Multisensory Temporal Order Judgments: When Two Locations Are Better Than One (original) (raw)
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Spatial Modulation of Tactile Temporal-Order Judgments
Perception, 2005
We report a series of three experiments designed to examine the effect of posture on tactile temporal processing. Observers reported which of two tactile stimuli, presented to the left and right index fingers (experiments 1 – 3; or thumb, experiment 3), was perceived first while adopting one of two postures—hands-close (adjacent, but not touching) or hands-far (1 m apart)—in the dark. Just-noticeable differences were significantly smaller in the hands-far posture across all three experiments. In the first two experiments we compared hand versus foot responses and found equivalent advantages for the hands-far posture. In the final experiment the stimuli were presented to either the same or different digit on each hand (index finger or thumb) and we found that only when the same digit on each hand was stimulated was there an advantage for the hands-far posture. The finding that temporal precision was better with greater distance contradicts predictions based on attention-switching mod...
Audiovisual temporal order judgments
Experimental Brain Research, 2003
In two experiments, we examined the extent to which audiovisual temporal order judgments (TOJs) were affected by spatial factors and by the dimension along which TOJs were made. Pairs of auditory and visual stimuli were presented from either the left and/or right of fixation at varying stimulus onset asynchronies (SOAs), and participants made unspeeded TOJs regarding either "Which modality was presented first?" (experiment 1), or "Which side was presented first?" (experiment 2). Modality TOJs were more accurate (i.e. just-noticeable differences, JNDs, were smaller) when the auditory and visual stimuli were presented from different spatial positions rather than from the same position, highlighting an important potential confound inherent in previous research. By contrast, spatial TOJs were unaffected by whether or not the two stimuli were presented in different modalities. A between-experiments comparison revealed more accurate performance (i.e. smaller JNDs) when people reported which modality came first than when they reported which side came first for identical bimodal stimulus pairs. These results demonstrate that multisensory TOJs are critically dependent on both the relative spatial position from which stimuli are presented and on the particular dimension being judged.
2019 IEEE World Haptics Conference (WHC)
When people judge the temporal order (TOJ task) of two tactile stimuli at the two hands while their hands are crossed, performance is much worse than with uncrossed hands [1]. This crossed-hands deficit is widely considered to indicate interferences of external spatial coordinates with body-centered coordinates in the localization of touch [2]. Similar deficits have also been observed when people are only about to move their hands towards a crossed position [3-5], suggesting a predictive update of external spatial coordinates. Here, we extend the investigation of the dynamics of external coordinates during hand movement. Participants performed a TOJ task while they executed an uncrossing or a crossing movement, and during presentation of the TOJ stimuli the present posture of the hands was crossed, uncrossed or in-between. Present, future and past crossed-hands postures decreased performance in the TOJ task, suggesting that the update of external spatial coordinates of touch includes both predictive processes and processes that preserve the recent past. In addition, our data corroborate the flip model of crossed-hands deficits [1], and suggest that more pronounced deficits come along with higher time requirements to resolve interferences.
Frontiers in Psychology, 2014
To respond to a touch, it is often necessary to localize it in space, and not just on the skin.The computation of this external spatial location involves the integration of somatosensation with visual and proprioceptive information about current body posture. In the past years, the study of touch localization has received substantial attention and has become a central topic in the research field of multisensory integration. In this review, we will explore important findings from this research, zooming in on one specific experimental paradigm, the temporal order judgment (TOJ) task, which has proven particularly fruitful for the investigation of tactile spatial processing. In a typical TOJ task participants perform nonspeeded judgments about the order of two tactile stimuli presented in rapid succession to different skin sites. This task could be solved without relying on external spatial coordinates. However, postural manipulations affect TOJ performance, indicating that external coordinates are in fact computed automatically. We show that this makes the TOJ task a reliable indicator of spatial remapping, and provide an overview over the versatile analysis options for TOJ. We introduce current theories of TOJ and touch localization, and then relate TOJ to behavioral and electrophysiological evidence from other paradigms, probing the benefit of TOJ for the study of spatial processing as well as related topics such as multisensory plasticity, body processing, and pain.
Multisensory Research
Exploring the world through touch requires the integration of internal (e.g., anatomical) and external (e.g., spatial) reference frames — you only know what you touch when you know where your hands are in space. The deficit observed in tactile temporal-order judgements when the hands are crossed over the midline provides one tool to explore this integration. We used foot pedals and required participants to focus on either the hand that was stimulated first (an anatomical bias condition) or the location of the hand that was stimulated first (a spatiotopic bias condition). Spatiotopic-based responses produce a larger crossed-hands deficit, presumably by focusing observers on the external reference frame. In contrast, anatomical-based responses focus the observer on the internal reference frame and produce a smaller deficit. This manipulation thus provides evidence that observers can change the relative weight given to each reference frame. We quantify this effect using a probabilistic...
