Maternal-infant contact and child development: Insights from the Kangaroo intervention

A "low-cost intervention" must, by definition, capitalize on the resources available in the natural ecology. Yet, transforming natural substances, behaviors, or patterns of relatedness into an organized intervention that can be subjected to scientific scrutiny requires more than the use of nature's offerings. As a first step, one must establish that the specific substance or activity advocated as intervention is not just "good for you", but that there are specific, theoretically-based, and empirically proven links between "cause" and "care". Second, the mechanisms by which the proposed intervention improves the level of functioning must be laid out for empirical testing. In this context, it is important to distinguish between natural resources that promote well-being in general from the use of these same resources for the treatment of a pathological state (i.e., use as prevention versus use as intervention). Third, specific outcomes of the intervention should be proposed and tested, not only a global promotion of well-being and development. Such specificity may further define chains of cause-care-cure in the case of lowcost interventions. Finally, at least in the domain of infant development, the role of the natural resource in shaping specific brain systems and its effects on structure-function relationship is an important aspect of the intervention. Thus, applying a "sensitive period" approach, which underscores the need for specific environmental inputs during unique time-windows in structurefunction relationship, is likely to increase the scientific value, testability, and generalizability of the proposed intervention.