Experimental studies of face perception tend to use small samples of participants taken from a narrow age range. This often makes it difficult to use the results in clinical studies. Combined with the fact that current face processing tests are of limited use for an in depth analysis of prosopagnosia it is often difficult to assess face recognition problems. Here we present the results from a study of a wide age group (21-50 yrs) tested with a comprehensive face perception battery that was developed to provide a new tool for critically measuring intact face perception. We critically review existing tests and motivate our choice for the present design which is unique in that it uses in the same task setting faces and objects and therefore allows a more specific evaluation of face specific abilities than was hitherto possible.

Exposure to incongruent auditory and visual speech produces both visual recalibration and selective adaptation of auditory speech identification. In an earlier study, exposure to an ambiguous auditory utterance (intermediate between /aba/ and /ada/) dubbed onto the video of a face articulating either /aba/ or /ada/, recalibrated the perceived identity of auditory targets in the direction of the visual component, while exposure to congruent non-ambiguous /aba/ or /ada/ pairs created selective adaptation, i.e. a shift of perceived identity in the opposite direction [Bertelson, P., Vroomen, J., & de Gelder, B. (2003). Visual recalibration of auditory speech identification: a McGurk aftereffect. Psychological Science, 14, 592–597]. Here, we examined the build-up course of the after-effects produced by the same two types of bimodal adapters, over a 1–256 range of presentations. The (negative) after-effects of non-ambiguous congruent adapters increased monotonically across that range, while those of ambiguous incongruent adapters followed a curvilinear course, going up and then down with increasing exposure. This pattern is discussed in terms of an asynchronous interaction between recalibration and selective adaptation processes.

We examined how visual recalibration of apparent sound location obtained at a particular location generalizes to untrained locations. Participants pointed toward the origin of tone bursts scattered along the azimuth, before and after repeated exposure to bursts in one particular location, synchronized with point flashes of light a constant distance to their left/right. Adapter tones were presented straight ahead in Experiment 1, and in the left or right periphery in Experiment 2. With both arrangements, different generalization patterns were obtained on the visual distractor's side of the auditory adapter and onthe opposite side. On the distractor side, recalibration generalized following a descending gradient; practically no generalization was observed on the other side. This dependence of generalization patterns on the direction of the discordance imposed during adaptation has not been reported before, perhaps because the experimental designs in use did not allow its observation.

Studies of multimodal integration have relied to a large extent on conflict situations, in which two sensory modalities receive incongruent data concerning one aspect of the source. Exposure to such situations produces immediate crossmodal biases as well as longer lasting aftereffects, revealing recalibrations of data-to-percept matches. In the natural environment, such phenomena might be adaptive, by reducing the perturbing effects of factors like noise or growth-induced changes in receptor organs, and by enriching the percept. However, experimental results generalize to real life only when they reflect automatic perceptual processes, and not response strategies adopted to satisfy the particular demands of laboratory tasks. Here, we focus on this issue and review ways of addressing it that have been developed recently.

In two experiments, we measured audio-visual crossmodal attraction on the time dimension, using a sensorimotor synchronization task. Synchronization performance made it possible to split up the total crossmodal attraction (demonstrated in earlier studies through inter-modal temporal order judgments) into its modality-specific components, the auditory bias of the visual event's perceived time of occurrence and the visual bias of the auditory event's perceived time of occurrence. Participants were asked to produce tapping movements in synchrony with a sequence of isochronously repeated pacing signals. In Experiment 1, pacing signals were light flashes, each preceded or followed, at one of several stimulus onset asynchronies (SOAs), by an auditory distracter that the participant was instructed to ignore. The timing of the tap was, in spite of that instruction, strongly biased toward the distracter. In Experiment 2, the converse task was used. The pacing signals were auditory and the to be ignored distracters, light flashes. The timing of the taps was biased significantly here also toward the distracter, but to a much lesser extent. Taken together, these results clearly demonstrate that audition plays a bigger role than vision in temporal ventriloquism and is probably generally superior to vision for processing the temporal dimension of events.

