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Social-Emotional Development: Infants and Toddlers

This lesson will help you understand how infants and toddlers develop socially and emotionally. You will learn about social-emotional milestones and what to do if you are concerned about the social-emotional development of an infant or toddler in your care.

  • Recognize infant and toddler social-emotional milestones.
  • Identify how adults can support the social-emotional skills of infants and toddlers.
  • Discuss what to do if you are concerned about the social-emotional development of an infant or toddler in your care. 



Emotional well-being during the early years has a powerful impact on social relationships. Children who are emotionally healthy are better able to establish and maintain positive relationships with adults, as well as with peers. Social-emotional development is essential to a young child’s sense of well-being. The relationships they form early on help shape who they are, who they become, and their understanding of the world. The important people in young children’s lives help lay the foundation for a range of social-emotional skills such as:

  • Self-regulation
  • Empathy
  • Turn-taking and sharing
  • Positive relationships with adults and peers

Social-Emotional Milestones

Through early relationships with nurturing and responsive adults, infants and toddlers learn how to be in relationships, how to get their needs and wants met, and how to identify and regulate emotions. Social and emotional development both include behaviors that represent children’s emotional growth and their ability to successfully navigate their world through interactions with adults and peers.  Since these skills develop together, this area of development is referred to as social-emotional development. Social-emotional milestones focus on children’s developing abilities to regulate their attention, emotions, and behavior, and to form positive relationships with adults and peers. It is important to highlight that within this area of development, infants and toddlers are creating a strong sense of self and building relationships with others at the same time.

The chart below highlights the expected social-emotional skills of infants and toddlers as they grow. Keep in mind that individual differences exist when it comes to the exact age at which infants and toddlers may meet these milestones. As highlighted in the Cognitive, Physical, and Communication courses, milestones are not checklists with which to judge children’s development. Rather, they provide a guide for when to expect certain skills or behaviors to emerge in young children, so you are prepared to meet their changing needs. Think of milestones as guidelines to help you understand and identify typical patterns of growth and development in infants and toddlers. Although the skills mentioned in the chart will develop in a predictable sequence over the first three years of life, each infant and toddler is unique in when they will master each skill. Your goal is to help all infants and toddlers grow and learn to their potential.

Social-Emotional Developmental Milestones in Infants & Toddlers

2 Months
  • Calms down when spoken to or picked up
  • Looks at your face
  • Smiles at people when they talk or smile
  • Cries when hungry wet, tired, or wants to be held
4 Months
  • Smiles on own to get attention
  • Begins making early noise sounds of laughter when prompted to laugh
  • Looks at you, moves, or makes sound to get or keep your attention
  • Smiles or coos at self in the mirror
6 Months
  • Knows familiar people
  • Enjoys looking at self in a mirror
  • Laughs
  • Plays by grabbing foot when laying on back
9 Months
  • Is shy, clingy, or fearful of strangers
  • Shows several facial expressions like happy, sad, angry, surprised
  • Looks when you call their name
  • Reacts when you leave (looks, reaches for you, or cries)
  • Smiles or laughs when you play peek-a-boo
12 Months
  • Plays games such as “pat-a-cake” and “peek-a-boo”
  • Lifts foot for shoe or sock when you dress them
  • Rolls ball back for you to return to them when playing
  • Shows preference for certain people and things
15 Months
  • Copies other children while playing
  • Shows you an object they like
  • Claps when excited
  • Hugs items like dolls and stuffed toys
  • Shows you affection (hugs, cuddles, kisses)
18 Months
  • Explores alone but with parent close by
  • Points to show something of interest
  • Puts hands out for you to wash them
  • Looks at a few pages in a book with you
  • Helps you dress them by pushing arm through sleeve or lifting a foot
24 Months
  • Notices when others are hurt or upset
  • Looks at your face to see how you react in new situations
  • Shows defiant behavior (doing what told not to do)
  • Imitates others, especially adults and other children
  • Shows more and more independence
30 Months
  • Plays next to other children and sometimes with them
  • Shows you what they can do by saying, “Look at me!”
  • Follows simple routines independently when told
  • Dresses self in loose clothing
36 Months
  • Calms down within 10 minutes after you leave
  • Notices other children and joins them in play
  • May get upset with major changes in routine
  • Shows affection for friends without prompting

