ESPP 2014 Symposium Abstract
Session 1: Perspectives on audio-visual interactions
Until recently research into sensory perception has focused on unisensory perception, and, in
particular, on vision. There has, however, been mounting awareness of the fact that our perceptual
systems are presented with multiple different sensory signals at any one time. This allows for the
possibility of multisensory interactions, where input from one sensory system has an influence on
what one perceives in another modality. So, for example, visual input can influence auditory
perception, a well-known example of this being the Ventriloquism Effect in which there is visual
capture of auditory location. So too, auditory input can exert an influence over visual perception.
For audio-visual interactions to occur the perceptual system must solve the problem of ascertaining
which signals pertain to the same object, and hence should be combined or bound together, and
which signals pertain to different objects, and hence should be segregated or kept apart. This is the
crossmodal binding problem. There is evidence that spatial, temporal and semantic congruence can
influence crossmodal binding and hence support audio-visual interactions. But there has also been a
suggestion that there are other kinds of matches—crossmodal correspondences between what
appear to be different kinds of stimulus features such as pitch & spatial elevation and loudness &
brightness—that also influence crossmodal binding. One important question to consider, in
understanding the conditions necessary for audio-visual interactions, is whether stimulus features
are in fact non-redundant in the way we might intuitively take them to be. This symposium will
examine this issue from different psychological, developmental, and philosophical perspectives.
Merle Fairhurst and Ophelia Deroy
The space of music: pitch, and other auditory dimensions
Yi-Chuan Chen, Gert Westermann, and Charles Spence
Development of audiovisual associations: nature or nurture?
Malika Auvray and Ophelia Deroy, Irène Fasiello and Vincent Hayward
Crossmodal correspondences between pitch and tactile movement in sighted, early, and late blind
people
Matthew Nudds and Alisa Mandrigin
Auditory perception and audiovisual interactions
Session 2: Individuating the Senses
Fiona Macpherson and Keith Wilson
Orthonasal and Retronasal Olfaction: One Sense or Two?
We discuss problems for the standard four ways of individuating the senses using the criteria of
representation, phenomenal character, proximal stimulus and sense organ. We argue that if we
reject a sparse view of how many senses there are or could be, according to which there is a small
number of discrete senses, then one can use these criteria all together to form a fine-grained
taxonomy of types of senses. We then examine the implications of such an approach for
individuating the smell, which has been labelled a ‘dual sense’ by Rozin (1982), following Gibson
(1968), due to its role in identifying externally located objects and contributing to the experience of
flavour in the mouth. We review the empirical evidence for the existence of dual olfactory type- or
token-senses, and the implications of this issue for creating a taxonomy of the senses and
multisensory interactions more generally.
Ophelia Deroy and Barry Smith (in absentia)
The Place of Olfaction in Conscious Experience
What role does olfaction play in our conscious lives? Smell seems to go missing in everyday
experience: many people claim to be unaware of smells until they deliberately sniff at things in the
immediate environment. On the other hand we smell because we breathe and we are constantly
bombarded by thousands of volatile molecules, and these odours can have an impact on our mood,
behaviour and food choices. So are smells in consciousness though we are not aware of them (or of
smelling things); do they go in and out of consciousness dependent on a shifting threshold; or are
they unrecognised as such because they provide a background to consciousness? Answering these
questions has consequences for how we should understand the modality (or modalities) of olfaction.
Colin Blakemore and Yuanyuan Zhao
What makes seeing different from hearing?
One of the reasons why philosophers are exercised about the number and individuation of human
senses is the distinctive subjective signature of each of our major senses. Consider vision: we know
from single-neuron recording in animals and neuroimaging studies in humans that different aspects
of visual experience (form, colour, motion, depth etc) are processed by different classes of neurons,
even in different parts of the cerebral cortex. Yet they are all indubitably visual in their ‘feel’.
Although these various components of a visual experience differ in subjective character, they share
the quality of being visual – never (or so it feels) to be confused with the experiences that constitute
hearing, touch, smell etc.
We are interested in the neural basis and the certainty of perceptual distinction between modalities.
We are testing whether the ability to distinguish visual and auditory stimuli is maintained close to the
threshold of forced-choice detection, where stimuli are not sufficiently intense reliably to trigger
conscious experiences.
What could be the neural representation of subjective modalities? Given the interest in the ‘neural
correlate of consciousness’ it is surprising that this question has attracted little interest from
neuroscientists. We consider three possible neurophysiological accounts of modality distinction:

The modality of experience is simply determined by which particular neurons carry the
signals. For instance, Ewald Hering proposed that an innate ‘retinal local sign’ determines the
perceived spatial location of a visual stimulus.

The modality is encoded in the temporal pattern of impulses in sensory neurons. Johannes
Müller’s original formulation of the Law of Specific Nerve ‘Energies’ is of this type.

The modality experienced is somehow imposed on perceptual representations by a ‘topdown’ process.
We shall review these hypotheses. Unfortunately there is contrary evidence for each of them.
This session is followed by a panel discussion (30 minutes).