It has been assumed that shapes are related to various personality traits. In a classical study, Lundholm (1921) reported that angular lines were more likely to be associated with traits such as hard, harsh, and cruel and curved lines were more likely to be associated with traits such as weak, gentle, and mild. Other studies (Berlyne, 1960, 1974; Zhang, Feick, & Price, 2006) showed that angular shapes were associated with traits that expressed energy, toughness, and strength, whereas rounded shapes were related to traits that expressed approachability, friendliness, and harmony. Jiang, Gorn, Galli, and Chattopadhyay (2016) found that circular brand logos activated softness, whereas angular brand logos triggered hardness. More recent research has indicated round-warm and square-competent associations. Liu, Bogicevic, and Mattila (2018), for instance, investigated the role of the shapes of displays in a restaurant on customer satisfaction and suggested that in busy settings, angularly shaped cues increased their satisfaction by perceiving competence of the service provider. On the contrary, in non-busy settings, circularly shaped cues enhanced their satisfaction via the perception of warmth of the provider. Okamura and Ura (2018a) confirmed that round eyeglasses increased the perception of warmth and square eyeglasses enhanced the perception of competence. Okamura and Ura (2018b) examined the influence of drawing circles or squares on impressions of the interpersonal environment and demonstrated that drawing circles resulted in warmer impressions, whereas drawing squares resulted in more competent impressions. Moreover, these associations have been found not only in the perceptions of others but also in the self- perception (Okamura & Ura, 2017).

The round-warm and square-competent associations are also supported by conceptual metaphor theory (CMT; Lakoff & Johnson, 1980), which explains that abstract concepts (e.g., personality) are mapped onto concrete concepts such as shapes in human cognition. In fact, personalities are expressed by the words for shapes (e.g., round off one's corners; be there or be square). Kövecses (2005) suggested that actual linguistic metaphors were expressions of conceptual metaphors. Therefore, it is reasonable to assume that shapes and personality traits are associated. Such concrete-abstract associations have been documented by a growing body of research (see the review of Landau, Meier, & Keefer, 2010). At the same time, the correspondence between concrete concepts derived from different sensory modalities has been found in cross-modal processing (Spence, 2011). For example, Guéguen and Jacob (2014) showed that a red cup was evaluated as containing the warmest beverage through the association between color and physical warmth. Moreover, Blazhenkova and Kumar (2018) demonstrated nonarbitrary shape correspondences between angular, or curved shapes, and attributes of the five senses such as vision, audition, gustation, olfaction, and tactile sensation. The mechanisms that underlie cross-modal correspondences are still to be identified (Velasco, Woods, Marks, Cheok, & Spence, 2016). However, one possible explanation could be that the round shape is related to the estimation of physical warmth.

Based on these findings, the purpose of the current study was twofold. First, it was attempted to replicate and extend the knowledge on the round-warm and square-competent associations in a study designed to overcome a significant weakness of previous research. Various studies on embodied cognition (some of them are described below) have demonstrated the influence of sensations on cognitions and behaviors by focusing on opposite sensations such as warmth and coldness, or softness and hardness. However, these studies manipulated only one of the two opposing sensations, and therefore, it is difficult to conclude which sensation influenced higher order processing. For instance, Jostmann, Lakens, and Schubert (2009) found that participants that held a resume with a heavy clipboard judged the applicant to be a more important person. The authors suggested that the metaphor-consistent effect in this process is “IMPORTANCE IS HEAVY”. However, it is also possible to construe the process in the reverse direction, such that participants holding a light clipboard judged the applicant to be less important. Such construal variations result from not setting a strict control condition. Various studies of embodied cognition contain the identical problem (e.g., Meier & Robinson, 2004; Williams & Bargh, 2008). The studies on the influence of shape priming on personality judgments have not resulted in any conclusions as to whether the round shape increases warmth perception or decreases competence perception or vice versa. Moreover, Honmoto, Yamamoto, and Sugamura (2014), for example, argued that a control condition with the medium temperature determined by using a thermometer is needed to control for the two experimental conditions of warmth and coldness in studies on the sensation of warmth. The current study was conducted with a pre-post design to investigate the direction of the influence to solve the problem of the experimental manipulation. It was hypothesized that a round shape would increase the warmth perception and a square shape would enhance competence perception through metaphorical associations.

The relationships between round shapes and warmth as a personality dimension, as well as physical dimension, were also examined. As mentioned above, round shapes are assumed to be associated with a warm personality. Moreover, Hu, Li, Jia, and Xie (2016) reported that behaving altruistically to others led to an increase in the estimate of physical warmth, suggesting the conceptual metaphor “SOCIAL WARMTH IS PHYSICAL WARMTH”. Taken together, these findings suggest that warmth as a personality variable, which is an abstract concept, could be associated with both round shapes and physical warmth, which are concrete concepts. It was hypothesized based on past research that the perceived warmth of the personality would mediate the relationship between round shapes and the estimate of physical warmth.

