Learning Objectives
By the end of this section, you will be able to:
- Identify milestones in social development in infancy and toddlerhood
- Describe the major elements of attachment theory
- Describe the development of the major attachment styles
- Explain environmental and cultural variation in attachment
Patrice is exhausted. Whenever she attempts to leave her fifteen-month-old son Marco in his playpen so she can do some housework, he erupts in wails. It breaks her heart to make her toddler so upset, but she knows he is safe, and the chores need to be done. Yet even when he is content and playing happily, the sight of his mother leaving the room causes Marco to panic.
It wasn’t always this way. Patrice remembers that when Marco was younger, she could take him to her parents’ house, and he would remain calm when she left him in the care of his aunts and uncles. But now she feels trapped and overwhelmed. Just leaving Marco for a minute while she retrieves freshly washed clothes from the laundry or brings recycling downstairs causes him to scream and reach for her. If she lets him out of his playpen, Marco will follow Patrice closely, crawling and scooting to stay as close to her as possible.
Patrice worries about what will happen when Marco starts to attend a childcare center in a few months. She expects that he will be upset every day when she leaves him there. She’s not sure what to do to alleviate the distress he experiences, and she feels immense guilt for needing to leave her son.
Although Patrice’s experience with Marco upsets her, it is typical and may be a sign of a healthy infant and a secure infant-caregiver attachment. In the early years of life, much infant and toddler behavior has strong biological components, as you’ve learned. Infants also require social interaction to grow and thrive. From the earliest age, they benefit from being held, spoken to, and loved. Without consistent social feedback from parents and caregivers, infants would struggle to understand and navigate the world around themselves (Astor et al., 2022; Bourne et al., 2022). In this section, you’ll explore how the social world of infants supports their emotional development and growth, the role of early social bonds, and some cultural variations in social and emotional development.
Imitation, Joint Attention, and Social Referencing
Shortly after birth, infants begin to look toward and attend to the voices of their primary caregivers. Typically, the voice of their biological mother is most familiar to them because they heard it in utero, and it provides comfort and reassurance (DeCasper & Fifer, 1980). As infants look toward voices, they begin to understand faces, and at approximately two months of age will produce their first social smile—an involuntary smile they make in response to seeing another smiling face (Wormann et al., 2012). Social smiles may not represent an infant’s actual mood or emotion, but they allow them to bond with their caregivers by mirroring their expression (Figure 4.11). What starts as natural imitation of and attention to a caregiver becomes purposeful imitation of others, and that observing a trusted caregiver’s response becomes a way for the infant to learn how to interpret new experiences.
Between two and four months of age, infants develop an important bonding mechanism called involuntary imitation, in which they immediately and reflexively imitate their caregiver. Andrew Meltzoff examined the range of ways newborns imitate adult facial expressions (Meltzoff & Moore, 1983, 1994). Infants have no voluntary control over this form of imitation. Instead, their brains’ mirror neurons, neurons that react when we observe another individual and then perform the same action ourselves, allow them to replicate a variety of facial expressions such as smiles, smirks, and tongue protrusions (Marshall & Meltzoff, 2014). Through this mirroring of a caregiver, involuntary imitation strengthens emotional bonds.
By eight to twelve months of age, infants can display voluntary imitation, in which they purposefully imitate the gestures and facial expression of another person. Voluntary imitation is conscious and controllable, but at this age it is limited to only immediate imitation. A one-year-old infant is unable to imitate something they saw hours or days in the past (Meltzoff, 1988; Paulus et al., 2011).
As you learned in 3.5 Language in Infants and Toddlers, around two to three months of age, infants begin more social interactions through eye contact, smiles, and exchanging coos and other sounds. By six months, the infant may be interested in and attending to a display of peek-a-boo, vocalizing during play, and interacting more with toys. A nine-month-old demonstrates more coordination and social skills during peek-a-boo and moves around more to explore. When infants focus their attention on the same object, person, or experience, as a social partner, it is known as joint attention. Joint attention can involve visual attention, such as both infant and caregiver looking at the same object, and attention from other senses such as touch or hearing (Gabouer & Bortfeld, 2021).
