4.2: Temperament and Personality in Infants and Toddlers

Learning Objectives

By the end of this section, you will be able to:

• Distinguish between temperament and personality, and describe models and types of temperament
• Describe the major environmental influences on temperament and early personality
• Explain Erikson’s first and second stage of psychosocial development

Tyler remembers when his older daughter Janelle was born. She was fussy and cried all night, slept at random times throughout the day, and preferred to be held by her father. But now that his second child Monique is here, Tyler cannot believe the difference. Monique seems so content, sleeps soundly, and wakes up happy. She’s social and coos happily when others hold her. Tyler wonders why his two daughters are so different. Has he become a better father, so his parenting style has led Monique to feel more secure? Perhaps. But most likely, Janelle and Monique were born with different temperaments, showing different moods and different levels of activity and sociability.

As Tyler’s daughters grow older, he may discover that the differences between them are sustaining and long-lasting, because temperament is often a precursor to personality. However, Tyler’s parenting also matters. The way he responds to Janelle and Monique’s temperamental and emotional needs can shape how effectively they develop a sense of trust, autonomy, and self-confidence, even in the first few years of life.

In this section, you’ll learn more about various theories of temperament, the way temperament unfolds and interacts with the environment, and the way personality begins to form in infants and toddlers.

Models of Temperament

Philosophers from Aristotle to John Locke believed in the notion of the tabula rasa—the idea that we are born as blank slates, waiting to be crafted and molded by experience (Petryszak, 1981). Behavioral psychologists have agreed with this perspective, as when John B. Watson (1930, p. 82) stated, “Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select.” This view shows the power of experience but misses the biological and genetic traits that interact with their environmental experiences as well as the active role infants have in their own development.

Although experience and environment certainly shape our lives, infants come into this world as unique individuals. One of the characteristics they bring with them is their temperament, which consists of the innate biological components of individuality present from birth. Temperamental traits are patterns of behavior that remain consistent and relatively stable throughout infancy and beyond (Goldsmith et al., 1987; Planalp & Goldsmith, 2020).

Easy, Difficult, and Slow-to-Warm-Up Temperaments

Psychology researchers Alexander Thomas and Stella Chess offer nine distinct temperamental traits originally derived by interviewing parents and teachers on their perceptions of infants’ behaviors (Thomas & Chess, 1977). Their comprehensive view of temperament begins with identifying an infant as high or low on each of these nine distinct behavioral traits (Figure 4.5). For example, an infant who tends to like a predictable daily routine would be described as high on expression of the rhythmicity trait, and an infant who appears to be shy or withdrawn in new social settings would be described as low on expression of approach. This detailed view of temperament helped to characterize a wider variety of infants’ behavior patterns. These nine traits allow researchers to classify an infant’s overall temperament into one of three temperament clusters: easy, difficult, or slow to warm up (Rothbart & Bates, 2007; Thomas & Chess, 1977; Rothbart & Bates, 2006).

Figure 4.5 Thomas and Chess’s (1977) temperamental model identifies nine traits. For each trait, infants may span a spectrum from low expression to high expression. (Thomas & Chess, 1977) (CC BY 4.0; Rice University & OpenStax)

While not all children fit neatly into one of the temperament clusters, around 65 percent of infants fall into one of the three typically identified: easy (40 percent), difficult (10 percent), and slow to warm up (15 percent) (Chess & Thomas, 1986). In their original research, Chess and Thomas (1986) found that many children demonstrated an easy temperament (resilient), meaning they are adaptable, can establish a routine quickly, and typically have a positive mood. For example, an infant high in rhythmicity and affect may have a positive mood and predictable behaviors. More recently, the term “resilient” has been introduced to describe easy infants who tend to be adaptable and able to thrive in a variety of contexts (van Leeuwen et al., 2004). A study noted that resilient children were higher on persistence and dependence on reward and attachment and lower on seeking novelty (Scaini et al., 2021). Encouraging persistence and other factors that promote resilience from an early age may boost long-term resilience and adaptability across the lifespan.

