Within social protection, antipoverty transfer programmes have significantly emerged in developing countries since the late 1990s. The effects of long-term participation and the assessment of the response of children's human capital formation to different levels of exposure are still unclear. This paper initially takes into consideration the Baland and Robinson (2000) human capital investment model to look into the economics of the length of exposure to antipoverty transfers. The model is presented in a framework shaped by the participation of households in a human development conditional cash transfer programme (CCT). An empirical contribution is made by estimating a dose-response function following Hirano and Imbens (2004). In this empirical setting, the length of exposure to Colombia's Familias en Acción CCT programme is employed as a continuous treatment affecting parental investment in children's human capital. The theoretical and empirical results show that a longer exposure to antipoverty programmes leads to a higher accumulation of years of education and school registration rates.