The effect of frame figure type and frame size on the line and the circle Ponzo illusions

Abstract:   To examine the determinants of the Ponzo illusion, we compared the perceived size of lines and circles presented within three different frames: two converging lines, two circles, and two squares. Twenty stimulus figures, consisting of two types of objects (lines/circles) × three types of frame figures (Ponzo/circles/squares) × three sizes of lower frames (small/medium/large), and two control figures were presented on a personal computer display. Twelve students performed three measurements (upper-object/lower-object/illusion) for each stimulus figure using the method of adjustment. To analyze the relationship between single object perception and the Ponzo illusion, we compared the calculated values of overestimation magnitude differences between the upper and lower objects with the actual obtained illusion values of the six object-frame conditions. The calculated values of the circle and the square frame figures corresponded to the difference between the upper single object and the lower single object. In contrast, the results of the Ponzo figure need an additional factor to explain the differences between the obtained and the calculated values. These results indicate that two factors are involved in the Ponzo illusion: (a) the framing effect affects the perceived size of the individual single objects, and (b) the comparison factor affects the comparison process of the two objects within the converging lines.     

The Effect Size of Variables Associated With Creativity: A Meta-Analysis

The main purpose of this study was to use meta-analysis to investigate the mean effect size of relevant variables associated with creative person, process, product, and environment. Altogether, 2,013 effect sizes from 111 studies were analyzed. The unweighted grand mean effect size of the 111 studies was 0.69, with a standard deviation (SD) of 0.63. Such result was significantly different from 0 at t (110) = 11.52, p < .01. When the averaged effect size of each study was weighted with the sample size of that study, the weighted grand mean effect size was 0.72. The important findings were: (a) the mean effect sizes associated with problem-solving creativity and verbal creativity were significantly larger than those associated with emotional creativity and nonverbal creativity, (b) variables having a large mean effect size were prestige of honors/awards, working circumstances favorable for creativity, defining problem, and retrieving knowledge, (c) most of the mean effect sizes of the problem solving procedures on the measures of problem solving exceeded the medium (0.5) of Cohen's guidelines. Areas to be further explored are suggested.     

An examination of the love-is-blind bias among gay men and lesbians

The present study examined evidence of the ‘love-is-blind bias’ (a tendency to perceive romantic partners as more attractive than the self) among gay men and lesbians. In total, 93 gay men and 140 lesbians provided self- and partner-ratings of physical attractiveness for a range of body components. Results of a series of t-tests showed that both gay men and lesbians rated their partners as significantly more attractive than themselves on all but one item, respectively. Effect sizes for these differences were moderate to large. Further analyses showed that lesbians provided higher self- and partner-ratings than gay men on some items, although effect sizes for these differences were small. Overall, these results provide evidence for the existence of a robust positive illusion in self–partner perceptions.     

Ontogeny of the Ponzo illusion: Effects of age,schooling, and environment(1)

Subjects were 384 Moroccan males (age range 6–22 yrs.), divided into 16 equal groups, according to the factorial design: age (4) × schooling (2) × environment (2). Subjects were tested on four Ponzo configurations (differing in contextual information) from Leibowitz et al. (1969), the Ponzo perspective stimulus from Segall et al. (1966), the CEFT from Witkin et al. (1971), and a measure of pictorial depth perception. Individual measures of contact with mass-media and urban life were collected on each subject. Analyses indicated that all main factors of age, schooling, and environment played important, and differing, roles in inducing illusion susceptibility. Piaget's (1969) theory of primary and secondary illusions was found useful in understanding the results of the Ponzo configurations used in the study. Primary illusion configurations were found to be relatively insensitive to experiential variables, and illusion susceptibility decreased with chronological age. In contrast, secondary illusion configurations were affected by many experiential factors, and illusion susceptibility was mediated through perceptual development and pictorial depth perception rather than chronological age. It was concluded that single-factor theories of ontogenetic change in illusion susceptibility were inadequate to explain the complex interactions found in this study.     

The effects of location,orientation, and cumulation of boxes in the Baldwin illusion

Three experiments were conducted on variants of the Baldwin illusion. Experiment 1 showed that placing a box on each side of the standard line produced a larger illusion than placing both boxes on the same side of the line. These results failed to support the assimilation theory proposed by Brigell, Uhlarik, and Goldhorn (1977). In Experiment 2, the side of a rectangular box was varied when that side was either parallel or perpendicular to the standard line. The parallel rectangle produced a function that was similar to the one found with the classical Baldwin figure, but the perpendicular boxes produced a monotonically decreasing function with a reversal of illusion evident at the large sizes. The latter function did not support any version of the assimilation theory. The findings of Experiment 3 replicated previous findings that showed that cumulating contours as box size increased had no effect on the illusion. These findings explain two longstanding puzzles about the Müller-Lyer illusion: why a multifinned form is not the sum of its single-finned parts and why the shrinkage form produces a smaller effect than does the expansion form.     

