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The study of chemosensory mental imagery is undoubtedly made more difficult because of the profound individual differences that have been reported in the vividness of (e.g.) olfactory mental imagery. At the same time, the majority of those researchers who have attempted to study people's mental imagery abilities for taste (gustation) have actually mostly been studying flavour mental imagery. Nevertheless, there exists a body of human psychophysical research showing that chemosensory mental imagery exhibits a number of similarities with chemosensory perception. Furthermore, the two systems have frequently been shown to interact with one another, the similarities and differences between chemosensory perception and chemosensory mental imagery at the introspective, behavioural, psychophysical, and cognitive neuroscience levels in humans are considered in this narrative historical review. The latest neuroimaging evidence show that many of the same brain areas are engaged by chemosensory mental imagery as have previously been documented to be involved in chemosensory perception. That said, the pattern of neural connectively is reversed between the 'top-down' control of chemosensory mental imagery and the 'bottom-up' control seen in the case of chemosensory perception. At the same time, however, there remain a number of intriguing questions as to whether it is even possible to distinguish between orthonasal and retronasal olfactory mental imagery, and the extent to which mental imagery for flavour, which most people not only describe as, but also perceive to be, the 'taste' of food and drink, is capable of reactivating the entire flavour network in the human brain.

The latest research demonstrates that people's perception of orange juice can be influenced by the shape/type of receptacle in which it happens to be served. Two studies are reported that were designed to investigate the impact, if any, that the shape/type of glass might exert over the perception of the contents, the emotions induced on tasting the juice and the consumer's intention to purchase orange juice. The same quantity of orange juice (100 ml) was presented and evaluated in three different glasses: a straight-sided, a curved and a tapered glass. Questionnaires were used to assess taste (aroma, flavour intensity, sweetness, freshness and fruitiness), pleasantness and intention to buy orange juice. Study 2 assessed the impact of the same three glasses in two digitally rendered atmospheric conditions (nature vs urban). In Study 1, the perceived sweetness and pleasantness of the orange juice was significantly influenced by the shape/type of the glass in which it was presented. Study 2 reported significant interactions between condition (nature vs urban) and glass shape (tapered, straight-sided and curved). Perceived aroma, flavour intensity and pleasantness were all significantly affected by the simulated audiovisual context or atmosphere. Compared to the urban condition, perceived aroma, freshness, fruitiness and pleasantness were rated significantly higher in the nature condition. On the other hand, flavour intensity and sweetness were rated significantly higher in the urban condition than in the natural condition. These results are likely to be relevant for those interested in providing food services, or company managers offering beverages to their customers.

There has been a rapid recent growth in academic attempts to summarise, understand, and predict the taste profile matching complex images that incorporate multiple visual design features. While there is now ample research to document the patterns of vision-taste correspondences involving individual visual features (such as colour and shape curvilinearity in isolation), little is known about the taste associations that may be primed when multiple visual features are presented simultaneously. This narrative historical review therefore presents an overview of the research that has examined, or provided insights into, the interaction of graphic elements in taste correspondences involving colour, shape attributes, texture, and other visual features. The empirical evidence is largely in line with the predictions derived from the proposed theories concerning the origins of crossmodal correspondences; the component features of a visual stimulus are observed to contribute substantially to its taste expectations. However, the taste associated with a visual stimulus may sometimes deviate from the taste correspondences primed by its constituent parts. This may occur when a new semantic meaning emerges as multiple features are displayed together. Some visual features may even provide contextual cues for observers, thus altering the gustatory information that they associate with an image. A theoretical framework is constructed to help more intuitively predict and conceptualise the overall influence on taste correspondences when visual features are processed together as a combined image.