Interactive play and synchrony involve joint attention and can facilitate cognitive, linguistic, and social development and improve early assessment of a toddler’s unique needs. For example, using joint attention and labeling helps improve infant vocabulary. In a recent study, researchers used dual head-mounted eye tracking to record where parents and infants look during toy play (Yu et al., 2019). They found that joint attention (when both look at the same thing) and sustained attention (how long infants focus on something) patterns predict vocabulary size at twelve and fifteen months. Sustained attention during joint attention was the strongest predictor of vocabulary growth (Yu et al., 2019). Research also shows that toddlers with autism spectrum disorder often have poorer joint attention and expressive language, indicating that early assessment of joint attention may provide caregivers early opportunities for offering scaffolded support to toddlers with autism (Adamson et al., 2019).
Along with voluntary imitation, one-year-old infants also display social referencing. This is the tendency to look to others during novel situations to understand how to feel and respond (Mireault et al., 2014). For example, in unusual or ambiguous situations, infants tend to look to the facial expression of their caregiver to interpret and respond to the experience. If a caregiver looks calm or happy, infants are more likely to interpret a novel situation as safe and exciting. If a caregiver looks nervous, upset, fearful, or angry, infants are more likely to become nervous, timid, or avoidant. This means a caregiver who is cautious with their responses can help an infant navigate tricky situations better. For example, on a trip to the pediatrician, a caregiver can maintain a positive expression and calm mood so the infant is less likely to feel anxious. And when a toddler has a small tumble and looks to their caregiver before deciding to cry, if the caregiver smiles and claps with praise for them for getting back up, they may just keep on playing. However, if they see you frowning or looking fearful, tears might erupt.
Link to Learning
In the still-face paradigm research, we can observe how much an infant thrives from positive emotional expressions and interactions with a primary caregiver. View this video of a still-face experiment to view it in action.
Social referencing can be especially helpful during times of joint attention, when an infant follows a caregiver’s body language or voice to attend to an intended stimulus (Figure 4.12). For example, when a caregiver points to a toy or an animal, an infant can understand and follow their caregiver’s gaze and gesture and attend to the same stimulus. Joint attention requires the ability to understand the perspective of another person, which is the basis of social cognition, or the ability to understand how or what others are thinking or feeling (Mundy & Newell, 2007).
Over the first year of life, infants develop voluntary imitation, social referencing, and joint attention skills through consistent interactions with their caregivers. The role of the caregiver is essential to healthy social development of infants and toddlers, particularly when it comes to infant attachment.
Attachment Theory
Although infants may receive care from multiple family members, the primary caregiver is the individual who spends the most time with the infant in the first year of life and becomes a central focus for the infant. The emotional and affective bond between an infant and their primary caregiver, known as attachment, is one of the most enduring and transformative affective relationships in our lives. Often the primary caregiver is the mother, but it may also be the father, grandmother, or another caregiver. Attachment can occur with any caregiver who provides stable and consistent care in any type of family, including adoptive parents (McConnachie et al., 2020). Over time, attachments can expand to include multiple family members (Matthews & Rosner, 1988).
Early Work on Attachment
Sigmund Freud wrote about infant-caregiver attachment as relying on oral stimulation through sucking and feeding. Because the primary caregiver is often responsible for feeding the infant, Freud believed this oral stimulation facilitated the strong bond between parent and child. Sigmund’s daughter Anna Freud expanded on this idea, theorizing that infants and caregivers bond through their biological unity and closeness. Erik Erikson also saw the development of trust over the first year of life as an essential psychosocial milestone.
Harry and Margaret Harlow were some of the first researchers to test theories on attachment, bonding, and the biological underpinnings of attachment (Harlow et al., 1965). Working with baby rhesus monkeys, Harlow constructed surrogate mothers made of wire frames covered in soft cloth and able to provide milk. Young monkeys “raised” by the surrogates had their physical health needs met but differed in their access to physical comfort. In one experiment, infant monkeys were given a choice of two surrogate mothers, one of wire with milk but no cloth, and another with cloth but no milk. The babies chose to spend nearly twenty-three hours a day cuddling the cloth mother and ventured to the wire mother only for food (Figure 4.13) (Harlow & Zimmerman, 1959). Contrary to Sigmund Freud’s ideas, these findings suggest that tactile comfort or the provision of cuddling and physical ease for emotional reassurance is a stronger component of primate attachment than oral stimulation and feeding (Radetzki, 2018).
In other experiments, the young monkeys were exposed to fear-inducing events, such as a strange room or a loud, moving toy. Infant monkeys in these experiments showed completely different responses based on the presence of a wire surrogate mother or a cloth surrogate mother. Those provided the cloth surrogate would seek physical contact with the mother before relaxing and exploring the room or the toy. In contrast, infant monkeys provided with only a wire surrogate mother showed strange behaviors, including rocking back and forth or clutching themselves, and did not explore (Harlow & Zimmerman, 1959; Harlow et al., 1965). The Harlows concluded that these differences showed just how important physical contact is to a healthy infant-mother bond and an infant’s sense of security.
