Information about an event takes different amounts of time to be processed depending on which sensory system the event activates. However, despite the variations in processing time for lights and sounds, the point of subjective simultaneity (PSS) for briefly presented audio/visual stimuli is usually close to true simultaneity. Here we confirm that the simultaneity constancy mechanism that achieves this for audio/visual stimulus pairs is adaptable, and extend the investigation to other multimodal combinations. We measured the PSS and just noticeable differences (JNDs) for temporal order judgements for three stimulus combinations (sound/light, sound/touch, and light/touch) before and after repeated exposure to each one of these pairs presented with a 100 ms asynchrony (i.e., nine adapt-test combinations). Only the perception of simultaneity of the sound/light pair was affected by our exposure regime: the PSS shifted after exposure to either a temporally staggered sound/light or light/touch pair, and the JND decreased following exposure to a sound/touch pair. No changes were found in the PSSs or JNDs of sound/touch or light/touch pairs following exposure to any of the three time-staggered combinations. Participants' reaction times (RT) to the three stimuli were also tested before and after each adaptation exposure. In general, exposure did not affect attention or processing time; the only change in RTs (of the 9 tested) was an increased RT for light following exposure to a sound/light pair with light leading. We suggest that the neural correlates of multisensory sound/light processing are resynchronised by a separate, more flexible simultaneity constancy mechanism than the light/touch or the sound/touch simultaneity processing systems.

Developmental dyslexia affects 5%-10% of the population, resulting in poor spelling and reading skills. While there are well-documented differences in the way dyslexics process low-level visual and auditory stimuli, it is mostly unknown whether there are similar differences in audiovisual multisensory processes. Here, we investigated audiovisual integration using the redundant target effect (RTE) paradigm. Some conditions demonstrating audiovisual integration appear to depend upon magnocellular pathways, and dyslexia has been associated with deficits in this pathway; so, we postulated that developmental dyslexics ("dyslexics" hereafter) would show differences in audiovisual integration compared with controls. Reaction times (RTs) to multisensory stimuli were compared with predictions from Miller's race model. Dyslexics showed difficulty shifting their attention between modalities; but such "sluggish attention shifting" (SAS) appeared only when dyslexics shifted their attention from the visual to the auditory modality. These results suggest that dyslexics distribute their crossmodal attention resources differently from controls, causing different patterns in multisensory responses compared to controls. From this, we propose that dyslexia training programs should take into account the asymmetric shifts of crossmodal attention.

The taste of cutlery: how the taste of food is affected by the weight, size, shape, and colour of the cutlery used to eat it Vanessa Harrar * and Charles Spence Abstract Background: Recent evidence has shown that changing the plateware can affect the perceived taste and flavour of food, but very little is known about visual and proprioceptive influences of cutlery on the response of consumers to the food sampled from it. In the present study, we report three experiments designed to investigate whether food tastes different when the visual and tactile properties of the plastic cutlery from which it is sampled are altered. We independently varied the weight, size, colour, and shape of cutlery. We assessed the impact of changing the sensory properties of the cutlery on participants' ratings of the sweetness, saltiness, perceived value, and overall liking of the food tasted from it.Results: The results revealed that yoghurt was perceived as denser and more expensive when tasted from a lighter plastic spoon as compared to the artificially weighted spoons; the size of the spoon only interacted with the spoon-weight factor for the perceived sweetness of the yoghurt. The taste of the yoghurt was also affected by the colour of the cutlery, but these effects depended on the colour of the food as well, suggesting that colour contrast may have been responsible for the observed effects. Finally, we investigated the influence of the shape of the cutlery. The results showed that the food was rated as being saltiest when sampled from a knife rather than from a spoon, fork, or toothpick. Conclusions: Taken together, these results demonstrate that the properties of the cutlery can indeed affect people's taste perception of everyday foods, most likely when expectations regarding the cutlery or the food have been disconfirmed. We discuss these results in the context of changing environmental cues in order to modify people's eating habits.

The flavour and pleasantness of food and drinks are affected by their colour, their texture or crunch, and even by the shape and weight of the plate or glass. But, can the colour of the bowl also affect the taste of the food it contains? To answer this question we served popcorn in four different coloured bowls, and participants rated sweetness, saltiness, and overall liking. The sweet popcorn, in addition to being sweet, was perceived as saltier when eaten out of a coloured (as compared to a white) bowl, and vice versa for the salty popcorn. These results demonstrate that colour in bowl design can be used to elicit perceptions of sweetness and saltiness in real foods.

What are the consequences of visual and tactile neural processing time differences when combining multisensory information about an event on the body's surface? Visual information about such events reaches the brain at a time that is independent of the location of the event. However, tactile information about such events takes different amounts of time to be processed depending on the distance between the stimulated surface and the brain. To investigate the consequences of these differences, we measured reaction times to touches and lights on different parts of the body and the perceived subjective simultaneity (PSS) for various combinations. The PSSs for pairs of stimuli were predicted by the differences in reaction times. When lights and touches were on different body parts (i.e. the hand and foot) a trend towards compensation for any processing time differences was found, such that simultaneity was veridically perceived. When stimuli were both on the foot, subjects perceived simultaneity when the light came on significantly earlier than the touch, despite similar processing times for these stimuli. When the stimuli were both on the hand, however, there was complete compensation for the significant processing time differences between the light and touch such that simultaneity was correctly perceived, a form of simultaneity constancy. To identify if there was a single simultaneity constancy mechanism or multiple parallel mechanisms, we altered the PSS of an auditory-visual stimulus pair and looked for effects on the PSS of a visual-touch pair. After repeated exposure to a light/sound pair with a fixed time lag between them, there was no effect on the PSS of a touch-light pair, suggesting multiple parallel simultaneity constancy mechanisms.