Method [TOP]

Results [TOP]

An exploratory factor analysis of the responses to the 16-item, Warmth-Competence Scale, was conducted using maximum likelihood estimation and Promax rotation. According to the authors’ theoretical perspective, it was assumed that the factor-structure of the scale would consist of two dimensions; warmth and competence. The results indicated a good fit to the data, χ²(89) = 221.52, p < .001, CFI = .92, RMSEA = .08, AIC = 290.63. The two dimensions that were identified were interpreted as competence (α = .86) and warmth (α = .89). Of the 16 items of the scale, warmth and competence were each assessed by 8 items. Then, it was conducted a 2 (shape: round/square) × 2 (phase: pre-evaluation/post-evaluation) × 2 (dimension: warmth/competence) analysis of variance (ANOVA) with the shape of the eyeglasses as a between-participants factor, and phase and dimension as within-participants factors. The results indicated a main effect of phase, F(1, 119) = 101.09, p < .001, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .46, indicating that the participants recognized their characteristics more deeply in the post-phase (M = 3.67, SE = 0.05) compared to the pre-phase (M = 3.04, SE = 0.04). A three-way interaction, F(1, 119) = 7.36, p = .008, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .06, and a two-way interaction between shape and phase, F(1, 119) = 6.71, p = .011, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .05, and phase and dimension, F(1, 119) = 13.93, p < .001, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .11, respectively were also observed. Simple interaction effects were found between shape and phase, F(1, 238) = 3.93, p = .049, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .03, shape and dimension, F(1, 238) = 13.46, p < .001, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .10, and phase and dimension, F(1, 119) = 19.95, p < .001, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .10. A simple-simple main effects test revealed that participants in the round condition (M = 3.78, SE = 0.10) judged themselves as warmer than those in the square condition (M = 3.39, SE = 0.10) in the post-phase, F(1, 476) = 8.59, p = .004, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .07. Moreover, the participants in the square condition (M = 3.90, SE = 0.10) evaluated themselves as more competent than in the round condition (M = 3.59, SE = 0.10) in the post-phase, F(1, 476) = 5.05, p = .025, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .04.

A one-way ANOVA was also conducted with eyeglass shape as the independent variable and the estimated value of the room temperature as the dependent variable. The ANOVA indicated that the participants in the round condition (M = 18.32, SE = 0.40) estimated the room temperature to be higher than those in the square condition (M = 17.00, SE = 0.41), F(1, 119) = 5.27, p = .023, ${\mathrm{\eta }}_{\mathrm{p}}^2$ = .04. A one-sample t-test was also conducted to examine differences between the actual temperature (20.5°C) and the estimated temperature, which indicated significant differences in the two conditions, the round condition: t(62) = 5.72, p < .001, the square condition: t(57) = 8.12, p < .001.

Finally, a statistical mediation analysis (MacKinnon, 2008) was conducted with eyeglass shape as the independent variable, room temperature as the dependent variable, and estimated perception of warmth or competence perception about themselves as the mediator to test for direct or indirect relationships between shape, warmth and competence perception, with physical temperature. This indicated that shape was significantly related to the temperature (warmth: β = -.22, p = .039, competence: β = -.19, p < .043), whereas the perception of personality was not (warmth: β = -.04, ns, competence: β = -.11, ns).

Discussion [TOP]

The results confirmed the first hypothesis that the round shape increased perceptions of warmth and the square shape enhanced perceptions of competence. This finding corroborated previous research (Liu, Bogicevic, & Mattila, 2018; Okamura & Ura, 2018b) by reinforcing the association: round-warm, square-competent.

However, the second hypothesis that the perceived warmth of the personality would mediate the relationship between the round shapes and the estimate of physical warmth was not confirmed by this study. Therefore, it is suggested that the round shape is directly connected to physical warmth. This is the first study to demonstrate cross-modal correspondences between shapes and physical warmth. The mechanism that underlies the metaphor-consistent effects of round-warm and square-competent associations is incompletely understood to date. The two possible explanations are showed hereby. One is Pinna (2011)’s explanation that round shapes may be a signal of warmth because the shape of the sun is round. Namely, the round shape is present in nature such that it is metaphor-consistent with warmth. On the contrary, square shapes are a consequence of the way in which four segments fit together, according to Gestalt principles of grouping and organization. Namely, they are a human invention and purely the creation of the human mind. Such images of these shapes are assumed to be the origin of the metaphorical associations.

The other is that the association is embodied. CMT refers to how abstract concepts such as psychological warmth or competence are grounded in physical constructs such as shapes or temperature. When we are embraced by our parents in our early childhood and feel psychological warmth, we simultaneously feel physical warmth (IJzerman & Semin, 2009). Thus, the association between physical and psychological warmth is based on the co-occurrence. It is possible that the association between roundness and physical warmth comes from the same parent-child experiences. For instance, being held by mothers brings some gentle and soft sensual experiences which are definitely closer to round shapes (e.g., breasts) than the square ones which can be dangerous with their sharp corners. Future research should shed light on this matter.

In conclusion, the results of the present study indicate that the round shape enhances the perception of warmth and the square shape increases the perception of competence. Moreover, the study demonstrates cross-modal correspondences between shapes and physical warmth.