In addition to a biological component, infant-caregiver attachment also has a cognitive component. In another theory of infant attachment known as object-relations theory, described by Karen Horney, infants learn how to interpret and understand the world first through their relationship with their primary caregiver (Horney, 1939). Initially, they discover they are separate from their caregiver. Then interactions with their caregiver help infants learn what to expect when interacting with their environment.
John Bowlby’s theory united the biological and cognitive components of attachment (Bowlby, 1951). Writing about the caregiver’s perspective, Bowlby proposed that parents may be motivated to provide care and comfort to an infant because of the infant’s rounded features (van der Horst & Kagan, 2011). An Austrian zoologist, Konrad Lorenz, named this attraction the kewpie doll effect after the toys known as kewpie dolls (Figure 4.14) (Dydynski, 2020; Lorenz, 1981). Like human infants, infants of most mammalian species have shorter limbs, proportionally larger eyes, and more rounded facial features than adults of the same species. Their appearance may influence the way mammalian brains respond to their young, motivating parents to provide reliable care and attention.
Attachment Stages
In addition to unifying the biological and cognitive aspects of attachment, Bowlby also theorized four stages of human infant attachment (Bowlby, 1951):
- Pre-attachment (birth to 2 months)
- Attachment in the making (2 to 7 months)
- Clear-cut attachment (7 to 24 months)
- Reciprocal relationship formation (24 months on)
In the first stage, pre-attachment, infants between birth and two months of age are considered to experience indiscriminate social responsiveness, a stage in which they have no preference about who provides care as long as their needs are met. They also learn they can influence their social environment through cries and smiles.
Infants’ ability to affect their environment grows through discriminating sociability in the second stage, attachment in the making, which lasts from two to seven months. Now infants are more aware of their influence on others, and of social reciprocity, or turn taking, especially while making vocalizations and smiles. They begin to understand trust, demonstrating Erikson’s first stage of psychosocial development. The time of discriminating sociability also marks the beginning of a preference for familiar caregivers. Infants begin to grow wary of unfamiliar people (Lin & Green, 2009). By ages four to six months, there may be signs of stranger anxiety, a fear reaction to people the infant does not often see, such as a grandparent who visits infrequently, as well as actual strangers (Bohlin & Hagekull, 1993; Brand et al., 2020). Stranger anxiety occurs even when familiar family members are near, and it shows that infants are starting to distinguish between the adults in their life.
Bowlby’s third stage, clear-cut attachment, occurs when infants are seven to twenty-four months old and experiencing the specific, enduring affective bonds for which this stage is named. That is, they have identified a primary caregiver. Bowlby believed this began with a single caregiver—the caregiver who spent the most time with them and responding to their needs. Later researchers upheld that attachment to multiple caregivers is possible. Cognitively, infants begin to understand that the world is a safe place as long as this person is near. They begin to show a strong preference for this adult, and as their locomotion skills develop, they will attempt to follow and stay close to this caregiver and may cry to protest their absence. These cries are a sign of separation anxiety, distress resulting from the removal of the primary caregiver. Separation anxiety tends to peak between fourteen and eighteen months of age and can be upsetting for both the infant and the caregiver (Kagan et al., 1978; Lamb, 1978).
The final stage in Bowlby’s attachment theory is the formation of reciprocal relationships, which begins to develop around age twenty-four months. Toddlers begin to understand that relationships still exist even when the people in them are not present. The absence of their primary caregiver becomes tolerable, and protest cries may decrease. Moreover, toddlers are forming an internal working model, a cognitive understanding of the way relationships work and their expectations, including whether to trust and rely on someone who is not constantly present.
Subtypes of Attachment
Mary Ainsworth, who studied under Bowlby, was interested in researching infant responses to separation from primary caregivers (Ainsworth et al., 1979). She devised a test known as the Strange Situation (Ainsworth et al., 1979; Van Rosmalen et al., 2015), in which an infant approximately twelve to eighteen months of age and their primary caregiver enter a welcoming laboratory setting, with seating and toys. Next, a research assistant known to be a stranger to the infant enters the room and initiates a series of events each lasting just a few minutes as described in Table 4.3.
