Answers

Why does my child hit, bite or push other kids?

Written by Matt MaLossi, parent behind How They're Wired.

Why it happens

• It's a stage most children pass through. In 2,253 children, about 8 in 10 mothers reported that their 2-year-old sometimes or often used physical aggression. It was present at 12 months, was reported most often at 24 and 36 months, and declined after about age 3.[2] In the 572-family study, about 28% of children showed little or no physical aggression, about 58% showed a modest amount, and about 14% followed a higher path.[1]
• Words are still catching up. In 2,057 children followed from 17 to 72 months, aggression and language showed small links in both directions between 17 and 41 months, and none after that. The links changed once parenting and non-verbal ability were accounted for.[3]
• What's underneath. Our reasoning For a young child, hitting or biting is often the fastest tool for a big feeling: wanting a toy, being tired or crowded, feeling left out. A child who reacts strongly and is slow to settle has more of these moments. We found no study that tests this for each child.
• Family stress matters, and help exists. In the 572-family study, children on the higher-aggression path were more often in families with younger siblings, lower income, family difficulties, or more coercive parenting early on.[1] These are risk factors, not verdicts, and the help that works is described below.

How temperament shapes this

The same hit can come from very different kids.

• If your child feels things strongly and settles slowly. In a study that followed 361 infants into preschool, children who showed more frustration and took longer to settle had more behavior problems at about age 4, especially when self-control was lower.[4] Our reasoning For this child, the hit may come when the feeling gets too big too fast.
• If your child is high-energy and impulsive. High activity and impulsivity predicted more acting-out behavior in that same study.[4] In 220 three-year-olds, lower effortful control went with more externalizing behavior, particularly impulsive and inattentive behavior.[5] Our reasoning Rough, crowded play can tip over fast for this child, so shorter turns and an adult close by help.
• If your child takes in a lot. A research review describes a trait called environmental sensitivity. Children who are higher in it are more affected by stressful surroundings, and they also gain more from supportive ones.[6] Our reasoning Loud, crowded rooms may be the trigger for this child. We found no study that tests this for hitting.

One thing to try

What the research says doesn't work

Supported by related research

Spanking or hitting back. The AAP cites a study in which children spanked more than twice a month at age 3 were more aggressive at age 5.[8] A meta-analysis of more than 160,000 children found no link between spanking and more compliance, and a link to more defiance.[9]

Yelling. In 967 families, harsh verbal discipline at age 13 went with more conduct problems a year later, even when parents were warm.[10]

If a daycare or school is raising concerns

Common practice, partly our reasoning

Ask what happens right before and right after, and where and when it happens (crowded play, transitions, a particular child). A pattern often shows up, and it tells you what to teach or change. A review of 13 trials found that group parenting programs improved behavior in children aged 3 to 12 with early conduct problems in the short term, so asking your pediatrician about one is a reasonable step.[11]

When to ask for more help

Talk with your pediatrician if the hitting or biting is frequent, hurts other children, causes injuries, continues past the early school years, happens in several places, or comes with delayed speech or big difficulty calming down. If a daycare or school is considering removing your child, ask your pediatrician for a check-in.

What the research can and can’t tell us

• The two large studies are of toddlers and preschoolers and rely on parent reports. For ages 6 to 10, the evidence is thinner. We found no study that focuses on biting specifically.
• The roughly 14% of children on a higher path is a reminder that, for some children, aggression does not fade on its own. That is why the help section matters.
• The risk factors are associations. Many children in those families do not become highly aggressive, and the study did not measure any child traits before 5 months.
• The link between language and aggression was small, was found only up to about 41 months, and changed direction once parenting and non-verbal ability were accounted for. We do not know which comes first.
• The idea that hitting is a fast tool for big feelings is our reasoning, and so is the link to temperament for any one child.
• The calm-stop, name-the-feeling, show-the-alternative steps are common practice. We found no study that tests those exact words. The Tuning in to Kids effects were small, and it is a whole program.
• The spanking research is correlational. Children who are aggressive may be spanked more. The yelling study followed 13- and 14-year-olds, not young children.
• The parenting-program review looked at short-term results for children with early conduct problems.
• We found no research-based cutoff for how much aggression needs an evaluation, so we give none.
• The temperament studies are of children under 5 and show links, not cause. Matching a step to a child's temperament is our reasoning. We found no trial that tests it, and the descriptions above are tendencies, not boxes a child fits into.
• Environmental sensitivity research is still young. The review concludes sensitivity is best seen as a continuum, the scale for children is for ages 8 and up, and we found no study that tests it for hitting.