A growing body of experimental research now demonstrates that neurologically normal individuals associate different taste qualities with design features such as curvature, symmetry, orientation, texture and movement. The form of everything from the food itself through to the curvature of the plateware on which it happens to be served, and from glassware to typeface, not to mention the shapes of/on food product packaging have all been shown to influence people's taste expectations, and, on occasion, also their taste/food experiences. Although the origins of shape-taste and other form-taste crossmodal correspondences have yet to be fully worked out, it would appear that shape qualities are occasionally elicited directly. However, more often, there may be a metaphorical attempt to translate the temporal qualities of taste sensations into a spatial analogue. At the same time, emotional mediation may sometimes also play a role in the affinity people experience between shape properties and taste. And finally, it should be acknowledged that associative learning of the relation between packaging shapes, glassware shapes, logos, labels and iconic food forms that commonly co-occur with specific taste properties (i.e., in the case of branded food products) may also play an important role in determining the nature of shape-taste correspondences. Ultimately, however, any attempt to use such shape-taste correspondences to nudge people's behaviour/perception in the real world is made challenging due to the fact that shape properties are associated with multiple qualities, and not just taste.

There has been a rapid growth of interest amongst researchers in the cross-modal correspondences in recent years. In part, this has resulted from the emerging realization of the important role that the correspondences can sometimes play in multisensory integration. In turn, this has led to an interest in the nature of any differences between individuals, or rather, between groups of individuals, in the strength and/or consensuality of cross-modal correspondences that may be observed in both neurotypically normal groups cross-culturally, developmentally, and across various special populations (including those who have lost a sense, as well as those with autistic tendencies). The hope is that our emerging understanding of such group differences may one day provide grounds for supporting the reality of the various different types of correspondence that have so far been proposed, namely structural, statistical, semantic, and hedonic (or emotionally mediated).

Mounting evidence demonstrates that people make surprisingly consistent associations between auditory attributes and a number of the commonly-agreed basic tastes. However, the sonic representation of (association with) saltiness has remained rather elusive. In the present study, a crowd-sourced online study ( n = 1819 participants) was conducted to determine the acoustical/musical attributes that best match saltiness, as well as participants' confidence levels in their choices. Based on previous literature on crossmodal correspondences involving saltiness, thirteen attributes were selected to cover a variety of temporal, tactile, and emotional associations. The results revealed that saltiness was associated most strongly with a long decay time, high auditory roughness, and a regular rhythm. In terms of emotional associations, saltiness was matched with negative valence, high arousal, and minor mode. Moreover, significantly higher average confidence ratings were observed for those saltiness-matching choices for which there was majority agreement, suggesting that individuals were more confident about their own judgments when it matched with the group response, therefore providing support for the so-called 'consensuality principle'. Taken together, these results help to uncover the complex interplay of mechanisms behind seemingly surprising crossmodal correspondences between sound attributes and taste.

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.

Multisensory processing is required for the perception of the majority of everyday objects and events. In the case of irrelevant stimuli, the multisensory processing of features is widely assumed to be modulated by attention. In the present study, we investigated whether the processing of audiovisual distractors is also modulated by higher-order cognition. Participants fixated a visual distractor viewed via a centrally-placed mirror and responded to a laterally-presented audiovisual target. Critically, a distractor tone was presented from the same location as the mirror, while the visual distractor feature was presented at an occluded location, visible only indirectly via mirror reflection. Consequently, it appeared as though the visual and auditory features were presented from the same location though, in fact, they actually originated from different locations. Nevertheless, the results still revealed that the visual and auditory distractor features were processed together just as in the control condition, in which the audiovisual distractor features were both actually presented from fixation. Taken together, these results suggest that the processing of irrelevant multisensory information is not influenced by higher-order cognition.

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.

We often estimate, or perceive, the quality of materials, surfaces, and objects, what the Japanese refer to as 'shitsukan', by means of several of our senses. The majority of the literature on shitsukan perception has, though, tended to focus on the unimodal visual evaluation of stimulus properties. In part, this presumably reflects the widespread hegemony of the visual in the modern era and, in part, is a result of the growing interest, not to mention the impressive advances, in digital rendering amongst the computer graphics community. Nevertheless, regardless of such an oculocentric bias in so much of the empirical literature, it is important to note that several other senses often do contribute to the impression of the material quality of surfaces, materials, and objects as experienced in the real world, rather than just in virtual reality. Understanding the multisensory contributions to the perception of material quality, especially when combined with computational and neural data, is likely to have implications for a number of fields of basic research as well as being applicable to emerging domains such as, for example, multisensory augmented retail, not to mention multisensory packaging design.

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.

