Sensory substitution devices (SSDs) are most familiar from their use with subjects who are deficient in a target modality (e.g. congenitally blind subjects), but there is no doubt that the use and potential value of SSDs extend to persons without such deficits. Recent work by Amedi and his team (in particular Levy-Tzedek et al. 2012) has begun to explore this. Their idea is that SSDs may facilitate behavioural transference (BT) across sense modalities. In this case, a motor skill (...) learned through visual perception might be subsequently employed in response to auditory perception, using an SSD as a mediator. They infer from the existence of such BT that the learned skill is amodally represented. After a brief overview I identify ways to more fully test for BT within this experimental paradigm and argue that their conclusion about amodal representation is premature. Additionally, I argue that their preferred SSD (Eyemusic) is of limited value for the project. While my remarks are critical, my intention is to be constructive, particularly in light of the fact that Levy-Tzedek et al. (2012), is, I believe, the first output from Amedi's lab concerning this line of research. (shrink)

What if a blind person could 'see' with her ears? Thanks to Sensory Substitution Devices (SSDs), blind people now have access to out-of-reach objects, a privilege reserved so far for the sighted. In this paper, we show that the philosophical debates have fundamentally been mislead to think that SSDs should be fitted among the existing senses or that they constitute a new sense. Contrary to the existing assumption that they get integrated at the sensory level, we present (...) a new thesis according to which they are not sensory, and get vertically integrated on the top of existing sensory abilities, from which they should be theoretically distinguished. (shrink)

Sensory substitution devices make use of one substituting modality to get access to environmental information normally accessed through another modality . Based on behavioural and neuroimaging data, some authors have claimed that using a vision-substituting device results in visual perception. Reviewing these data, we contend that this claim is untenable. We argue that the kind of information processed by a SSD is metamodal, so that it can be accessed through any sensory modality and that the phenomenology (...) associated with the use of a SSD is best described in terms of spatial phenomenology, only. (shrink)

One of the central limitations of sensory substitution devices (SSDs) is their inability to reproduce the non-sensory feelings that are normally associated with visual experiences, especially hedonic and aesthetic responses. This limitation is sometimes reported to cause SSD users frustration. To make matters worse, it is unclear that improvements in acuity, bandwidth, or training will resolve the issue. Yet, if SSDs are to actually reproduce visual experience in its fullness, it seems that the reproduction of non-sensory (...) feelings will be of some importance. We offer a novel solution. Researchers can produce hedonic and aesthetic responses by eliciting these feelings artificially, pairing distal objects that should be pleasurable to pleasurable stimulus outputs from the SSD. We outline two strategies for accomplishing this: first, by means of a prefixed, hardwired, association of pleasant distal objects to pleasant stimulus outputs from the SSD; second, by means of a flexible, feedback-based association which creates associations based on a subject-directed matching of distal objects to patterns of stimuli from the SSD which the subject takes to have the corresponding hedonic properties. We evaluate some problems with both strategies, and we argue that the feedback-based strategy is more promising. Researchers can use this strategy to help the blind, allowing them to take pleasure in the objects they perceive using SSDs. (shrink)

Sensory substitution devices (SSDs) aim to compensate for the loss of a sensory modality, typically vision, by converting information from the lost modality into stimuli in a remaining modality. “The vOICe” is a visual-to-auditory SSD which encodes images taken by a camera worn by the user into “soundscapes” such that experienced users can extract information about their surroundings. Here we investigated how much detail was resolvable during the early induction stages by testing the acuity of blindfolded sighted, (...) naïve vOICe users. Initial performance was well above chance. Participants who took the test twice as a form of minimal training showed a marked improvement on the second test. Acuity was slightly but not significantly impaired when participants wore a camera and judged letter orientations “live”. A positive correlation was found between participants' musical training and their acuity. The relationship between auditory expertise via musical training and the lack of a relationship with visual imagery, suggests that early use of a SSD draws primarily on the mechanisms of the sensory modality being used rather than the one being substituted. If vision is lost, audition represents the sensory channel of highest bandwidth of those remaining. The level of acuity found here, and the fact it was achieved with very little experience in sensory substitution by naïve users is promising. (shrink)

Block (Trends Cogn Sci 7:285–286, 2003) and Prinz (PSYCHE 12:1–19, 2006) have defended the idea that SSD perception remains in the substituting modality (auditory or tactile). Hurley and Noë (Biol Philos 18:131–168, 2003) instead argued that after substantial training with the device, the perceptual experience that the SSD user enjoys undergoes a change, switching from tactile/auditory to visual. This debate has unfolded in something like a stalemate where, I will argue, it has become difficult to determine whether the perception (...) acquired through the coupling with an SSD remains in the substituting or the substituted modality. Within this puzzling deadlock two new approaches have been recently suggested. Ward and Meijer (Conscious Cogn 19:492–500, 2010) describe SSD perception as visual-like but characterize it as a kind of artificially induced synaesthesia. Auvray et al. (Perception 36:416–430, 2007) and Auvray and Myin (Cogn Sci 33:1036–1058, 2009) suggest that SSDs let their users experience a new kind of perception. Deroy and Auvray (forthcoming) refine this position, and argue that this new kind of perception depends on pre-existing senses without entirely aligning with any of them. So, they have talked about perceptual experience in SSDs as going "beyond vision". In a similar vein, MacPherson (Oxford University Press, New York, 2011a) claims that “if the subjects (SSD users) have experiences with both vision-like and touch-like representational characteristics then perhaps they have a sense that ordinary humans do not” (MacPherson in Oxford University Press, New York, 2011a, p. 139). (shrink)