| Step | Action | Observation |
|---|---|---|
| 1 | Caregiver and infant are left alone in testing room. | Infant’s response to novel room, interest in toys, social referencing, and eye contact with caregiver |
| 2 | Stranger (research assistant) enters the testing room. | Infant’s response to novel person, social referencing, and eye contact with caregiver |
| 3 | First separation; caregiver exits testing room. | Infant’s response to absence of caregiver; infant’s soothability and reaction to stranger’s attempts to comfort |
| 4 | First reunion; caregiver reenters testing room. Stranger quietly exits testing room. | Infant’s response to return of caregiver |
| 5 | Second separation; once infant is calm, caregiver leaves testing room again. | Infant’s response to absence of caregiver |
| 6 | Stranger reenters testing room. | Infant’s reaction to stranger’s attempts to comfort |
| 7 | Second reunion; caregiver reenters the testing room. | Infant’s reaction to return of caregiver |
Over the course of the experiment, infants and caregivers are separated and reunited twice. During the first separation, a stranger is present to help provide comfort. During the second separation, the infant is momentarily left alone while being observed through a one-way mirror or through a video camera. During this second separation, the stranger returns first and attempts to comfort the infant before the caregiver returns the final time.
When Ainsworth first conducted the Strange Situation in the United States, she found that nearly 65 percent of infants engaged in social referencing behaviors, glancing back at caregivers during the first few steps of the test (Ainsworth et al., 1979). Then they became upset and cried during the separations but were calm, happy, and excited to see their primary caregiver again during each reunion. Ainsworth believed these infants felt safe and secure if their caregiver was present, and she named their pattern of behavior secure attachment. Secure attachment involved the idea that the caregiver acted as a secure base for the infant; in other words, the caregiver gave the infant a safe place from which to explore the world around them (Fraley &. Spieker, 2003). Sensitive and responsive caregiving and synchrony are likely to promote secure attachment.
Meanwhile, approximately 20 percent of infants appeared more independent and indifferent to the absence of their caregivers. They made less eye contact and engaged in less social referencing. When the caregiver exited the room, these infants were less likely to become upset and less likely to be responsive to the caregiver’s return. Ainsworth believed these infants had learned to be less reliant on their caregivers. She called this pattern of behaviors insecure avoidant attachment.
A third group of infants, about 10 percent of participants, tended to cling closely to caregivers in the early steps of the test, and some were too nervous to play with toys in the testing room. They became extremely distressed during separations but were also agitated and upset during reunions. In some situations, they seemed angry when caregivers returned. This behavioral pattern was called insecure ambivalent attachment but is also sometimes referred to as anxious or resistant. Infants who display this pattern are thought to be so dependent on their caregiver, and so distressed by separation, that reunions are also emotionally distressing events.
Finally, about 5 percent of infants did not follow any of these patterns. Displaying what is called disorganized attachment, they sometimes appeared confused or showed mixed emotions that could not be classified. This response may indicate they were unsure what to expect from their caregivers due to inconsistent care or mental illness. In some cases, it may also indicate abuse or neglect in the household (Granqvist et al., 2017).
The four behavioral patterns—secure, avoidant, ambivalent, and disorganized—have been connected to a variety of developmental outcomes. Infants who display secure attachment at twelve months of age are more likely to demonstrate positive social skills as toddlers and young children, to engage in more pretend play, and to understand trust in relationships (Ding et al., 2014; Grossman et al., 1985). Attachment patterns may also differ somewhat for neurodivergent children including children with autism; however, a large percentage of neurodivergent children develop secure attachment (Potter-Dickey et al., 2020). For infants in the United States, avoidant attachment has been linked with less close infant-caregiver relationships, and ambivalent attachment has been linked with anxious behavior and wariness (Granqvist et al., 2017; Groh et al., 2012). However, these findings must be interpreted in the context of cultural norms and values.
Link to Learning
Review this video that demonstrates the Strange Situation devised by Mary Ainsworth to learn more.
Cultural Variations in Social Development and Attachment Security
Early researchers once thought that attachment was formed universally across cultures and was influenced by evolutionary adaptive traits in our species. However, cultural and ecological processes also influence infant attachment. For instance, self-exploration during the first year of life is less common in many non-Western cultures, where infants are held or carried for a greater proportion of time and where there is more focus on fostering relatedness over autonomy (Keller 2012; Keller & Otto, 2009).2 Infants may also be prohibited from exploration away from their caregiver. Both Indonesian and Nigerian mothers tend to give disapproval and fearful looks when children attempt to venture too far away, and Japanese mothers may prevent independent self-exploration by following and initiating touch with their infant (Morelli, 2015).