Food product-extrinsic sounds (i.e., those auditory stimuli that are not linked directly to a food or beverage product, or its packaging) have been shown to exert a significant influence over various aspects of food perception and consumer behaviour, often operating outside of conscious awareness. In this review, we summarise the latest evidence concerning the various ways in which what we hear can influence what we taste. According to one line of empirical research, background noise interferes with tasting, due to attentional distraction. A separate body of marketing-relevant research demonstrates that music can be used to bias consumers' food perception, judgments, and purchasing/consumption behaviour in various ways. Some of these effects appear to be driven by the arousal elicited by loud music as well as the entrainment of people's behaviour to the musical beat. However, semantic priming effects linked to the type and style of music are also relevant. Another route by which music influences food perception comes from the observation that our liking/preference for the music that we happen to be listening to carries over to influence our hedonic judgments of what we are tasting. A final route by which hearing influences tasting relates to the emerging field of 'sonic seasoning'. A developing body of research now demonstrates that people often rate tasting experiences differently when listening to soundtracks that have been designed to be (or are chosen because they are) congruent with specific flavour experiences (e.g., when compared to when listening to other soundtracks, or else when tasting in silence). Taken together, such results lead to the growing realization that the crossmodal influences of music and noise on food perception and consumer behaviour may have some important if, as yet, unrecognized implications for public health.

Theorizing around the topic of attention and its role in human information processing largely emerged out of research on the so-called spatial senses: vision, audition, and to a lesser extent, touch. Thus far, the chemical senses have received far less research interest (or should that be attention) from those experimental psychologists and cognitive neuroscientists interested in the topic. Nevertheless, this review highlights the key role that attentional selection also plays in chemosensory information processing and awareness. Indeed, many of the same theoretical approaches/experimental paradigms that were originally developed in the context of the spatial senses, can be (and in some cases already have been) extended to provide a useful framework for thinking about the perception of taste/flavour. Furthermore, a number of those creative individuals interested in modifying the perception of taste/flavour by manipulating product-extrinsic cues (such as, for example, music in the case of sonic seasoning) are increasingly looking to attentional accounts in order to help explain the empirical phenomena that they are starting to uncover. However, separate from its role in explaining sonic seasoning, gaining a better understanding of the role of attentional distraction in modulating our eating/drinking behaviours really ought to be a topic of growing societal concern. This is because distracted diners (e.g., those who eat while watching TV, fiddling with a mobile device or smartphone, or even while driving) consume significantly more than those who mindfully pay attention to the sensations associated with eating and drinking.

Several studies have examined how music may affect the evaluation of food and drink, but the vast majority have not observed how this interaction unfolds in time. This seems to be quite relevant, since both music and the consumer experience of food/drink are time-varying in nature. In the present study we sought to fix this gap, using Temporal Dominance of Sensations (TDS), a method developed to record the dominant sensory attribute at any given moment in time, to examine the impact of music on the wine taster's perception. More specifically, we assessed how the same red wine might be experienced differently when tasters were exposed to various sonic environments (two pieces of music plus a silent control condition). The results revealed diverse patterns of dominant flavours for each sound condition, with significant differences in flavour dominance in each music condition as compared to the silent control condition. Moreover, musical correspondence analysis revealed that differences in perceived dominance of acidity and bitterness in the wine were correlated in the temporality of the experience, with changes in basic auditory attributes. Potential implications for the role of attention in auditory flavour modification and opportunities for future studies are discussed.

We introduce a novel methodology to assess the influence of the emotion induced by listening to music on the consumer's multisensory tasting experience. These crossmodal effects were analyzed when two contrasting music tracks (positive vs negative emotion) were presented to consumers while tasting beer. The results suggest that the emotional reactions triggered by the music influenced specific aspects of the multisensory tasting experience. Participants liked the beer more, and rated it as tasting sweeter, when listening to music associated with positive emotion. The same beer was rated as more bitter, with higher alcohol content, and as having more body, when the participants listened to music associated with negative emotion. Moreover, participants were willing to pay 7-8% more for the beer that was tasted while they listened to positive music. This novel methodology was subsequently replicated with two different styles of beer. These results are discussed along with practical implications concerning the way in which music can add significant value to how a consumer responds to a brand.

