The lady's not for turning: rotation of the Thatcher illusion

Inversion is especially detrimental to the processing of faces. This is clearly demonstrated by the Thatcher illusion. It has been suggested that this detriment is due to a loss of holistic or configural processing for inverted faces (Bartlett and Searcy, 1993 Cognitive Psychology 25 281-316). Stürzel and Spillmann (2000 Perception 29 937-942) suggest that this loss of configural processing occurs suddenly as a face is rotated slowly from upright to inverted. This hypothesis is tested in a study of the reaction times taken to indicate that a face has been Thatcherised at various angles of orientation. The results suggest that there is a gradual loss of configural information rather than a rapid switch from one type of processing to another.     

Sine of an illusion

In an informally observed sine-wave figure in which the vertical extent between contours was constant, apparent extent in the crest and trough (the 'turns') appeared greater than in the straight oblique sections of the figure. This observation was confirmed in two experiments in which the vertical extents were matched by two vertically arranged dots. It was found that in a turn the apparent extent was greater than the true extent, but in a straight section both extents were about equal. These outcomes were confirmed when the two sections were each separated from the figure and presented alone. The illusion is explained in terms of a perceptual compromise between the vertical extent and the greater overall dimensions of the section at the turn of the sine-wave figure and is thereby held to be the same in principle as the Müller-Lyer illusion.     

Feedback versus an illusion in time

The accuracy of many perceptual comparisons depends greatly on the order in which the to-be-compared stimuli are presented. With comparisons of durations around 300 ms, these presentation-order effects do not diminish, even with extended practice, when feedback about response accuracy is withheld. Providing such feedback greatly diminishes presentation-order effects and coincidentally produces substantial increases in response accuracy. The feedback acts in part through inducing response biases and in part through changes in sensitivity. The contradiction between studies which report time-order errors in duration comparison and those which do not is attributable to differences in the use of information feedback.     

New motion illusion caused by pictorial motion lines

Motion lines (MLs) are a pictorial technique used to represent object movement in a still picture. This study explored how MLs contribute to motion perception. In Experiment 1, we reported the creation of a motion illusion caused by MLs: random displacements of objects with MLs on each frame were perceived as unidirectional global motion along the pictorial motion direction implied by MLs. In Experiment 2, we showed that the illusory global motion in the peripheral visual field captured the perceived motion direction of random displacement of objects without MLs in the central visual field, and confirmed that the results in Experiment 1 did not stem simply from response bias, but resulted from perceptual processing. In Experiment 3, we showed that the spatial arrangement of orientation information rather than ML length is important for the illusory global motion. Our results indicate that the ML effect is based on perceptual processing rather than response bias, and that comparison of neighboring orientation components may underlie the determination of pictorial motion direction with MLs.     

Questions about questions: New views on an old prejudice

The belief that good analysts do not ask, and do not answer, questions is a still-living strange recommendation, transmitted throughout psychoanalytic generations. The authors have extensively reviewed electronic databases and technical texts. They found that interrogative acts are largely omitted from technical considerations, generating a prejudice that does not consider questions as proper psychoanalytic tools, and they discuss possible foundations for this belief. The authors believe that the few authors that have touched on this issue have done so in a non-systematic and frequently incomplete form. Linguistic philosophy presents questions as speech acts : actions that are able to alter the equilibrium of dialogical discourses. This view permits psychoanalysts to understand the potentiality of questions to introduce psychic change because they can, simultaneously, interfere in the self, in the other and in the intersubjective relationship. An internal state of curiosity is described as a component of the mind of the analyst. Based on the argument of the ubiquity of the state of curiosity of the analyst, the authors carried out a set of technical propositions, regarding, on the one hand, when questions are not to be introduced (for instance, in the presence of free associations) and, on the other hand, when they would be useful as expanding factors of the preconscious-conscious system. Considering psychoanalyses as experiences of curiosity, they emphasize that both the internal state of curiosity of the analyst, and the eventual verbal questions put to the patient are potentially positive factors for psychic change. The authors present several clinical vignettes.     

New strings for old: The role of similarity processing in an incidental learning task

This paper reports three experiments that examine the role of similarity processing in McGeorge and Burton's (1990) incidental learning task. In the experiments subjects performed a distractor task involving four-digit number strings, all of which conformed to a simple hidden rule. They were then given a forced-choice memory test in which they were presented with pairs of strings and were led to believe that one string of each pair had appeared in the prior learning phase. Although this was not the case, one string of each pair did conform to the hidden rule. Experiment 1 showed that, as in the McGeorge and Burton study, subjects were significantly more likely to select test strings that conformed to the hidden rule. However, additional analyses suggested that rather than having implicitly abstracted the rule, subjects may have been selecting strings that were in some way similar to those seen during the learning phase. Experiments 2 and 3 were designed to try to separate out effects due to similarity from those due to implicit rule abstraction. It was found that the results were more consistent with a similarity-based model than implicit rule abstraction per se.     

Disowning one's seen real body during an out-of-body illusion

Under normal circumstances, we experience that our center of awareness is located behind our eyes and inside our own body. To learn more about the perceptual processes that underlie this tight coupling between the spatial dimensions of our consciously perceived self and our physical body, we conducted a series of experiments using an 'out-of-body illusion'. In this illusion, the conscious sense of self is displaced in the testing room by experimental manipulation of the congruency of visual and tactile information and a change in the visual perspective. We demonstrate that when healthy individuals experience that they are located in a different place from their real body, they disown this body and no longer perceive it as part of themselves. Our findings are important because they reveal a relationship between the representation of self-location in the local environment and the multisensory representation of one's own body.     

New and old perspectives

Some comments are offered on the recent BJGC symposium on the 'new career'. A variety of roads for coping with the increasing need for effective and efficient career interventions are suggested.     

Variations on the Hermann grid: an extinction illusion

When the white disks in a scintillating grid are reduced in size, and outlined in black, they tend to disappear. One sees only a few of them at a time, in clusters which move erratically on the page. Where they are not seen, the grey alleys seem to be continuous, generating grey crossings that are not actually present. Some black sparkling can be seen at those crossings where no disk is seen. The illusion also works in reverse contrast.     

Pigeons perceive the Ebbinghaus-Titchener circles as an assimilation illusion

A target circle surrounded by larger "inducer" circles looks smaller, and one surrounded by smaller circles looks larger than they really are. This is the Ebbinghaus-Titchener illusion, which remains one of the strongest and most robust of contrast illusions. Although there have been many studies on this illusion in humans, virtually none have addressed how nonhuman animals perceive the same figures. Here the authors show that the Ebbinghaus-Titchener figures also induce a strong illusion in pigeons but, surprisingly, in the other direction; that is, all five successfully trained pigeons judged the target circle surrounded by larger circles to be larger than it really is and vice versa. Further analyses proved that neither the gaps between target and inducer circles nor the cumulative weighted surface of these figural elements could account for the birds' responses. Pigeons are known to show similarities to humans on various cognitive and perceptual tasks including concept formation, short-term memory, and some visual illusions. Our results, taken together with pigeons' previously demonstrated failure at visual completion, provide strong evidence that pigeons may actually experience a visual world too different for us to imagine.