It is helpful to remember that expectations about developmental milestones are driven by cultural values and preferences. Theorist Lev Vygotsky said that adults share their cultural values and beliefs with children through daily interactions. Ideas, beliefs, and expectations about child development are just some of the ways cultures are unique. Becoming aware of and respecting these differences can help you better understand the family experiences that help shape the infants and toddlers in your care.

Connection of Social-Emotional Development to Other Areas of Development

With our evolving understanding of brain development in young children, we continue to learn about the ways adult caregivers can be supportive and successful in helping children develop and learn. This growing understanding also includes how adult caregivers can help children develop social-emotional skills. Through nurturing and trusting relationships, infants and toddlers learn about the world. Their brains mature through interactions, and they learn how to form relationships, communicate, respond to challenges, and how to recognize, experience, and regulate their emotions from their relationships with caregivers.

When infants and toddlers feel safe and have their needs met, they are more likely to observe, explore, play, interact, and experiment with people and objects. These experiences lead young children to learn and remember new things. This foundation for learning depends greatly on the quality of infants’ and toddlers’ early environments and relationships.

Understanding and Supporting the Social-Emotional Development of Infants and Toddlers

Let’s revisit the definition of social-emotional health according to Zero to Three:

Within the context of one’s family, community, and cultural background, social-emotional health is the child’s developing capacity to:

  • form secure relationships
  • experience and regulate emotions
  • explore and learn

Considering the components highlighted within this definition, below are additional ways to understand and support the social-emotional development of the infants and toddlers in your care.

Birth to 3 months:

  • The first three months are a time all about helping an infant learn to feel safe, comfortable, secure, and curious about their world: “Your smile and gentle touch help me to feel safe and happy.”
  • When caregivers respond to an infant’s cues with comfort and care, infants develop trust: “Your soothing voice and touch lets me know you love me and that you will meet my needs.”
  • Infants use sounds, facial expressions, and body movements to tell caregivers what they need and how they are feeling: “I am learning how to tell you what I need. Sometimes I look away when I need a break. I may yawn when I am feeling tired. This may look different for me than it does for my peers.”
A smiling infant

3 to 6 months:

  • The infant is active, responsive, and increasingly in control of his or her body: “I stretch my arms toward you when I want you to pick me up and hold me gently.”
  • Infant offers smiles and communicates with a gaze and basic vocalizations: “I am smiling to let you know I am ready to communicate.”
  • Sense of security and well-being are totally dependent upon relationships with important caregivers.
  • Emphasis is on routine and exploration—showing caregivers what they like and dislike, and how they prefer to sleep, eat, and play: “I am beginning to notice daily routines and the things we do together. When you turn the lights down, I know that it is time for sleep.”
A staff member and an infant sit by a mirror

6 to 9 months:

  • Moving and exploring is the goal – infants become eager explorers who are thrilled to discover that they can make things happen.
  • Infants are learning to solve problems: “When a toy drops, I look to see where it went. I expect you will help me to get it back. I then try it again to see if I can make the same thing happen again.”
  • An infant is beginning to understand that people still exist even when they are out of sight: “I realize that my mommy is about to leave me. I will cry in hopes that she stays. Being separated from her is hard for me.”
An infant plays with a book

9 to 12 months:

  • Infants are enjoying increased independence. “Please stay calm even when I demand to do things on my own. It is hard work for me to learn and figure out all of these new things and sometimes I get frustrated, but I want to keep trying.”
  • Infants can understand more than they can verbally communicate: “I need your help to learn the words for certain objects and actions. Identify things as we see and do them. Eventually, I will learn the words and phrases I need to communicate.”
  • Infants enjoy doing things repeatedly. “Watch me practice and figure out how things work. Repetition is also helping me build my memory.”
  • Infants take action with a goal in mind: “When I crawl away from you quickly, I am not trying to upset you. I am having fun and do not want my diaper changed right now.  This is how I take control of my world and let you know how I am feeling. Please talk to me and give me time to transition from my activity, and let me know that when we are done, I can go back to what I was doing.”

