Students' mental load, stress, and performance when working with symbolic or symbolic–textual molecular representations

Abstract

In science education, representations are necessary inter alia for the understanding of relationships between structures and systems. However, several studies have identified difficulties of students when working with representations. In the present study, we investigated students' responses (regarding their preference, test performance, mental load (ML), and stress) toward two kinds of representations: symbolic representations, which only use abstract symbols, versus combined symbolic–textual representations, which additionally comprise textual elements. Therefore, students were randomly assigned to one of two treatment groups: one group worked on test tasks accompanied by symbolic representations, and the others worked on the same tasks, but with symbolic–textual representations. Thereafter, the students' test performance and ML were assessed. The level of perceived stress and the salivary cortisol concentration were measured before and after the test and again a few minutes later. Additionally, heart rate variability parameters were assessed continuously. We found a strong preference of the test version with symbolic representations. Additionally, the students showed better test performance and lower ML when they worked with symbolic representations. However, the level of perceived stress was comparable between both groups and there was no strong physiological stress response: The cortisol concentration decreased in both groups and the heart rate was relatively similar. However, during the second half of the test, we observed a significantly higher ratio between low and high heartbeat frequencies in the group with symbolic–textual representations and we found an indirect influence of the kind of representation on test performance through its effect on ML. The poorer test performance and higher ML in connection with symbolic–textual representations confirm previous studies, which found that symbolic–textual representations pose major problems for students. Thus, teachers should enable students to understand symbolic–textual representations and consider carefully whether they can use symbolic representations instead, especially when they teach complex content.

Analyzing Relationships Between Causal and Assessment Factors of Cognitive Load: Associations Between Objective and Subjective Measures of Cognitive Load, Stress, Interest, and Self-Concept

“…Thus, it is plausible to assume a relationship between subjective measures and heart rate-or hormone-based objective measures of cognitive load, which is rarely investigated yet. One study of the authors found a significant positive correlation between selfreported mental load (i.e., perceived task complexity) and perceived stress but no or rather small correlations between self-reported mental load and physiological stress responses (cortisol concentration, heart rate variability; Minkley et al, 2018). Veltman and Gaillard (1993) report similar findings and conclude that cortisol concentration might not be a valid indicator for mental activity and that heart rate variability might indicate cognitive load only in high demanding tasks.…”

“…Besides the measurement of the heart rate itself (heart rate, e.g., Solhjoo et al, 2019), some heart rate variability measures were also used in educational and psychological research, including the ratio between high frequency and low frequency components (LF/HF ratio, e.g., Minkley et al, 2018), and the time-related root mean square of successive differences (RMSSD, e.g., Minkley et al, 2018). If a person is confronted with a complex problem or task, where demands exceed their resources, the RMSSD typically decreases (e.g., Malik et al, 1996), as it represents parasympathetic activity which in turn characterizes relaxation (Laborde et al, 2017).…”

“…The aims of this study are to evaluate the convergence between subjective (self-reports on mental load and mental effort) and objective (heart rate measures LF/HF ratio, RMSSD and heart rate) measures of cognitive load (Leppink et al, 2013;Solhjoo et al, 2019) and to provide evidence for the assumed relationships between assessment factors of cognitive load, that is mental effort and mental load (Paas and van Merriënboer, 1994) and conceptually related causal factors in terms of positive and negative motivation and affect, that is self-concept, interest and perceived stress (cf. Moreno, 2010;Minkley et al, 2014;Minkley et al, 2018;Solhjoo et al, 2019).…”

“…The data come from three earlier studies, one of which (study 1) has been published elsewhere (Minkley et al, 2018), and which are secondarily analyzed for the purpose of this study. In each of the three studies, high school students participated in a one-day out of school learning project about molecular biology techniques with instructional and practical hands-on phases, aimed at identifying genetically modified food in the teaching and learning laboratory at Ruhr-Universität Bochum.…”

“…As such, cognitive load is an established construct in education and psychology, often used as a guidance to optimize instructional designs (e.g., Paas and van Merriënboer, 1994;Kirschner et al, 2006) and is considered as a control variable in assessment contexts (e.g. Minkley et al, 2018;Nehring et al, 2012). It is assumed that measures of cognitive load under various experimental conditions represent the working memory resources exerted or required during task performance.…”