In comparison, an infant with difficult temperament (undercontrolled/exuberant) is described as having negative mood, high intensity, and an irregular routine and is slow to adapt to new experiences. More recently, this temperamental style has been referred to as “undercontrolled” or “exhuberant”, highlighting that the child’s biological disposition might clash with that of the parents, resulting in what might be perceived as defiance (Komsi et al., 2006; Stifter et al., 2008). An undercontrolled or exuberant child is likely to struggle to develop self-regulation or effortful control, but these skills can be developed both as the brain matures and with parental support (Bates et al., 2019).

Finally, an infant who has a slow-to-warm-up temperament (overcontrolled/inhibited) has a pleasant disposition but particularly low adaptability; if conditions are stable, such infants are content, but when novel events occur, they become cautious and possibly withdrawn. Adults often describe this type of infant or toddler as shy. More recently, the terms “overcontrolled” and “inhibited” have been used to highlight that these infants may be more prone to anxious or fearful behavior patterns (Komsi et al., 2006; Stifter et al., 2008). They may have very high levels of behavioral inhibition, or the tendency to withdraw or be cautious, which is likely to have strong genetic roots (Kagan, 1984). However, here again research shows that even though these infants are likely to stay inhibited and shy decades later, they can still improve their emotion regulation and social skills with supportive environments and time (Suarez et al., 2021; Tang et al., 2020).

All infants will be distractible at some times and focused at others and have a range of moods and activity levels. For example, having occasional tantrums does not mean an infant has a difficult temperament. However, the infant’s trends and preferences show the beginnings of their temperament and shape their experience in the environment.

Link to Learning

Review this video on temperamental traits to learn more about original research by Thomas and Chess.

Surgency, Negative Affectivity, and Effortful Control

Psychologist Mary Rothbart (1981) used the initial theory of temperament to develop detailed questionnaires on infant and toddler behavior and identified three temperamental traits with a strong biological basis: surgency, negative affectivity, and effortful control. Also called extraversion, surgency is a trait characterized by high levels of physical activity, sociability, and spontaneity. In contrast, negative affectivity is a tendency to experience and express distress, discomfort, and avoidance behavior and is associated with lower emotion regulation. Finally, effortful control includes traits related to impulse control and inhibition, including the ability to maintain attention and control responses to experiences. According to Rothbart (2007), these traits exist in different combinations. For instance, surgency corresponds to both activity and sociability, and effortful control corresponds to both distractibility and persistence. For instance, an infant who is high in both surgency and negative affectivity would be prone to anger, but an infant low in surgency but high in effortful control may enjoy quiet enduring tasks such as puzzles and cognitive toys (Shiner et al., 2012). Rothbart’s theory of temperament laid the groundwork for more scientific studies of temperament including the things that influence temperament and the stability of temperament over time (Planalp & Goldsmith, 2020; Putnam & Stifter, 2008).

Environmental Influences on Temperament

Although temperamental traits are biologically innate in infancy, environmental and contextual factors also play a role in their expression, perhaps increasingly so as we age (Goldsmith et al., 1987). The way parents respond to infants can modify their temperamental expressions, either reinforcing or discouraging them.

Imagine an infant high in approach and adaptability and low in sensitivity whose parent likes to travel and go to new places. This infant may feel comfortable accompanying the parent to new parks, airports, and cities because they enjoy new people, places, and experiences. Thus, the parent’s behavior is reinforcing the infant’s temperament. This situation is described as high in goodness of fit, meaning the infant’s temperament and surrounding environment match and complement each other (Thomas & Chess, 1977).

Now imagine an infant high in activity and distractibility and low in persistence whose parent likes to work at home. This infant may want to move around, discover new things, and constantly shift attention and focus. However, the parent may encourage the infant to settle in one place and focus on a task for a long period of time. This behavior is discouraging the infant’s biologically based temperament, and the situation is therefore low in goodness of fit because the parent and infant are mismatched in terms of behavioral desires.