Procedure-specific estimates of structural and strategic factors in the Horizontal-Vertical illusion

The present study examined potential differences in structural and strategic factor estimates involved in the Horizontal-Vertical (HV) illusion. Performance on adjustment and production-task forms of the illusion was examined under the conditions of intertrial feedback, continued visual inspection, combined feedback and visual inspection, as well as control procedures. Estimates of structural and strategic factors were procedure-specific and, for each task, the correction of inaccurate strategic factors was significantly greater for the feedback than the visual-inspection and control groups. There were no significant additive effects when feedback was combined with visual inspection. The illusion results from an overestimation of the length of vertical lines, seems to be predominantly cognitive in nature, and exists in the absence of line bisection and a comparison line.     

Fixed set in the perception of size in relation to lightness

When control subjects compared the sizes of two circles of different lightness, the lightness-size illusion was observed, i.e., the darker circle was perceived to be smaller. However, after experimental subjects were shown a large, light circle and a smaller, darker circle repeatedly, the subjective size of the dark circle increased. It decreased after repeated exposures to a small, light circle and a large, dark one. These changes in perception were assumed to be contrast effects produced by an experimentally fixed set and were similar to changes observed when the same method was previously applied by this author to the size-weight illusion. Despite differences in modality and dimension of perception, every application of the fixed-set method resulted in analogous patterns. When the situation of the set-fixing experiment and that of the critical experiment were similar to each other, the fixed set was activated more and greater contrast effects were produced.     

Estimating the mean effect size in meta-analysis: Bias,precision, and mean squared error of different weighting methods

Although use of the standardized mean difference in meta-analysis is appealing for several reasons, there are some drawbacks. In this article, we focus on the following problem: that a precision-weighted mean of the observed effect sizes results in a biased estimate of the mean standardized mean difference. This bias is due to the fact that the weight given to an observed effect size depends on this observed effect size. In order to eliminate the bias, Hedges and Olkin (1985) proposed using the mean effect size estimate to calculate the weights. In the article, we propose a third alternative for calculating the weights: using empirical Bayes estimates of the effect sizes. In a simulation study, these three approaches are compared. The mean squared error (MSE) is used as the criterion by which to evaluate the resulting estimates of the mean effect size. For a meta-analytic dataset with a small number of studies, theMSE is usually smallest when the ordinary procedure is used, whereas for a moderate or large number of studies, the procedures yielding the best results are the empirical Bayes procedure and the procedure of Hedges and Olkin, respectively.     

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.     

The Fraser illusion: complex figures

The cause of the Fraser illusion, which occurs when a line made up of tilted segments itself appears tilted, is examined further. In this series of experiments, we used figures that resembled the original Fraser illusion; they were more complex than those reported on in our previous paper (Stuart & Day, 1988). The figures were used to explore two theories of the Fraser illusion further: that it is the result of interactions between orientation selective units, and that it is a consequence of the local, distributed processing of orientation. The presence of background elements like those used in the original illusion led to an increase in the strength of the illusion, but the shape of these elements had no differential effect on illusion strength. There was a differential effect of the background on the assimilative and contrast illusions, owing respectively to small and large tilts of the inducing elements. The illusion was markedly reduced at small visual angles when the background was absent, but it was only slightly affected when the background was present. All these findings are difficult to explain in terms of interactions between single units, either at the same or at different scales in the image. The effects of luminance contrast and isoluminance on the illusion were not consistent with either theory, but they indicated that researchers need to consider the role of figure-ground organization in this illusion.     

The orientation of a parallel-line texture between the verticals can modify the strength of the Poggendorff illusion

In the present experiments, we attempted to evaluate the modification of the strength of the Poggendorff illusion as a function of the different orientation of a parallel-line texture filling the space between the vertical lines. In Experiment 1, the standard version of the Poggendorff configuration was tested against four different parallel-line textures oriented at 0°, 45°,90°, and 135° with respect to the obliques. The results showed that the illusory effect was a linear function of the progressive discrepancy between the angle of the lines of the texture and that of the obliques. In Experiment 2, we tested the same textures used in Experiment 1 after the elimination of the two vertical lines. The data obtained approximated a linear function, as in the previous experiment, but the alignment errors were consistently lower. The statistical analysis performed on the data of all eight experimental conditions shows that both factors—texture and presence/absence of verticals—were significant, but most of the effect was due to the texture factor. The results may be interpreted through the “perceptual compromise hypothesis,” originally proposed for the bisection forms of the Poggendorff illusion, but with important modifications. The data are also discussed in terms of their implications for other theories proposed for the Poggendorff illusion.     

