闪光融合频率仪器

前言 在视觉心理生理的教学和研究工作中,常常需要测量闪光融合的临界频率的仪器。闪光融合临界频率指的是,当视觉刺激不是连续作用而是断续作用的时候,随着断续频率的增加,人就不再感觉到断续的刺激,而看到连续、恆定的刺激。这种现象就叫做闪光融     

不同环境照度下手机屏幕亮度最优参数研究－以三星某手机为例

已有研究表明环境照度、计算机显示器的屏幕亮度和对比度会影响用户的任务操作绩效。本研究采用视觉搜索任务,从行为绩效、主观评价以及眼睛疲劳度指标来考察环境照度、手机屏幕亮度对视觉搜索绩效的影响,并提出在不同的环境照度下手机屏幕亮度的最优值设置参数。结果表明：（1）当手机屏幕亮度保持不变时,不同环境亮度下的搜索绩效差异显著。（2）当环境照度为0lx时,手机屏幕亮度的最优值在11cd/m2左右;环境照度为100lx时,手机屏幕亮度的最优值是68cd/m2左右,环境照度为500lx时,手机屏幕亮度最优值是257cd/m2左右。     

亮度对白光和色光临界融合频率的影响

本实验研究了不同亮度级的光谱色光(440,460,540,560,640,660nm)和白光的CFF。结果表明:除极高亮度(5087td)外,CFF与logI函数均呈线性关系。白光表现了最大的CFF,其图线斜率大于任何色光的图线斜率。可以见到:亮度是CFF和logI之间关系的最重要的决定因素之一。在所用的色光中,绿色不论在CFF绝对值或其图线斜率方面均高于光谱两端色光的相应数据。从而可以推断:波长对CFF和logI之间关系的效应不可忽视。光谱两端色光曲线的差别明显,而同色区内相邻色的曲线间差异则不显著,这又一次说明波长的区别对CFF的意义重大。在某些亮度水平上白光CFF绝对值低于色光,虽然在最高亮度级时其最大CFF值高于所有色光的相应数据。我们的研究结果再次提出,有必要对CIE V(λ)在某些条件下应用的适当性进行重新考虑。     

不同屏面背景亮度下正确辨认荧光屏(CRT)颜色字符亮度对比度阈的实验研究

本研究的目的是了解屏面背景亮度与正确辩认CRT 红、绿、蓝三种颜色字符所需亮度对比度阈间的变化关系。结果表明:(1)CRT 颜色字符的视觉辩认绩效与屏面背景亮度和字符亮度对比度有关。随背景亮度的提高,正确辩认CRT 红、绿、蓝三种颜色字符的亮度对比度阈均随之下降,且在一定的作业绩效水平上,背景亮度与字符亮度对比度阈间存在“代偿关系”以及“代偿比例转换”的关系;(2)在同等背景亮度下,正确辩认CRT 红、绿、蓝三种颜色字符的亮度对比度阈间存在一定差异,其中,红色字符的亮度对比度阈明显低于蓝色字符。     

运动视觉的奇次倍频现象

当刺激图形为高速运动的方波光栅时,可观测到一种新的奇次谐波现象。当被试光栅为某些临界时间频率时,奇次谐波光栅静止不动,稍微偏离这些临界值,谐波光栅开始运动,其表现运动方向,或者与被试光栅相同,或者相反,这取决于被试光栅的时间频率高于或低于临界频率。本文使用视觉时空采样假设和付氏分析,初步解释了这一现象。     

视场大小对色光和白光的临界融合频率的影响

本实验采用闪烁光度法。刺激光为红光(670nm)、绿光(560nm)、蓝光(450nm)和白光。亮度级为200尼特、20尼特和2尼特。视场约为2°、1°、0.5°和0.25°。受试者3人,均属色觉正常者,具有一定实验经验。结果表明:在同一亮度级上,大小相同的视场内,绿光的CFF都明显地高于明度相同的红光和蓝光的CFF;在同一亮度级上,色光和白光的CFF都随着视场面积的增加而增加。并且CFF-Log面积接近线性关系;在不同亮度级上,CFF-Log面积的直线料率并不相同。2尼特时的直线斜率小于20尼特、200尼特时的直线斜率。     

