A multidimensional scaling model for the size-weight illusion

The kinds of individual differences in perceptions permitted by the weighted euclidean model for multidimensional scaling (e.g., INDSCAL) are much more restricted than those allowed by Tucker's Three-mode Multidimensional Scaling (TMMDS) model or Carroll's Idiosyncratic Scaling (IDIOSCAL) model. Although, in some situations the more general models would seem desirable, investigators have been reluctant to use them because they are subject to transformational indeterminacies which complicate interpretation. In this article, we show how these indeterminacies can be removed by constructing specific models of the phenomenon under investigation. As an example of this approach, a model of the size-weight illusion is developed and applied to data from two experiments, with highly meaningful results. The same data are also analyzed using INDSCAL. Of the two solutions, only the one obtained by using the size-weight model allows examination of individual differences in the strength of the illusion; INDSCAL can not represent such differences. In this sample, however, individual differences in illusion strength turn out to be minor. Hence the INDSCAL solution, while less informative than the size-weight solution, is nonetheless easily interpretable.This paper is based on the first author's doctoral dissertation at the Department of Psychology, University of Illinois at Urbana-Champaign. The aid of Professor Ledyard R Tucker is gratefully acknowledged.     

The line-motion illusion can be reversed by motion signals after the line disappears

In the line-motion illusion, a briefly flashed line appears to propagate from the locus of attention, despite being physically presented on the screen all at once. It has been proposed that the illusion reflects low-level visual information processing that occurs faster at the locus of attention (Hikosaka et al 1993 Vision Research 33 1219-1240; Perception 22 517-526). Such an explanation implicitly embeds the assumption that speeding or slowing of neural signals will map directly onto perceptual timing. This 'online' hypothesis presupposes that signals which arrive first are perceived first. However, other evidence suggests that events in a window of time after the disappearance of a visual stimulus can influence the brain's interpretation of that stimulus (Eagleman and Sejnowski 2000 Science 287 2036-2038; 289 1107a; 290 1051a; 2002 Trends in Neuroscience 25 293). If the online hypothesis were true, we should expect that events occurring after the flashing of the line would not change the illusion. Consistent with our hypothesis that awareness is an a posteriori reconstruction, we demonstrate that the perceived direction of illusory line-motion can be reversed by manipulating stimuli after the line has disappeared.     

Different involuntary mechanisms underlie priming and LOP effects in stem completion tests

The role of intentional retrieval, involuntary conscious memory, and lexical processing in priming and levels‐of‐processing (LOP) effects in stem completion tests was investigated in three experiments. First, Experiment 1 provided strong evidence against the intentional retrieval hypothesis for the implicit LOP effects. LOP effects in the explicit test were dependent on intertrial interval at test, whereas LOP effects in the implicit test were not. Second, support was provided for the involuntary conscious memory hypothesis. Implicit memory (priming) was associated with awareness in all three experiments and the implicit LOP effect was associated with awareness in two of the three experiments. Third, it was concluded that lexical processing per se played a limited role in both priming and implicit LOP effects. Although priming was sensitive to normative rates of production in Experiment 1 and the number of solutions in all three experiments, it was insensitive to frequency manipulations. The LOP effect was insensitive to number of solutions, normative rates of production, and frequency manipulations. In addition, LOP and priming effects were uncorrelated in the implicit memory tests. It was concluded that production processes (e.g., Gabrieli et al., 1999), rather than lexical processes, played a crucial role in stem completion priming. In contrast, the LOP effect was attributed to the involuntary interaction of episodic and perceptual memory.     

Number of solutions effects in stem decision: Support for the distinction between identification and production processes in priming

Three experiments explored the distinction between identification and production processes (e.g., Gabrieli et al., 1999). A stem decision test was introduced, in which participants were asked to state whether there were any English words that began with the presented three-letter stems. In Experiment 1, stem decision priming was robust for single-solution stems, but much reduced for many-solution stems. In Experiment 2, the solutions effect in stem decision was replicated in a within-subjects design, as was the contrast between the presence of priming in a many-solution stem completion test and the absence of priming in a many-solution stem decision test. In Experiment 3, for each critical many-solution stem in the stem decision test, participants studied three words that began with those three letters. Again, priming was not observed. These results were consistent with the notions that (a) many-solution stem completion relies on production processes, (b) the stem decision test eliminates production processes, and (c) single-solution priming relies on identification processes, regardless of whether the test is stem completion or stem decision.     