Temperamental differences between parents and children aren’t necessarily a bad thing; parents can support goodness of fit while also encouraging the child to develop a bit more adaptability through experience. For example, a parent who prefers to be more sedentary can make it a point to get up and move with or engage in a brief activity with the child, while also showing the child the joys of relaxing together.

Goodness of fit has often been used in parent-child relationship research and applications to describe the way different temperament types (easy, difficult, and slow to warm up) interact with one another and with the environment (de Schipper et al., 2004; Mangelsdorf et al., 1990; De Schipper et al., 2004). An infant with easy temperament and a parent with easy temperament are likely to form a high goodness of fit in many circumstances. Infants’ difficult temperaments may strain goodness of fit, particularly if the parent also has a difficult temperament. Such infants are likely to benefit from the parents staying calm, responding in caring ways, and avoiding power assertion parenting strategies (Lunkenheimer et al., 2020; Rodriguez et al., 2019). Finally, a slow-to-warm up baby is likely to benefit from having more time to adapt to new situations (Natsuaki et al., 2013). Although much of our temperament is genetically based, parents’ temperaments and their role in creating goodness of fit can positively shape long-term healthy development by providing the child with skills that help them individually thrive.

Link to Learning

Want to learn more about creating goodness of fit and the match between caregiver temperament and infant/toddler temperament? This website provides temperament toolkits to help caregivers learn about their own temperament and the temperaments of the infants and toddlers they care for. Also provided are individualized tips for creating a better match.

Cultural influences may also have an impact on shaping temperament. Gonda and colleagues (2010) found that highly active temperaments were more common in Portugal, negative mood was more prevalent in Lebanon, and more intense mood swings were more common in Korea. One possible explanation for these findings is that cultural values may select the behaviors in infants that are encouraged or discouraged (Haslam et al., 2020). For example, some parents may emphasize proximity or dependence as a value, while others may emphasize independence. However, these differences may not develop in infancy. Comparisons of U.S. and Spanish adults have found that those in the United States were more motivated by new experiences and challenging tasks, whereas Spanish individuals were more motivated by rewards and the avoidance of punishments. These differences were more pronounced in later childhood (Al-Halabi et al., 2011).

Our environment and temperament interact with one another at every level of social and cultural experience to shape our developmental outcomes over time. A strong goodness of fit at the family level and a good cultural fit represent an easier interaction between individual and context.

Life Hacks: A Goodness of Fit for Everyone

Every infant is unique in terms of temperamental style, so promoting a high goodness of fit means being aware of the environmental needs of each temperamental type. Caregivers also demonstrate their own temperament and personality style, so finding a good match between the infant and caregiver can help both caregiver and child to develop a healthy relationship and promote the child’s developmental well-being overall.

Easy/resilient babies are adaptable and easygoing, so providing enjoyable stimulation, new experiences, and small challenges is a great way to inspire their developing minds. Such activities can include walking around the neighborhood to discover new parks and street scenes, playing music at home, and engaging in sensory play with baby-safe materials.

Difficult/undercontrolled infants have strong emotions and unpredictable patterns and need more patience and flexibility. This means practicing calming and relaxing techniques such as giving the infant a relaxing bath or rocking and carrying them frequently. Another useful strategy is preparing meals ahead of time, so that when emotions flare up, caregivers can pause long enough to help calm the infant down.

Slow-to-warm-up/overcontrolled infants are nervous and sensitive and need some extra reassurance at times. Introducing them gradually to new foods, letting them have some quiet time during big family events, and allowing them to keep a familiar toy or blanket nearby are ways of helping them feel safer and more secure. Recognizing that they may have a favorite person they want next to them and not rushing them into hugging and playing with relatives can also help.

Overall, it’s important that the caregiver works to know their own temperament as well as that of the infant to find those areas where they are compatible and those areas where they may have different temperamental traits. Caregivers can then adjust some of their caregiving techniques to best support their child. Remember, the caregiver typically has many more emotional and social coping techniques and tools than the infant or toddler. Therefore, a caregiver adapting to meet the child’s needs can improve relationship quality and goodness of fit for everyone.