Reactions to separation from the primary caregiver may also differ due to cultural processes. Although the development of separation anxiety follows a similar trajectory across cultures, it disappears earlier in communal environments in which infants are tended to by a variety of caregivers, such as in Israeli kibbutzim or Mayan intergenerational homes (Friedlmeier et al., 2011).
These cultural differences in exploration and separation anxiety affect the outcome of the Strange Situation across cultures. For instance, German infants are more likely to be categorized as having insecure avoidant attachment compared to U.S. infants (Grossman et al., 1985). The reason may be that German children are encouraged to explore at an earlier age, and their behavioral attachment pattern at twelve months is not linked with developmental maladjustment later. Different attachment patterns on the Strange Situation do not always indicate caregiver-child attachment issues, instead culture may simply shape differences in parent-child relationship styles.
Japanese infants tend to display a higher level of distress and be categorized as having an ambivalent attachment at twelve months of age than U.S. infants (Rothbaum et al., 2000), possibly due to the close physical contact maintained between infant and primary caregiver during the first year of life. This high level of distress does not predict wariness in Japanese children at later ages, however, because self-exploration is encouraged at later ages. In other words, Japanese parent-child relationships may follow a slightly different trajectory beginning with a focus on teaching relatedness before autonomy.
Intersections and Contexts
Co-sleeping and Attachment
In many cultures around the world, bed-sharing or co-sleeping—sharing a bed or mattress with infants—is commonplace (Chung & An, 2014.) In Africa, Asia, and Latin America, co-sleeping is seen as a beneficial way to bond with an infant; keep them safe, comfortable, and happy; and ensure the whole family gets a good night’s sleep (Mileva-Seitz et al., 2017). In European cultures, co-sleeping has been less common over the past few centuries, and infants are more likely to be placed in separate bassinets or cribs.
In recent decades, some Western families have been pivoting away from a separate crib and toward co-sleeping. Some parents choose to co-sleep to support breastfeeding, to promote attachment, or to support sleep for both infant and caregiver (Kruse et al., 2024).3 Co-sleeping, when practiced safely, may help promote well-being and bonding for infants and caregivers. For example, some research has found that co-sleeping supports mother-infant synchrony, attachment, and co-regulation (Barry, 2022). Research also suggests that co-sleeping is heavily influenced by family and cultural values and norms and may be important for caregivers who value proximity and physical touch (Barry, 2019).
While co-sleeping may support breastfeeding, it is also potentially beneficial to a caregiver’s goals to promote bonding and attachment. Research on sleeping arrangements in families has also found that fathers who co-sleep report stronger bonds with their infants than fathers who do not co-sleep, though they also report higher parenting stress (Gettler et al., 2021). The choice to co-sleep, by bed-sharing or room-sharing, or place infants in their own room is likely a complicated one for many parents based on cultural values, individual family values, and whether the culture encourages or discourages co-sleeping (Kruse et al., 2024). In addition, families may need to consider safe sleeping practices based on the family and public health guidelines (as discussed in 3.1 Physical Development in Infants and Toddlers).
Cultural processes may also affect transgenerational attachment—the attachment patterns passed down through generations of one family (LeVine, 2014). In Canada during the twentieth century, many Indigenous children were separated from their parents and forced to attend residential schools (Figure 4.15). There they often faced severe abuse and neglect, and many died from unsanitary conditions and lack of medical attention (Aguiar & Halseth, 2015). Many who survived and grew up to become parents struggled to form secure attachments with their own children, highlighting the way emotional trauma from one generation can impact those in the future. Understanding the emotional needs and assets of current generations of Indigenous children requires understanding their family and cultural history (Choate & Tortorelli, 2022).
Not all survivors of intergenerational trauma pass this burden to future generations. Individual resilience in the face of adversity may allow for the formation of healthy and secure attachments, positive coping strategies, and overall well-being (Egeland et al., 1988). Such resilience has been seen especially among Holocaust survivors and their families (Shrira et al., 2011). Attachment theory opened our understanding of the important connections between experiences like caregiver-infant interactions and the infant’s physical maturation and biological temperament for shaping emotion regulation and healthy development outcomes, including resilience (Sroufe, 2021).
