How multisensory perception promotes purchase intent in the context of clothing e-customisation.

With the continuing development of internet technologies, an increasing number of consumers want to customise the products they buy online. In order to explore the relationship between perception and purchase intent, a conceptual framework was developed that was based on the link between multisensory perception, positive emotions, and purchase intent in fashion e-customisation marketing. We discuss the outcomes derived from consumers' experiences in fashion e-customisation and analyse the relationships between variables. Questionnaires were used to collect data for this quantitative study (n = 398 participants). The data was analysed using factor analysis, correlation analysis, and regression analysis. The findings contribute to the field of clothing e-customisation by identifying the effects of visual perception, haptic imagery, and auditory stimulation on arousal, and purchase intent. Visual perception and haptic imagery exerted a positive influence over dominance. We also identify the effects of arousal and dominance on purchase intent, and assess the mediating effects of these variables on visual perception, haptic mental imagery, and purchase intent. The results highlight how fashion e-customisation marketing strategies can be adopted by managers in order to increase positive emotions and how multisensory perception can potentially be used to influence consumers' purchase behaviour.

'Tasting Imagination': What Role Chemosensory Mental Imagery in Multisensory Flavour Perception?

A number of perplexing phenomena in the area of olfactory/flavour perception may fruitfully be explained by the suggestion that chemosensory mental imagery can be triggered automatically by perceptual inputs. In particular, the disconnect between the seemingly limited ability of participants in chemosensory psychophysics studies to distinguish more than two or three odorants in mixtures and the rich and detailed flavour descriptions that are sometimes reported by wine experts; the absence of awareness of chemosensory loss in many elderly individuals; and the insensitivity of the odour-induced taste enhancement (OITE) effect to the mode of presentation of olfactory stimuli (i.e., orthonasal or retronasal). The suggestion made here is that the theory of predictive coding, developed first in the visual modality, be extended to chemosensation. This may provide a fruitful way of thinking about the interaction between mental imagery and perception in the experience of aromas and flavours. Accepting such a suggestion also raises some important questions concerning the ecological validity/meaning of much of the chemosensory psychophysics literature that has been published to date.

Temperature-Based Crossmodal Correspondences: Causes and Consequences.

The last few years have seen an explosive growth of research interest in the crossmodal correspondences, the sometimes surprising associations that people experience between stimuli, attributes, or perceptual dimensions, such as between auditory pitch and visual size, or elevation. To date, the majority of this research has tended to focus on audiovisual correspondences. However, a variety of crossmodal correspondences have also been demonstrated with tactile stimuli, involving everything from felt shape to texture, and from weight through to temperature. In this review, I take a closer look at temperature-based correspondences. The empirical research not only supports the existence of robust crossmodal correspondences between temperature and colour (as captured by everyday phrases such as 'red hot') but also between temperature and auditory pitch. Importantly, such correspondences have (on occasion) been shown to influence everything from our thermal comfort in coloured environments through to our response to the thermal and chemical warmth associated with stimulation of the chemical senses, as when eating, drinking, and sniffing olfactory stimuli. Temperature-based correspondences are considered in terms of the four main classes of correspondence that have been identified to date, namely statistical, structural, semantic, and affective. The hope is that gaining a better understanding of temperature-based crossmodal correspondences may one day also potentially help in the design of more intuitive sensory-substitution devices, and support the delivery of immersive virtual and augmented reality experiences.

The Multisensory Experience of Handling and Reading Books.

The failure of e-books to take over from the traditional print format, as was so confidently predicted would happen only a few years ago, highlights how there is more to reading than merely the content of what we see. In fact, like any other object, the experience of interacting with a book, especially an old or historic volume, offers the reader the potential for a multisensory encounter. One that involves not only what the book looks and feels like, both the weight of the volume and the feel of the pages, but also the distinctive smell. In fact, one might also want to consider the particular sound made by the pages as they are turned over. However, it is the smell of older, and seemingly more olfactorily-redolent, works that appears to be especially effective at triggering nostalgic associations amongst readers. It is therefore only by understanding the multisensory nature of handling books, as stressed by this review, that one can really hope to fully appreciate the enduring appeal of the traditional format in the modern digital era. Several recent exhibitions that have attempted to engage their visitors by means of exploring the multisensory appeal of historic books or manuscripts in their collections are briefly discussed. While the multisensory mental imagery that is typically evoked by reading is unlikely to differ much between the print and e-book formats, there is nevertheless still some evidence to suggest that physical books can occasionally convey information more effectively than their digital counterparts.

Assessing the Role of Emotional Mediation in Explaining Crossmodal Correspondences Involving Musical Stimuli.