More questions parents ask

• Why does my child melt down in public places?
• Why does bedtime turn into a battle?
• Why is saying goodbye so hard for my child?
• Why is everything such a battle with my child?
• Why won't my child eat new foods?
• Why does it feel like my kid never hears what I'm saying?

Sources

1. Longitudinal study Tremblay, Nagin, Séguin, Zoccolillo, Zelazo, Boivin, Pérusse & Japel. Physical aggression during early childhood: Trajectories and predictors. Pediatrics, 114(1), e43–e50, 2004. View study572 families followed from 17 to 42 months. Mother reports. It shows risk factors, not causes.
2. Community study Alink, Mesman, van Zeijl, Stolk, Juffer, Koot, Bakermans-Kranenburg & van IJzendoorn. The early aggression curve: Development of physical aggression in 10- to 50-month old children. Child Development, 77(4), 954–966, 2006. View study2,253 children at 12, 24 and 36 months, 271 followed a year later. Parent reports, mostly Dutch families. It covers toddlers and preschoolers only.
3. Longitudinal study Girard, Pingault, Falissard, Boivin, Dionne & Tremblay. Physical aggression and language ability from 17 to 72 months: Cross-lagged effects in a population sample. PLoS ONE, 9(11), e112185, 2014. View study2,057 children followed from 17 to 72 months. The links were small, ran both ways before about 41 months, and changed once parenting and non-verbal ability were accounted for.
4. Longitudinal study Gartstein, Putnam & Rothbart. Etiology of preschool behavior problems: Contributions of temperament attributes in early childhood. Infant Mental Health Journal, 33(2), 197–211, 2012. View study361 infants followed to about age 4 (187 at the last visit), mostly white, middle-class families. Parent reports, so it shows links, not cause.
5. Community study Olson, Sameroff, Kerr, Lopez & Wellman. Developmental foundations of externalizing problems in young children: The role of effortful control. Development and Psychopathology, 17(1), 25–45, 2005. View study220 three-year-olds. It shows an association, and only for impulsive and inattentive behavior.
6. Research review Greven, Lionetti, Booth, Aron, Fox, Schendan, Pluess, Bruining, Acevedo, Bijttebier & Homberg. Sensory processing sensitivity in the context of environmental sensitivity: A critical review and development of research agenda. Neuroscience & Biobehavioral Reviews, 98, 287–305, 2019. View studyA critical review. The authors say knowledge is still lagging and better measures are needed.
7. Randomized trial Burkhardt, Roosli & Muller. The Tuning in to Kids parenting program delivered online improves emotion socialization and child behavior in a first randomized controlled trial. Scientific Reports, 2024. View study141 parents of children aged 3 to 6. The authors call the effects small. It tests a whole program, not one step.
8. Medical policy statement Sege & Siegel, American Academy of Pediatrics. Effective discipline to raise healthy children. Pediatrics, December 2018. View studyA pediatricians' policy statement. The link goes to the AAP news release about it.
9. Meta-analysis Gershoff & Grogan-Kaylor. Spanking and child outcomes: Old controversies and new meta-analyses. Journal of Family Psychology, 2016. View studyOver 160,000 children across about 50 years of studies. Correlational.
10. Longitudinal study Wang & Kenny. Longitudinal links between fathers' and mothers' harsh verbal discipline and adolescents' conduct problems and depressive symptoms. Child Development, 85(3), 908–923, 2014. View study967 two-parent families, adolescents aged 13 to 14. Self-reports, so it shows links, not cause.
11. Systematic review Furlong, McGilloway, Bywater, Hutchings, Smith & Donnelly. Behavioural and cognitive-behavioural group-based parenting programmes for early-onset conduct problems in children aged 3 to 12 years. Cochrane Database of Systematic Reviews, Issue 2, CD008225, 2012. View study13 trials, 1,078 participants. Short-term results only. Covers children with early conduct problems, not every strong-willed child.

The full list of everything we cite is on the Sources page.

General information for parents, not medical advice or a diagnosis. Read our statement.