Philosophy, Psychology and Neuroscience Research Seminars 2014/15
|Monday 13 October 2014*||
Frank Durgin (Psychology, Swarthmore)
Commentator: Alisa Mandrigin (Philosophy, University of Warwick)
|Wednesday 15 October 2014||
Frank Durgin (Psychology, Swarthmore)
Note: This talk will take place in the Murray Room, Level 4, 65 Oakfield Avenue.
|Monday 20 October 2014||
Robert Audi (Philosophy, Notre Dame)
Commentator: Anna Bergqvist (Philosophy, MMU)
|‘Normativity and generality in ethics and aesthetics’|
|Monday 24 November 2014*||
Colin Blakemore (Neuroscience, Institute of Philosophy, London)
|‘What has science ever done for perception?’|
|Monday 16 February 2015||
John Heil (Philosophy, Washington University in St Louis)
Commentator: Neil McDonnell (Philosophy, Glasgow)
|‘Emergence and panpsychism’|
|Monday 16 March 2015*||
Bob Kentridge (Psychology, Durham)
Commentator: Keith Allen (Philosophy, York)
|‘Colour sensation and colour perception’|
|Monday 20 April 2015*||
Charles Spence (Psychology, Oxford)
|‘Cross-modal correspondences: Looking for links between sound symbolism and synaesthesia, and their application to multisensory marketing’|
|Monday 11 May 2015||
Adam Zeman (Psychology, Exeter)
|‘The Eye’s Mind’|
*Talk sponsored by the AHRC Rethinking the Senses Project.
For a list of previous speakers, see Philosophy of Mind and Psychology Research Seminar.
‘The angular expansion hypothesis of locomotor space perception’
The conscious perception of locomotor space (or action space) seems to be greatly distorted (ground distances appear much shorter than they are; hills look much steeper than they are, etc.) yet perception provides the basis for excellent control of action. Could large and systematic distortions in perceived locomotor space be for the purpose of action control? As a rough analogy, note that perceptual sensitivity trumps perceptual accuracy in the control of action – or watchmakers wouldn’t use magnifying glasses. I will review a large body of evidence suggesting that many well-documented and systematic biases in the perception of locomotor space arise from an angular coding scheme that may provide more efficient motor specification and/or feedback sensitivity for the control of action. Two interesting characteristics of the theory are that (1) its development is based on parameter measurement rather than null-hypothesis testing, and (2) much of the data used in support of the theory was collected or replicated by other labs before the theory was proposed. The critical new empirical observation of the theory is that while angular variables, like egocentric direction, are fundamental to action control, they are grossly and systematically distorted in spatial perception. This observation is sufficient to explain a great deal of historical data. The critical new theoretical observation is that stable distortions of this sort may be quite useful for action.
The use of the scientific method in the study of conscious perceptual experience is intended to prevent it from becoming a tumbling ground for whimsy. Taking perceptual experience seriously can be a very productive scientific enterprise, but the distinction between measurable perceptual bias and experimental artefact or publication bias has often been strikingly hard to pin down. Here I will review some of the empirical observations that have led a number of researchers to question the merits of whole classes of claims that have been splashing across the pages of prominent journals. Based on my own work, I will emphasize the explanatory advantages of the participant compliance (or demand characteristic) account of several otherwise strange and surprising findings that are ostensibly perceptual. But I will also place this type of basic psychological explanation of these kinds of findings within a broader theoretical context of systematic confirmation bias in psychological science. That is, ongoing crises concerning statistical hypothesis testing in psychology, the concomitant crisis concerning replication, and the ever-present risk of scientific “truthiness” encouraged by a rational cost-benefit analysis of selection bias in journals ought all be relevant factors in the evaluation of the recent flood of claims regarding the strangely metaphorical embodiment of perception.
