Friederike Helm

Dimensional Comparison Theory

Dimensional comparison theory (DCT) defines dimensional comparisons as intraindividual comparisons that a person draws between his or her own achievements in two domains or subjects. DCT assumes that dimensional comparisons influence students’ academic self-concepts, causing stronger self-concept differences between subjects perceived as dissimilar, such as math and English, than between subjects perceived as more similar, like math and physics. However, there have been no experimental studies testing the causal effect of perceived subject similarity on domain-specific self-concepts. In the present research, three experimental studies analyzed the effects of experimentally induced higher or lower perceived subject similarity on academic self-concept differences: Study 1 (N = 351), with math and German; Study 2a (N = 148), with math and physics; and Study 2b (N = 161), with English and German, show that, in line with expectations, induced lower perceived subject similarity led to stronger self-concept differences than did higher perceived similarity. Some implications of the results for DCT are discussed.

Dimensional Comparisons and Their Consequences for Self-Concept, Motivation, and Emotion

A comparison process that is distinct from but related to social and temporal comparisons is introduced – dimensional comparison. Using an internal frame of reference, dimensional comparison entails a single individual or group comparing his or her ability in a target domain with his or her ability in a standard domain (e.g., “How good am I in math compared to English?”). Dimensional comparisons usually reduce self-concept in the worse-off domain and increase self-concept in the better-off domain. This article presents the basic principles of dimensional comparison in 10 hypotheses, covering their antecedents and their consequences for self-concept, motivation, and emotion, as indicated by introspective, path-analytic, and experimental studies.

A double-edged sword? On the benefit, detriment, and net effect of dimensional comparison on self-concept.

Dimensional comparison theory (DCT; Möller & Marsh, 2013) assumes that students compare their academic achievement intraindividually across domains to form domain-specific self-concepts. Upward dimensional comparisons are believed to lead to lower self-concepts in the worse-off domain, while downward dimensional comparisons should lead to higher self-concepts in the better-off domain. Furthermore, DCT assumes the net effect of upward and downward dimensional comparisons to be beneficial to the self. To test these assumptions, 3 experiments and 2 field studies were conducted investigating the relative effects of upward and downward dimensional comparisons as well as their net effect. In Studies 1 (N = 149), 2 (N = 150) and 3 (N = 300), participants were asked to infer self-concepts of fictitious students after receiving experimentally manipulated information about their achievements in 2 domains, whereas participants in Studies 4 (N = 2,268) and 5 (N = 20,662) assessed their own self-concepts in German and mathematics. In all studies, downward dimensional comparisons resulted in higher self-concepts, whereas upward dimensional comparisons led to lower self-concepts. The net effect of dimensional comparisons was always found to be not statistically different from zero. The findings therefore support the central prediction of DCT on the discreteness of the effects of upward and downward dimensional comparisons, yet do not support the assumed positivity of their net effect. Furthermore, results indicate the effect patterns to be rather universal as they were stable across different samples, domains, achievement situations, research designs, and types of assessment.

On the effects of social, temporal, and dimensional comparisons on academic self-concept

Students evaluate their domain-specific abilities by comparing their own achievement in a certain domain with the achievement of others (social comparison), with their own prior achievement (temporal comparison), and with their own achievement in other domains (dimensional comparison). This article is the first to analyze the simultaneous effects of social, temporal, and dimensional comparisons on students’ academic self-concepts of various domains in experimental and field studies. In Study 1 (N = 120), students judged their ability self-concept after having received experimentally manipulated social, temporal, and dimensional comparison feedback. In Study 2 (N = 924), students had to rate their math and German self-concept and were asked to directly compare their achievement to social, temporal, and dimensional comparison standards. In the longitudinal Study 3a (N = 3,054) and 3b (N = 14,008), the three types of comparisons were modeled in an extended internal/external frame of reference model (Marsh, 1986) containing paths from math and verbal achievement level and achievement change to math and verbal self-concept. In all studies, social, temporal, and dimensional comparisons showed significant effects on self-concept. For each comparison process, downward comparisons with worse-off standards resulted in higher self-concepts, whereas upward comparisons with better-off standards resulted in lower self-concepts. These results are in accordance with the theories underlying social, temporal, and dimensional comparison processes and support their integration into a combined framework.