Robert Pepperell

Background: Our understanding of the relationship between neural activity and psychological states has advanced greatly in recent decades. But we are still unable to explain conscious experience in terms of physical processes occurring in our brains. Methods: This paper introduces a conceptual framework that may contribute to an explanation. All physical processes entail the transfer, transduction, and transformation of energy between portions of matter as work is performed in material systems. If the production of consciousness in nervous systems is a physical process, then it must entail the same. Here the nervous system, and the brain in particular, is considered as a material system that transfers, transduces, and transforms energy as it performs biophysical work. Conclusions: Evidence from neuroscience suggests that conscious experience is produced in the organic matter of nervous systems when they perform biophysical work at classical and quantum scales with a certain level of dynamic complexity or organization. An empirically grounded, falsifiable, and testable hypothesis is offered to explain how energy processing in nervous systems may produce conscious experience at a fundamental physical level.

I consider predictive processing (PP) from the perspective of an artist who also conducts scientific research into art and perception. This paper presents artworks I have made and statements from other artists that exemplify some of PP's core principles. But it also raises questions about the extent to which current applications of PP theory provide a comprehensive account of art experience. Prediction error minimization, a key mechanism of PP, has been proposed as a cause of positive aesthetic affect because artworks offer opportunities for reward through disambiguation and learning. However, there are many cases where prediction errors proliferate in art experiences in a way that enhances aesthetic affect. Here I suggest the inability of our perceptual systems to minimize prediction errors when beholding certain artworks can evoke heightened states of fascination and exhilaration. Moreover, powerful artworks provide opportunities for maximizing prediction errors, within certain bounds, by evoking states of paradox, contradiction and illogicality. I conclude that beholding such artworks can intensify our sense of being by making us more alive to the world. This article is part of the theme issue ‘Art, aesthetics and predictive processing: theoretical and empirical perspectives’.

Prior to the discovery of linear perspective in the fifteenth century, European artists based their compositions more on imagination than the direct observation of nature. Medieval paintings, therefore, can be thought of as ‘mental projections’ of space rather than optical projections, and were sometimes regarded as ‘primitive’ by historians as they lacked the spatial consistency of later works based on the rules of linear perspective. There are noticeable differences in the way objects are depicted in paintings of the different periods. For example, human figures in pre-linear perspective works often vary greatly in size in ways that are not consistent with the laws of optics. Some art historians have attributed this to ‘hierarchical scaling’ in which larger figures have greater narrative significance. But there are examples of paintings that contradict this explanation. In this paper we will consider an alternative to the hierarchical scaling hypothesis: that medieval artists used relative size to elicit empathy and to reflect the perceptual structure of imagination. This hypothesis was first proposed by the art historian Oskar Wulff, but has largely been dismissed since. We argue that artists of this period, far from being naïve, used sophisticated techniques for directing the attention of the viewer to a particular figure in a painting and encouraging them to ‘see’ the depicted space from that figure’s point of view. We offer some experimental evidence in support of this hypothesis and suggest that the way artists have depicted space in paintings has an important bearing on how we imagine and perceive visual space.

This article addresses the question of whether machine understanding requires consciousness. Some researchers in the field of machine understanding have argued that it is not necessary for computers to be conscious as long as they can match or exceed human performance in certain tasks. But despite the remarkable recent success of machine learning systems in areas such as natural language processing and image classification, important questions remain about their limited performance and about whether their cognitive abilities entail genuine understanding or are the product of spurious correlations. Here I draw a distinction between natural, artificial, and machine understanding. I analyse some concrete examples of natural understanding and show that although it shares properties with the artificial understanding implemented in current machine learning systems it also has some essential differences, the main one being that natural understanding in humans entails consciousness. Moreover, evidence from psychology and neurobiology suggests that it is this capacity for consciousness that, in part at least, explains for the superior performance of humans in some cognitive tasks and may also account for the authenticity of semantic processing that seems to be the hallmark of natural understanding. I propose a hypothesis that might help to explain why consciousness is important to understanding. In closing, I suggest that progress toward implementing human-like understanding in machines—machine understanding—may benefit from a naturalistic approach in which natural processes are modelled as closely as possible in mechanical substrates.

Slow looking is an increasingly prevalent strategy for enhancing visitor engagement in the gallery, yet there is little research to show why looking at artworks for longer should be beneficial. The curator of a recent exhibition of Pierre Bonnard at the Tate Gallery in London encouraged viewers to look slowly in order to enrich their experience of Bonnard’s paintings. This article explores some of the reasons why Bonnard’s work, in particular, rewards the viewer who spends more time studying it. The authors draw on various scientific studies of the ways in which observers process color contrasts, spatial configuration and figure-ground segregation in artworks and in everyday vision. They propose that prolonged interactions with works of art can facilitate perceptual learning, and they suggest ways in which these effects could be empirically studied using psychological methods.