‘Normativity and generality in ethics and aesthetics’
Moral properties such as being wrong or being obligatory are not brute but based on other kinds of properties, such as being a lie or being promised. Aesthetic properties such as being graceful or being beautiful are similar to moral properties in being based on other kinds of properties, but in the aesthetic cases it may be impossible to specify just what these grounding properties are. Does any single property ground poetic beauty in the way promising grounds obligation to do the promised deed? If aesthetic properties do differ from moral properties in this way, may we conclude that, although ethics is like aesthetics in being a realm of intuitive and perceptual knowledge—or at least intuitive and perceptual sensitivity—it is unlike aesthetics because the latter lacks principles that connect grounding properties with aesthetic properties? Are there any such generalities in aesthetics, or even aesthetic generalities connecting aesthetic properties with other aesthetic properties? If there are, how much like or unlike rules and principles in ethics are they? This paper explores all these questions in the light of examples from the arts, with poetry as the main case study.
‘What has science ever done for perception?’
Sensory physiology and psychology have made important contributions to our understanding of perception, but there remain deep unsolved questions. I shall start with two assumptions: 1) the high metabolic cost of impulses puts value on elimination of redundancy and on sparse coding; 2) genetic mechanisms and experience-dependent plasticity contribute to the creation of stimulus selectivity in sensory neurons. These principles are essential the same as two of the dogmas of Barlow’s (1972) classic neuron doctrine for perceptual psychology. However, I shall question two other dogmas of Barlow—that impulse rate indicates only the certainty that the preferred feature is present; and that the content of perception is not dependent on combinatorial rules of usage of nerve cells.
The encoding properties of low-level sensory neurons are always are essentially ambiguous, in the sense that variation of the stimulus along many dimensions leads to variation in the probability of impulses. Hence there is no feature whose presence could be unambiguously signalled by impulses in such a neuron. It follows that disambiguation involves comparison of signals in several neurons, either explicitly, through convergence on to a shared target neuron, of by some other mechanism for comparing the activity of different neurons. I shall argue that one of the functions of non-primary sensory areas in the cortex of higher mammals is to make explicit the spatial and temporal relationships between the activity of separate neurons in the primary area. An interesting question is whether all the discriminable aspects of a sensory experience correspond to such explicit encoding.
Sensory receptors, and the central neurons that receive signals from them, have evolved to provide organisms with information that is useful in guiding their behaviour. ‘Information’ must be defined not only mathematically, but it terms of behavioural significance. Any biological interpretation of sensory processing would, then, emphasise the value of its conclusions—reverse-engineered, inductive inferences about the nature of things and events in the outside world (and within the animal). In those terms it is not at all surprising that perception is multisensory: integration of information from different senses can provide more reliable evidence about the location and nature of events. What is surprising is that we are aware of the raw, unimodal elements of experience (Block’s phenomenal consciousness; qualia), which don’t seem to matter in terms of behaviour. If I spot a ripe strawberry and pick it, what matters is the knowledge that it is a strawberry and that it is ripe. Activation of red-catching cones in my retina helps me with that identification, but why do I need to experience the redness directly?
What is even more remarkable, given the evident mingling of sensory information, is how robust the phenomenal awareness of the modality of experiences seems to be. Recently, Yuanyuan Zhao and I have been testing the apparent robustness of the modal ‘tagging’ of sensory experience. In detection tasks in which the stimulus is either a flash of light or a sound beep, in random sequence, there is, surprisingly, no difference in threshold or certainty of awareness for each modality compared with control experiments with stimuli of only one modality. And, even more surprising, the modality can be identified more reliably than the stimulus can be detected. Observers are remarkably reliable at identifying the modality of a stimulus, even when they are unsure that they have had a sensory experience.
From a functional perspective, why should I be so distinctly aware that the shape, colour and location of a strawberry are visual experiences, while its odour is an olfactory experience, when both help me to identify it as a strawberry?
Even though different components of a visual experience (shape, colour, motion, depth etc) seem to depend on explicit representation in different regions of extrastriate visual cortex, they all share the same modal sense of being visual. Since virtually all visual signals arrive at the primary visual cortex (V1) and are then distributed to extrastriate regions, is it possible that the awareness of modality ‘arises’ in V1, even if the content of experience depends on explicit representation in the activity of neurons outside V1.
