TEMPORAL INTEGRATION OF PERCEPTUAL RESPONSE TO SUPRALIMINAL ELECTRICAL STIMULATION

E kman , G., F röberg , J. & F rankenhaeuser , M. Temporal integration of perceptual response to supraliminal electrical stimulation. Scand. J. Psychol ., 1968, 9, 83–88.—The effect of duration of electrical stimulation on perceived unpleasantness was investigated in 10 subjects. Duration of stimulation ranged from 0.05 to 3.00 sec. Three levels of intensity were investigated representing 2, 3, and 4 times the individual sensation threshold. For all stimulus intensities perceived unpleasantness was a simple logarithmic function of stimulus duration over the whole temporal range. This relation describes the trend of both the group data and the data from most individual subjects. The results support previous findings over a narrower temporal range and agree with results recently obtained in several additional sense modalities.     

SCALES OF UNPLEASANTNESS OF ELECTRICAL STIMULATION

The subjective unpleasantness elicited by an A.C. current of 50 c/sec. applied to two fingers was scaled by 14 subjects using the methods of magnitude and of category estimation. Nine current intensities, ranging between 2 and 10 times the individual sensation thresholds, were used as stimuli. A power function yielded a good fit to the magnitude-estimation data; the exponent was 1.81. The difference between this value and a considerably higher exponent reported by previous investigators was interpreted in terms of the wider stimulus range used in the present study. The relation between the category scale and the magnitude scale had the same general form as that found in several previous investigations.     

PSYCHOPHYSICAL SCALES OF THE ODOR INTENSITY OF AMYL ACETATE

The paper presents psychophysical scales of amyl acetate in benzyl benzoate sniffed from cotton. Four scales obtained by direct scaling procedures, ratio estimation and magnitude estimation, yield functions of the form R = kSⁿ , with n ranging from 0.39 to 0.57. These data support earlier findings that the intensity of smell is a negatively accelerated function of stimulus intensity. In addition, comparison of magnitude and category scales indicate that the subjective intensity of smell is a prothetic continuum. Finally, further analysis of subjective ratios as a function of stimulus ratios again shows that ( a ) the magnitude scale is a ratio scale and ( b ) the function obtained conforms to the power law.     

Effects of attention manipulation on judgments of duration and of intensity in the visual modality

The “attentional model” of time estimation assumes that temporal judgments depend on the amount of attention allocated to the temporal processor (the timer). One of the main predictions of this model is that an interval will be judged shorter when attention is not allocated to the temporal parameters of the task. Previous studies combining temporal and nontemporal tasks (dual-task method) have suggested that the time spent processing the target duration might be a key factor: The less time devoted by the subject to the temporal task, the shorter the judged duration. In the two experiments presented here, subjects were asked to judge both the duration of a visual stimulus and an increment in intensity occurring at any time during this stimulus. In the second experiment, trials without intensity increments were added. The main result is that the judged duration was shorter when the increment occurred later in the stimulus or did not occur. In those cases, subjects had been expecting increment occurrence during most part of the stimulus and thus had focused for a shorter time on stimulus duration. We propose that attention shifts related to expectancy and to detection of the increment reduce subjective duration.     

恐惧的代价：疼痛恐惧、心理忧虑和躯体化对疼痛感知预测作用的比较

首次在无痛群体中比较疼痛恐惧、心理忧虑和躯体化对疼痛感知的预测作用大小及调节和中介关系。以多个同类量表得分的Z分数加和作为三者的因子分,以冷压痛觉测验（CPT）疼痛指标（阈限、耐受性、强度、不愉快度）为目标变量,通过分层回归及调节和中介作用分析,发现疼痛恐惧对疼痛不愉快度的预测作用最强,心理忧虑对疼痛体验（强度、不愉快度）的预测作用被疼痛恐惧完全中介,躯体化只有在高疼痛恐惧条件下才显著负向预测疼痛不愉快度。综上,疼痛恐惧是三因素中预测CPT疼痛体验的主要因素。     

