Introduction Although much is known about theory of mind (ToM) development during childhood, data on how these skills develop in adolescence is scarce. This cavity is due in part to the limited knowledge about measures of advanced theory of mind. Methods The study examined the relation among six common story‐based tasks designed to measure advanced ToM in two age groups of Polish adolescents: early (13‐year‐olds; 78 girls) and late (16‐year‐olds; 143 girls) adolescents. Results Factor models for individual tasks were constructed, followed by an examination of the underlying structure that explained the variability of factor scores. Only in half of the tasks, the results revealed an age‐related increase in advanced ToM. Contrary to expectation, results showed a lack of correlations among story‐based advanced ToM tasks in the two adolescent groups. Conclusions The results suggest a lack of coherence among advanced story‐based ToM tasks and the need for further development of reliable and valid advanced ToM measures which are sensitive enough to show increasingly complex social reasoning abilities in adolescence.

Self-esteem is continuous and has stable characteristics, but it may also change, e.g., during transitions from one educational level to the next. In a prospective cross-sectional study over a year and a half, 250 Polish early adolescents ( N = 109, 54 girls; mean age at T1 = 12.68 years, SD = 0.49) and middle adolescents ( N = 141, 107 girls; mean age at T1 = 15.80, SD = 0.44) were tested three times using Harter’s Self-Perception Profile for Adolescents, assessing both global self-esteem and self-evaluation in eight domains. The change and consistency of self-esteem were analyzed, at both group and individual levels. At the group level, the following results were found: (1) continuity of self-esteem in five domains (scholastic competence, athletic competence, physical appearance, close friendship, and romantic appeal) and in global self-esteem and discontinuity in only three domains (social acceptance, job competence, and behavioral conduct); (2) significant inter-individual variation in the change not explained by age; and (3) higher self-esteem (in five domains) in early adolescents. At the individual level, the stability in most domains was weak, but was restored over the second year at the new school. The complexity of the developmental change and consistency in self-esteem in adolescence was highlighted, emphasizing the need for analyzing both group and individual change.

Vocabulary acquisition appeared to be slower in Polish than in English, probably because of the complexity of the language. However, the languages were very similar with respect to vocabulary composition findings.