Effects of redundant visual stimuli on temporal order judgments
Perception & Psychophysics, 2004
Four experiments were conducted in order to compare the effects of stimulus redundancy on temporal order judgments (TOJs) and reaction times (RTs). In Experiments 1 and 2, participants were presented in each trial with a tone and either a single visual stimulus or two redundant visual stimuli. They were asked to judge whether the tone or the visual display was presented first. Judgments of the relative onset times of the visual and the auditory stimuli were virtually unaffected by the presentation of redundant, rather than single, visual stimuli. Experiments 3 and 4 used simple RT tasks with the same stimuli, and responses were much faster to redundant than to single visual stimuli. It appears that the traditional speedup of RT associated with redundant visual stimuli arises after the stimulus detection processes to which TOJs are sensitive.
Temporal judgments in multi–sensory space
Neuropsychologia, 2016
To successfully interact with the environment requires a combination of stimulus recognition as well as localization in both space and time, with information moreover coming from multiple senses. Several studies have shown that auditory stimuli last subjectively longer than visual ones of equal duration. Recently, it has also been suggested that stimulus position affects duration perception. The present study investigated how lateral spatial presentation influences sub-second visual and auditory duration judgments. Five experiments were conducted using the duration discrimination paradigm, wherein two stimuli are presented sequentially and participants are asked to judge whether the second stimulus (comparison) is shorter or longer in duration than the first (standard). The number of stimulus positions and the way in which different modality trials were presented (mixed or blocked) varied. Additionally, comparisons were made either within or across modalities. No stable effect of location itself was found. However, in mixed modality experiments there was a clear over-estimation of duration in visual trials when the location of the comparison was different from the standard. This effect was reversed in the same location trials. Auditory judgments were unaffected by location manipulations. Based on these results, we propose the existence of an error-mechanism, according to which a specific duration is added in order to compensate for the loss of duration perception caused by spatial attention shifts between different locations. This mechanism is revealed in spatial and modality-mixed circumstances wherein its over-activation results in a systematic temporal bias.
Dissociating the neural correlates of tactile temporal order and simultaneity judgements
Scientific Reports, 2016
Perceiving temporal relationships between sensory events is a key process for recognising dynamic environments. Temporal order judgement (TOJ) and simultaneity judgement (SJ) are used for probing this perceptual process. TOJ and SJ exhibit identical psychometric parameters. However, there is accumulating psychophysical evidence that distinguishes TOJ from SJ. Some studies have proposed that the perceptual processes for SJ (e.g., detecting successive/simultaneity) are also included in TOJ, whereas TOJ requires more processes (e.g., determination of the temporal order). Other studies have proposed two independent processes for TOJ and SJ. To identify differences in the neural activity associated with TOJ versus SJ, we performed functional magnetic resonance imaging of participants during TOJ and SJ with identical tactile stimuli. TOJ-specific activity was observed in multiple regions (e.g., left ventral and bilateral dorsal premotor cortices and left posterior parietal cortex) that ov...
Effects of Voluntary Movements on Audio-Tactile Temporal Order Judgment
IEICE Transactions on Information and Systems, 2014
The present study aims to investigate the effect of voluntary movements on human temporal perception in multisensory integration. We therefore performed temporal order judgment (TOJ) tasks in audio-tactile integration under three conditions: no movement, involuntary movement, and voluntary movement. It is known that the point of subjective simultaneity (PSS) under the no movement condition, that is, normal TOJ tasks, appears when a tactile stimulus is presented before an auditory stimulus. Our experiment showed that involuntary and voluntary movements shift the PSS to a value that reduces the interval between the presentations of auditory and tactile stimuli. Here, the shift of the PSS under the voluntary movement condition was greater than that under the involuntary movement condition. Remarkably, the PSS under the voluntary movement condition appears when an auditory stimulus slightly precedes a tactile stimulus. In addition, a just noticeable difference (JND) under the voluntary movement condition was smaller than those under the other two conditions. These results reveal that voluntary movements alternate the temporal integration of audio-tactile stimuli. In particular, our results suggest that voluntary movements reverse the temporal perception order of auditory and tactile stimuli and improve the temporal resolution of temporal perception. We discuss the functional mechanism of shifting the PSS under the no movement condition with voluntary movements in audio-tactile integration.