Karin M. Bausenhart

The locus of temporal preparation effects: Evidence from the psychological refractory period paradigm

In reaction time (RT) tasks, responses are especially fast when participants can anticipate the onset of an imperative response signal. Although this RT facilitation is commonly attributed to temporal preparation, it is unclear whether this preparation shortens the duration of early or late processes. We used the effect propagation property of the psychological refractory period paradigm to localize the effect of temporal preparation. Manipulation of temporal uncertainty affected the RT of Task 1, regardless of the level of stimulus onset asynchrony (SOA). Consistent with the prediction of an early locus of temporal preparation, this effect propagated completely to the RT of Task 2 at short SOAs, but propagation diminished virtually to zero at long SOAs.

Trial-by-trial updating of an internal reference in discrimination tasks: evidence from effects of stimulus order and trial sequence

In psychophysics, participants are often asked to discriminate between a constant standard and a variable comparison. Previous studies have shown that discrimination performance is better when the comparison follows, rather than precedes, the standard. Prominent difference models of psychophysics and decision making cannot easily explain this order effect. However, a simple extension of this model class involving dynamical updating of an internal reference accounts for this order effect. In addition, this Internal Reference Model (IRM) predicts sequential response effects. We examined the predictions of IRM in two duration discrimination experiments. The obtained results are in agreement with the predictions of IRM, suggesting that participants update their internal reference on every trial. Additional simulations show that IRM also accounts for the negative sequential effects observed in single-stimulus paradigms.

Temporal preparation improves temporal resolution : Evidence from constant foreperiods

Recent research shows that temporal preparation within a constant foreperiod design improves the spatial resolution of visual perception. The present experiments were designed to investigate whether similar benefits of temporal preparation can be observed in a task that requires high temporal resolution. In three experiments, we assessed the effect of temporal preparation on temporal order judgments (TOJs). In Experiment 1, short foreperiods facilitated TOJ for two spatially adjacent dots. This finding was replicated in Experiment 2, in which the temporal order of two spatially overlapping stimuli (“+” and “x”) had to be discriminated. Experiment 3 investigated the time course of temporal preparation by extending these findings to a wide range of different foreperiod durations. The present findings corroborate recent evidence for a perceptual locus of temporal preparation. Most importantly, they show that temporal preparation within a constant foreperiod design improves the temporal resolution of visual perception, independently of whether TOJ requires a decision about the location or about the identity of the target stimuli.

Knowing when to hear aids what to hear

Temporal preparation often has been assumed to influence motor stages of information processing. Recent studies, however, challenge this notion and provide evidence for a facilitation of visual processing. The present study was designed to investigate whether perceptual processing in the auditory domain also benefits from temporal preparation. To this end, we employed a pitch discrimination task. In Experiment 1, discrimination performance was clearly improved when participants were temporally prepared. This finding was confirmed in Experiment 2, which ruled out possible influences of short-term memory. The results support the notion that temporal preparation enhances perceptual processing not only in the visual, but also in the auditory, modality.

Temporal preparation decreases perceptual latency: Evidence from a clock paradigm

A clock paradigm was employed to assess whether temporal preparation decreases the time to detect the onset of a stimulus—that is, perceptual latency. In four experiments participants watched a revolving clock hand while listening to soft or loud target tones under high or low temporal preparation. At the end of each trial, participants reported the clock hand position at the onset of the target tone. The deviation of the reported clock hand position from the actual position indexed perceptual latency. As expected, perceptual latency decreased with target tone intensity. Most importantly, however, greater temporal preparation decreased perceptual latency in all four experiments, especially for soft tones, which supports rather directly the idea that temporal preparation diminishes the duration of perceptual processing.

Temporal preparation influences the dynamics of information processing: Evidence for early onset of information accumulation

When participants can temporally prepare for a visual target stimulus, responses to this stimulus are faster and more accurate. Recent accounts attribute these effects either to an earlier accumulation of stimulus information or to an increased rate of information sampling. The present study examines whether temporal preparation induces such changes in the dynamics of information processing by investigating speed-accuracy trade-off (SAT) functions. Shorter onsets and higher asymptotes of the estimated SAT functions were found for high temporal preparation conditions. These results provide evidence for an earlier onset of information accumulation in the visual system when temporal preparation is high.

