The increasing inclusion of socio-demographic variables in studies of cognitive development in children points to a renewed interest in the scientific community to identify how context shapes human development. Along this line of knowledge, this study aims to examine the relationship between development of verbal working memory, age, socioeconomic status, type of school and daily activities performed by 159 Colombian children aged 6 and 8 years old. Their verbal working memory was assessed using the Progression and Regression Digit Span Test, and the Letters and Numbers Tests of the WISC-IV. Results show that older children perform better in both tests, and that children of middle and upper classes who attend private schools are those who score higher on the Progression and Regression Digit Span Test. In addition, it was found that activities like using the computer, practicing sports and doing homework allow a better performance in the above mentioned task. Results of this study suggest that the Progression and Regression Digit Span task depends on socio-demographic variables, while the Letters and Numbers Test does not seem to be linked to them.