12 to 18 months:

  • Infants and toddlers are watching others and imitate what they see: “I have been watching and am able to use things the way they are supposed to be used. Watch me talk on this toy telephone!”
  • Infants and toddlers are using skills to explore and discover the boundaries of what they can do: “I may get frustrated when you try to feed me because I want to do it on my own.”
  • Infants and toddlers are beginning to understand feelings of self and others: “My feelings can be hard for me to handle. I may become frustrated and have tantrums. I need your help to calm down and identify my emotions. Let me know that it is okay to feel frustrated or upset.”
A toddler pretends with a play phone

18 to 24 months:

  • Toddlers work hard to be in control, explore the boundaries of their experiences, and engage in problem solving: “I am beginning to sort things. Notice how I put my train cars in one place and all of my other cars in another.”
  • They are increasingly aware of themselves as separate from others and are becoming more enthusiastic about playing with peers.
  • They are starting to show negative behaviors (hitting, biting, kicking) in response to frustration: “I may understand the words ‘no’ and ‘stop’ but cannot control my feelings and actions. Please be patient and help me when I get frustrated. Instead of telling me what I cannot do, give me alternatives to my undesirable behavior such as hitting a pillow or kicking a ball.”
Two toddlers lay on the floor with ribbons

24 to 36 months:

  • Toddlers are using language to express thoughts and feelings: “When you started to put the blocks away too soon, I yelled, ‘That’s not right!’ I wanted to make a path for the cows before we put things away.”
  • Toddlers are using enhanced thinking skills to solve problems: “I am getting really good at playing pretend. I can act out my own stories and use a bottle to feed my teddy bear. Sometimes, I feel scared because I am not certain yet what is real and what is pretend.”
  • Toddlers take pride in their accomplishments, such as, pouring milk: “Be patient and prepared for me to make mistakes. This is how I am learning independence. Acknowledge what I can do instead of what I cannot do.”
A staff member assists a toddler as he tries pouring milk into his glass during family-style dining

Supporting All Infants and Toddlers

Every child is born with their own unique way of approaching the world. This is called temperament. Some young children, for example, are constantly on the move while others prefer to sit and watch the world around them. Some children enjoy new experiences and meeting new people while others are slower to warm up in new situations.

In young children, temperament is commonly defined as the individual differences in emotional responses and reaction to the environment.  As Murphy and Moon (2010) describe, “infants and young children vary greatly in their interest in different sensory areas, in the intensity of their attention to sensory stimuli, and in their sensitivity to feelings of comfort and discomfort, familiarity and strangeness, and the emotional context in which sensory experiences occur.”

Infants are born with a unique temperament. There is no right or wrong, good or bad temperament. By understanding temperament, you can continue to use what you know about infants and toddlers to encourage their strengths and support their needs.  In the Apply section, you will review more information about temperament and consider what it means for your role as a responsive caregiver.

It is important to note that no matter how well you understand temperament and are attuned and responsive to the needs of the children in your care, there will be times that a child may not appear to be developing appropriate social-emotional skills. This may be related to inborn (nature) or environmental (nurture) influences. The caregiving strategies in this lesson apply and relate to all children; however, some children may require an additional level of support. Each infant and toddler has a unique pattern of growth. In your work, you should observe and track each young child’s particular strengths and possible areas of need. Make the screening and assessment process part of your ongoing routine. This will help you to recognize and celebrate infants’ and toddlers’ accomplishments. It also helps you to identify any aspects of the child’s development that is not in line with the expected age range.

