The temporal cross-capture of audition and vision.

We report that when a flash and audible click occur in temporal proximity to each other, the perceived time of occurrence of both events is shifted in such a way as to draw them toward temporal convergence. In one experiment, observers judged when a flash occurred by reporting the clock position of a rotating marker. The flash was seen significantly earlier when it was preceded by an audible click and significantly later when it was followed by an audible click, relative to a condition in which the flash and click occurred simultaneously. In a second experiment, observers judged where the marker was when the click was heard. When a flash preceded or followed the click, similar but smaller capture effects were observed. These capture effects may reveal how temporal discrepancies in the input from different sensory modalities are reconciled and could provide a probe for examining the neural stages at which evoked responses correspond to the contents of conscious perception.     

Cross-modal detection using various temporal and spatial configurations

To better understand temporal and spatial cross-modal interactions, two signal detection experiments were conducted in which an auditory target was sometimes accompanied by an irrelevant flash of light. In the first, a psychometric function for detecting a unisensory auditory target in varying signal-to-noise ratios (SNRs) was derived. Then auditory target detection was measured while an irrelevant light was presented with light/sound stimulus onset asynchronies (SOAs) between 0 and ±700 ms. When the light preceded the sound by 100 ms or was coincident, target detection (d') improved for low SNR conditions. In contrast, for larger SOAs (350 and 700 ms), the behavioral gain resulted from a change in both d' and response criterion (β). However, when the light followed the sound, performance changed little. In the second experiment, observers detected multimodal target sounds at eccentricities of ±8°, and ±24°. Sensitivity benefits occurred at both locations, with a larger change at the more peripheral location. Thus, both temporal and spatial factors affect signal detection measures, effectively parsing sensory and decision-making processes.     

Continuous measurement of visible persistence

In the synchrony judgment paradigm, observers judge whether a click precedes or follows the onset of a light flash and, on other trials, whether or not a click precedes light termination. The interclick interval defines the duration of visible persistence. An elaboration of this method consists of two phases: In Phase 1, the luminance of a reference stimulus is psychophysically matched to the peak brightness of the test flash. Five luminance values between .1 and 1.0 of the reference stimulus are used subsequently. In Phase 2, a random one of the five reference stimuli, a test flash, and a click are presented; the observer judges whether the click occurred before or after the brightness of test flash reached the reference value (on onset trials) or decayed below it (on termination trials). This method was validated on 3 subjects with test stimuli whose luminance rises and decays slowly in time, and then was used to trace out the precise subjective rise and decay (temporal brightness response function) of brief flashes.     

Comparing mislocalizations with moving stimuli: The Fröhlich effect,the flash-lag,and representational momentum

When observers are asked to localize the onset or the offset position of a moving target, they typically make localization errors in the direction of movement. Similarly, when observers judge a moving target that is presented in alignment with a flash, the target appears to lead the flash. These errors are known as the Fröhlich effect, representational momentum, and flash-lag effect, respectively. This study compared the size of the three mislocalization errors. In Experiment 1, a flash appeared either simultaneously with the onset, the mid-position, or the offset of the moving target. Observers then judged the position where the moving target was located when the flash appeared. Experiments 2 and 3 are exclusively concerned with localizing the onset and the offset of the moving target. When observers localized the position with respect to the point in time when the flash was presented, a clear mislocalization in the direction of movement was observed at the initial position and the mid-position. In contrast, a mislocalization opposite to movement direction occurred at the final position. When observers were asked to ignore the flash (or when no flash was presented at all), a reduced error (or no error) was observed at the initial position and only a minor error in the direction of the movement occurred at the final position. An integrative model is proposed, which suggests a common underlying mechanism, but emphasizes the specific processing components of the Fröhlich effect, flash-lag effect, and representational momentum.     

