Computation of mean size is based on perceived size

The present study investigated whether computation of mean object size was based on perceived or physical size. The Ebbinghaus illusion was used to make the perceived size of a circle different from its physical size. Four Ebbinghaus configurations were presented either simultaneously (Experiment 1) or sequentially (Experiment 2) to each visual field, and participants were instructed to attend only to the central circles of each configuration. Participants’ judgments of mean central circle size were influenced by the Ebbinghaus illusion. In addition, the Ebbinghaus illusion influenced the coding of individual size rather than the averaging. These results suggest that perceived rather than physical size was used in computing the mean size.     

Mental comparison of size and magnitude: size congruity effects

Paivio (1975) found that the latency to choose the larger of two named objects does not depend on congruity between the object sizes and the sizes of the object names. Because size congruity does affect latencies for pictorially presented objects, Paivio interpreted this result as support for the dual coding hypothesis. However, Experiment 1 demonstrated that Paivio's results were an artifact of his experimental design. Size congruity does affect latencies to choose the larger of two named objects when object pairs are not repeated. When the same object pairs are used repeatedly, as in Paivio's experiment, the effect disappears. In this case the response is probably remembered, so that the objects need not be compared. To determine the processing stages affected by size congruity, both the distance between stimulus sizes and the size congruity were manipulated in Experiment 2. Three groups of subjects chose either the greater Arabic digit, the greater named digit, or the larger named object. Size congruity interacted with distance only for Arabic digits. For both Arabic digits and named digits, the interference caused by size incongruity was greater than the facilitation caused by size congruity, whereas for object names, the facilitation was greater than the interference. A model of the interaction between physical size comparisons and conceptual size comparisons is proposed to account for these results.     

Figural after-effects, retinal size, and apparent size

The results of earlier experiments on the question of whether figural after-effects are affected by apparent as opposed to retinal size are shown to be inconclusive. A new hypothesis is proposed namely that both factors may be responsible for producing figural aftereffects, and four experiments have been made to test it. Situations were used in which the apparent sizes of the figures were determined by the size-constancy effect. It was found that where retinal sizes of test and inspection figures are the same and apparent sizes are different, figural after-effects in the direction which would be predicted on the basis of apparent sizes are obtained. It was further shown that where retinal and apparent sizes are in conflict, whether a figural after-effect is seen or not, and the direction of the figural after-effect, depends upon the balance between these two factors.     

Measures of effect size

Two different approaches have been used to derive measures of effect size. One approach is based on the comparison of treatment means. The standardized mean difference is an appropriate measure of effect size when one is merely comparing two treatments, but there is no satisfactory analogue for comparing more than two treatments. The second approach is based on the proportion of variance in the dependent variable that is explained by the independent variable. Estimates have been proposed for both fixed-factor and random-factor designs, but their sampling properties are not well understood. Nevertheless, measures of effect size can allow quantitative comparisons to be made across different studies, and they can be a useful adjunct to more traditional outcome measures such as test statistics and significance levels.     

Visual size difference discrimination: Effect of disc size and retinal locus

Ability to discriminate between the sizes of two adjacently presented discs of light is considered both as a function of the size of the discs and the retinal locus of their presentation. Ss were required to report whether a comparison disc was seen as larger or the same size as a standard disc when the two were presented briefly together. Results showed that the and required for 50% difference discrimination was independent of the size of the disc and was constant at about 30 sec of arc. For peripheral presentations, the jnd was found to increase in a linear manner with increasing eccentricity of presentation. Comparisons are drawn between the results obtained and peripheral visual acuity data and it is speculated that similar processes are involved in both situations.     

从效应量应有的性质看中介效应量的合理性

效应量的作用有两个方面, 一是弥补了统计检验的不足, 二是使得效应有可比性。结合统计显著性和效应量, 才能得出适当的统计结论。效应量应当具有一些基本性质, 包括与测量单位无关、单调性、不受样本容量的影响。国际上流行的中介效应量κ平方就是因为缺乏单调性而引发质疑和研究, 从而被彻底终结了其作为中介效应量的合法性。R平方型中介效应量同样有缺乏单调性的问题。文末讨论了如何报告中介效应量以及有待研究的问题。     

On effect size

The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension, measure/index, and value), outline 10 corollaries that follow from our definition, and review ideal qualities of effect sizes. Our definition of effect size is general and subsumes many existing definitions of effect size. We define effect size as a quantitative reflection of the magnitude of some phenomenon that is used for the purpose of addressing a question of interest. Our definition of effect size is purposely more inclusive than the way many have defined and conceptualized effect size, and it is unique with regard to linking effect size to a question of interest. Additionally, we review some important developments in the effect size literature and discuss the importance of accompanying an effect size with an interval estimate that acknowledges the uncertainty with which the population value of the effect size has been estimated. We hope that this article will facilitate discussion and improve the practice of reporting and interpreting effect sizes.     