Temporal reproductions are influenced by an internal reference: Explaining the Vierordt effect

Several findings from duration perception literature suggest that when making decisions about time, participants rely on an internal reference memory for time rather than merely on the current physical stimuli. According to a recent account, such an internal reference is formed by a continuous dynamic updating process that integrates duration information from previous trials and the current trial. In the present work, we show how such a dynamic mechanism can account for the classical yet unresolved Vierordt effect, which refers to the overestimation of relatively short and the underestimation of relatively long temporal intervals. We conducted an experiment to examine this and related predictions by means of a temporal reproduction task. Specifically, participants were presented with two successive time intervals - a standard s with constant duration and a comparison c with variable duration. Instead of performing a comparison judgment, however, the participants were subsequently cued to reproduce one of the two presented stimuli. Reproductions were affected not only by the temporal position of the to-be-reproduced stimulus, but also by the stimuli presented on earlier trials. These results support the notion of a dynamically updated internal reference underlying our judgments about the time elapsed, which might also be the basis of the Vierordt effect.

Attention delays perceived stimulus offset

Yeshurun and Levy (2003) [Transient spatial attention degrades temporal resolution. Psychological Science, 14, 225 -231.] have suggested that visual attention enhances the activation of the parvocellular system and thus delays the perceived offset of a stimulus. We tested this assumption in a spatial cueing paradigm in which participants responded to stimulus offset. Consistent with this assumption, offset reaction time (RT) was prolonged for attended compared to unattended stimuli. For onset RT, however, we confirmed the well-known spatial cueing effect that attention speeds up the detection of stimulus onset. The results provide direct evidence for the proposal made by Yeshurun and Levy.

Multimodal Integration of Time Visual and Auditory Contributions to Perceived Duration and Sensitivity

Recent studies suggest that the accuracy of duration discrimination for visually presented intervals is strongly impaired by concurrently presented auditory intervals of different duration, but not vice versa. Because these studies rely mostly on accuracy measures, it remains unclear whether this impairment results from changes in perceived duration or rather from a decrease in perceptual sensitivity. We therefore assessed complete psychometric functions in a duration discrimination task to disentangle effects on perceived duration and sensitivity. Specifically, participants compared two empty intervals marked by either visual or auditory pulses. These pulses were either presented unimodally, or accompanied by task-irrelevant pulses in the respective other modality, which defined conflicting intervals of identical, shorter, or longer duration. Participants were instructed to base their temporal judgments solely on the task-relevant modality. Despite this instruction, perceived duration was clearly biased toward the duration of the intervals marked in the task-irrelevant modality. This was not only found for the discrimination of visual intervals, but also, to a lesser extent, for the discrimination of auditory intervals. Discrimination sensitivity, however, was similar between all multimodal conditions, and only improved compared to the presentation of unimodal visual intervals. In a second experiment, evidence for multisensory integration was even found when the task-irrelevant modality did not contain any duration information, thus excluding noncompliant attention allocation as a basis of our results. Our results thus suggest that audiovisual integration of temporally discrepant signals does not impair discrimination sensitivity but rather alters perceived duration, presumably by means of a temporal ventriloquism effect.

Formation and representation of temporal reference information

We review psychophysical studies on temporal judgments which demonstrate that these judgments not only depend on current stimulation but also on task-irrelevant context information and the history of stimulus input. Consequently, models that take only current stimulation into account (e.g., the standard difference model) are incapable to explain these extraneous influences. However, models that incorporate the concept of internal references can account for several of these influences. Typical models from this class are the internal reference model, Bayesian inference, memory mixing, and sensation weighting. Further research is needed to elucidate the general properties of internal references. For this purpose, we provide questions that might guide future empirical investigation and thus shape theoretical advances in the field.