References
Adamson, L. B., Bakeman, R., Suma, K., & Robins, D. L. (2019). An expanded view of joint attention: Skill, engagement, and language in typical development and autism. Child Development, 90(1), e1–e18. https://psycnet.apa.org/record/2017-45912-001
Aguiar, W., & Halseth, R. (2015). Aboriginal peoples and historic trauma: The process of intergenerational transmission. National Collaborating Centre for Aboriginal Health. https://www.ccnsa-nccah.ca/docs/context/RPT-HistoricTrauma-IntergenTransmission-Aguiar-Halseth-EN.pdf
Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. (1979). Patterns of Attachment: A psychological study of the strange situation. Psychology Press. https://doi.org/10.4324/9781315802428
Astor, K., Lindskog, M., Juvrud, J., Wangchuk, Namgyel, S. C., Wangmo, T., Tshering, K., & Gredeback, G. (2022). Maternal postpartum depression impacts infants’ joint attention differentially across cultures. Developmental Psychology, 58(12), 2230–2238. https://doi.org/10.1037/dev0001413
Barry, E. S. (2019). Co-sleeping as a proximal context for infant development: The importance of physical touch. Infant Behavior and Development, 57, 101385. https://doi.org/10.1016/j.infbeh.2019.101385
Barry, E. S. (2022). Using complexity science to understand the role of co-sleeping (bedsharing) in mother-infant co-regulatory processes. Infant Behavior and Development, 67, 1–15. https://doi.org/10.1016/j.infbeh.2022.101723
Bohlin, G., & Hagekull, B. (1993). Stranger wariness and sociability in the early years. Infant Behavior and Development, 16(1), 53–67. https://doi.org/10.1016/0163-6383(93)80028-7
Bourne, S. V., Korom, M., & Dozier, M. (2022). Consequences of inadequate caregiving for children’s attachment, neurobiological development, and adaptive functioning. Clinical Child and Family Psychology Review, 25(1), 166–181. https://doi.org/10.1007/s10567-022-00386-4
Bowlby, J. (1951). Maternal care and mental health. Bulletin of the World Health Organization, 3, 355–533. https://psycnet.apa.org/record/1951-06740-001
Brand, R. J., Escobar, K., & Patrick, A. M. (2020). Coincidence or cascade? The temporal relation between locomotor behaviors and the emergence of stranger anxiety. Infant Behavior and Development, 58, 101423. https://doi.org/10.1016/j.infbeh.2020.101423
Choate, P., & Tortorelli, C. (2022). Attachment theory: A barrier for Indigenous children involved with child protection. International Journal of Environmental Research and Public Health, 19(14), 8754. https://doi.org/10.3390/ijerph19148754
Chung, S., & An, H. (2014). Cultural issues of co-sleeping in Korea. Sleep Medicine Research, 5(2), 37–42. https://www.researchgate.net/publication/274703691_Cultural_Issues_of_Co-Sleeping_in_Korea http://dx.doi.org/10.17241/smr.2014.5.2.37
DeCasper, A. J., & Fifer, W. P. (1980). Of human bonding: Newborns prefer their mothers’ voices. Science, 208(4448), 1174–1176. https://doi.org/10.1126/science.7375928
Ding, Y.-h., Xu, X., Wang, Z.-y., Li, H.-r., & Wang, W.-p. (2014). The relation of infant attachment to attachment and cognitive and behavioral outcomes in early childhood. Early Human Development, 90(9), 459–464. https://doi.org/10.1016/j.earlhumdev.2014.06.004
Dydynski, J. M. (2020). Modeling cuteness: Moving towards a biosemiotic model for understanding the perception of cuteness and Kindchenschema. Biosemiotics, 13, 223–240. https://doi.org/10.1007/s12304-020-09386-9
Egeland, B., Jacobvitz, D., & Sroufe, L. A. (1988). Breaking the cycle of abuse. Child Development, 59(4), 1080–1088. https://doi.org/10.1111/j.1467-8624.1988.tb03260.x
Fraley, R. C., & Spieker, S. J. (2003). Are infant attachment patterns continuous or categorically distributed? A taxometric analysis of Strange Situation behavior. Developmental Psychology, 39(3), 387–404. https://doi.org/10.1037/0012-1649.39.3.387
Friedlmeier W., Corapci, F., & Cole, P. M. (2011). Emotion socialization in cross-cultural perspective. Social and Personality Psychology Compass, 5(7), 410–427. https://doi.org/10.1111/j.1751-9004.2011.00362.x