Driven to distraction? The effect of simulated red light running camera flashes on attention and oculomotor control

Do similar factors influence the allocation of attention in visually sparse and abstract laboratory paradigms and complex real-world scenes? To explore this question we conducted a series of experiments that examined whether the flash that accompanies a Red Light Running Camera (RLRC) can capture observers' attention away from important roadway changes. Inhibition of Return (IOR) and eye movement direction served as indices of the spatial allocation of attention. In two experiments, participants were slower to respond to the brake lights of a vehicle in a driving scene when an RLRC flash occurred nearby or were slower to initiate eye movements to brake light signals (IOR effects). In a third experiment, we found evidence that less prevalent RLRC flashes disrupted eye movement control. Results suggest that attention can be misdirected as a result of RLRC flashes and provide additional evidence that findings from simple laboratory paradigms can predict the allocation of attention in complex settings that are more familiar to observers.     

Conditional acceleration and external disinhibition of operant lever pressing by prereward, neutral, and reinforcing stimuli

Rats responding under a differential-reinforcement-of-low-rate schedule increased their rates of lever pressing during a 20-second click/flash stimulus that preceded the delivery of a response-independent food pellet. The increase could not be attributed to suppression of collateral behavior that has been said to mediate temporally-spaced responding. We propose that the prereward stimulus functioned as an external disinhibitor of lever pressing that had been inhibited by the constraints of the operant schedule. Support is derived from the observed disinhibitory effects of a 10-second unpaired click/flash stimulus and of unsignaled, response-independent pellets that were presented while the animals were responding under the same schedule.     

Attention and interference in the perception of brief visual displays

When a single target was displayed 100-200 ms after a five-item array, observers were remarkably poor at deciding whether or not the target was in the array; performance was much better when the target either preceded the array or followed it by a longer interval. This effect was independent of a number of visual display parameters, suggesting that it was not due to visual contour interaction. In addition, visual similarity did not interact with the effect, indicating that it probably did not occur during item identification either. However, when observers added one to a digit target before deciding whether it occurred in the array, the effect was substantially reduced. The results suggested a model in which abstract identity information about the target is confused with the array at certain temporal intervals. A quantitative version of this model fit the data quite well.     

The effects of presenting a click in syllable-initial position on the speech of stutterers: Comparison with a metronome click

The speech of ten stutterers, recorded while they were listening to a concurrent metronome click and with a click which was triggered so that it occurred at the beginning of every syllable, was assessed. Speech rate and number of disfluencies were measured in each speaking condition. The results indicated that fewer disfluencies occurred (relative to normal reading performance) when a metronome or syllable-initial click was presented.In a perceptual experiment, a group of normal listeners was presented with samples of each of the stutterers' speech from all three speaking conditions. The listeners were asked to choose that which sounded most natural. The speech recorded from the condition where a click occurred at syllable onset was judged more natural than normal speech or speech recorded while the stutterers heard a metronome click.     

What speeds up the internal clock? Effects of clicks and flicker on duration judgements and reaction time

Four experiments investigated the effect of pre-stimulus events on judgements of the subjective duration of tones that they preceded. Experiments 1 to 4 used click trains, flickering squares, expanding circles, and white noise as pre-stimulus events and showed that (a) periodic clicks appeared to “speed up” the pacemaker of an internal clock but that the effect wore off over a click-free delay, (b) aperiodic click trains, and visual stimuli in the form of flickering squares and expanding circles, also produced similar increases in estimated tone duration, as did white noise, although its effect was weaker. A fifth experiment examined the effects of periodic flicker on reaction time and showed that, as with periodic clicks in a previous experiment, reaction times were shorter when preceded by flicker than without.     

时间任务需求对无关情绪面孔注意捕获的影响

注意捕获是指与任务无关的刺激能够不自觉地吸引注意的现象。实验一采用视觉搜索任务,考察与主任务无关的情绪面孔的注意捕获水平及其机制,实验二进一步探究时间任务需求对无关情绪面孔注意捕获的影响。结果发现:与其他情绪面孔相比,愤怒的情绪面孔捕获了更多的注意,且受到整体情绪加工的影响;时间任务需求影响了目标刺激的注意选择,但愤怒优势效应不受到时间任务需求的影响,因此可能是一种较为自动化的加工过程。     