The nature and severity of cognitive impairment associated with adjuvant chemotherapy in women with breast cancer: a meta-analysis of the current literature

OBJECTIVE: Several studies have identified that adjuvant chemotherapy for breast cancer is associated with cognitive impairment; however, the magnitude of this impairment is unclear. This study assessed the severity and nature of cognitive impairment associated with adjuvant chemotherapy by conducting a meta-analysis of the published literature to date. METHOD: Six studies (five cross-sectional and one prospective) meeting the inclusion criteria provided a total of 208 breast cancer patients who had undergone adjuvant chemotherapy, 122 control participants and 122 effect sizes (Cohen's d) falling into six cognitive domains. First, the mean of all the effect sizes within each cognitive domain was calculated (separately for cross-sectional and prospective studies); second, a mean effect size was calculated for all of the effect sizes in each cross-sectional study; and third, regression analyses were conducted to determine any relationships between effect size for each study and four different variables. RESULTS: For the cross-sectional studies, each of the cognitive domains assessed (besides attention) showed small to moderate effect sizes (-0.18 to -0.51). The effect sizes for each study were small to moderate (-0.07 to -0.50) and regression analysis detected a significant negative logarithmic relationship (R2 = .63) between study effect size and the time since last receiving chemotherapy. For the prospective study, effect sizes ranged from small to large (0.11-1.09) and indicated improvements in cognitive function from the beginning of chemotherapy treatment to 3 weeks and even 1 year following treatment. CONCLUSION: This meta-analysis suggests that cognitive impairment occurs reliably in women who have undergone adjuvant chemotherapy for breast cancer but that the magnitude of this impairment depends on the type of design that was used (i.e., cross-sectional or prospective). Thus, more prospective studies are required before definite conclusions about the effects of adjuvant chemotherapy on cognition can be made.     

The vertical-horizontal illusion in a visually-rich environment

In the vertical-horizontal illusion the vertical dimension of a figure typically appears longer than the horizontal. Although there is a large body of research literature on this illusion, all of it refers to simple figures with well-drawn lines, exhibited against plain backgrounds. Our experiment has investigated the illusion using real-world objects in a visually-rich environment. Ten male and 10 female Ss were asked to judge the heights of 10 objects of various sizes and shapes. They made their estimates by having the experimenter mark off a horizontal distance that corresponded to the judged height of the object. Each S estimated the height of each object once a day for three consecutive days. The results show that, by and large, the illusion can be demonstrated for real objects in a visually-rich environment. There was, however,considerable variation among the objects. It appears that estimates of this kind may be influenced by size, size constancy, anchor effects, and angle of regard, along with other, as yet, unidentified factors.     

The filled-duration illusion: The function of temporal and nontemporal set

Studies of the perception of time have demonstrated that large visual stimuli presented for the same duration as small stimuli will appear to have been presented longer. Two theoretical approaches have been offered to explain this effect. Both have emphasized the absolute amount of information in the stimulus. Thus, both would predict the effect when size is varied between sessions. The present study found no effect of size when size was held constant within sessions, but a substantial effect resulted when size was varied within sessions. Also examined was the range of stimulus durations used within a session. In one condition, patterns of various sizes were presented at 15, 30, or 45 msec, while in a second condition, the same patterns were presented to a different group of subjects at 15, 85, or 155 msec. The size effect was significantly reduced when longer time intervals were presented. A third group of subjects was shown patterns at even longer times but with a reduced range (155, 170, and 185 msec). Here the size effect was of equal magnitude to that of the 15-msec interval condition. The implications of these results are that current theoretical explanations of the filled-duration illusion rely on incorrect assumptions.     

Bisecting the Ponzo illusion.

A modification of the Ponzo illusion, in which the judged lines are centered in different sized obliques, was presented to matched normal and mentally retarded males (ns = 8) under conditions of equal and unequal retinal sizes. Magnitude of illusion was affected by IQ (WISC) and by physical proximity rather than retinal contour. The results seem to imply a central rather than peripheral explanation for the illusion.     