感觉记忆中含语义对象的视觉表征

感觉记忆能够以特征形式构建对视觉对象表面信息的表征, 然而对于具有重要意义的潜在抽象信息, 尚未有研究考察其是否影响感觉记忆的视觉表征。结合掩蔽技术与部分报告法范式考察了感觉记忆的视觉表征中是否包含语义信息。以阿拉伯数字作为目标, 实验1与实验2分别采用正立与倒置的汉字大写数字作为掩蔽刺激, 比较其与白噪音刺激的掩蔽效应。结果显示, 汉字大写数字的掩蔽效应均强于白噪音刺激, 且正立汉字大写数字的掩蔽效果较倒置汉字大写数字更强。实验3采用汉字大写数字与汉字常用字分别作为掩蔽刺激, 结果显示汉字大写数字的掩蔽效果强于汉字常用字。上述结果显示, 刺激间的语义相似性带来了视觉表征冲突, 表明感觉记忆的视觉表征中包含了刺激的语义信息。     

视听刺激突显性对视觉主导效应的影响

本研究使用空间任务-转换范式,控制视、听刺激的突显性,探讨自下而上注意对视觉主导效应的影响。结果表明视、听刺激突显性显著地影响视觉主导效应,实验一中当听觉刺激为高突显性时,视觉主导效应显著减弱。实验二中当听觉刺激为高突显性并且视觉刺激为低突显性时,视觉主导效应进一步减弱但依然存在。结果支持偏向竞争理论,在跨通道视听交互过程中视觉刺激更具突显性,在多感觉整合过程中更具加工优势。     

注意对视听语义整合加工的影响

采用2×3的被试内实验设计,将注意条件和目标刺激类型作为实验变量,考察了指向不同感觉通道的注意对视听语义整合加工的不同影响。结果发现,只有在同时注意视觉和听觉刺激时,被试对语义一致的视听刺激反应最快,即产生冗余信号效应。而在选择性注意一个感觉通道时,语义一致的视听刺激并不具有加工优势。进一步分析发现,在同时注意视觉和听觉时语义一致视听刺激的加工优势源自于其视觉和听觉成分产生了整合。也就是说,只有在同时注意视觉和听觉时,语义一致视听刺激才会产生整合,语义不一致视听刺激不会产生整合。而在选择性注意一个感觉通道时,不论语义是否一致,视听刺激均不会产生整合。     

视听时、空一致性对Pip-and-Pop效应的影响

多感觉整合遵循空间原则和时间原则, 有研究表明Pip-and-Pop效应产生的原因是多感觉整合, 那么Pip-and-Pop效应是否同样遵循空间原则和时间原则呢?本研究采用动态视觉搜索范式, 通过两个眼动实验考察空间一致性(实验1)和时间一致性(实验2)对Pip-and-Pop效应的影响。结果发现：(1)当视觉目标颜色变化伴随一个同侧的听觉刺激时所产生的Pip-and-Pop效应最大, 对侧条件没有发现Pip-and-Pop效应。(2)视听刺激同时呈现所产生的Pip-and-Pop效应最大, 随视听刺激呈现时间间隔的增加Pip-and-Pop效应逐渐减弱直至消失。结果表明, 视听时、空一致性对Pip-and-Pop效应具有调节作用, 这为多感觉整合在产生Pip-and-Pop效应中的作用提供了证据。     

The pigeon's perception of saturation.