Gabouer, A., & Bortfeld, H. (2021). Revisiting how we operationalize joint attention. Infant Behavior and Development, 63, 101566. https://doi.org/10.1016/j.infbeh.2021.101566
Gettler, L. T., Kuo, P. X., Sarma, M. S., Lefever, J. E. B., Cummings, E. M., McKenna, J. J., & Braungart-Rieker, J. M. (2021). US fathers’ reports of bonding, infant temperament and psychosocial stress based on family sleep arrangements. Evolution, Medicine, and Public Health, 9(1), 460–469. https://doi.org/10.1093/emph/eoab038
Granqvist, P., Sroufe, L. A., Dozier, M., Hesse, E., Steele, M. van Ijzendoorn, M., Solomon, J., Schuengel, C., Fearon, P., Bakermans-Kranenburg, M., Steele, H., Cassidy, J., Carlson, E., Madigan, S., Jacobvitz, D., Foster, S., Behrens, K., Rifkin-Graboi, A., Gribneau, N., . . . Duschinsky, R. (2017). Disorganized attachment in infancy: A review of the phenomenon and its implications for clinicians and policy-makers. Attachment & Human Development, 19(6), 534–558. https://doi.org/10.1080/14616734.2017.1354040
Groh, A. M., Roisman, G. L., van Ijzendoorn, M. H., Bakermans-Kranenburg, M. J., & Fearon, R. P. (2012). The significance of insecure and disorganized attachment for children’s internalizing symptoms: A meta-analytic study. Child Development, 83(2), 591–610. https://psycnet.apa.org/record/2012-07173-018
Grossman, K., Grossman, K. E., Gottfried, S., Gerhard S. & Unzer, L. (1985). A wide view of attachment and exploration: The influence of mothers and fathers on the development of psychological security from infancy to young adulthood. Handbook of Attachment. Guilford. https://psycnet.apa.org/record/2008-13837-037
Harlow, H. F., Dodsworth, R. O., & Harlow, M. K. (1965). Total social isolation in monkeys. Proceedings of the National Academy of Sciences, 54(1), 90–97. https://doi.org/10.1073/pnas.54.1.90
Harlow, H. F., & Zimmermann, R. R. (1959). Affectional responses in the infant monkey. Science, 130, 421–432. https://psycnet.apa.org/doi/10.1126/science.130.3373.421 https://doi.org/10.1126/science.130.3373.421
Horney, K. (1939). The emphasis on childhood. New Ways in Psychoanalysis (pp. 113–153). W. W. Norton & Company. https://psycnet.apa.org/record/1939-03649-000
Kagan, J., Lapidus, D. R., & Moore, M. (1978). Infant antecedents of cognitive functioning: A longitudinal study. Child Development, 49(4), 1005–1023. https://doi.org/10.2307/1128740
Keller, H. (2012). Autonomy and relatedness revisited: Cultural manifestations of universal human needs. Child Development Perspectives, 6(1), 12–18. https://doi.org/10.1111/j.1750-8606.2011.00208.x
Keller, H. & Otto, H. (2009). The cultural socialization of emotional regulation during infancy. Journal of Cross-Cultural Psychology, 40(6), 996–1011. https://doi.org/10.1177/0022022109348576
Kruse, S. P., D’Souza, L., Tuncer, H. G. G., & Stewart, S. E. (2024). Sources of attitudes towards parent-child co-sleeping and their effects: A systematic scoping review. Family Process. https://doi.org/10.1111/famp.13022
Lamb, M. E. (1978). Qualitative aspects of mother-infant and father-infant attachments. Infant Behavior & Development, 1(1), 265–275. https://doi.org/10.1016/S0163-6383(78)80038-1
LeVine, R. (2014). Attachment theory as cultural ideology. In H. Otto & H.. Keller (Eds.), Different Faces of Attachment: Variations of a Universal Human Need (pp. 50–65). Cambridge University Press. https://doi.org/10.1017/CBO9781139226684.005
Lin, H.-C., & Green, J. A. (2009). Infants’ expressive behaviors to mothers and unfamiliar partners during face-to-face interactions from 4 to 10 months. Infant Behavior & Development, 32(3), 275–285. http://dx.doi.org/10.1016/j.infbeh.2009.03.002
Lorenz, K. Z. (1981). The foundations of ethology. New York: Springer Science. https://doi.org/10.2307/1422147
Marshall, P. J., & Meltzoff, A. N. (2014). Neural mirroring mechanisms and imitation in human infants. Philosophical transactions of the Royal Society of London, Series B, Biological sciences, 369(1644), 20130620. https://doi.org/10.1098/rstb.2013.0620