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.

Associations between heaviness and bass/low-pitched sounds reverberate throughout music, philosophy, literature, and language. Given that recent research into the field of cross-modal correspondences has revealed a number of robust relationships between sound and flavour, this exploratory study was designed to investigate the effects of lower frequency sound (10 Hz to 200 Hz) on the perception of the mouthfeel character of palate weight/body. This is supported by an overview of relevant cross-modal studies and cultural production. Wines were the tastants - a New Zealand Pinot Noir and a Spanish Garnacha - which were tasted in silence and with a 100 Hz (bass) and a higher 1000 Hz sine wave tone. Aromatic intensity was included as an additional character given suggestions that pitch may influence the perception of aromas, which might presumably affect the perception of wine body. Intensity of acidity and liking were also evaluated. The results revealed that the Pinot Noir wine was rated as significantly fuller-bodied when tasted with a bass frequency than in silence or with a higher frequency sound. The low frequency stimulus also resulted in the Garnacha wine being rated as significantly more aromatically intense than when tasted in the presence of the higher frequency auditory stimulus. Acidity was rated considerably higher with the higher frequency in both wines by those with high wine familiarity and the Pinot Noir significantly better liked than the Garnacha. Possible reasons as to why the tones used in this study affected perception of the two wines differently are discussed. Practical application of the findings are also proposed.

We explored the putative existence of crossmodal correspondences between sound attributes and beverage temperature. An online pre-study was conducted first, in order to determine whether people would associate the auditory parameters of pitch and tempo with different imagined beverage temperatures. The same melody was manipulated to create a matrix of 25 variants with five different levels of both pitch and tempo. The participants were instructed to imagine consuming hot, room-temperature, or cold water, then to choose the melody that best matched the imagined drinking experience. The results revealed that imagining drinking cold water was associated with a significantly higher pitch than drinking both room-temperature and hot water, and with significantly faster tempo than room-temperature water. Next, the online study was replicated with participants in the lab tasting samples of hot, room-temperature, and cold water while choosing a melody that best matched the actual tasting experience. The results confirmed that, compared to room-temperature and hot water, the experience of cold water was associated with both significantly higher pitch and fast tempo. Possible mechanisms and potential applications of these results are discussed.

Taste liking influences the way in which people match tastes to shapes. However, taste-shape matching cannot be explained entirely by taste hedonics. Here, we assess whether variations in taste intensity influence such crossmodal correspondences. Participants were presented with five basic tastants in two concentrations and had to rate them on roundness/angularity shape scales, as well as in terms of liking, and intensity. The results revealed that taste quality, intensity, and participants' liking of the taste significantly predicted the roundness/angularity of the tastants. The results also revealed a positive correlation between perceived intensity and roundness/angularity for each of the tastants except sweet, and a negative correlation between liking and roundness/angularity for all of the tastes. These results are discussed in terms of the mechanism(s) that underlie the crossmodal correspondence between taste and shape.

We report two experiments designed to investigate the consequences of manipulating the harmonic content of background music on taste perception. The participants in the present study evaluated samples of mixed fruit juice whilst listening to soundtracks that had either been harmonised with consonant or dissonant musical intervals. Each sample of juice was rated on three computer-based scales: One scale was anchored with the words sour and sweet, while the other two scales involved hedonic ratings of the music and of the juice. The results of an internet-based pre-test revealed that participants reliably associated the consonant soundtracks with sweetness and the dissonant soundtracks with sourness. The results of the on-site experiments demonstrated that participants rated the juices as tasting significantly sweeter in the consonant than in the dissonant music condition, irrespective of the melody or instrumentation that were evaluated. These results therefore provide empirical support for the claim that the crossmodal correspondence between a higher level musical attribute (namely, harmony) and basic taste can be used to modify the evaluation of the taste of a drink.

