This thesis aims to explore the role of temperamental emotionality in the
development and early intervention of externalising behavioural problems (EBP).
Given the evidence that early EBP has a lasting negative impact on adjustment
outcomes, interventions are suggested to be offered as early as possible. Longitudinal
research provides general support for temperamental emotionality as a risk factor for
persistent early EBP and some evidence of its mediation between adverse parenting
and EBP. However, it remains unclear whether temperamental emotionality should
be targeted by parenting interventions to reduce early EBP. If temperamental
emotionality can be measured accurately earlier and it leads to EBP, this may provide
an earlier point of intervention.
Study 1 examined measurement agreement between a caregiver-reported
temperament questionnaire and an observational measure using parent-infant
interactions as emotion elicitors. The findings of an absent or medium positive
association between caregiver-reported and observed temperamental emotionality
indicate that both measures capture different but somewhat overlapping components
of temperamental emotionality. Study 2 and Study 3 were conducted with 300
toddlers at risk of behavioural difficulties and their parents, who were randomised to
III
receive Video feedback Intervention to promote Positive Parenting and Sensitive
Discipline (VIPP-SD) or treatment as usual. Study 2 found that decreases in caregiverreported negative emotionality, but not observed negative emotionality, were
associated with decreases in EBP, Attention-Deficit/Hyperactivity Disorder symptoms
and conduct problems. This supports negative emotionality as a general vulnerability
across subtypes of early EBP. The finding of mediation of decreased negative
emotionality between improved overreactive parenting and EBP indicates the
importance of negative emotionality in coercive parent-child processes to early EBP.
Study 3 experimentally tested whether negative emotionality could be a malleable
target for VIPP-SD to reduce early EBP but found no evidence. Future research on how
temperamental emotionality impacts parent-child transactional processes is
worthwhile for innovating early intervention.