A wide variety of crossmodal correspondences, defined as the often surprising connections that people appear to experience between simple features, attributes, or dimensions of experience, either physically present or else merely imagined, in different sensory modalities, have been demonstrated in recent years. However, a number of crossmodal correspondences have also been documented between more complex (i.e., multi-component) stimuli, such as, for example, pieces of music and paintings. In this review, the extensive evidence supporting the emotional mediation account of the crossmodal correspondences between musical stimuli (mostly pre-recorded short classical music excerpts) and visual stimuli, including colour patches through to, on occasion, paintings, is critically evaluated. According to the emotional mediation account, it is the emotional associations that people have with stimuli that constitutes one of the fundamental bases on which crossmodal associations are established. Taken together, the literature that has been published to date supports emotional mediation as one of the key factors underlying the crossmodal correspondences involving emotionally-valenced stimuli, both simple and complex.

On the Relative Nature of (Pitch-Based) Crossmodal Correspondences.

This review deals with the question of the relative vs absolute nature of crossmodal correspondences, with a specific focus on those correspondences involving the auditory dimension of pitch. Crossmodal correspondences have been defined as the often-surprising crossmodal associations that people experience between features, attributes, or dimensions of experience in different sensory modalities, when either physically present, or else merely imagined. In the literature, crossmodal correspondences have often been contrasted with synaesthesia in that the former are frequently said to be relative phenomena (e.g., it is the higher-pitched of two sounds that is matched with the smaller of two visual stimuli, say, rather than there being a specific one-to-one crossmodal mapping between a particular pitch of sound and size of object). By contrast, in the case of synaesthesia, the idiosyncratic mapping between inducer and concurrent tends to be absolute (e.g., it is a particular sonic inducer that elicits a specific colour concurrent). However, a closer analysis of the literature soon reveals that the distinction between relative and absolute in the case of crossmodal correspondences may not be as clear-cut as some commentators would have us believe. Furthermore, it is important to note that the relative vs absolute question may receive different answers depending on the particular (class of) correspondence under empirical investigation.

Assessing the influence of sound parameters on crossmodal cuing in different regions of space.

To date, crossmodal spatial cuing research has primarily investigated spatial attention modulated by the positioning of auditory cues, without addressing the question of the role played by sound parameters such as intensity change, waveform structure, or duration. Therefore in the present study, we investigated exogenous spatial cuing following the presentation of auditory cues having different intensity profiles (looming or receding), waveforms (triangular structured waveform or white noise), and durations (250 ms or 500 ms). Auditory cues were presented from one of four locations (front-left, front-right, rear-left, or rear-right). The participants had to make speeded elevation discrimination responses to visual targets presented from the front (on the left or right). The magnitude of the cuing effect was larger following the presentation of a structured looming auditory cue than a structured receding cue. On the other hand, there was no statistical difference between the magnitude of the cuing effect in the looming and in the receding intensity profiles when white noise cues were used. Such findings are consistent with previous reports. Furthermore, the magnitude of the cuing effect was larger when the cues were presented from the front than from the rear. On the contrary, other recent findings showed that the presentation of a 100 ms constant-intensity auditory cue exogenously oriented visual attention to the cued hemifield, regardless of whether the cues were presented from the front or rear. Therefore, the findings reported here demonstrated that sound parameters can modulate the exogenous orienting of crossmodal spatial attention.

"A sweet smile": the modulatory role of emotion in how extrinsic factors influence taste evaluation.

It has recently been demonstrated that the reported tastes/flavours of food/beverages can be modulated by means of external visual and auditory stimuli such as typeface, shapes, and music. The present study was designed to assess the role of the emotional valence of the product-extrinsic stimuli in such crossmodal modulations of taste. Participants evaluated samples of mixed fruit juice whilst simultaneously being presented with auditory or visual stimuli having either positive or negative valence. The soundtracks had either been harmonised with consonant (positive valence) or dissonant (negative valence) musical intervals. The visual stimuli consisted of images of emotional faces from the International Affective Picture System (IAPS) with valence ratings matched to the soundtracks. Each juice sample was rated on two computer-based scales: One anchored with the words sour and sweet, while the other scale required hedonic ratings. Those participants who tasted the juice sample while presented with the positively-valenced stimuli rated the juice as tasting sweeter compared to negatively-valenced stimuli, regardless of whether the stimuli were visual or auditory. These results suggest that the emotional valence of food-extrinsic stimuli can play a role in shaping food flavour evaluation and liking.

Drawing sounds: representing tones and chords spatially.