The following general strategies can help you care for infants and toddlers who are experiencing social and emotional challenges.

  • Observe and notice the infant’s or toddler’s cues and responses to environmental stimuli. Think about ways to limit the noise level or visual stimuli.
  • Observe and ask yourself if you notice increased frustration or irritability in the infant or toddler during particular routines or times of day. Consider ways to alter the routine to support the child.
  • Think about ways to maintain physical closeness and offer a gentle touch to help infants and toddlers maintain a sense of control.

You should always talk with a child’s parents to learn about any changes in home or other routines. You may recommend that parents contact their health-care provider and ask about completing a developmental screening for their child to identify any possible developmental delays. Talk with your trainer, coach, or administrator about additional community resources and specialists who may offer additional support.


Promoting Social-Emotional Development in Infants and Toddlers

Watch this video to learn about strategies for infants and toddlers who are experiencing social and emotional difficulties.


You can promote social-emotional development of infants and toddlers in several ways:

  • Respond with care to infants' and toddlers' needs.
  • Acknowledge an infant or toddler who points to a picture of themselves or their family – “That’s right, that is a picture of you and your dad!”
  • Model caring behaviors and empathy during all interactions.
  • Read stories about feelings and show infants and toddlers pictures of different emotions.
  • Build strong relationships with the families of infants and toddlers in your care.


Take a moment to list behaviors that you believe indicate healthy social-emotional development. Compare your list with the behaviors noted within this lesson’s chart. Next, download the handout, Encouraging Social-Emotional Development During the First Three Years. While thinking about the infants and toddlers in your care, identify behaviors that you notice regularly and the ways you can encourage these behaviors during the first three years of life. Then, share and discuss your responses with a trainer, coach, or administrator.


Use the handout, Learning More About Temperament, to explore additional online resources to better understand the temperament of infants and toddlers. Pick one of the resources and use the information to learn more about the temperament of a specific infant or toddler in your care.


Developmental delay:
This may be suspected when children do not meet developmental milestones at the expected times; delays can occur in any area of development
Developmental milestones:
A set of skills or behaviors that most children can do at a given age range
Developmental screening:
A tool used to help identify children who are not developing as expected and who may need supports; screening can be completed by pediatricians, teachers, and others who know the child and have a knowledge of child development
Emotional self-regulation:
The ability to adjust our emotional state to a comfortable level of intensity so we can accomplish our goals
Social-emotional competence:
Healthy relationships with caregivers and friends, a positive self-awareness and ability to control emotions, and the ability to independently participate in daily routines and play across a variety of environments


Which of the following is a social-emotional developmental milestone of a typical 12-month-old?
Finish this statement: When an infant drops a toy over and over again, the appropriate response is…
Which of the following is not a strategy that can help care for infants and toddlers who are experiencing social and emotional difficulties?
References & Resources

Berk, L. E. (2013). Child development (9th ed.). Pearson.

Centers for Disease Control and Prevention. (2021). Developmental milestones.

Copple, C., Bredekamp, S., & Koralek, D. (2013). Developmentally appropriate practice: Focus on infants and toddlers. National Association for the Education of Young Children

Early Childhood Learning & Knowledge Center. (2018, May 30). Introduction to temperament.

Murphy, L. B. & Moon, R. (2010, February 22). Babies and their senses. Zero to Three.

Paul H. Brookes Publishing Co. Inc. (2022). Ages and stages questionnaire (ASQ).

Trawick-Smith, J. W. (2013). Early childhood development: A multicultural perspective (6th ed.). Pearson.

Wittmer, D. S., & Petersen, S. H. (2017). Infant and toddler development and responsive program planning: A relationship-based approach. (4th ed.). Pearson Publishing.