Toddler Irritability as Distinct From Typical Toddler Anger Reactivity

Open Access
Larose, Alicia Jean
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Pamela Cole, Thesis Supervisor
  • Cynthia Huang Pollock, Honors Advisor
  • Irritability
  • toddlerhood
  • anger dysregulation
  • temper tantrums
Background: Irritability, defined by frequent, extreme, unpredictable anger outbursts including temper tantrums, has recently gained interest among researchers (Stringaris, Zavos, Leibenluft, Maughan, & Eley, 2012; Leibenluft, 2011). Yet little is known about the developmental course of irritability throughout childhood and whether and when it is a clinically meaningful factor distinct from the normative anger reactivity of toddlers. The first aim of the thesis is to determine whether irritability can be differentiated, from anger reactivity, as a unique and coherent factor in a group of 27-month-olds (M = 27.45; SD = 1.33). The second aim is to test the validity of the irritability construct by examining the extent to which toddler irritability was related to the degree and extent of anger children show during a variety of tasks. Methods: The sample is composed of 546 toddlers and their parents, participants in an NIH-supported longitudinal study, the Early Growth and Development Study (EGDS). For Aim One, a selection of parent-reported ratings of toddler characteristics was analyzed using Principal Components Analysis (PCA) to determine if irritability could be distinguished from anger reactivity. For Aim Two, the Irritability and Anger scales, based on the PCA results, were correlated to independent observations of the toddlers in three laboratory procedures that varied in the likelihood they would elicit frustration. Results: The PCA yielded two factors—one that was labeled Anger and a second one that was labeled Irritability. The Irritability scores comprised six items from mother reports, and seven items from father reports, of toddler behavior. The Anger score reported by mothers and fathers was positively correlated with the frequency of aversive behavior during the clean-up task (r = 0.20, p<.01 and r = 0.27, p<.01, respectively) and mothers’ report of toddlers Anger was positively correlated with the ratio of negative affect during the waiting activity (r = 0.12 , p<.05). The Irritability score was not related to the child’s behavior during the observational tasks, with the exception of father reports of toddler Irritability, which was modestly but significantly correlated (r = 0.13, p<.05) with the duration of child distress during the free play task. Conclusions: Toddler irritability is related to anger reactivity but emerges as a unique component based on parent ratings of child behavior. This factor appears to reflect toddler anger that is more intense, less predictable, and more frequent. However, it was not related to observed toddler behavior, with the exception of fathers’ report of irritability being related to the length of time toddlers were distressed during a task that most children find pleasant.