Research on the crossmodal correspondences has revealed that seemingly unrelated perceptual information can be matched across the senses in a manner that is consistent across individuals. An interesting extension of this line of research is to study how sensory information biases action. In the present study, we investigated whether different sounds (i.e. tones and piano chords) would bias participants' hand movements in a free movement task. Right-handed participants were instructed to move a computer mouse in order to represent three tones and two chords. They also had to rate each sound in terms of three visual analogue scales (slow-fast, unpleasant-pleasant, and weak-strong). The results demonstrate that tones and chords influence hand movements, with higher-(lower-)pitched sounds giving rise to a significant bias towards upper (lower) locations in space. These results are discussed in terms of the literature on forward models, embodied cognition, crossmodal correspondences, and mental imagery. Potential applications sports and rehabilitation are discussed briefly.

Crossmodal Correspondences: Four Challenges.

The renewed interest that has emerged around the topic of crossmodal correspondences in recent years has demonstrated that crossmodal matchings and mappings exist between the majority of sensory dimensions, and across all combinations of sensory modalities. This renewed interest also offers a rapidly-growing list of ways in which correspondences affect--or interact with--metaphorical understanding, feelings of 'knowing', behavioral tasks, learning, mental imagery, and perceptual experiences. Here we highlight why, more generally, crossmodal correspondences matter to theories of multisensory interactions.

Lessons of synaesthesia for consciousness: Learning from the exception, rather than the general.

The question of whether the mechanisms underlying synaesthesia are similar to those ones underlying widespread cases of multisensory interactions tends to overshadow the question of whether their manifestations can be thought of as being continuous with one another. Here we focus on the conscious manifestations of synaesthesia and crossmodal correspondences and consider the dimensions along which these could be organised on a continuum. While synaesthesia and crossmodal correspondences may differ regarding the degree of vividness, frequency, specificity of the conscious manifestation, and control over its content, we demonstrate that these dimensions fail to lead to the expected continuous distribution. We suggest that the traditional distinction between conscious and non-conscious conditions might not be sufficient to separate synaesthesia from crossmodal correspondences, but highlight that the conscious manifestations that characterize synaesthesia remain exceptional and cannot be reconciled with other occasional occurrences of crossmodal mental imagery documented in the case of crossmodal correspondences.

Combined effects of motor response, sensory modality, and stimulus intensity on temporal reproduction.

The ability to estimate a filled interval of time is affected by numerous non-temporal factors, such as the sensory modality, duration, and the intensity of the stimulus. Here we explore the role of modality (auditory or visual), stimulus intensity (low vs. high), and motor response speed on the ability to reproduce the duration of short (<1 s) filled intervals. In accordance with the literature, the reproduced duration was affected by both the modality and the intensity of the stimulus; longer reproduction times were generally observed for visual as compared to auditory stimuli, and for low as compared to high-intensity stimuli. We used general estimating equations in order to determine whether these factors independently affected participants' ability to reproduce a given duration, after eliminating the variability associated with reaction time, since it covaried with the reproduced durations. This analysis revealed that stimulus duration, modality, and intensity were all significant independent predictors of the reproduced durations. Additionally, duration interacted with intensity when reproducing auditory intervals. That is, after taking into account the general speeding-up effect that high-intensity stimuli have on responses, they seem to have an additional effect on the rate of the internal clock. These results support previous evidence suggesting that auditory and visual clocks run at different speeds.

Spatial summation of pain in humans investigated using transcutaneous electrical stimulation.

UNLABELLED: Spatial summation of pain is well accepted but surprisingly understudied. Area-based summation refers to the increase in pain evoked by increasing the area of stimulation. Distance-based summation refers to the increase in pain evoked by increasing the distance between multiple stimuli. Although transcutaneous electrical stimulation has several advantages over other experimental pain paradigms, whether or not this modality evokes spatial summation remains unknown. We aimed to answer this question in order to lay the foundation for critical studies of spatial summation. Twenty-five healthy participants received stimuli on their forearm, and the primary outcome, pain intensity, was compared across 5 spatial configurations-1 with a single stimulus and 4 paired configurations at 0-, 5-, 10-, and 20-cm separations. Importantly, the potential confounder of a proximal-distal gradient in nociceptive sensitivity was removed in this study. Pain intensity was higher in response to the paired stimuli than in response to the single stimulus (P < .001), and the paired stimuli separated by 5, 10 and 20 cm, evoked greater pain than stimuli at a separation of 0 cm (P < .001), thus confirming both area- and distance-based summation, respectively. We conclude that transcutaneous electrical stimulation is appropriate for future investigations of spatial summation. PERSPECTIVE: Distance-based summation is likely implicated in some clinical pain. However, current understanding for spatial summation is limited. This study demonstrates that transcutaneous electrical stimulation is safe, feasible, and valid for future investigations of spatial summation and will allow critical questions to be answered.