Early Personality

Temperament is a building block of personality, but what is personality? An individual’s personality consists of patterns of behavior, attitudes, thoughts, and emotions that are consistent across contexts in childhood, adolescence, and adulthood. Temperament is visible as observable behaviors readily assessed in infancy, whereas personality also includes internal motivation, desires, and preferences. Personality and temperament both involve inherited traits and are relatively stable over time (Planalp & Goldsmith, 2020).

Theories of personality vary widely, but most trait theories propose a set of traits or personality characteristics that are stable in individuals across place, time, and social interactions and exist on a spectrum from high to low. This is similar to the nine temperament traits discovered by Thomas and Chess (1977). One early trait theory that helped connect infant/toddler temperament to emerging personality came from psychologists Hans and Sybil Eysenck. The Eysencks (Eysenck, 1990, 1992; Eysenck & Eysenck, 1963) viewed people as having two specific personality dimensions: extroversion/introversion and neuroticism/stability. Extroversion/introversion is related to being sociable and outgoing or shy and preferring solitude. Neuroticism/stability is related to being more or less emotionally and behaviorally regulated. A later prominent trait theory is the Big Five Factor theory, which posits five personality traits that appear in early childhood and endure throughout the lifespan (Donahue, 1994). They are openness, conscientiousness, extraversion, agreeableness, and neuroticism. This theory is reviewed more fully in 6.1 Social and Emotional Development in Early Childhood.

As children grow, their personality develops from their temperament in various ways (Rothbart et al., 2000), and some components of infant temperament have been associated with personality later in life. For instance, high sociability in infancy is positively correlated with high extraversion later, characterized by an outgoing, talkative, confident demeanor (Hampson, 2007). Emotional intensity in infancy is associated with neuroticism, and early persistence is linked with conscientiousness (Strickhouser & Sutin, 2020). As children mature and gain experience with the environment, their temperament characteristics will shift slightly over time. For example, when their caregiver provides goodness of fit and supports the infant’s emotional needs, the infant is likely to develop better emotion regulation and control over time.

Psychosocial Development

Many of the major theories you learned about in Chapter 1 Lifespan Psychology and Developmental Theories are considered grand theories, theories that attempt to explain universal experiences. Erik Erikson’s theory of psychosocial development is a grand theory that helps explain how personality and individuality change over the entire lifespan through a series of developmental stages (Erikson, 1985).

Erikson’s psychosocial theory of development (1985) grew out of Sigmund Freud’s earlier theory of infant psychosexual development. Erikson’s theory indicates psychological development continues throughout the lifespan beginning with the psychological interactions between an infant and their caregiver and continues into late adulthood.

According to Erikson, the lifespan includes eight distinct stages, each containing a significant psychological dilemma the person needs to resolve (Figure 4.6). Each dilemma can result in either an adaptive or a maladaptive consequence. For example, if a child’s caregivers are not supportive over their early needs, they may struggle with trusting others (maladaptive), whereas a child whose caregivers were generally supportive is more likely to trust those around them more easily (adaptive). However, if a person initially experiences the maladaptive consequence, they can later readdress this dilemma at a subsequent stage (Johnson, 1993; Zock, 2018). For example, if an infant initially developed distrust, they may be able to gain a trusting relationship with others through early intervention and supportive caregiving. It should be noted, however, that while a maladaptive outcome may be corrected later, early support and healthy development from the start are typically ideal and easiest. Erikson’s theory is often portrayed as a series of steps; each developmental period represents the earliest point a dilemma is encountered, but individuals can go backward down the steps and resolve earlier dilemmas at later times (Gilleard & Higgs, 2016).