短时距知觉中的面积效应

初步探讨了短时距（１─５ｓ）下时距刺激的面积大小和立体框架大小对时距知觉的影响及其成因。结果表明：刺激的面积大小对短时距知觉的影响极其显著;存在两种不同反应类型的被试─－大小依存者与非大小依存者,在不同反应类型的被试中刺激的立体框架大小对短时距知觉的影响不同,刺激的立体框架大小对大小依存者的短时距知觉的影响极其显著,但对非大小依存者的影响不显著。     

LOUDNESS AS A FUNCTION OF THE DURATION OF AUDITORY STIMULATION

The perceived loudness of a 1000 c/s tone was measured by a direct scaling method under different conditions of intensity (19–35 db) and duration (50–500 msec) of stimulation. It was found that loudness grows as a logarithmic function of stimulus duration; the relation was verified for ten individual subjects and four levels of intensity. In addition, the relation between temporal threshold and level of intensity was tentatively described.     

虚拟学习环境下图形加工的认知负荷研究

基于单探测变化觉察和双任务范式,采用项目数量（3）×呈现时间（2）×文字线索（2）混合实验设计,对沉浸式虚拟学习环境图形加工特征和认知负荷进行探讨,以任务绩效法与主观测量法评定认知负荷。44名大学生的实验结果显示：（1）项目数量对虚拟空间图形识记主任务绩效和主观认知负荷有显著影响,项目数量越多,主任务正确率越低,反应时越长,主观评定认知负荷越高,同时加工刺激数量以4个为宜;（2）呈现时间对虚拟空间图形识记次任务绩效有显著影响,呈现时间越长,次任务正确率越高,呈现时间超过0.5s有利于次任务加工;（3）文字线索对虚拟图形识记认知负荷有显著影响,重复性文字线索会增加认知负荷。结果表明,在沉浸式虚拟环境中,图形加工的认知负荷特点与平面和三维图形基本一致,项目数量多、呈现时间短以及有重复性文字线索时,认知负荷更高;任务绩效和主观测量评定指标在反映认知负荷强度上不完全一致。     

Is subjective shortening in human memory unique to time representations?

Three experiments compared forgetting of the duration of a bar-like visual stimulus with forgetting of its length. The main aim of the experiments was to investigate whether subjective shortening (a decrease in the subjective magnitude of a stimulus as its retention interval increased) was observable in length judgements as well as in time judgements, where subjective shortening has been often observed previously. On all trials of the three experiments, humans received two briefly presented coloured bars, separated by adelay ranging from 1 to 10 s, and the bars could differ in length, duration of presentation, or both. In Experiment 1 two groups of subjects made either length or duration judgements, and subjective shortening-type forgetting functions were observed only for duration. Experiments 2 and 3 used the same general procedure, but the stimuli judged could differ both in length and duration within a trial, and different subject groups (Experiment 2) or the same subjects in two conditions (Experiment 3) made either length or duration judgements of stimuli, which were on average physically identical. Subjective shortening was only found with duration, and never with length, supporting the view that subjective shortening may be unique to time judgements.     

THE INFLUENCE OF AUDITORY STIMULUS INTENSITY ON APPARENT DURATION

B erglund , B., B erglund , U., E kman , G. & F rankenhaeuser , M. The influence of auditory stimulus intensity on apparent duration. Scand J. Psychol ., 1969, 10 21–26.— apparent duration of an auditory signal of 1000 C/S was measured by the method of magnitude estimation. Ten different stimulus intensities ranging from 57 to 104 dB were used in combination with three different durations: 50, 250, and 500 msec. The results showed that the apparent duration of the signal grew as a logarithmic function of stimulus intensity. These results are consistent with the hypothesis relating apparent duration to activation level as well as with results of similar experiments involving electrical and vibrotactile stimulation.     

