On the syndrome of the "spare limb": one case

We describe a case of a brain-damaged patient who had a peculiar bodily illusion which could not be labelled an hallucination but seemed somatognosically and phenomenologically similar to the phantom limb without amputation. The patient, who showed left hemiplegia, felt a third upper limb (without seeing it) which he himself defined as "spare." The spare limb was not deformed; it could be moved and controlled by the patient, and there was no sensation of pain. The patient did not show psychopathological or cognitive disorders. A possible interpretation of the phenomenon is as a "phantom movement" of the paralysed limb: the mental representation of the movement of the limb was dissociated from the bodily representation of his own limb and so was still present in his consciousness despite the paralysis.     

Absolute and relative effects of similarity and distance on grouping

Four experiments are reported, the aim of which was to explore the achromatic-colour and distance relations that determine the probability of achromatic surfaces grouping perceptually. The first two experiments were performed to test Wertheimer's conjecture that similarity and dissimilarity of achromatic colours jointly determine grouping. The results indicate that only similarity of achromatic colours determines grouping. Data from the other two experiments show that grouping is determined by absolute, relative, and Gillam's distances. These findings agree with previous literature showing that different algorithms or mechanisms determine grouping by similarity and grouping by distance. Additionally, these findings show that the single factor of grouping by distance also depends on multiple algorithms or mechanisms.     

Luminance determinants of perceived surface stratification in two-dimensional achromatic transparent patterns

Two overlapping transparent surfaces forming a two-dimensional pattern stand out in front of each other alternately. Let y denote the luminance of the region where these surfaces overlap and b the luminance of the background. In achromatic patterns, the probability that the lighter transparent surface appears to be in front of the other surface is known to increase with y and with b. The present results show that grouping by achromatic colour similarity cannot explain the effect of b. An alternative conjecture is that the luminance factors that control perceived surface segregation can explain the effects of y and b. Such an explanation predicts a new effect: the probability that one transparent surface appears to be in front increases with the absolute difference in luminance between the surface and the background. The present results confirm this prediction.     

On the determinants of surface brightness

The brightness of an achromatic surface with luminance S on an achromatic background with luminance B varies with S, with B, and with the luminance step deltaL at the border of the surface. In agreement with previous findings indicating that the visual system can perform as a photometer, the results of the two experiments reported here show that S and B determined surface brightness independently of deltaL when the surface was adjacent to and when it was separated from the background. This finding suggests that surface brightness depends on the integration of neural signals representing magnitudes of absolute luminance. A weighted-average model of this integration is proposed.     

Working memory and updating processes in reading comprehension

In this study, we examine the relation between reading comprehension ability and success in working memory updating tasks. Groups of poor and good comprehenders, matched for logical reasoning ability, but different in reading comprehension ability, were administered various updating tasks in a series of experiments. In the first experiment, the participants were presented with lists of words, the length of which (4-10 words) was unknown beforehand, and were required to remember the last 4 words in each series. In this task, we found a decrease in performance that was related to longer series and poor reading ability. In the second experiment, we presented lists of nouns referring to items of different sizes, in a task that simulated the selection and updating of relevant information that occurs in the on-line comprehension process. The participants were required to remember a limited, predefined number of the smallest items presented. We found that poor comprehenders not only had a poorer memory, but also made a greater number of intrusion errors. In the third and fourth experiments, memory load (number of items to be selected) and suppression request (number of potentially relevant items) were manipulated within subjects. Increases in both memory load and suppression requests impaired performance. Furthermore, we found that poor comprehenders produced a greater number of intrusion errors, particularly when the suppression request was increased. Finally, in a fifth experiment, a request to specify the size of presented items was introduced. Poor comprehenders were able to select the appropriate items, although their recall was poorer. Altogether, the data show that working memory abilities, based on selecting and updating relevant information and avoiding intrusion errors, are related to reading comprehension.     

Psychological Correlates of Populist Attitudes

Studies of demand-side populism with a focus on attitudinal and behavioral factors are becoming more popular, but only a few have explored the phenomenon's psychological determinants. We tackle the lack of conversation between populism scholars and political psychologists and test the impact of conspiracy beliefs, moral disengagement, need for cognition, and belief in simple solutions on populist attitudes. We use the most widespread ideational definition in an attempt to bring clarity to demand-side populism, as the literature often conflates the concept of populism with adjacent ideological and psychological factors. We analyze representative samples from two very different countries (Italy and Turkey) to test our hypotheses. We use two of the most often-used measures of populist attitudes and also explore populism's individual building blocks: people-centrism, antielitism, and a Manichean worldview. We consistently find conspiracy beliefs (and our control variable of institutional trust) as primary sources of populist attitudes, whereas the impact of the other psychological factors is more dependent on context and operationalization. Our article calls for more conceptual clarity, careful theorization, and more work on the refinement of available survey measures. We also highlight the importance of national contexts and the dangers of generalization based on individual country studies.     

Exploring the Link Between Mind Wandering,Mindfulness, and Creativity: A Multidimensional Approach

Even if mind wandering (MW) and mindfulness have traditionally been intended as separate and antithetical constructs, the roles of these 2 mental states on creative behavior were jointly explored in this article. In particular, MW was analyzed in light of a recent approach suggesting a differentiation between deliberate and spontaneous MW, whereas mindfulness was analyzed by distinguishing its 5 different constitutional dimensions: observing, acting with awareness, describing, nonreactivity, and nonjudging. The influence on creativity of these 2 mental states was analyzed using a sample of 77 undergraduate students both on a performance index (i.e., originality) and on a self-report index (i.e., creative achievement). Results showed that MW and mindfulness dimensions predicted creative behavior both alone and in combination, suggesting a complex interdependence between these 2 mental states within the creative thinking process. In particular, the critical importance of distinguishing between deliberate and spontaneous MW was revealed by a final path analysis, which revealed the opposite effects of these 2 dimensions on originality and creative achievement. That is, deliberate MW positively predicted creative performance, whereas spontaneous MW was negatively associated with such performance. Moreover, the nonreactivity and awareness dimensions of mindfulness, the latter in interaction with deliberate MW, emerged as main predictors of response originality. Finally, the describing facet of mindfulness predicted creative achievement both directly and indirectly through an interaction with deliberate MW. The implications emerging from the adoption of a multi-dimensional approach to the analysis of MW and mindfulness in the study of creativity are discussed herein.     

The Impact of Stigma and Social Support on Development of Post-traumatic Growth Among Persons Living with HIV

Given high rates of trauma in people living with HIV (PLH) and the health benefits of posttraumatic growth (PTG), understanding how to foster PTG in PLH exposed to trauma could be of interest to clinical psychologists working with this population. The current study examined factors theoretically related to development of PTG in PLH, namely HIV-related stigma, disclosure of HIV status, and emotional support. A sample of 334 HIV-positive adults answered a battery of self-report questionnaires. HIV-related stigma, disclosure to sexual partners, and emotional support were significant predictors of PTG: stigma was associated with lower PTG, whereas disclosure and emotional support were associated with higher PTG. Disclosure and emotional support remained significantly associated with PTG in the model including demographic factors and stigma. These findings highlight the need for development of interventions that can aid PLH in disclosing their HIV status to sexual partners and increasing available social support.