Assessing the benefits of multisensory audiotactile stimulation for overweight individuals.

We report an experiment designed to examine whether individuals who are overweight would perform differently when trying to detect and/or discriminate auditory, vibrotactile, and audiotactile targets. The vibrotactile stimuli were delivered either to the participant's abdomen or to his hand. Thirty-six young male participants were classified into normal, underweight, or overweight groups based on their body mass index. All three groups exhibited a significant benefit of multisensory (over the best of the unisensory) stimulation, but the magnitude of this benefit was modulated by the weight of the participant, the task, and the location from which the vibrotactile stimuli happened to be presented. For the detection task, the overweight group exhibited a significantly smaller benefit than the underweight group. In the discrimination task, the overweight group showed significantly more benefits than the other two groups when the vibrotactile stimuli were delivered to their hands, but not when the stimuli were delivered to their abdomens. These results might raise some interesting questions regarding the mechanisms underlying audiotactile information processing and have applied relevance for the design of the most effective warning signal (e.g., for drivers).

Training, hypnosis, and drugs: artificial synaesthesia, or artificial paradises?

The last few years have seen the publication of a number of studies by researchers claiming to have induced "synaesthesia," "pseudo-synaesthesia," or "synaesthesia-like" phenomena in non-synaesthetic participants. Although the intention of these studies has been to try and shed light on the way in which synaesthesia might have been acquired in developmental synaesthestes, we argue that they may only have documented a phenomenon that has elsewhere been accounted for in terms of the acquisition of sensory associations and is not evidently linked to synaesthesia. As synaesthesia remains largely defined in terms of the involuntary elicitation of conscious concurrents, we suggest that the theoretical rapprochement with synaesthesia (in any of its guises) is unnecessary, and potentially distracting. It might therefore, be less confusing if researchers were to avoid referring to synaesthesia when characterizing cases that lack robust evidence of a conscious manifestation. Even in the case of those other conditions for which conscious experiences are better evidenced, when training has been occurred during hypnotic suggestion, or when it has been combined with drugs, we argue that not every conscious manifestation should necessarily be counted as synaesthetic. Finally, we stress that cases of associative learning are unlikely to shed light on two highly specific characteristic of the majority of cases of developmental synaesthesia in terms of learning patterns: First, their resistance to change through exposure once the synaesthetic repertoire has been fixed; Second, the transfer of conditioned responses between concurrents and inducers after training. We conclude by questioning whether, in adulthood, it is ever possible to acquire the kind of synaesthesia that is typically documented in the developmental form of the condition. The available evidence instead seems to point to there being a critical period for the development of synaesthesia, probably only in those with a genetic predisposition to develop the condition.

Cross-correlation between auditory and visual signals promotes multisensory integration.

Humans are equipped with multiple sensory channels that provide both redundant and complementary information about the objects and events in the world around them. A primary challenge for the brain is therefore to solve the 'correspondence problem', that is, to bind those signals that likely originate from the same environmental source, while keeping separate those unisensory inputs that likely belong to different objects/events. Whether multiple signals have a common origin or not must, however, be inferred from the signals themselves through a causal inference process. Recent studies have demonstrated that cross-correlation, that is, the similarity in temporal structure between unimodal signals, represents a powerful cue for solving the correspondence problem in humans. Here we provide further evidence for the role of the temporal correlation between auditory and visual signals in multisensory integration. Capitalizing on the well-known fact that sensitivity to crossmodal conflict is inversely related to the strength of coupling between the signals, we measured sensitivity to crossmodal spatial conflicts as a function of the cross-correlation between the temporal structures of the audiovisual signals. Observers' performance was systematically modulated by the cross-correlation, with lower sensitivity to crossmodal conflict being measured for correlated as compared to uncorrelated audiovisual signals. These results therefore provide support for the claim that cross-correlation promotes multisensory integration. A Bayesian framework is proposed to interpret the present results, whereby stimulus correlation is represented on the prior distribution of expected crossmodal co-occurrence.

Limb-specific autonomic dysfunction in complex regional pain syndrome modulated by wearing prism glasses.

