“…Picture books for toddlers under 2 years often contain simple words with few references to mental states, while those for children over 6 years vary greatly in the amount of text and frequently include complex language related to mental states. Since previous studies analyzed picture books for 3‐ to 4‐year‐olds (Farkas et al., 2020) and 3‐ to 6‐year‐olds (Dyer‐Seymour et al., 2004; Shatz et al., 2006), our age selection is appropriate. To ensure the suitability of the books for preschoolers aged 3–5, we consulted the age recommendations for each book from its original sources, the editorial suggestions of publishers, and age estimation based on grammatical structure and word richness (Fujita et al., 2017).…”