- Barlow, H. B. (1972), ‘Single units and sensation: a neuron doctrine for perceptual psychology’, Perception 1: 371–94
- Pennartz, C. M. A. (2009), ‘Identification and integration of sensory modalities: neuronal basis and relation to consciousness’, Consciousness & Cognition 18: 718–93
John Heil (Washington University in St. Louis)
‘Emergence and panpsychism’
The paper examines an argument sometimes used to support panpsychism. Qualities of complex objects are explained in two ways. First, as in the case of mass, wholes have some characteristic because their parts do. Second, as in the case of liquidity, characteristics of wholes are not characteristics of their parts but ‘emerge’ intelligibly from characteristics of those parts. We lack an intelligible story as to how conscious qualities could emerge in assemblages of parts that themselves lack such qualities. Therefore, either the fundamental particles (or some of them) have conscious qualities or consciousness is wholly mysterious. The paper calls this line of reasoning into question and suggests that its plausibility rests on largely unexamined assumptions that should be rejected.
Bob Kentridge (University of Durham)
‘Colour sensation and colour perception’
The visual system might exploit variations in the wavelength of light for a number of purposes. We most often think of wavelength as something that allows us to attribute particular colours to objects. Boundaries between regions of a scene with different wavelength composition might also contribute to the process of segmenting objects from their backgrounds independently from the perception of object colour. I will question whether either of these aspects of wavelength processing are necessarily associated with having an experience of colour. I will review work on the neurological condition of cerebral achromatopsia with respect to border processing and the perception of form from colour (e.g. Kentridge et al., 2004, Neuropsychologia 42 821–30) and more recent work on colour constancy and masking with respect to the perception of surface colour (Norman et al., 2014, Current Biology 24 2822–6).
Charles Spence (University of Oxford)
‘Cross-modal correspondences: Looking for links between sound symbolism and synaesthesia, and their application to multisensory marketing’
“Are lemons fast or slow?”; “Is carbonated water round or angular?” Most people agree on their answers to these questions. These are examples of correspondences, that is, the tendency for a feature, in one sensory modality, either physically present, or merely imagined, to be matched (or associated) with a feature, either physically present, or merely imagined, in another modality. Crossmodal correspondences appear to exist between all pairings of senses, and have been shown to affect everything from people’s speeded responses to their performance in unspeeded psychophysical tasks. While some correspondences are culture-specific (e.g., the correspondence between angularity and bitterness), others are likely to be universal (e.g., the correspondence between auditory pitch and visual or haptic size, for example). Intriguingly, some animals (e.g., chimpanzees), as well as young infants, appear to be sensitive to certain crossmodal correspondences. In this talk, I will discuss a number of the explanations that have been put forward to account for the existence of crossmodal correspondences. I will also examine the relationship between crossmodal correspondences and sound symbolism, and tackle the thorny question of whether crossmodal correspondences should be thought of as a kind of synaesthesia that is common to us all. Finally, I will highlight some of the latest marketing applications that are now emerging from basic research on crossmodal correspondences in the design of everything from beverage labels through to the music you listen to while drinking your coffee (or cognac), and the dishes that are starting to appear at modernist restaurants.
- Spence, C. (2011). ‘Crossmodal correspondences: A tutorial review’. Attention, Perception & Psychophysics, 73, 971–95
- Spence, C. (2012). ‘Managing sensory expectations concerning products and brands: Capitalizing on the potential of sound and shape symbolism.’ Journal of Consumer Psychology, 22, 37–54
- Spence, C. (2012). ‘Synaesthetic marketing: Cross sensory selling that exploits unusual neural cues is finally coming of age’. The Wired World in 2013, November, 104–7
Adam Zeman (University of Exeter)
‘The Eye’s Mind’
Imagination is one of the most distinctively human intellectual capacities. It is multifaceted, but the ability to call images to the mind’s eye, to ‘visualise’ is an important element. Cognitive neuroscience is beginning to reveal the neurological basis of visualisation, complementing an older literature on the effects of brain damage on the capacity to visualise. The possibility that some people may never acquire this capacity was raised by Francis Galton, but remains rather poorly explored. I will introduce current thinking about the neural processes that underlie visualisation, and ask how they may help to explain cases of congenital or acquired ‘aphantasia’, one of the topics of our current AHRC-funded Science in Culture Innovation Award.