Hearing what the eyes see: auditory encoding of visual temporal sequences

When the senses deliver conflicting information, vision dominates spatial processing, and audition dominates temporal processing. We asked whether this sensory specialization results in cross-modal encoding of unisensory input into the task-appropriate modality. Specifically, we investigated whether visually portrayed temporal structure receives automatic, obligatory encoding in the auditory domain. In three experiments, observers judged whether the changes in two successive visual sequences followed the same or different rhythms. We assessed temporal representations by measuring the extent to which both task-irrelevant auditory information and task-irrelevant visual information interfered with rhythm discrimination. Incongruent auditory information significantly disrupted task performance, particularly when presented during encoding; by contrast, varying the nature of the rhythm-depicting visual changes had minimal impact on performance. Evidently, the perceptual system automatically and obligatorily abstracts temporal structure from its visual form and represents this structure using an auditory code, resulting in the experience of "hearing visual rhythms."     

Involuntary attention and brightness contrast

Carrasco, Ling, and Read (2004) reported that involuntary attention increased perceived contrast. We replicated Carrasco et al. and then tested an alternative hypothesis: With stimuli near threshold, a peripheral cue biased observers to believe a stimulus had been presented in the cued location. Consistent with this hypothesis, the effect disappeared when we used higher-contrast stimuli. We further tested the guessing-bias hypothesis in three ways: (1) In a detection experiment, the cue affected bias, but did not increase d'; (2) when the cue followed the stimulus, we obtained the same results as when the cue preceded the stimulus; (3) in one experiment, some trials contained no stimulus, yet observers responded that the cued blank stimulus had higher contrast than the uncued blank stimulus. The results suggest that the effects of a noninformative peripheral cue are best described in terms of nonperceptual biases.     

Speech dominance and handedness in the normal human

Spectral analysis was used to measure the coherence or similarity of form between occipital and temporal evoked potentials. In both right- and left-handers, coherence was greater in the left hemisphere for click stimuli and in the right hemisphere for flash stimuli. Similar asymmetries occurred in left but not right speech dominant patients whose speech lateralization has been determined by the intracarotid amytal test. Right-handers and males, however, showed significantly larger amplitudes of auditory responses in the right hemisphere. Left-handers and females reversed this pattern. It was concluded that within a basically left speech dominant organization, males and right-handers would emphasize the verbal, temporal structure of auditory information and the nonverbal, spatial structure of visual information. Females and left-handers would tend to reverse this emphasis.     

Perception of clicks in music

Subjects were asked to judge the position of a click that occurred during a short piece of music. Clicks were, on average, judged to be later than their actual position. The click and the music were presented through headphones to different ears, and the clicks were judged to be significantly later if they arrived at the right ear rather than at the left. There was also a significant tendency for clicks to be attracted to phrase boundaries in the music. These last two results are similar to those from experiments with a click during speech, but the late judgments of a click in music contrast with the early judgments of a click in speech.     

The visual perception of distance ratios outdoors

We conducted an experiment to evaluate the ability of 32 younger and older adults to visually perceive distances in an outdoor setting. On any given trial, the observers viewed 2 environmental distances and were required to estimate the distance ratio—the length of the (usually) larger distance relative to that of the shorter. The stimulus distance ratios ranged from 1.0 (the stimulus distances were identical) to 8.0 (1 distance interval was 8.0 times longer than the other). The stimulus distances were presented within a 26 m × 60 m portion of a grassy field. The observers were able to reliably estimate the stimulus distance ratios: The overall Pearson r correlation coefficient relating the judged and actual distance ratios was 0.762. Fifty-eight percent of the variance in the observers’ perceived distance ratios could thus be accounted for by variations in the actual stimulus ratios. About half of the observers significantly underestimated the distance ratios, while the judgments of the remainder were essentially accurate. Significant modulatory effects of sex and age occurred, such that the male observers’ judgments were the most precise, while those of the older males were the most accurate.     

Novelty and saliency in attentional capture by unannounced motion singletons

The present study examined attentional capture by an unannounced motion singleton in a visual search task. The results showed that a motion singleton only captured attention on its first unannounced occurrence when the observers had not encountered moving items before in the experiment, whereas it failed to capture when observers were familiar with moving items. This indicates that motion can capture attention independently of top-down attentional control settings, but only when motion as a feature is unexpected and new. An additional experiment tested whether salient items can capture attention when all stimuli possess new and unexpected features, and novelty information cannot guide attention. The results showed that attention was shifted to the location of the salient item when all items were new and unexpected, reinforcing the view that salient items receive attentional priority. The implications of these results for current theories of attention are discussed.     

