## 4 Discussion
### Limitations  
Our research encountered several limitations that should be considered. While the texts used were of similar difficulty, there were additional factors beyond typeface shape that may have influenced the outcomes. Firstly, participants might have reacted differently to specific texts based on their interests. For instance, adults and children might showvaried emotional responses to content such as descriptions of animals. This variability could have contributed to the differences observed across age groups.  
Secondly, the typefaces employed in this study varied in certain shape features that could influence reading metrics, including typographic tonal density and character size. Although the x-height was standardised, other elements such as the dimensions of ascenders and descenders differed among typefaces. This discrepancy altered the amount of white space around the ascenders and descenders, which consequently affected line spacing, even when the leading was uniformly set (at 140%). Variations in white space and the internal shapes of typeface letters inevitably led to differences in typographic tonal density, even with consistent x-height adjustments. Future investigations could focus on isolating specific features of typefaces, such as stroke shape, while controlling for all other attributes, to better understand their effects on reading.  
Thirdly, the COVID-19 pandemic posed challenges to the inclusion of larger sample sizes, reducing the statistical power of our analyses. Future studies would benefit from involving more participants to strengthen the findings.  
Due to pandemic restrictions, measurements with the university students were conducted in the laboratory for visual perception, whereas measurements with elementary school students were conducted on the premises of the elementary school. The differences in the experimental conditions might have affected our results. However, we made every effort to replicate the conditions of the laboratory on school premises as closely as possible to minimise differences in room illumination and, consequently, the effect of light on the readers (we ensured that the windows were covered, the lighting was artificial and uniform, and there were no surfaces that could cause glare or reflections on the computer screen; we also made sure the environment was quiet and peaceful).  
Despite these limitations, we believe that our results provide valuable insights into the effect of typeface shape on reading. The study utilised multiple measures of text processing, and although the fixed effects examined were not very pronounced, the results consistently suggest that reading with round/rounded typefaces, which were perceived as sweeter and consequently more pleasant than angular/pointed ones, was smoother, more pleasant, and somewhat more effective.  
These initial findings emphasise the importance of considering typeface shape and cross-modal correspondence in reading research and comparing the results of different studies. Future research is needed to corroborate these observations and to investigate the wider effects of typeface shape and cross-modal correspondence in the process of reading.