In the well-known visual bias of auditory location (alias the ventriloquist effect), auditory and visual events presented in separate locations appear closer together, provided the presentations are synchronized. Here, we consider the possibility of the converse phenomenon: crossmodal attraction on the time dimension conditional on spatial proximity. Participants judged the order of occurrence of sound bursts and light flashes, respectively, separated in time by varying stimulus onset asynchronies (SOAs) and delivered either in the same or in different locations. Presentation was organized using randomly mixed psychophysical staircases, by which the SOA was reduced progressively until a point of uncertainty was reached. This point was reached at longer SOAs with the sounds in the same frontal location as the flashes than in different places, showing that apparent temporal separation is effectively longer in the first condition. Together with a similar one obtained recently in a case of tactile-visual discrepancy, this result supports a view in which timing and spatial layout of the inputs play to some extent inter-changeable roles in the pairing operation at the base of crossmodal interaction.

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When auditory and visual events, such as sound bursts and light flashes, occur close together in time but at somewhat disparate locations, source localization for one modality interacts with that for the other modality in characteristic ways (Bermant & Welch, 1976; Bertelson, 1994, 1998; Radeau, 1994). These interactions are interesting because they may help us to understand the processes by which a coherent representation of extrapersonal space is established and maintained. It has become customary to apply the collective term ventriloquism to all cases of auditory–visual spatial interaction, because the most familiar example from everyday life is the illusion created by performing ventriloquists, whereby the speech they produce without visible articulatory movements appears to come from a puppet they move in approximate synchrony with the speech sounds. A similar illusion is, of course, experienced by most movie audiences when they hear the spoken soundtrack as emanating from the actor’s moving mouth on the screen. Several previous studies have considered whether such ventriloquism is due primarily to sensory factors or to more cognitive factors. In this article, we test, for the first time, whether ventriloquism depends on the direction of deliberate visual attention. Ventriloquism has been formally demonstrated in many situations with spatial discordance between concurrent auditory and visual events and is revealed both by its online effects and by its aftereffects. The on-line effects include a cross-modal influence on unimodal localization, sometimes called crossmodal bias.1 This is shown when a subject is asked to localize the stimulation from just one of the two modalities (e.g., by pointing or by verbal report),

Previously, we showed that the visual bias of auditory sound location, or ventriloquism, does not depend on the direction of deliberate, orendogenous, attention (Bertelson, Vroomen, de Gelder, & Driver, 2000). In the present study, a similar question concerning automatic, orexogenous, attention was examined. The experimental manipulation was based on the fact that exogenous visual attention can be attracted toward asingleton—that is, an item different on some dimension from all other items presented simultaneously. A display was used that consisted of a row of four bright squares with one square, in either the left- or the rightmost position,smaller than the others, serving as the singleton. In Experiment 1, subjects made dichotomous left-right judgments concerning sound bursts, whose successivelocations were controlled by a psychophysical staircase procedure and which were presented in synchrony with a display with the singleton either left or right. Results showed that the apparent location of the sound was attractednot toward the singleton, but instead toward the big squares at the opposite end of the display. Experiment 2 was run to check that the singleton effectively attracted exogenous attention. The task was to discriminate target letters presented either on the singleton or on the opposite big square. Performance deteriorated when the target was on the big square opposite the singleton, in comparison with control trials with no singleton, thus showing that the singleton attracted attention away from the target location. In Experiment 3, localization and discrimination trials were mixed randomly so as to control for potential differences in subjects’ strategies in the two preceding experiments. Results were as before, showing that the singleton attracted attention, whereas sound localization was shifted away from the singleton. Ventriloquism can thus be dissociated from exogenous visual attention and appears to reflect sensory interactions with little role for the direction of visual spatial attention.

The term ventriloquism refers to various manifestations of crossmodal spatial interaction between auditory and visual inputs which are observed in sensory conflict situations. These involve on-line manifestations like perceptual fusion in spite of spatial discrepancy and immediate crossmodal bias, by which localization of data in one modality are attracted toward conflicting data in the other modality, and also off-line aftereffects. Existing data concerning the variables on which the occurrence of the phenomena depend are reviewed, with insistence on the distinction between sensory and cognitive factors. A question which has been neglected in the literature consists of separating genuine perceptual contributions to the phenomena from voluntary post-perceptual adjustments. Using a new paradigm based on psychophysical staircases, we have shown that the visual bias of auditory location occurs even when the subject is not aware of the auditory-visual discrepancy, hence cannot reduce to voluntary corrections. Other experiments have demonstrated that ventriloquism cannot be explained by deliberate shifts of spatial attention. It is concluded that ventriloquism reflects a phenomenon of automatic crossmodal pairing, that is, formation of a cross-modal perceptual unit which takes place at a pre-conscious processing stage and thus must be clearly distinguished from conscious perceptual fusion.