Data from the Christchurch longitudinal study (Fergusson & Lynskey, 1996) demonstrate a
linear relationship between the numbers of risk factors (e.g. poverty, parent conflict, separation,
poor parent–children interaction) in a child’s environment and the number of psychosocial
problems at ages 15–16 years. Increasing opportunity for interaction among risk factors increases
as a function of increasing numbers of risk factors. Thus, the effect of multiple risk factors can be
exponential. The same might be said of resilience. Just as risk factors have been posited to lay a
foundation for a negative chain of events, protective factors may similarly ensue a positive chain
reaction leading to favourable developmental outcomes (Egeland et al. 1993). For example,
Werner and Smith (1992) have suggested that a positive temperament increases the likelihood of
eliciting a positive response from others early in development. A positive temperament may well
be a seminal resilience promoting factor, having developmental resonance across the life span.
Providing opportunities for the development of positive chain reactions lie at the foundation of
successful intervention.