Physical aggression and language ability from 17 to 72 months: cross-lagged effects in a population sample

Abstract

Background: Does poor language ability in early childhood increase the likelihood of physical aggression or is language ability delayed by frequent physical aggression? This study examined the longitudinal associations between physical aggression and language ability from toddlerhood to early childhood in a population sample while controlling for parenting behaviours, non-verbal intellectual functioning, and children's sex.

Methods: Children enrolled in the Quebec Longitudinal Study of Child Development (QLSCD) (N = 2, 057) were assessed longitudinally from 17 to 72 months via parent reports and standardized assessments.

Results: The cross-lagged models revealed modest reciprocal associations between physical aggression and language performance from 17 to 41 months but not thereafter.

Conclusions: Significant associations between physical aggression and poor language ability are minimal and limited to the period when physical aggression and language performance are both substantially increasing. During that period parenting behaviours may play an important role in supporting language ability while reducing the frequency of physical aggression. Further studies are needed that utilize multiple assessments of physical aggression, assess multiple domains of language abilities, and that examine the potential mediating role of parenting behaviours between 12 and 48 months.

Figure 1. Crossed-lagged model: Aggression and language development from 17–72 months.

Full Information Maximum Likelihood used. Note: ***Significant at the .001 level. **Significant at the .010 level. *Significant at the .050 level.

Figure 2. Crossed-lagged model with controls: Aggression and language development from 17–72 months.

Full Information Maximum Likelihood used. Note: ***Significant at the .001 level. **Significant at the .010 level. *Significant at the .050 level. For visual simplicity of the model we report here only significant associations up to 41 months as no significant cross-lagged associations between aggression and language were found thereafter. The full model may be requested from authors. We also note that while not included in the visual model for simplicity, sex was associated with Aggression at 17 and 29 months (i.e., β = .05, p = .024, β = .05, p = .017, respectively), and with Language at 17 and 29 months (i.e., β = –.12, p = .000, and β = –.09, p = .000, respectively). Finally, all parenting factors were collected at 29 months.