Figure 4.6 Erikson's psychosocial theory of development identifies eight stages, or developmental tasks, encountered at different points in the lifespan. (CC BY 4.0; Rice University & OpenStax)

The first stage of psychosocial development in Erikson’s theory is trust versus mistrust, and it occurs from approximately age 0 to 1 year. At this stage, infants are reliant on caregivers to keep them warm, dry, fed, and safe. If a caregiver readily meets their infant’s needs, responds to their cries, and is a reliable source of comfort, the infant will likely develop a sense of trust. If cries are unmet and caregivers’ actions are unpredictable, the infant may instead develop a sense of mistrust toward their caregiver and in other relationships in future (Beebe & Steele, 2013). Because individuals can resolve earlier dilemmas later with intervention and support, however, a child who did not acquire trust in the first year of life or who experienced adversity can still develop trust in a caregiver who meets and responds to their needs consistently (Nusser et al., 2023).

It Depends: Will Picking Up a Baby Spoil Them?

You may have heard that picking up a baby and responding each time they cry will lead the baby to become “spoiled” or over reliant on the care of others. However, research on the physical, psychological, and emotional needs of infants has shown that this is not true. Infants will not cry to manipulate their caregivers, though they may cry because they are hungry, wet, cold, lonely, or scared (Rosier & Cassels, 2021; Wilson et al., 1981). Moreover, infants who are cuddled more in the first few months tend to cry less later, suggesting that picking up and responding to an infant is helpful to their sleep habits and regulation (Middlemiss et al., 2017) (Figure 4.7).

Figure 4.7 A caregiver holding and comforting an infant when they cry can help the infant build the foundations of self-regulation and emotion regulation. (credit: “wisdom kissing ozare” by “cheriejoyful”/Flickr, CC BY 2.0)

But what happens if a caregiver cannot respond every time, or if they are too exhausted to respond? The cry-it-out approach is intended to teach an infant to self-soothe between six and eighteen months and is a common method some parents use. Some research indicates the cry-it-out approach is not linked to insecure attachment or behavioral problems in toddlerhood (Bilgin & Wolke, 2020; Davis & Kramer, 2021). Therefore, picking up and cuddling an infant, or giving them some time to calm down on their own, might both be fine given the right circumstances and the infant’s age. Many infants begin to show the ability to self-soothe around six months of age (Goodlin-Jones et al., 2001). In general, being aware of an infant’s cries, being responsive when an infant signals they need comfort, and giving them time to self-soothe when they are able can be a great strategy for long-term good sleep and well-being for all (Hada et al., 2021; Middlemiss et al., 2017).

Erikson’s second stage is autonomy versus doubt, from ages one to three years. As toddlers grow and develop new skills, many attempt to dress and feed themselves and to assert their opinions about what they would like to do. Caregivers who encourage toddlers to try new activities and build self-confidence may foster a positive sense of autonomy, giving toddlers assurance that they can achieve age-appropriate tasks on their own. However, caregivers who intervene, intrude, and prevent a toddler from attempting new skills may foster a sense of self-doubt or shame, which might prevent the child from attempting new and challenging tasks in the future (Andreadakis et al., 2019). Caregivers can help a toddler struggling with this stage by encouraging them to try new skills, challenging them in small and comfortable ways, and remaining patient and calm.

Link to Learning

Do you think you have a good idea of Erikson’s stages? Try this short matching game on Erikson’s eight stages to practice.

References

Al-Halabi, S., Herrero, R., Saiz, P. A., Garcia-Portilla, M. P., Errasti, J. M., Corcoran, P., Bascaran, M. T., Bousono, M., Lemos, S., & Bobes, J. (2011). A cross-cultural comparison between Spain and the USA: Temperament and character distribution by sex and age. Psychiatry Research, 186(2–3), 397–401. https://doi.org/10.1016/j.psychres.2010.07.021

Andreadakis, E., Joussemet, M., & Mageau, G. A. (2019). How to support toddlers’ autonomy: Socialization practices reported by parents. Early Education and Development, 30(3), 297–314. doi.org/10.1080/10409289.2018.1548811

