Methods

In total, 483 respondents were recruited through a web-based panel in China. The mean age of the participants was 28.8 (SD 8.84) years. A majority of participants self-identified as female (n= 300, 62.1%). We used a 2 (text-based emotion design: yes vs no) by 2 (icon-based emotion design: yes vs no) between-subjects factorial experimental design. Participants were asked to imagine they had abdominal pain and then consult a prediagnostic chatbot online. The participants were randomly assigned to one of the four conditions. They were shown a screenshot of a conversation with the chatbot. After viewing the screenshot, participants were asked to answer a series of questions about perceived emotional intensity, psychological distance, and behavioral intention (see Multimedia Appendix 1).

Results

The results of a 2-way ANOVA showed that both icon-based (mean icon 4.15, SD 1.41; mean no 3.62, SD 1.44; F 1,479= 14.4; P<. 001; η 2= 0.03) and text-based designs significantly enhanced the perceived emotional intensity (mean text 4.35, SD 1.38; mean no 3.46, SD 1.40; F 1,479= 51.2; P<. 001; η 2= 0.10). H1 was therefore supported. Furthermore, we observed an interaction effect between icon-and text-based designs (F 1,479= 7.96; P=. 006; η 2= 0.02). In particular, when text-based designs were not used, icon-based designs increased the emotional intensity (mean icon 3.87, SD 1.39; mean no 3.05, SD 1.26; F 1,243= 23.2; P<. 001; η 2= 0.09). However, when text-based designs were used, the effect of icon-based designs disappeared (mean icon 4.41, SD 1.40; mean no 4.29, SD 1.35; F 1,236= 0.45; P=. 50; η 2= 0.002). These findings were consistent with H2.