Matthews, S. H., & Rosner, T. T. (1988). Shared filial responsibility: The family as the primary caregiver. Journal of Marriage and the Family, 185–195. https://doi.org/10.2307/352438
McConnachie, A. L., Ayed, N., Jadva, V., Lamb, M., Tasker, F., & Golombok, S. (2020). Father-child attachment in adoptive gay father families. Attachment & Human Development, 22(1), 110–123. https://doi.org/10.1080/14616734.2019.1589067
Meltzoff, A. N. (1988). Infant imitation after a 1-week delay: long-term memory for novel acts and multiple stimuli. Developmental Psychology, 24(4), 470–476. https://doi.org/10.1037/0012-1649.24.4.470
Meltzoff, A. N., & Moore, K. M. (1983). Newborn infants imitate adult facial gestures. Child Development, 54(3), 702–709. https://doi.org/10.2307/1130058
Meltzoff, A. N., & Moore, K. M. (1994). Imitation, memory, and the representation of persons. Infant Behavior and Development, 17(1), 83–99. https://doi.org/10.1016/0163-6383(94)90024-8
Mileva-Seitz, V. R., Bakermans-Kranenburg, M. J., Battaini, C., & Luijk, M. P. C. M. (2017). Parent-child bed-sharing: The good, the bad, and the burden of evidence. Sleep Medicine Reviews, 32, 4–27. https://doi.org/10.1016/j.smrv.2016.03.003
Mireault, G. C., Crockenberg, S. C., Sparrow, J. E., Pettinato, C. A., Woodard, K. C., & Malzac, K. (2014). Social looking, social referencing and humor perception in 6- and 12-month-old infants. Infant Behavior & Development, 37(4), 536–545. https://doi.org/10.1016/j.infbeh.2014.06.004
Morelli, G. (2015). The evolution of attachment theory and cultures of human attachment in infancy and childhood. The Oxford Handbook of Human Development and Culture (pp. 149–164). Oxford University Press. https://doi.org/10.1093/oxfordhb/9780199948550.013.10
Mundy, P. & Newell, L. (2007). Attention, joint attention, and social cognition. Current Directions in Psychological Science, 16(5), 269–274. https://doi.org/10.1111/j.1467-8721.2007.00518.x
Paulus, M., Hunnius, S., Vissers, M., & Bekkering, H. (2011). Bridging the gap between the other and me: The functional role of motor resonance and action effects in infants’ imitation. Developmental Science, 14(4), 901–910. https://doi.org/10.1111/j.1467-7687.2011.01040.x
Potter-Dickey, A., Letourneau, N., & de Koning, A.P.J. (2020). Associations between Neurodevelopmental Disorders and Attachment Patterns in Preschool-Aged Children: Systematic Review. Current Developmental Disorders Reports, 7, 277–289. https://doi.org/10.1007/s40474-020-00219-5
Radetzki, P. (2018). Harlow’s famous monkey study: The historical and contemporary significance of the nature of love. Canadian Journal of Family and Youth, 10(1), 205–234. http://dx.doi.org/10.29173/cjfy29349
Rothbaum, F., Pott, M., Azuma, H., Miyake, K., & Weisz, J. (2000). The development of close relationships in Japan and the United States. Paths of symbolic harmony and generative tension. Child Development, 71(5), 1121–1142. https://doi.org/10.1111/1467-8624.00214
Shrira, A., Palgi, Y., Ben-Ezra, M., & Shmotkin, D. (2011). Transgenerational effects of trauma in midlife: Evidence for resilience and vulnerability in offspring of Holocaust survivors. Psychological Trauma: Theory, Research, Practice, and Policy, 3(4), 394. https://doi.org/10.1037/a0020608
Sroufe, L. A. (2021). Then and now: The legacy and future of attachment research. Attachment & Human Development, 23(4), 396–403. https://doi.org/10.1080/14616734.2021.1918450
Van der Horst, F. C. P. & Kagan, J. (2011). John Bowlby: From Psychoanalysis to Ethology; Unraveling the Roots of Attachment Theory. Wiley. https://doi.org/10.1002/9781119993100
Wormann, V., Holodynski, M., Kartner, J., & Keller, H. (2012). A cross-cultural comparison of the development of the social smile: A longitudinal study of maternal and infant imitation in 6- and 12-week-old infants. Infant Behavior & Development, 35(3), 335–347. https://doi.org/10.1016/j.infbeh.2012.03.002
Yu, C., Suanda, S. H., & Smith, L. B. (2019). Infant sustained attention but not joint attention to objects at 9 months predicts vocabulary at 12 and 15 months. Developmental Science, 22(1), e12735. https://doi.org/10.1111/desc.12735