Haiku poetry is the world’s shortest poetic form and includes 5-7-5 morae and a seasonal word (Iida, 2008). In a haiku, one or two images are composed and a breakpoint, called a kire (cut), is efficiently used to integrate them (Blasko & Merski, 1998). While the Japanese are naturally comfortable with the 5-7-5 rhythm (Niikuni et al., 2022), rhymes are not common in haikus. Owing to its controlled format and clear rules, haiku poetry can potentially explore the frontier of verbal art, which has many unexplored elements compared with accumulated research in visual and auditory arts (cf., micropoems) (Hugentobler & Lüdtke, 2021; Jacobs, 2015). Empirical studies have examined how poetry has been aesthetically appreciated, both regarding cognition and emotion (Hitsuwari & Nomura, 2024; Johnson-Laird & Oatley, 2022; Obermeier et al., 2016; Pițur & Miu, 2022; Wassiliwizky et al., 2017). Similarly, haiku poets have suggested a relationship between the emotions and cognition evoked by a haiku’s beauty (Kishimoto, 2008). Some recent empirical studies have examined this relationship. Regarding emotions, positive (Belfi et al., 2018; Hitsuwari & Nomura, 2022a) and mixed emotions, such as awe and nostalgia, (Hitsuwari & Nomura, 2022b) explain the beauty. Regarding cognition, imagery vividness explains the aesthetic appeal of haiku (Belfi et al., 2018; Mehl et al., 2023). Furthermore, cognitive ambiguity reduces their appeal (Hitsuwari & Nomura, 2022b). However, these results contradict the high evaluation of grief haiku (Imase et al., 2010) and importance of ambiguity in haiku and poetry (Nitta, 2016; Wallot & Menninghaus, 2018). These findings are insufficient since negative emotions (Menninghaus et al., 2017) and resolution of ambiguity (Muth & Carbon, 2013) contribute to aesthetic experiences in visual and auditory arts. Consideration of the processes involved in alleviating negative emotions, as well as increment of positive emotions and resolution of ambiguity that explain a haiku’s uniqueness and its commonality with previous findings, is required. Therefore, this study aimed to provide a deeper understanding of the beauty of haikus and focused on the process of emotional and cognitive changes during appreciation.
Several process models of emotion and cognition during art appreciation have been developed (Leder & Nadal, 2014; Leder et al., 2004; Menninghaus et al., 2017; Pelowski et al., 2017). In Menninghaus et al.’s (2017) model, negative art appreciation could be enhanced by an ''embracing'' component that enhanced art appreciation via positive integration and incorporation of the power of the negative emotions. Therefore, the interactions between positive and negative emotions and role of mixed emotions were highlighted. This suggests that changes in negative and positive emotions are important in an art experience. Another process model (Pelowski et al., 2017) stated that viewers could make several interpretations and thoughts when there was low relevance to the self and low schema consistency in the top-down cognitive process. As individuals continue to view an artwork, they encounter information that resolves discrepancy and may lead to insight with aesthetic evaluation. Supporting this process, experiments have captured the association between ambiguity and beauty at more than one time-point. Muth and Carbon (2013) presented ambiguous images repeatedly for 500 ms each and asked participants to repeat their liking and clarity ratings. They found that the largest increase in liking occurred immediately after the resolution of ambiguity (i.e., insight). Thus, paying attention to the emotional and cognitive changes in art appreciation is important. The impact of these changes on beauty can be examined by evaluating haiku poems with a clear 5-7-5 structure. Haiku is ideal to examine this process owing its controlled shortness; however, expected results could be extended to other poetic forms and art genres.
We examined the abovementioned emotional and cognitive change processes and asked participants to evaluate the haiku in lines 1, 2, and 3 one-by-one while a more precise method to measure the change processes was introduced. Emotional processes, such as the perception and expression of emotional states and social signaling, could be acquired by manipulating joysticks (Girard & Wright, 2018; Sharma et al., 2020). Although a flourishing approach in studies on the aesthetic appreciation of temporal art, especially music (Bachorik et al., 2009; Grewe et al., 2007; Nagel et al., 2007), the continuous self-rating of spoken poetry does not affect physiological responses or post-appreciation ratings. Hence, this type of continuous rating during appreciation is also possible in poetry (Wagner et al., 2021). In this study, participants reported their emotions on two dimensions, valence and arousal, via a joystick as the haiku was gradually presented. These dimensions were also used in previous studies (Bliss-Moreau et al., 2020; Russell, 1980; Sharma et al., 2020 for practical examples using joysticks).
Additionally, eye movements were compatible with continuous response, such as joysticks, and included features of temporality and unconsciousness. This methodology was also accumulated in verbal art fields, such as poetry (Blohm et al., 2022; Menninghaus & Wallot, 2021; Scheepers et al., 2013). In particular, studies used haiku and eye-movement measurements and revealed that people appreciated haiku differently based on the presence and position of the kire (cut) and type of haiku (Geyer et al., 2020; Hermann et al., 2017). A study compared haikus and slogans, with the same 5-7-5 syllable structure, and found that the pupil diameter was larger when haiku was viewed as aesthetic poetry compared with viewing slogans (Niikuni et al., 2022). Although pupil diameter was positively related to aesthetic evaluation in other art genres, such as painting and music (Kuchinke et al., 2009; Laeng et al., 2016), the relationship is more complex in haiku. One study reported no correlation (Spee et al., 2024). Therefore, this study measured pupil diameter as a supplementary measure, in addition to gradual haiku rating and joysticks.
Extending on previous studies that only captured cognition and emotion at a single timepoint during poetry appreciation, this study aimed to examine the multidimensional effects of changes in cognition and emotion on haiku evaluation and combined haiku ratings in steps, continuous ratings via a joystick, and pupil diameter measurements. In particular, increased positive emotion and arousal and decreased negative emotion and emotional/cognitive ambiguity during haiku appreciation could lead to beauty. Furthermore, dynamic changes in emotions during haiku appreciation could be captured via joysticks for the first time. Simultaneously, changes in pupil diameter, as an exploratory measure of aesthetic evaluation, would be positively related to beauty.