The role of the lateral occipital cortex in aesthetic appreciation of representational and abstract paintings: A TMS study

Abstract

Neuroimaging studies of aesthetic appreciation have shown that activity in the lateral occipital area (LO)—a key node in the object recognition pathway—is modulated by the extent to which visual artworks are liked or found beautiful. However, the available evidence is only correlational. Here we used transcranial magnetic stimulation (TMS) to investigate the putative causal role of LO in the aesthetic appreciation of paintings. In our first experiment, we found that interfering with LO activity during aesthetic appreciation selectively reduced evaluation of representational paintings, leaving appreciation of abstract paintings unaffected. A second experiment demonstrated that, although the perceived clearness of the images overall positively correlated with liking, the detrimental effect of LO TMS on aesthetic appreciation does not owe to TMS reducing perceived clearness. Taken together, our findings suggest that object-recognition mechanisms mediated by LO play a causal role in aesthetic appreciation of representational art.

Introduction

The eighteenth century philosopher Friedrich Schiller believed that beauty had the potential to reconcile what he viewed as humans’ inherently conflicting sensual (material) and formal (spiritual) essences. The appreciation of beauty, Schiller (1895) argued, emerges from a harmonious relation between intellectual contemplation and bodily sensation, between thinking and feeling. Converging psychological and neurophysiological evidence accumulated during the last fifty years supports Schiller’s insight: aesthetic appreciation indeed involves a complex interaction among cognitive, sensorimotor, and emotional processes (Chatterjee, 2011, Chatterjee and Vartanian, 2014, Leder et al., 2004, Nadal and Skov, 2013). Neuroimaging and neurophysiological studies continue to shed light on the distributed network of brain regions that underlies aesthetic appreciation (e.g., Cela-Conde et al., 2004, Cela-Conde et al., 2009, Cela-Conde et al., 2013, Cupchik et al., 2009, Ishizu and Zeki, 2011, Kawabata and Zeki, 2004, Lacey et al., 2011, Salimpoor et al., 2013, Vartanian and Goel, 2004). However, the specific role of the component regions, and the factors that modulate their activity, require further clarification (Nadal, 2013).

Here we focus our attention on the lateral occipital area (LO). Although LO is a key region within the object recognition pathway, involved in many aspects of objects processing (for reviews, Grill-Spector, 2003, Lacey and Sathian, 2011), such as extracting shape information from both two- and three-dimensional objects (Kourtzi and Kanwisher, 2000, Malach et al., 1995), object size judgments (Eger et al., 2008, Pourtois et al., 2009), and even semantic aspects (i.e., object categorization and naming) (Eger et al., 2008), its functions may go beyond mere shape detection and object recognition. Specifically, LO is one of the brain regions whose activity has been related to aesthetic experience of visual art in neuroimaging studies (Cupchik et al., 2009, Ishizu and Zeki, 2013, Lacey et al., 2011, Vartanian and Goel, 2004). Importantly for our study, Lacey et al. (2011) found that activity in right LO correlated positively with aesthetic evaluation of artistic images. Therefore, it seems that LO activity during the viewing of artworks is not strictly related to the extraction of low-level shape/object information: it is also related to the aesthetic appreciation of an image, at least when the image is artistic, and hence more naturally fosters an aesthetic orientation (Huang et al., 2011, Kirk et al., 2009, Noguchi and Murota, 2013).

However, whether LO plays a causal role in aesthetic appreciation of art is currently not known, as available neuroimaging evidence is by definition only correlational. In this study, we aimed to address this issue by using transcranial magnetic stimulation (TMS), given that brain stimulation allows the assessment of causal links between brain activity and behavior (Pascual-Leone, Walsh, & Rothwell, 2000). Previous work has shown the potential of TMS to clarify the role of target brain regions in aesthetic appreciation. For instance, the aesthetic appreciation of human bodies is altered by applying TMS over sensory and motor brain regions (Calvo-Merino et al., 2010, Cazzato et al., 2014). In our study, we presented participants with a series of images, and asked them to indicate whether they liked each of them or not, and to further indicate the extent to which they liked them on a 1–7 Likert scale, while interfering with LO activity using TMS. The images were representational and abstract paintings. Lacey and colleagues only used representational paintings, but there is evidence that aesthetic appreciation of abstract and representational paintings may rely on at least partially different brain mechanisms (e.g., Cattaneo et al., 2014a, Cattaneo et al., 2014b, Lengger et al., 2007). Hence, if the contribution of LO to aesthetic processing is strictly related to object-recognition mechanisms, then TMS over LO should selectively interfere with the appreciation of representational but not abstract artworks, given that the latter lack all discernible object content. If, on the contrary, applying TMS to LO also decreases liking of abstract paintings, the role of LO in aesthetic appreciation must go beyond the mere processing of object information.