This is a guest blog post by Dr Keith Wilson, Post-doctoral researcher, ‘Rethinking the Senses: Uniting the Philosophy and Neuroscience of Perception’.
The Glasgow Science Festival (GSF) showcases some the outstanding contributions made by Glasgow and Glasgow-based researchers to science, technology, engineering, maths and medicine. This year, myself and my colleagues on the Rethinking the Senses and Value of Suffering projects – both hosted at the University of Glasgow’s Centre for the Study of Perceptual Experience (CSPE) -, took the opportunity to exhibit some of the latest interdisciplinary research into the science and philosophy of perception to a public audience at GSF 2015. The result was a lively and varied mixture of activities and talks, including a film screening, that invited visitors to explore the strange and often surprising world of multisensory perception and illusions.
Whilst it might seem unusual for arts and humanities researchers to exhibit at a science festival, as one of the AHRC Science in Culture theme’s large-grant projects, Rethinking the Senses investigates the nature of perceptual experience from the perspectives of science, philosophy and the arts. In particular, we examine how the current trend towards a ‘multisensory’ approach to sensory perception can help us better understand the way in
which we experience and interact with the world. This goes beyond the traditional ‘five senses’ of vision, hearing, touch, taste and smell—a division that was familiar to Aristotle—and considers lesser known senses (e.g. proprioception, balance, pain, thermo- and mechanoreception), as well as interactions between and across the senses.
Building on the success of our earlier ‘Hidden Senses’ event, our team devised a series of fun and interactive activities that challenged the preconceptions of hundreds of Glasgow’s Kelvingrove Art Gallery and Museum visitors about what they could taste, hear, taste, see and feel as part of a weekend-long event featuring researchers from across the sciences. Amongst other things, we tested:
- visitors’ abilities to identify the ‘taste’ of sweets without using their sense of smell (very difficult since both taste and smell are required to judge flavour)
- whether or not they were ‘supertasters’ (as recently demonstrated on the BBC’s
Masterchef programme by AHRC leadership fellow Barry Smith)
- if people’s evaluation of ‘good’ and ‘bad’ smells is affected visual imagery (it is!)
- whether they could hear the difference between hot and cold liquids being poured in to a cup (you can!)
We also replicated a series of visual, auditory and tactile illusions including the waterfall illusion, the McGurk effect, and the rubber hand illusion in which sensations of touch seem to be located in a prosthetic dummy hand rather than one’s own hand, which remains concealed behind a partition. Visitors were then invited to record their experiences on an Activity Passport, the results of which will be made available via the CSPE website.
Many of the above cases involve information from one sensory modality, e.g. vision or smell, influencing another, e.g. touch or taste, thereby creating a truly multimodal experience. For instance, in the McGurk illusion, a heard phoneme /ba/ fuses with a seen lip movement /da/ to produce the experience of a third illusory phoneme /ga/. Whether the illusory sound is heard, seen, or both in combination, is an interesting and difficult question to answer since the resulting experience is partly generated by vision, and thus changes when participants close their eyes.
Increasingly, scientists and philosophers are realising that such examples are not just isolated curiosities, but illustrate important aspects of how our perceptual and sensory systems combine information from multiple sources into a single conscious experience in which it is no longer apparent which sense, or combination of senses, is operative. Indeed, whether we should think of hearing, vision or taste as distinct senses at all is one of the philosophical questions we hope to shed some light upon during the course of the project.
Science and Philosophy
In addition to the event at Kelvingrove, some of our lead investigators gave talks on the science and philosophy behind our research. These shared the Festival’s themes of food, drink, and light, the latter commemorating the 150th anniversary of the groundbreaking discoveries of Scottish physicist James Clark Maxwell. The talks were well attended, with over 150 participants signing up for Charles Spence’s ‘The Perfect Meal’ and Michael Brady’s ‘The Value of Suffering’. Impressively, there were 270 sign-ups for for the ‘Vision, Perception and Illusion’ presentation by Fiona Macpherson and Colin Blakemore.
In his ‘Vision Impossible!’ talk, RTS principal investigator Colin Blakemore discussed the great problem the brain faces in turning the light which falls upon the retinas into the rich and coherent visual experience we normally enjoy. Fiona Macpherson focused upon the philosophical nature of hallucinations and illusions, and in particular the waterfall illusion in which some subjects report the effect of illusory motion without any change in position—which would seem impossible. This being the Science Festival, Professor Macpherson asked members of the audience to record their experiences of the illusion via a questionnaire designed to test the accuracy of this description.
All in all, GSF 2015 offered a wonderful opportunity to present and communicate our research to a wider audience, and we were delighted with the warm and enthusiastic response received. As philosophers and scientists, we spend many hours debating the finer points of multisensory integration and the nature of experience. However, it’s important not to lose touch with the sense of fascination we all feel when encountering a visual illusion for the first time, or witness the surprise and wonder on a child’s face upon realising that what we call ‘taste’ is in fact largely derived from the sense of smell.
To that extent, perceptual experience is not only a problem to be studied by scientists and philosophers, but a shared feature of human experience through which we navigate and discover the world. Events like the Glasgow Science Festival give us an important opportunity to share what we’ve learned, stimulate people’s imaginations, and in turn raise public awareness of, and support for, the arts and humanities as part of the wider search for knowledge that enriches us all.