Odor intensity after self-adaptation and cross-adaptation

Psychophysical functions for the odor intensity of n-propanol and n-pentanol were obtained after no adaptation and after self-adaptation and cross-adaptation. Adaptation caused the psychophysical function to become steeper and generally concave downward in log-log coordinates. Increase in the in tensity of a: self-adapting stimulus produced relatively greater increases in the steepness of the functions than did increases in adapting duration. A comparison between the odorants revealed that propanol and pentanol have equal self-adapting effects when their respective adapting concentrations are matched for subjective intensity. Cross-adaptation had approximately the same effect as self-adaptation on the form of the psychophysical function, but a cross-adapting stimulus of a specified subjective intensity was less effective than a self-adapting stimulus of the same intensity. Adaptation to pentanol caused a larger reduction in the perceived intensity of propanol than adaptation to propanol caused in the perceived intensity of pentanol.     

Experimental comparison of dyspnea and pain

Dyspnea and pain are similarly unpleasant, alarming physical sensations, but studies examining both sensations in combination are lacking. In the present study, dyspnea was induced in 7 healthy volunteers by breathing through inspiratory resistive loads and the effects were compared with those of a heat pain stimulus. End-tidal partial pressures of carbon dioxide (PET_CO2), inspiratory time (Ti), breathing frequency (f), experienced unpleasantness, and intensity were measured. No difference was observed between dyspnea and pain in experienced intensity and unpleasantness (p >.05). During dyspneic stimulation, slightly higherTi was found than for pain (p<.08). PET_CO2 showed slight increases during the dyspneic versus the baseline and painful conditions (ΔPET_CO2=1.5 and 1.3 mmHg, respectively;p<.01 andp<.05). This study shows that the effects of dyspnea and heat pain can be compared within one experiment; both stimuli can be presented with similar intensity and unpleasantness, which is a prerequisite for comparing responses to them. The changes in PET_CO2 between our conditions were minimal, allowing an application of the present design to future fMRI studies.     

Stress Induced Oral Behaviors and Facial Pain

Facial pain is frequently associated with environmental stress and emotional distress. One hypothetical mechanism by which stress is translated into pain is through stress induced motor function (e.g., teeth clenching, grinding, nail biting). Existent data partially supports these stress-hyperactivity models although they have also come under theoretical and empirical attack. The purpose of this study was to examine the relationship between oral behaviors and pain in an analog sample of facial pain sufferers and student controls. Subjects engaged in a controlled clenching task and reported on subjective facial pain intensity and unpleasantness at 5 specified times over the subsequent 48 hours. A one-way ANCOVA indicated group differences in self reported oral habits (p < .05) with the facial pain group reporting great frequency of oral habits. Two repeated measures ANCOVAs (i.e., pain intensity and pain unpleasantness), controlling for baseline pain ratings, indicated a between groups effect with facial pain sufferers experiencing significantly greater pain over the 48 hours postexperiment (p < .05). This study supports a hyperactivity model of facial pain and provides clues about relevant factors in facial pain development.     

Subjective shortening with filled and unfilled auditory and visual intervals in humans?

Two experiments tested humans on a memory for duration task based on the method of Wearden and Ferrara (1993), which had previously provided evidence for subjective shortening in memory for stimulus duration. Auditory stimuli were tones (filled) or click-defined intervals (unfilled). Filled visual stimuli were either squares or lines, with the unfilled interval being the time between two line presentations. In Experiment 1, good evidence for subjective shortening was found when filled and unfilled visual stimuli, or filled auditory stimuli, were used, but evidence for subjective shortening with unfilled auditory stimuli was more ambiguous. Experiment 2 used a simplified variant of the Wearden and Ferrara task, and evidence for subjective shortening was obtained from all four stimulus types.     