Spatial factors of brightness illusion in the Ehrenstein figure

The strength of brightness illusion in an Ehrenstein figure has been examined as a function of two variables--inducing line length and gap size--by a two-alternative forced-choice procedure. The results show an interaction between the two variables; the length of the inducers and gap size are both involved in the formation of the brightness illusion, with gap size as the stronger factor. A spatial limit (corresponding to a gap size of 2.4 deg) was found, below which the illusion is always present regardless of the length of the inducers. An area ratio, defined as the ratio of the area of the ring formed by the four inducing lines of an Ehrenstein figure to the area of the illusory surface, takes into account the different spatial factors studied in the experiment and the global size of the Ehrenstein figure. The strength of the illusion was found to increase linearly with increasing values of the area ratio.     

Body ownership affects visual perception of object size by rescaling the visual representation of external space

Size perception is most often explained by a combination of cues derived from the visual system. However, this traditional cue approach neglects the role of the observer’s body beyond mere visual comparison. In a previous study, we used a full-body illusion to show that objects appear larger and farther away when participants experience a small artificial body as their own and that objects appear smaller and closer when they assume ownership of a large artificial body (“Barbie-doll illusion”; van der Hoort, Guterstam, & Ehrsson, PLoS ONE, 6(5), e20195, 2011). The first aim of the present study was to test the hypothesis that this own-body-size effect is distinct from the role of the seen body as a direct familiar-size cue. To this end, we developed a novel setup that allowed for occlusion of the artificial body during the presentation of test objects. Our results demonstrate that the feeling of ownership of an artificial body can alter the perceived sizes of objects without the need for a visible body. Second, we demonstrate that fixation shifts do not contribute to the own-body-size effect. Third, we show that the effect exists in both peri-personal space and distant extra-personal space. Finally, through a meta-analysis, we demonstrate that the own-body-size effect is independent of and adds to the classical visual familiar-size cue effect. Our results suggest that, by changing body size, the entire spatial layout rescales and new objects are now perceived according to this rescaling, without the need to see the body.     

权力对控制错觉的影响

本研究采用实验法探讨了权力及其合理性对控制错觉的影响。结果发现:（1）权力启动会对控制错觉产生影响,即相较于低权力,高权力会导致个体产生高估的控制错觉;（2）权力的合理性与权力水平在控制感上存在交互效应,即权力关系合理时,高权力导致高估的控制错觉,而权力关系不合理时,低权力导致高估的控制错觉。这表明控制错觉会受到动态的基于情境的权力关系以及权力合理性的影响。     

Shattering the illusion of control: Multi-shot versus single-shot gambles

The illusion of control refers to a phenomenon whereby people believe their chances of success at a task are greater than would be warranted by objective analysis. This article raises two questions. First, how robust is the illusion of control? Second, how might the illusion be ‘shattered?’ Previous experimental demonstrations involved situations that can be likened to unique or single-shot gambles. If, however, the phenomenon is robust, it should occur in repeated or multi-shot gambles in which the outcome depends on a series of gambles involving the same underlying random process. It should also appear in single-shot gambles that are framed so as to superficially resemble multi-shot gambles. We label this the strong illusion of control hypothesis. On the other hand, because people have a better appreciation of probabilistic concepts in tasks they are able to represent as relative frequencies, the introduction of a multi-shot or ‘pseudo-multi-shot’ context might cue people to the random nature of the task, thereby shattering the illusion. The weak illusion of control hypothesis holds that the illusion of control will occur in single-shot but not in multi-shot or pseudo-multi-shot gambles. Two studies are reported that support the weak hypothesis. Alternative explanations are considered and implications are discussed.     

Mindfulness-based stress reduction for patients with anxiety disorders: evaluation in a randomized controlled trial

The aim of this study was to investigate the effect of mindfulness-based stress reduction (MBSR) for patients with heterogeneous anxiety disorders. Seventy-six self-referred patients were randomized to MBSR or a waiting-list control condition. Eight participants did not complete the eight-week MBSR intervention. Treatment completers improved significantly on all outcome measures compared to controls. The completer sample showed medium to large effect sizes on measures of anxiety (Cohen’s d = 0.55–0.97), and a large effect size for symptoms of depression (Cohen’s d = 0.97). Intention-to-treat analyses yielded effect sizes in the small to moderate range (Cohen’s d = 0.32–0.76). Gains were maintained at six months follow-up. The percentage of participants reaching recovered status was highest for symptom measures of depression and anxiety, and lower for worry and trait anxiety. Mediation analyses indicated that mindfulness fully mediated changes in acute anxiety symptoms, and partially mediated changes in worry and trait anxiety. However, the present study did not find evidence of temporal precedence for the proposed mediator. In the absence of true mediation and an active control condition, it cannot be ruled out that results are due to non-specific aspects of treatment. Despite these and other limitations, we conclude that MBSR is an effective treatment for anxiety disorders and related symptomatology.