The sense of small number discrimination: The predictive value in infancy and toddlerhood for numerical competencies in kindergarten

• No relation was found between infants' small number discrimination and later numerical competencies.
• Toddlers' small number discrimination relates to later conceptual counting.
• Toddlers' small number discrimination relates to later arithmetic operations.
• Infants' and toddlers' small number discrimination do not relate mutually.
• Results may inspire follow-up studies in toddlers with low number discrimination.

Extending previous research on the predictive value of large number discrimination, this study explored the role of infants' and toddlers' small number discrimination for numerical competencies in kindergarten (NCK). Although no significant relationship could be found between number discrimination in infancy (8 months, T1) and NCK (48 months, T3), the predictive value of toddlers' number discrimination (24 months, T2) for NCK could be demonstrated at least for some NCK. The finding that only toddlers' small number discrimination related to NCK raised thoughts about the task, age, set size, stability and development of number discrimination or other influencing factors. Future research should study all small set sizes (not only 1 vs. 3) and a broader range of NCK in a larger sample. Nevertheless, whereas infants' small number discrimination might be too early to predict NCK, performance in toddlerhood might be addressed in the future to establish a measure to detect at-risk mathematical development.