Developmental Delays and Behavior

Defined

A developmental delay occurs when a child does not reach developmental milestones within the expected time frame in one or more domains, cognitive (including language/communication), physical, or social/emotional. While occasional variation in milestone achievement is typical, persistent delays across settings may signal an underlying condition or environmental factor that requires attention (American Psychiatric Association, 2013). Causes of developmental delays are multifaceted and may include genetic conditions (e.g., Down syndrome, Fragile X), prenatal exposures to toxins or infections (e.g., alcohol, lead, cytomegalovirus), birth complications (e.g., prematurity, oxygen deprivation), or environmental adversity such as neglect, malnutrition, or chronic stress (Zeanah et al., 2011; Shonkoff & Phillips, 2000).

Delays can influence behavior in multiple ways, often showing up in the classroom or home as challenging interactions, avoidance, or misinterpretations of ability. Other behaviors that may warrant additional concerns for healthy development include the following.

Frustration and Aggression

Children with delayed communication skills may struggle to express their needs, wants, or emotions. When adults or peers cannot understand them, they may resort to tantrums, hitting, or biting as a form of expression. Over time, these behaviors can be mislabeled as “willful misbehavior” rather than signs of an unmet developmental need.

Inattention and Hyperactivity

Delays in executive functioning—such as planning, impulse control, and working memory—may mimic or overlap with symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD). Educators must carefully consider whether inattention or hyperactivity stems from immaturity in self-regulation, a true clinical condition, or both (Barkley, 2015).

Social Withdrawal

A child who struggles with fine motor skills (e.g., difficulty holding crayons or climbing playground equipment) or language skills may avoid peer interaction to reduce embarrassment or because they are excluded by peers. Social withdrawal can lead to fewer opportunities to practice essential skills, reinforcing the delay in a negative cycle.

Anxiety and Low Self-Esteem

Repeated experiences of failure or difficulty meeting expectations may cause children to develop anxiety about trying new tasks. This can manifest in avoidance, perfectionism, or behavioral outbursts when challenged.

Importantly, developmental delays often co-occur with other risk factors that compound their impact. Children living in poverty may face limited access to high-quality early learning environments, health care, and nutritious food, all of which influence developmental progress. Exposure to Adverse Childhood Experiences (ACEs), such as abuse, neglect, or household instability, can intensify delays by disrupting brain architecture and stress-regulation systems (Felitti et al., 1998). Lack of access to early education or intervention services further reduces the likelihood that delays will be identified and addressed in a timely manner.

For these reasons, evaluating behavior in children with developmental delays requires a holistic, ecological perspective. Educators and professionals must consider not only the child’s individual developmental profile but also the broader social, cultural, and environmental context. This approach reduces the risk of mislabeling behaviors and ensures children receive supports tailored to both their developmental needs and lived experiences.

References

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596
2. Barkley, R. A. (2015). Attention-Deficit/Hyperactivity Disorder: A handbook for diagnosis and treatment (4th ed.). Guilford Press.
3. Felitti, V. J., Anda, R. F., Nordenberg, D., Williamson, D. F., Spitz, A. M., Edwards, V., … & Marks, J. S. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults: The adverse childhood experiences (ACE) study. American Journal of Preventive Medicine, 14(4), 245-258.
4. Shonkoff, J. P., & Phillips, D. A. (Eds.). (2000). From neurons to neighborhoods: The science of early childhood development. National Academies Press.
5. Zeanah, C. H., Egger, H. L., Smyke, A. T., Nelson, C. A., Fox, N. A., & Marshall, P. J. (2011). Sensitive periods. In Handbook of infant mental health (pp. 226–241). Guilford Press.