In unilateral upper-limb complex regional pain syndrome (CRPS), the temperature of the hands is modulated by where the arms are located relative to the body midline. We hypothesized that this effect depends on the perceived location of the hands, not on their actual location, nor on their anatomical alignment. In 2 separate cross-sectional randomized experiments, 10 (6 female) unilateral CRPS patients wore prism glasses that laterally shifted the visual field by 20°. Skin temperature was measured before and after 9-minute periods in which the position of one hand was changed. Placing the affected hand on the healthy side of the body midline increased its temperature (Δ°C=+0.47 ± 0.14°C), but not if prism glasses made the hand appear to be on the body midline (Δ°C=+0.07 ± 0.06°C). Similarly, when prism glasses made the affected hand appear to be on the healthy side of the body midline, even though it was not, the affected hand warmed up (Δ°C=+0.28 ± 0.14°C). When prism glasses made the healthy hand appear to be on the affected side of the body midline, even though it was not, the healthy hand cooled down (Δ°C=-0.30 ± 0.15°C). Friedman's analysis of variance and Wilcoxon pairs tests upheld the results (P<0.01 for all). We conclude that, in CRPS, cortical mechanisms responsible for encoding the perceived location of the limbs in space modulate the temperature of the hands.

Role of audiovisual synchrony in driving head orienting responses.

Many studies now suggest that optimal multisensory integration sometimes occurs under conditions where auditory and visual stimuli are presented asynchronously (i.e. at asynchronies of 100 ms or more). Such observations lead to the suggestion that participants' speeded orienting responses might be enhanced following the presentation of asynchronous (as compared to synchronous) peripheral audiovisual spatial cues. Here, we report a series of three experiments designed to investigate this issue. Upon establishing the effectiveness of bimodal cuing over the best of its unimodal components (Experiment 1), participants had to make speeded head-turning or steering (wheel-turning) responses toward the cued direction (Experiment 2), or an incompatible response away from the cue (Experiment 3), in response to random peripheral audiovisual stimuli presented at stimulus onset asynchronies ranging from -100 to 100 ms. Race model inequality analysis of the results (Experiment 1) revealed different mechanisms underlying the observed multisensory facilitation of participants' head-turning versus steering responses. In Experiments 2 and 3, the synchronous presentation of the component auditory and visual cues gave rise to the largest facilitation of participants' response latencies. Intriguingly, when the participants had to subjectively judge the simultaneity of the audiovisual stimuli, the point of subjective simultaneity occurred when the auditory stimulus lagged behind the visual stimulus by 22 ms. Taken together, these results appear to suggest that the maximally beneficial behavioural (head and manual) orienting responses resulting from peripherally presented audiovisual stimuli occur when the component signals are presented in synchrony. These findings suggest that while the brain uses precise temporal synchrony in order to control its orienting responses, the system that the human brain uses to consciously judge synchrony appears to be less fine tuned.

Facilitating masked visual target identification with auditory oddball stimuli.

When identifying a rapidly masked visual target display in a stream of visual distractor displays, a high-frequency tone (presented in synchrony with the target display) in a stream of low-tone distractors results in better performance than when the same low tone accompanies each visual display (Ngo and Spence in Atten Percept Psychophys 72:1938-1947, 2010; Vroomen and de Gelder in J Exp Psychol Hum 26:1583-1590, 2000). In the present study, we tested three oddball conditions: a louder tone presented amongst quieter tones, a quieter tone presented amongst louder tones, and the absence of a tone, within an otherwise identical tone sequence. Across three experiments, all three oddball conditions resulted in the crossmodal facilitation of participants' visual target identification performance. These results therefore suggest that salient oddball stimuli in the form of deviating tones, when synchronized with the target, may be sufficient to capture participants' attention and facilitate visual target identification. The fact that the absence of a sound in an otherwise-regular sequence of tones also facilitated performance suggests that multisensory integration cannot provide an adequate account for the 'freezing' effect. Instead, an attentional capture account is proposed to account for the benefits of oddball cuing in Vroomen and de Gelder's task.

Audiovisual crossmodal correspondences and sound symbolism: a study using the implicit association test.

A growing body of empirical research on the topic of multisensory perception now shows that even non-synaesthetic individuals experience crossmodal correspondences, that is, apparently arbitrary compatibility effects between stimuli in different sensory modalities. In the present study, we replicated a number of classic results from the literature on crossmodal correspondences and highlight the existence of two new crossmodal correspondences using a modified version of the implicit association test (IAT). Given that only a single stimulus was presented on each trial, these results rule out selective attention and multisensory integration as possible mechanisms underlying the reported compatibility effects on speeded performance. The crossmodal correspondences examined in the present study all gave rise to very similar effect sizes, and the compatibility effect had a very rapid onset, thus speaking to the automatic detection of crossmodal correspondences. These results are further discussed in terms of the advantages of the IAT over traditional techniques for assessing the strength and symmetry of various crossmodal correspondences.