Bates, J. E., McQuillan, M. E., & Hoyniak, C. P. (2019). Parenting and temperament. In M. H. Bornstein (Ed.), Handbook of parenting: Children and parenting (3rd ed., pp. 288–321). Routledge/Taylor & Francis Group. doi.org/10.4324/9780429440847-9

Beebe, B., & Steele, M. (2013). How does microanalysis of mother-infant communication inform maternal sensitivity and infant attachment? Attachment & Human Development, 15(5–6), 583–602. doi.org/10.1080/14616734.2013.841050

Bilgin, A., & Wolke, D. (2020). Parental use of ‘cry it out’ in infants: No adverse effects on attachment and behavioural development at 18 months. Journal of Child Psychology and Psychiatry, 61(11), 1184–1193. doi.org/10.1111/jcpp.13223

Chess, S., & Thomas, A. (1986). Temperament in clinical practice. Guilford Press. https://www.guilford.com/books/Tempe.../9780898628135

Davis, A. M. B., & Kramer, R. S. S. (2021). Commentary: Does ‘cry it out’ really have no adverse effects on attachment? Reflections on Bilgin and Wolke (2020). The Journal of Child Psychology & Psychiatry, 62(12), 1488–1490. doi.org/10.1111/jcpp.13390

De Schipper, J. C., Tavecchio, L.W. C., Van IJzendoorn, M. H., & Van Zeijl, J. (2004). Goodness-of-fit in center day care: Relations of temperament, stability and quality of care with the child’s adjustment. Early Childhood Research Quarterly, 19(2), 257–272. https://doi.org/10.1016/j.ecresq.2004.04.004

Donahue, E. M. (1994). Do children use the Big Five, too? Content and structural form in personality description. Journal of Personality, 62(1), 45–66. doi.org/10.1111/j.1467-6494.1994.tb00794.x

Erikson, E. H. (1985). The life cycle completed: A review. W. W. Norton & Co. psycnet.apa.org/record/1994-98893-000

Eysenck, H. J. (1990). An improvement on personality inventory. Current Contents: Social and Behavioral Sciences, 22(18), 20.

Eysenck, H. J. (1992). Four ways five factors are not basic. Personality and Individual Differences, 13(6), 667–673. https://doi.org/10.1016/0191-8869(92)90237-J

www.sciencedirect.com/scienc...9188699290237J

Eysenck, S. B. G., & Eysenck, H. J. (1963). The validity of questionnaire and rating assessments of extroversion and neuroticism, and their factorial stability. British Journal of Psychology, 54(1), 51–62. doi.org/10.1111/j.2044-8295.1963.tb00861.x

Gilleard, C., & Higgs, P. (2016). Connecting life span development with the sociology of the life course: A new direction. Sociology, 50(2), 301–315. doi.org/10.1177/0038038515577906

Goldsmith, H. H., Buss, A. H., Plomin, R., Rothbart, M. K., Thomas, A., Chess, S., Hinde, R. A., McCall, R. B. (1987). Roundtable: What is temperament? Four approaches. Child Development, 58(2), 505–529. www.jstor.org/stable/1130527

Gonda, X., Vázquez, G. H., Akiskal, K. K., & Akiskal, H. S. (2010). From putative genes to temperament and culture: Cultural characteristics of the distribution of dominant affective temperaments in national studies. Journal of Affective Disorders, 131(1–3), 45–51. https://doi.org/10.1016/j.jad.2010.12.003

Goodlin-Jones, B. L., Burnham, M. M., Gaylor, E. E., & Anders, T. F. (2001). Night waking, sleep-wake organization, and self-soothing in the first year of life. Journal of Developmental and Behavioral Pediatrics, 22(4), 226–233. doi.org/10.1097/00004703-200108000-00003

Hada, A., Imura, M., & Kitamura, T. (2021). Parent to baby emotions: Parental immediate emotional reactions towards infant crying. The Open Psychology Journal, 14(1), 338–341. dx.doi.org/10.2174/1874350102114010338