Wartime faith-based reactions among traumatized Kosovar and Bosnian refugees in the United States

In William James' view, one function of prayer is a faith-based, conscious approach to a higher power when in distress. Accordingly, this study investigates the use of private prayer among Muslim war refugees from Kosovo and Bosnia (N?=?138). Results show that these refugees were highly traumatized and most counted on private prayer for coping with their wartime difficulties. Four major types of prayer familiar to Americans were employed by roughly two-thirds to 86% of this sample. As expected, most types of prayer were associated with both wartime traumatic distress and greater religiousness. Also, 77% used prayer so that their enemies would “pay for what they have done.” However, this type of prayer was predicted only by higher levels of education and not by religiousness or traumatization. The need for examining the general and specific social contexts of prayer, such as war and terror, and prayer itself, perceived as a common human experience, are discussed. A structural equation model indicated that war-related trauma was associated directly only with negative religious coping but indirectly with positive coping, mediated by levels of emotional distress. Religiousness was related directly only to positive coping. These findings are discussed with respect to their theoretical and clinical implications.     

Religion and Selected Health Behaviors Among Latinos in Texas

Though research has shown that religion provides a protective influence with respect to a number of health-related outcomes, little work has examined its influence on patterns of alcohol (especially binge drinking) and tobacco consumption among Latinos in Texas. Thus, we used a probability sample of Texas adults to test this relationship via logistic regression. Our results revealed that clear distinctions emerge on the basis of both denomination and frequency of attendance. Specifically, Protestants who regularly attend religious services are significantly more likely to be abstainers and to have never smoked, while those with no religious affiliation exhibit relatively unfavorable risk profiles. These findings persist despite a range of socio-demographic controls. Our study supports the assertion that religion may serve as an important protective influence on risky health behaviors.     

Behavioral interventions may prolong remission in patients with inflammatory bowel disease

Inflammatory Bowel Diseases (IBDs) are chronic, relapsing and remitting gastrointestinal conditions with no known cure. Previous studies have linked behavioral factors, including stress and medication adherence, to relapse.

Purpose

We sought to determine the effect of participation in a behavioral self-management program on incidence of flare within 12 months following behavioral intervention when compared to the natural history of flare incidence prior to program participation.

Results

Results from a 2-level regression model indicated that those participants in the treatment group were 57% less likely to flare in the following 12 months (compared to 18% in the control group). The decline in “flare odds” was about 2 times greater in treatment versus controls (OR = 0.52, t(34) = 2.07, p < 0.05). Office visits, ER visits, and disease severity (all p < 0.05) were identified as moderators of flare risk.

Conclusions

We have demonstrated 1) a statistical model estimating the likelihood of flare rates in the 12 months following a behavioral intervention for IBD (compared to a control condition), and 2) that the introduction of a behavioral intervention can alter the natural course of a chronic, relapsing and remitting gastrointestinal condition such as IBD.     

Religious Doubts and Sleep Quality: Findings from a Nationwide Study of Presbyterians #090709revised

A growing literature examines the correlates and sequelae of spiritual struggles, such as religious doubts. To date, however, this literature has focused primarily on a handful of mental health outcomes (e.g., symptoms of depression, anxiety, negative affect), while the possible links with other aspects of health and well-being, such as poor or disrupted sleep, have received much less attention. After reviewing relevant theory and previous studies, we analyze data from a nationwide sample of Presbyterian Church (USA) members to test the hypothesis that religious doubts will be inversely associated with overall self-rated sleep quality, and positively associated with the frequency of sleep problems and the use of sleep medications. We also hypothesize that part of this association will be explained by the link between religious doubts and psychological distress. Results offer moderate but consistent support for these predictions. We end with a discussion of the implications of these findings, a brief mention of study limitations, and some suggestions for future research.