The authors investigated the performance of 172 Grade 4 students (9 to 10 years) over 12 months on a 36-item test that comprised items from 6 distinct graphical languages (e.g., maps) commonly used to convey mathematical information Results revealed (a) difficulties in Grade 4 students' capacity to decode a variety of graphics, (b) significant improvements in students' performance on graphical languages over time, (c) gender differences across graphical languages, and (d) influence of spatial ability on decoding performance. Implications of this study include the need for supporting development of students' ability to decode graphics beyond activities usually investigated in mathematics curricula.
Lowrie, T., & Diezmann, C. (2007). Solving graphics problems: Student performance in the Junior Grades. The Journal of Educational Research, 100(6), 369-377. https://doi.org/10.3200/JOER.100.6.369-378