Hampson, S. E., Andrews, J. A., Barckley, M., & Peterson, M. (2007). Trait Stability and Continuity in Childhood: Relating Sociability and Hostility to the Five-Factor Model of Personality. Journal of Research in Personality, 41(3), 507–523. https://doi.org/10.1016/j.jrp.2006.06.003

Haslam, D., Poniman, C., Filus, A., Sumargi, A., & Boediman, L. (2020). Parenting style, child emotion regulation and behavioral problems: The moderating role of cultural values in Australia and Indonesia. Marriage & Family Review, 56(4), 320–342. doi.org/10.1080/01494929.2020.1712573

Johnson, J. G. (1993). Relationships between psychosocial development and personality disorder symptomatology in late adolescents. Journal of Youth and Adolescence, 22, 33–42. psycnet.apa.org/doi/10.1007/BF01537902

Kagan, J. (1984). The nature of the child. Basic Books. https://archive.org/details/natureofchild00kaga

Komsi, N., Räikkönen, K., Pesonen, A.-K., Heinonen, K., Keskivaara, P., Järvenpää, A.-L., & Strandberg, T. E. (2006). Continuity of temperament from infancy to middle childhood. Infant Behavior & Development, 29(4), 494–508. https://doi.org/10.1016/j.infbeh.2006.05.002

Lunkenheimer, E., Hamby, C. M., Lobo, F. M., Cole, P. M., & Olson, S. L. (2020). The role of dynamic, dyadic parent–child processes in parental socialization of emotion. Developmental Psychology, 56(3), 566–577. doi.org/10.1037/dev0000808

Mangelsdorf, S., Gunnar, M., Kestenbaum, R., Lang, S., & Andreas, D. (1990). Infant proneness-to-distress temperament, maternal personality, and mother-infant attachment: Associations and goodness of fit. Child Development, 61(3), 820–831. doi,org/10.2307/1130966

Middlemiss, W., Stevens, H., Ridgway, L., McDonald, S., & Koussa, M. (2017). Response-based sleep intervention: Helping infants sleep without making them cry. Early Human Development, 108, 49–57. http://dx.doi.org/10.1016/j.earlhumdev.2017.03.008

Natsuaki, M. N., Leve, L. D., Harold, G. T., Neiderhiser, J. M., Shaw, D. S., Ganiban, J., Scaramella, L. V., & Reiss, D. (2013). Transactions between child social wariness and observed structured parenting: Evidence from a prospective adoption study. Child Development, 84(5), 1750–1765. doi.org/10.1111/cdev.12070

Nusser, L., Zimprich, D., & Wolf, T. (2023). Themes of trust, identity, intimacy, and generativity in important autobiographical memories: Associations with life periods and life satisfaction. Journal of Personality, 91(5), 1110–1122. doi.org/10.1111/jopy.12786

Petryszak, N. G. (1981). Tabula rasa—its origins and implications. Journal of the History of the Behavioral Sciences, 17(1), 15–27. doi.org/10.1002/1520-6696(19...4%3E3.0.CO;2-3

Planalp, E. M., & Goldsmith, H. H. (2020). Observed Profiles of Infant Temperament: Stability, Heritability, and Associations With Parenting. Child Development, 91(3), e563–e580. doi.org/10.1111/cdev.13277

Putnam, S. P., & Stifter, C. A. (2008). Reactivity and regulation: The impact of Mary Rothbart on the study of temperament. Infant and Child Development, 17(4), 311–320. doi.org/10.1002/icd.583

Rodriguez, C. M., Wittig, S. M. O., & Christl, M.-E. (2019). Psychometric evaluation of a brief assessment of parents’ disciplinary alternatives. Journal of Child and Family Studies, 28, 1490–1501. https://doi.org/10.1007/s10826-019-01387-8

Rosier, J. G., & Cassels, T. (2021). From “Crying Expands the Lungs” to “You’re Going to Spoil That Baby”: How the Cry-It-Out Method Became Authoritative Knowledge. Journal of Family Issues, 42(7), 1516–1535. doi.org/10.1177/0192513X20949891

