Social animals have enduring affiliative relationships (i.e., social bonds) with conspecifics. It has been reported that individuals who have strong social bonds are adaptive in terms of reproduction (e.g., Cameron, Setsaas & Linklater, 2009). Moreover, the similarity principle suggests that individuals may choose a similar group member as a partner of the affiliative interaction and start to form social bonds with him/her (de Waal & Luttrell, 1986). In fact, domestic horses (Equus caballus) build more strong social bonds with their more similar age group members (Wilds, 2019). However, it is still unclear whether horses prefer the similar age conspecifics before interacting with them. In this study, we investigated whether domestic horses show a visual preference for the same-age conspecifics by using photos of stranger horses (old age, same-age or young age) in single presentations. The participant horses’ gaze, approach, and touch behaviors toward the photos did not change regardless of the stranger horse’s age. These results suggest that domestic horses do not show a visual preference for the same-age conspecifics without any interactions with them.

Speech-to-text interpreting is a peer-supporting activity by student supporters to transcribe in-class audio information into words immediately to provide deaf and hard-of-hearing students. The present study aimed to measure relationship between experience of speech-to-text interpreting and working memory capacity. Specifically, we hypothesized that working memory capacity（WMC）of experienced supporters should be higher relative to that of inexperienced. We used Reading Span Test（RST）and Listening Span Test（LST）to measure to WMC in 16 experienced and 12 inexperienced student supporters and conducted a three-way ANOVA. The results did not support the hypothesis in that the RST scores of inexperienced students were higher relative to those of experienced. However, the LST scores supported the hypothesis. We speculate that the present RST results did not support the hypothesis because of（1）dissimilarity between the test material and the support activity,（2）increased number of strategies due to greater difficulty in RST relative to LST, and（3）decreased motivation of experienced participants. Given the finding that experienced participants yielded higher LST scores，LST may predict performance in speech-to-text interpreting activities.