Three experiments used similar methods to investigate the pigeon's perception of saturation of monochromatic lights. This trial-wise procedure consisted of brief presentations of positive and negative stimuli in random sequence. Pecks to the positive stimuli were occasionally reinforced on a low fixed-ratio schedule. The first study determined absolute thresholds for "white" and monochromatic lights by establishing a discrimination between lights of various radiances and a dark key. Experiment II investigated generalization from a white light to various monochromatic lights under conditions that minimized the use of luminance as a cue. The third experiment examined discrimination of various monochromatic lights along a colorimetric purity continuum; responses to white light were reinforced, while responses to lights that combined white and monochromatic lights in various proportions were not. The results indicated that lights of different wavelength differ in saturation, but that all are discriminable from white. Wavelengths between 550 and 600 nm are least saturated for the pigeon, and saturation increases markedly as wavelength decreases below this region of the spectrum.     

Dark adaptation of foveal cones during the cone-plateau period

Following substantial bleaching by "white" light, absolute threshold, relative spectral sensitivity and sensation of hue of monochromatic lights were measured at the central fovea during the cone-plateau period. The absolute-threshold level was found to increase and then decrease markedly, the relative spectral sensitivity remained invariant, while the sensation of hues of monochromatic lights from the long- and middle-wave regions of the spectrum changed toward hues of shorter wavelengths.     

The reaction-time/luminance relationship for pigeons to lights of different spectral compositions

Pigeons learned to peck a key when it was illuminated during a 2-sec trial. A white-noise ready signal preceded the onset of the light; a response terminated the trial and occasionally produced reinforcement. For every trial, reaction time was recorded as the temporal interval between light onset and keypeck response. The initial experiment used “white” light; subsequent experiments used monochromatic lights of 525 and 625 nm. Within each session, the luminance of the light stimulus varied randomly over a three-log-unit range. For white light, overlapping ranges were used to extend the total luminance variation to six log units. Resulting reaction-time/luminance functions for white light were decreasing over most of the range. However, a rise in reaction time with increasing luminance was seen in the midluminance region and again at very high values. At 625 nm, the function decreased rapidly at low luminances and then leveled off or rose; at 525 nm, it was relatively flat at low luminances, where reaction times were lower than they were to photopically matched 625-nm values. Sensory and nonsensory factors might contribute to the shapes of these functions, which may be too complex to be used for psychophysical scaling.     

Preference for intermittent reinforcement

Two experiments were conducted demonstrating that under certain conditions pigeons may peck at a higher rate on a key that produces intermittent reinforcement following a delay than on one that always produces reinforcement following the same delay duration. In both experiments, concurrent chain schedules were employed. In Experiment I, a single peck on one key led to a white light and a delay of 15 sec, which always terminated with food. A peck on the other key led to its illumination by one of two colored lights and a delay period of 15 sec. The delay was followed by either food presentation or timeout, either one lasting 3 sec. In a control group, the lights on this key were not correlated with food or timeout. Under the correlated stimuli, birds more often pecked the key leading to intermittent reinforcement, whereas with uncorrelated stimuli they pecked the key leading to the white light and 100% reinforcement. In Experiment II, concurrent variable-interval schedules were employed in the first link. The results showed generally that the relative rate was higher on the key leading to intermittent reinforcement when the stimuli were correlated with reinforcement and timeout than on the key leading to 100% reinforcement. There was some indication that this performance was affected by (1) the duration of the delay, (2) the percentage of reinforcement on the key yielding the higher percentage of reinforcement (the key with the white light), and (3) prior experimental conditions.     

Stimulus novelty and intraseries primacy in GSR adaptation

GSR records were obtained for four groups of 20 Ss. Group I was presented with a series of four different lights (amber, blue, green, and white) appearing 20 times each, in apparent random order. The procedure was similar for the other three groups except that in group 2, a novel stimulus (a red light) appeared instead of the sixth amber light; in group 3, it appeared instead of the 16th amber light; and, in group 4, it appeared instead of the 16th amber light. Typical GSR adaptation phenomena were observed in all groups. The introduction of the novel stimulus appeared to have no effect on the course of GSR adaptation.     

Infants are trichromats.