Over the last decade, scientists working on the topic of multisensory integration, as well as designers and marketers involved in trying to understand consumer behavior, have become increasingly interested in the non-arbitrary associations (e.g., sound symbolism) between different sensorial attributes of the stimuli they work with. Nevertheless, to date, little research in this area has investigated the presence of these crossmodal correspondences in the tactile evaluation of everyday materials. Here, we explore the presence and nature of the associations between tactile sensations, the sound of non-words, and people's emotional states. Samples of cotton, satin, tinfoil, sandpaper, and abrasive sponge, were stroked along the participants' forearm at the speed of 5 cm/s. Participants evaluated the materials along several dimensions, comprising scales anchored by pairs of non-words (e.g., Kiki/Bouba) and adjectives (e.g., ugly/beautiful). The results revealed that smoother textures were associated with non-words made up of round-shaped sounds (e.g., Maluma), whereas rougher textures were more strongly associated with sharp-transient sounds (e.g., Takete). The results also revealed the presence of a number of correspondences between tactile surfaces and adjectives related to visual and auditory attributes. For example, smooth textures were associated with features evoked by words such as 'bright' and 'quiet'; by contrast, the rougher textures were associated with adjectives such as 'dim' and 'loud'. The textures were also found to be associated with a number of emotional labels. Taken together, these results further our understanding of crossmodal correspondences involving the tactile modality and provide interesting insights in the applied field of design and marketing.

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.

The last 50 years or so has seen great optimism concerning the potential of sensory substitution and augmentation devices to enhance the lives of those with (or even those without) some form of sensory loss (in practice, this has typically meant those who are blind or suffering from low vision). One commonly discussed solution for those individuals who are blind has been to use one of a range of tactile-visual sensory substitution systems that represent objects captured by a camera as outline images on the skin surface in real-time (what Loomis, Klatzky and Giudice, 2012, term general-purpose sensory substitution devices). However, despite the fact that touch, like vision, initially codes information spatiotopically, I would like to argue that a number of fundamental perceptual, attentional, and cognitive limitations constraining the processing of tactile information mean that the skin surface is unlikely ever to provide such general-purpose sensory substitution capabilities. At present, there is little evidence to suggest that the extensive cortical plasticity that has been demonstrated in those who have lost (or never had) a sense can do much to overcome the limitations associated with trying to perceive high rates of spatiotemporally varying information presented via the skin surface (no matter whether that surface be the back, stomach, forehead, or tongue). Instead, the use of the skin will likely be restricted to various special-purpose devices that enable specific activities such as navigation, the control of locomotion, pattern perception, etc.

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.

The time-course of cross-modal semantic interactions between pictures and either naturalistic sounds or spoken words was compared. Participants performed a speeded picture categorization task while hearing a task-irrelevant auditory stimulus presented at various stimulus onset asynchronies (SOAs) with respect to the visual picture. Both naturalistic sounds and spoken words gave rise to cross-modal semantic congruency effects (i.e., facilitation by semantically congruent sounds and inhibition by semantically incongruent sounds, as compared to a baseline noise condition) when the onset of the sound led that of the picture by 240 ms or more. Both naturalistic sounds and spoken words also gave rise to inhibition irrespective of their semantic congruency when presented within 106 ms of the onset of the picture. The peak of this cross-modal inhibitory effect occurred earlier for spoken words than for naturalistic sounds. These results therefore demonstrate that the semantic priming of visual picture categorization by auditory stimuli only occurs when the onset of the sound precedes that of the visual stimulus. The different time-courses observed for naturalistic sounds and spoken words likely reflect the different processing pathways to access the relevant semantic representations.

We examined the crossmodal effect of the presentation of a simultaneous sound on visual detection and discrimination sensitivity using the equivalent noise paradigm (Dosher and Lu, 1998). In each trial, a tilted Gabor patch was presented in either the first or second of two intervals embedded in dynamic 2D white noise with one of seven possible contrast levels. The results revealed that the sensitivity of participants' visual detection and discrimination performance were both enhanced by the presentation of a simultaneous sound, though only close to the noise level at which participants' target contrast thresholds started to increase with the increasing noise contrast. A further analysis of the psychometric function at this noise level revealed that the increase in sensitivity could not be explained by the reduction of participants' uncertainty regarding the onset time of the visual target. We suggest that this crossmodal facilitatory effect may be accounted for by perceptual enhancement elicited by a simultaneously-presented sound, and that the crossmodal facilitation was easier to observe when the visual system encountered a level of noise that happened to be close to the level of internal noise embedded within the system.