## 2 Materials and Methods
### Experimental Material Design  
We selected the common themes present in the following 176 interface icons from the internet, primarily concerning home appliances, animals and plants, vehicles, daily necessities, etc., for experimental simulation redesign. In extracting concrete and abstract graphics based on subject content, we mainly refer to [PERSON]'s product identification theory [48]. The theory proposes that the features of a complex product should be extracted sequentially from the gestalt (the outline of the product), the shape of the high-order parts, and the low-order parts. Therefore, outline features are mainly extracted in concrete icons, while in abstract icons, attribute features are mainly extracted. Many previous studies have shown that the visual cognitive performance of icons may be affected by the following four dimensions: visual complexity, familiarity, semantic distance, and concreteness [17; 49]. The visual complexity of a graphic symbol refers to the number of zigzag lines or details it contains; those with more are considered complex, those with less are considered simple [32]. The familiarity of a graphic symbol refers to the frequency with which users use the graphic symbol. The higher the frequency, the higher the familiarity, and vice versa [50]. The semantic distance of graphic symbols refers to the proximity of the relationship. The closer the relationship is, the stronger the relationship is, and vice versa [51]. Concreteness refers to the relationship between the meanings of graphic symbols and real things. The more obvious the connection, the more concrete, and vice versa [15]. Since concreteness is related to the degree of abstraction and representation of icons, semantic distance is associated with the construal level of words. Therefore, in establishing the relationship, we try to control the visual complexity and familiarity of all icons within a specific range and choose the common daily content as the theme. The 176 themes were randomly divided into 2 groups for a redesign of the combined icons. Four student designers redesigned the icon representation part, and the text part was brainstormed by another four student designers. The 44 themes in each group consisted of a linear concrete or abstract graphic and a set of text. Line shapes and words were the same color, with RGB values of 255, 255 and 255. The outline pixels of the linear graphics were 4 px, the size was 30 \(\times\) 30 mm, and the design style was kept uniform. The text size was 15 pt. The font was Boldface, with 2-3 Chinese characters. The background color RGB values were 0, 0 and 0. A total of 176 words were matched (44 concrete graphic + 44 concrete text, 44 concrete graphic + abstract text, 44 abstract graphic + concrete text, and 44 abstract graphic + 44 abstract text). The experimental material is shown in Figure 1.  
We recruited 20 volunteers (10 males and 10 females, aged 19-26, mean = 23.1) to assess the visual complexity of 120 pairs of graphics and text (1 = very simple, 5 = very complex), familiarity (1 = very unfamiliar, 5 = very familiar), semantic distance (1 = not very closely related, 5 = closely related), and concreteness (1 = abstract, 5 = concrete). According to the scoring results, 160 graphic and text combination icons (40 for Ci + Ct, 40 for Ci + At, 40 for Ai + Ct, and 40 for Ai + At) were selected for formal experiments. As shown in Table 1, we used one-way ANOVA to analyze the evaluation results of the cognitive icon characteristics. The results show that there was no significant difference in visual complexity among the four groups of icons, with a mean of 3.13 and standard deviation of 0.725 (F (3, 159) = 0.822, \(p\) = 0.483). There was no significant difference in familiarity between the four icon groups; the mean was 3.24 and the standard deviation was 0.865 (F (3, 156) = 0.319, \(p\) = 0.812). There was a significant difference between the four icon groups in terms of the semantic distance between the abstract and concrete graphics (F (1, 158) = 36.735, \(p\) < 0.05).