The size coding of responses: The size of switches and the force feedback

We aimed to understand which factors have a functional role in the size coding of responses, either the size of the switches or the force required to trigger each switch. This question is of relevance because it allows a better understanding of processes underlying action coding. In each trial, participants saw a small or large object. Depending on its colour, the participants had to press one of two switches. In the “size” condition, the response device consisted of two switches of different visual size, but both required the same amount of force. In the “force-feedback” condition, the response device consisted in two switches of identical visual size, but one switch required more force than the other. We found a compatibility effect in the “size,” not in the “force-feedback” condition, supporting that the size-coding of responses would be due to the size of the switches.     

The role of instructions and familiar size in absolute judgments of size and distance

The effects of familiar size and instructions (apparent, objective) on direct reports of size and distance were evaluated. Subjects estimated the size and distance of two different-sized playing cards or two unfamiliar stimuli under either apparent or objective instructions. The stimuli were presented successively at a distance of 5.48 m under reduced-cue conditions. The form of the instructions selectively influenced the effect of familiar size on absolute judgments of size and distance, with apparent instructions minimizing, and objective instructions promoting, familiar-size effects. The ratio of the distance judgments of the first to the second presented stimuli approximated the relative retinal sizes of the two objects under both apparent and objective instructions, while the ratio of size judgments tended to be either influenced by or independent of the object’s relative retinal sizes under apparent and objective instructions, respectively. These results are consistent with Gogel’s theory of off-size perception and, in particular, with the claim that, in comparison with apparent instructions, objective instructions are more likely to direct observers to base their judgments on cognitive, as opposed to perceptual, sources of spatial information.     

Retinal size as a determiner of the direction of size distortion in figural after-effects

When dealing with size distortions, the direction of the distortion is determined by the retinal size of the T-figure with respect to the retinal size of the I-figure. When the T-figure is retinally smaller than the I-figure it is distorted toward appearing even smaller; when it is retinally larger than the I-figure it is distorted toward appearing even larger; and when the two are retinally equal, there is no distortion. If the T-figures are too much larger or smaller than the I-figure, the distortion ceases. The traditional distance paradox is observed where the distance is defined retinally. The apparent size of the figures is irrelevant to a prediction of what sort of distortion takes place. Sutherland's hypothesis that apparent size determines the direction of distortion when retinal sizes are equated is not supported.     

The size illusion: visual and kinaesthetic information in size perception

Earlier studies have shown the size of kinaesthetically presented two-dimensional movement patterns to be significantly overestimated. Whether this size overestimation is characteristic of the kinaesthetic system alone has not been established. Two experiments are reported which were designed to investigate size judgment made after kinaesthetic and visual pattern presentation and the effect of environmental cues on the perception of movement patterns. In experiment 1 patterns were presented kinaesthetically (experimenter guided hand movements around the outline of the pattern) or in combination with visual information given by a moving light (pinpoint light attached to the stylus which was moved around the pattern); visual and kinaesthetic cues were either congruent or conflicting with each other; and environmental cues were either present or absent. In experiment 2 static visual display was compared with visually traced pattern presentation, again with or without environmental cues. Overall the results showed that, regardless of experimental manipulation, in all cases where the information was given over time the subject perceived the pattern larger than reality. After static visual display, overestimation of size did not occur.     

Visual transformation of size.

To investigate human visual identification of different-sized objects as identically shaped, matching reaction times were measured for pairs of simultaneously presented random figures. In three experiments, reaction time for correct reactions to test pairs of figures of the same shape and orientation consistently increased approximately linearly as a function of the linear size ratio of the figures. In the second experiment, where this ratio was defined for control pairs as well as for test pairs, reaction time for correct reactions to control pairs showed a similar increase as a function of size ratio. The results suggest that the task was performed by a gradual process of mental size transformation of one of the members of each pair of figures to the format of the other one.