Children’s understanding of yesterday and tomorrow

•Preschoolers’ temporal judgments are affected by both cognitive and linguistic factors.•Cognitively, forward temporal reasoning is easier for preschoolers than backward temporal reasoning.•Linguistically, preschoolers understand the term yesterday better than tomorrow. A picture–sentence matching task was used to investigate children’s understanding of yesterday and tomorrow. In Experiment 1, 3- to 5-year-olds viewed two pictures of an object with a visible change of state (e.g., a carved pumpkin and an intact pumpkin) while listening to sentences referring to past or future actions (“I carved the pumpkin yesterday” or “I’m gonna carve the pumpkin tomorrow”) and selected the matching picture. Children performed better with past tense sentences than with future tense sentences, and including tomorrow in future tense sentences increased accuracy. In the next two experiments, 4- and 5-year-olds (Experiment 2) and adults (Experiment 3) completed the same task but with sentences containing conflicting temporal information (“I carved the pumpkin tomorrow”). Children tended to select pictures depicting the outcome of actions regardless of tense or temporal adverb, whereas adults’ judgments were based on temporal adverbs. In Experiment 4, 3- to 5-year-olds completed tasks requiring either forward or backward temporal reasoning about sentences referring to before, after, yesterday, today, and tomorrow. Across sentence types, forward temporal reasoning was easier for children than backward temporal reasoning. Altogether, results indicated that children understand yesterday better than tomorrow due to the increased cognitive demands involved in reasoning about future events.