Sensation magnitude of vibrotactile stimuli

A systematic investigation of the subjective magnitude of vibrotaction was undertaken to: (1) determine the growth of sensation as a function of stimulus intensity; (2) establish contours of equal subjective magnitude; and (3) compare over a wide range of frequency and intensity the psychophysical methods of direct scaling and intensity matching. The results show that the data obtained by direct scaling are comparable to the data obtained by interfrequency matching. The subjective magnitude function is a power function with a slope of about 0.89 for frequencies up to 350 Hz. Near threshold the growth of sensation is proportional to the physical intensity. Contours of equal subjective magnitude for vibration across 10 frequencies and at 11 levels of intensity are given.     

Pain intensity and pain unpleasantness in triathletes: A study examining their associations with pain catastrophizing and pain expectations

ObjectiveTriathletes represent a growing and unique population of individuals willing to endure significant mental and physical stress to practice the sport they love. However, little is known about the pain experienced while training for and competing in a triathlon and how psychological factors influence this experience. This study will assess pain experienced by triathletes in training and competition, and investigate the association between pain catastrophizing and pain expectations with triathlon pain intensity and pain unpleasantness.DesignIn this observational study, a sample of 261 triathletes completed two online surveys before and after participating in a triathlon.ResultsModerate levels of pain intensity and pain unpleasantness were reported during training and competition. Pain catastrophizing was positively associated with expected and actual triathlon pain unpleasantness, but not with pain intensity. Expected pain intensity was also significantly associated with pain intensity experienced while competing, whereas expected pain unpleasantness was significantly related to both triathlon pain intensity and unpleasantness. Finally, regression analysis revealed pain catastrophizing and pain expectations to be unique predictors of triathlon pain intensity and pain unpleasantness.ConclusionThis study highlights the important role of psychological factors in triathletes' experience of pain and could eventually help tailor interventions aimed at improving the practice of triathlon.     

Controlled attention sharing influences time estimation

A seminal attentional model of time estimation predicts that subjective duration will be positively correlated to the amount of attention given to temporal processing. This prediction holds under prospective conditions, in which one is forewarned that judgments of time will be asked, in contrast to retrospective conditions, in which such judgments are required after the relevant period without any prior warning. In three experiments, an attention-sharing method was used. Subjects were asked to control the amount of attention that they devoted to one or the other component of a dual-task paradigm. The first experiment involved word categorization and reproduction of duration. The following experiments, based on signal detection theory, required discrimination of both the duration and the intensity of a single stimulus, in the visual (Experiment 2) or the auditory (Experiment 3) modality. The results indicate that when the attention is directly controlled by the subject, the subjective duration shortens as the amount of attention devoted to the temporal task diminishes. The implications of these results for the possible existence of an internal timer are considered.     

Comparison is not just subtraction: effects of time- and space-order on subjective stimulus difference

In five experiments, participants made comparative judgments of paired successive or simultaneous stimuli. Time- or space-order errors were obtained, which varied with the interstimulus interval (ISI) or stimulus duration, as well as with the stimulus level. The results, in terms of scaled subjective differences, are well described by Hellstr?m's (1979) sensation-weighting model. With successive presentation, in comparisons of line length and tone loudness, the first stimulus had the greater weight in determining the subjective difference for short ISIs, the second for longer ISIs. In comparisons of duration (auditory and visual), the second stimulus had the greater weight. For simultaneously presented line lengths, the left stimulus had the greater weight.     

Perceived unpleasantness and facial reactions to auditory stimuli

This study examined whether facial electromyographic (EMG) reactions differentiate between identical tone stimuli which subjects perceive as differently unpleasant. Subjects were repeatedly exposed to a 1000 Hz 75 dB tone stimulus while their facial EMG from the corrugator and zygomatic muscle regions were measured. Skin conductance and heart rate responses were also measured. The subjects rated the unpleasantness of the stimulus and based on these ratings they were divided into two groups, High and Low in perceived unpleasantness. As predicted the facial EMG activity reflected the perceived unpleasantness. That is, the High group but not the Low group reacted with an increased corrugator response. The autonomic data, on the other hand, did not differ between groups. The results are consistent with the proposition that the facial muscles function as a readout system for emotional reactions and that facial muscle activity is intimately related to the experiential level of the emotional response system.