Bowlby and Mary Ainsworth. Developmental Psychology, 28(5), 759–775. https://doi.org/10.1037/0012-1649.28.5.759.
Duschinsky, R. (2020). Cornerstones of attachment research. Oxford University Press. Oxford Academic.
Madigan, S., Deneault, A.-A., Duschinsky, R., Bakermans-Kranenburg, M. J., Schuengel, C., van IJzendoorn, M. H., Ly, A., Fearon, R. M. P., Eirich, R., and Verhage, M. L. (2024). Maternal and paternal sensitivity: Key determinants of child attachment security examined through meta-analysis. Psychological Bulletin, 150(7), 839–872. https://doi.org/10.1037/bul0000433.
Madigan, S., Fearon, R. M. P., van IJzendoorn, M. H., Duschinsky, R., Schuengel, C., Bakermans-Kranenburg, M. J., Ly, A., Cooke, J. E., Deneault, A.-A., Oosterman, M., and Verhage, M. L. (2023). The first 20,000 strange situation procedures: A meta-analytic review. Psychological Bulletin, 149(1–2), 99–132. https://doi.org/10.1037/bul0000388.
Posada, G., Lu, T., Trumbell, J., Kaloustian, G., Trudel, M., Plata, S. J., and colleagues. (2013). Is the secure base phenomenon evident here, there, and anywhere? A cross-cultural study of child behavior and experts' definitions. Child Development, 84(6), 1896–1905. https://doi.org/10.1111/cdev.12084.
Van Rosmalen, L., van der Horst, F., and van der Veer, R. (2016). From secure dependency to attachment: Mary Ainsworth's integration of Blatz's security theory into Bowlby's attachment theory. History of Psychology. https://doi.org/10.1037/hop0000015.
Waters, E., and Deane, K. E. (1985). Defining and assessing individual differences in attachment relationships: Q-methodology and the organization of behavior in infancy and early childhood. Monographs of the Society for Research in Child Development, 50(1–2), 41–65. https://doi.org/10.2307/3333826.