The loss or absence of vision is probably one of the most incapacitating events that can befall a human being. The importance of vision for humans is also reflected in brain anatomy as approximately one third of the human brain is devoted to vision. It is therefore unsurprising that throughout history many attempts have been undertaken to develop devices aiming at substituting for a missing visual capacity. In this review, we present two concepts that have been prevalent over the last (...) two decades. The first concept is sensory substitution, which refers to the use of another sensory modality to perform a task that is normally primarily sub-served by the lost sense. The second concept is cross-modal plasticity, which occurs when loss of input in one sensory modality leads to reorganization in brain representation of other sensory modalities. Both phenomena are training-dependent. We also briefly describe the history of blindness from ancient times to modernity, and then proceed to address themeansthat have been used to help blind individuals, with an emphasis on modern technologies, invasive (various type of surgical implants) and non-invasive devices. With the advent of brain imaging, it has become possible to peer into the neural substrates of sensory substitution and highlight the magnitude of the plastic processes that lead to a rewired brain. Finally, we will address the important question of the value and practicality of the available technologies and future directions. (shrink)

Much of the literature directed at the Extended Mind Thesis has revolved around parity issues, focussing on the problem of how to individuate the functional roles and on the relevance of these roles for the production of human intelligent behaviour. Proponents of EMT have famously claimed that we shouldn’t take the location of a process as a reliable indicator of the mechanisms that support our cognitive behaviour. This functionalist understanding of cognition has however been challenged by opponents of EMT [such (...) as Rupert ; Adams & Aizawa ], who have claimed that differences between internal, biological processes and putatively extended ones not only exist but are actually crucial to undermine the idea that inner and outer are functionally equivalent. This debate about how to individuate the functional roles has led to a treacherous stand-off, in which proponents of EMT have been trapped under the persistent accusation of causal/constitution conflation. My strategy for responding to this charge is to look precisely at those functional differences highlighted by critics of EMT. I reckon that extended cognitive systems are endowed with quite different properties from systems that are “brain bound” and argue that it is precisely these differences that allow human minds to transcend their biological limitations. I thus defend a complementarity version of the extended mind, according to which externally located resources and internal biological elements make a different but complementary contribution to bringing about intelligent behaviour [Sutton ]. My defence of complementarity is based on both the phylogeny and the ontogeny of cognitive systems. I initially explore the interrelation between brain and cognitive development from a neuroconstructivist perspective [Quartz & Sejnowski ; Mareshal et al. ] and then argue that our brains do not have fixed functional architectures but are sculpted and given form by the activities we repeatedly engage in. As a result of repeated engagements in socio-cultural tasks, relevant brain pathways undergo substantial rewiring. Development thus scaffolds our brains, which become geared into working in symbiotic partnership with external resources. [Kiverstein & Farina ]. On these grounds, I call into question any tendency to interpret the human biological nature as fixed and endogenously pre-determined and side with proponents of DST [Oyama ; Griffiths & Gray ] and ontogenetic niche construction [Stotz ] in arguing that we should think of natural selection as operating on whole developmental systems composed of living organisms in culturally enriched niches. [Wheeler & Clark]. Complementarity defences of EMT argue that many of the kinds of cognition humans excel at can only be accomplished by brains working together with a body that directly manipulates and acts on the world [Rowlands ; Menary ]. I take Sensory Substitution Devices as my empirical case study. SSDs exploit the remarkable plasticity of our brains and with training supply a novel perceptual modality that compensates for loss or impaired sensory channel. I argue that the coupling with these devices triggers a new mode of phenomenal access to the world, something I propose to label as a kind of “artificial synaesthesia [Ward & Meijer ].This new mode of access to the world transforms our cognitive skills and gives rise to augmented processes of deep bio-technological symbiosis. SSDs therefore become mind enhancing tools [Clark ] and a perfect case study for Complementarity. Having shown the relevance of SSDs for EMT, I then take up the possibility that these devices don’t just relocate the boundaries of cognition but may also stretch the bounds of perceptual awareness. I explore the possibility that perceivers using SSDs count as extended cognitive systems and therefore argue that the experiences they enjoy should be counted as extended conscious experiences.[Kiverstein & Farina, ]. SSDs are quite often said to involve some form of incorporation.[Clark ]. Rupert has challenged this idea and its relevance for EMT on the grounds of his embedded approach. Particularly, he has explained tool-use in terms of the causal interaction between the subject and its detached tool. In the final chapter of my dissertation I critically look at his objections and argue that all his arguments fail to apply to SSDs. In SSD perception in fact the tool becomes geared to work in symbiotic partnership with the active subject and then get factored into its’ body schema so that both of them come to form a single system of cognitive analysis. (shrink)