Back to Reality: Children's Comprehension of Yesterday & Tomorrow for Real vs. Hypothetical Events

Time words like ‘yesterday’ and ‘tomorrow’ are hard for children to learn because the referents of these words are highly abstract, and can only be understood in the context in which they are produced. For example, ‘yesterday’ means something different on Monday and on Wednesday. The abstract nature of these deictic time words also poses an interesting problem for researchers who study their acquisition. In the present study, we tested 60 3- and 4-year-old children on their understanding of ‘yesterday’ and ‘tomorrow’ using three tasks that were similar in structure, but differed in their reliance on children’s autobiographical experience and hypothetical reasoning skills. Results indicate that, when asked about their own experiences, children as young as age 3 demonstrated an understanding of these time words, and could successfully express their knowledge on a spatial timeline. However, even 4-year-olds struggled to reason about hypothetical events. The results suggest that autobiographical measures that reflect the actual passage of time may be more sensitive measures of children’s early temporal knowledge relative to tasks that require children to construct hypothetical timelines of events. The implications of these findings and avenues for future research are discussed.