Two experiments were conducted to demonstrate that human infants 3 months of age perceive color in a normal, trichromatic manner. In the first experiment, the visual attention of 30 infants was monitored in a habituation-dishabituation paradigm that used spectral and white lights with brightness factors eliminated. Infants discriminated white from monochromatic light in a region of the spectrum (490–500 nm) where color-normal adults can but color-deficient adults cannot. In the second experiment which also used a habituation paradigm, eight infants showed good discrimination between hues in a region of the spectrum (560–580 nm) where color-deficient adults typically show no hue discrimination. Results from these studies of the neutral zone and hue discrimination evidence trichromatic vision in infancy and are discussed in the context of their several clinical, social, and intellectual implications.     

On cross-modal similarity: auditory-visual interactions in speeded discrimination

A series of four experiments explored how cross-modal similarities between sensory attributes in vision and hearing reveal themselves in speeded, two-stimulus discrimination. When subjects responded differentially to stimuli on one modality, speed and accuracy of response were greater on trials accompanied by informationally irrelevant "matching" versus "mismatching" stimuli from the other modality. Cross-modal interactions appeared in (a) responses to dim/bright lights and to dark/light colors accompanied by low-pitched/high-pitched tones; (b) responses to low-pitched/high-pitched tones accompanied by dim/bright lights or by dark/light colors; (c) responses to dim/bright lights, but not to dark/light colors, accompanied by soft/loud sounds; and (d) responses to rounded/sharp forms accompanied by low-pitched/high-pitched tones. These results concur with findings on cross-modal perception, synesthesia, and synesthetic metaphor, which reveal similarities between pitch and brightness, pitch and lightness, loudness and brightness, and pitch and form. The cross-modal interactions in response speed and accuracy may take place at a sensory/perceptual level of processing or after sensory stimuli are encoded semantically.     

Stimulus novelty and intraseries primacy in GSR adaptation

GSR records were obtained for four groups of 20 Ss. Group I was presented with a series of four different lights (amber, blue, green, and white) appearing 20 times each, in apparent random order. The procedure was similar for the other three groups except that in group 2, a novel stimulus (a red light) appeared instead of the sixth amber light; in group 3, it appeared instead of the 11th amber light; and, in group 4, it appeared instead of the 16th amber light. Typical GSR adaptation phenomena were observed in all groups. The introduction of the novel stimulus appeared to have no effect on the course of GSR adaptation.     

Multidimensional scaling of color difference in the pigeon

Pigeons were required to discriminate between “identical” vs “different” pairs of lights in a yes/no signal-detection task with a symmetrical payoff matrix. If the two lights projected on the two halves of the bipartite field constituting the center response key in a three-key chamber were identical in wavelength composition, a single peck on the right key was reinforced with food. If the two lights differed in wavelength composition, then left-key pecks were reinforced. In Experiment 1, each of six pigeons experienced all possible pairs of 11 spectral lights and 1 purple light (66 pairs). In Experiment 2, the set of lights was expanded to 15 (105 pairs) and included a white light. The percentage of correct choices was taken as an index of the dissimilarity between the two lights constituting a pair. The rank-order information available in these dissimilarity measures was used to determine coordinate projections for each light in a two-dimensional Euclidean space. The configuration obtained in this manner was interpreted as a color circle for the pigeon.     

Compounding of discriminative stimuli from the same and different sensory modalities

Rats' responding was maintained by fixed-interval schedules of reinforcement in the presence of a tone or two separate lights. The lights were either of low, moderate, or high intensity. Compounds of these single discriminative stimuli each maintained a greater frequency of response than did the single stimuli, and the compound composed of stimuli from different sensory modalities (light+tone) maintained a greater level of responding than did the compound composed of stimuli from the same sensory modality (light+light). Combining lights of different intensity had no differential effect on responding. However, in the second experiment, a compound composed of a light and a tone, each of greater intensity than the light and tone of another compound, initially maintained a higher frequency of response, demonstrating intensity effects during stimulus compounding when the increase in intensity occurs through the component stimuli. This intensity effect, however, was only transitory.