Judgments of synchrony between auditory and moving or still visual stimuli.

The flash-lag effect is a visual illusion wherein intermittently flashed, stationary stimuli seem to trail after a moving visual stimulus despite being flashed synchronously. We tested hypotheses that the flash-lag effect is due to spatial extrapolation, shortened perceptual lags, or accelerated acquisition of moving stimuli, all of which call for an earlier awareness of moving visual stimuli over stationary ones. Participants judged synchrony of a click either to a stationary flash of light or to a series of adjacent flashes that seemingly bounced off or bumped into the edge of the visual display. To be judged synchronous with a stationary flash, audio clicks had to be presented earlier--not later--than clicks that went with events, like a simulated bounce (Experiment 1) or crash (Experiments 2-4), of a moving visual target. Click synchrony to the initial appearance of a moving stimulus was no different than to a flash, but clicks had to be delayed by 30-40 ms to seem synchronous with the final (crash) positions (Experiment 2). The temporal difference was constant over a wide range of motion velocity (Experiment 3). Interrupting the apparent motion by omitting two illumination positions before the last one did not alter subjective synchrony, nor did their occlusion, so the shift in subjective synchrony seems not to be due to brightness contrast (Experiment 4). Click synchrony to the offset of a long duration stationary illumination was also delayed relative to its onset (Experiment 5). Visual stimuli in motion enter awareness no sooner than do stationary flashes, so motion extrapolation, latency difference, and motion acceleration cannot explain the flash-lag effect.     

Cerebral Asymmetry and Decision Strategies in Mental Rotation: A Psychophysical Analysis

The accuracy with which observers judged the parity of pairs of rotated images in the two visual fields was determined from receiver operating characteristic (ROC) analysis of confidence ratings. In one experiment, observers judged whether pairs of letters were of the same parity (that is, both normal or both backwards) or of different parities (one normal and one backwards). A small right visual field advantage in the observers' accuracy was found in this mental rotation task. In a second experiment, observers judged whether pairs of pictures were of the same parity or of different parities. Unlike the first experiment, no evidence of a consistent visual field advantage was found in this mental rotation task. The decision strategy adopted by the observers in making same-different judgements about rotated stimuli was examined. The symmetrical shape of the ROCs obtained was consistent with the adoption of the likelihood-ratio decision strategy, a result which supplemented previous evidence that this decision strategy is adopted when same-different judgements are made about multidimensional stimuli.     

The influence of melodic context on pitch recognition judgment

Subjects made delayed pitch comparisons between tones that were each preceded by tones of lower pitch. The pitches of these preceding tones were so chosen that in some conditions the melodic intervals formed by the standard (S) and comparison (C) combinations were identical, and in others they differed. A strong effect of melodic relational context was demonstrated. When the S and C combinations formed identical melodic intervals, there was an increased tendency for the S and C tones to be judged as identical. And when the S and C combinations formed different melodic intervals, there was an increased tendency for the S and C tones to be judged as different. These effects occurred both when the S and C tones were identical in pitch and also when these differed, and they occurred despite instructions to attend only to the S and C tones.     

Abrupt onsets capture attention independent of top-down control settings

Previous research using a spatial cuing paradigm in which a distractor cue preceded the target has shown that new objects presented with abrupt onsets only capture attention when observers are set to look for them (e.g., Folk, Remington, & Johnston, 1992). In the present study, we used the same spatial cuing paradigm as Folk et al. (1992) to demonstrate that even when observers have an attentional set for a color singleton or a specific color feature, an irrelevant new object presented with an abrupt onset interfered with search. We also show that the identity of the abrupt-onset distractor affects responses to the target, indicating that at some point spatial attention was allocated to the abrupt onset. We conclude that abrupt onsets ornew objects override a top-down set for color. Abrupt onsets or new objects appear to capture attention independently of top-down control settings.