Rothbart, M. K. (1981). Measurement of temperament in infancy. Child Development, 52(2), 569–578. doi.org/10.2307/1129176

Rothbart, M. K. (2007). Temperament, development, and personality. Current Directions in Psychological Science: A Journal of the American Psychological Society, 16(4), 207–212. doi.org/10.1111/j.1467-8721.2007.00505.x

Rothbart, M. K., Ahadi, S. A., & Evans, D. E. (2000). Temperament and personality: Origins and outcomes. Journal of Personality and Social Psychology, 78(1), 122–135. doi.org/10.1037/0022-3514.78.1.122

Rothbart, M. K., & Bates, J. E. (2006). Temperament. In N. Eisenberg, W. Damon, & R. M. Lerner (Eds.), Handbook of child psychology: Social, emotional, and personality development (6th ed., pp. 99–166). John Wiley & Sons. psycnet.apa.org/record/2006-08776-003

Scaini, S., Caputi, M., Giani, L., & Forresi, B. (2021). Temperament profiles to differentiate between stress-resilient and stress-affected children during Covid-19 pandemic. Psychology Hub, 38(3), 7–16. https://dx.doi.org/10.13133/2724-2943/17582

Shiner, R. L., Buss, K. A., McClowry, S. G., Putnam, S. P., Saudino, K. J., & Zentner, M. (2012). What is temperament now? Assessing progress in temperament research on the twenty-fifth anniversary of Goldsmith et al. (1987). Child Development Perspectives, 6(4), 436–444. doi.org/10.1111/j.1750-8606.2012.00254.x

Stifter, C. A., Putnam, S., & Jahromi, L. (2008). Exuberant and inhibited toddlers: Stability of temperament and risk for problem behavior. Development and Psychopathology, 20(2), 401–421. https://doi.org/10.1017/S0954579408000199

Strickhouser, J. E., & Sutin, A. R. (2020). Family and neighborhood socioeconomic status and temperament development from childhood to adolescence. Journal of Personality, 88(3), 515–529. dx.doi.org/10.1111/jopy.12507

Suarez, G. L., Morales, S., Miller, N. V., Penela, E. C., Chronis-Tuscano, A., Henderson, H. A., & Fox, N. A. (2021). Examining a developmental pathway from early behavioral inhibition to emotion regulation and social anxiety: The moderating role of parenting. Developmental Psychology, 57(8), 1261–1273. doi.org/10.1037/dev0001225

Tang, A., Crawford, H., Morales, S., Degnan, K. A., Pine, D. S., & Fox, N. A. (2020). Infant behavioral inhibition predicts personality and social outcomes three decades later. Proceedings of the National Academy of Sciences, 117(18), 9800–9807. doi.org/10.1073/pnas.1917376117

Thomas, A., & Chess, S. (1977). Temperament and development. Brunner/Mazel. https://www.cambridge.org/core/journ...4A7E911678FC00

Van Leeuwen, K., De Fruyt., F., & Mervielde, I. (2004). A longitudinal study of the utility of the resilient, overcontrolled, and undercontrolled personality types as predictors of children’s and adolescents’ problem behaviour. International Journal of Behavioral Development 28(3), 210–220. doi.org/10.1080/01650250344000424

Watson, J. B. (1930). Behaviorism (Rev. ed.). W. W. Norton & Co. psycnet.apa.org/record/1931-00040-000

Wilson, A. L., Witzke, D. B., & Volin, A. (1981). What it means to “spoil” a baby: Parents’ perception. Clinical Pediatrics, 20(12) 798–802. doi.org/10.1177/000992288102001208

Zock, H. (2018). Human development and pastoral care in a postmodern age: Donald Capps, Erik H. Erikson, and beyond. Journal of Religion and Health, 57(2), 437–450. https://doi.org/10.1007/s10943-017-0483-0