Experimental and meta-analytic evidence that source variability of misinformation does not increase eyewitness suggestibility independently of repetition of misinformation.

Considerable evidence has shown that repeating the same misinformation increases its influence (i.e., repetition effects). However, very little research has examined whether having multiple witnesses present misinformation relative to one witness (i.e., source variability) increases the influence of misinformation. In two experiments, we orthogonally manipulated repetition and source variability. Experiment 1 used written interview transcripts to deliver misinformation and showed that repetition increased eyewitness suggestibility, but source variability did not. In Experiment 2, we increased source saliency by delivering the misinformation to participants via videos instead of written interviews, such that each witness was visibly and audibly distinct. Despite this stronger manipulation, there was no effect of source variability in Experiment 2. In addition, we reported a meta-analysis (k = 19) for the repeated misinformation effect and a small-scale meta-analysis (k = 8) for the source variability effect. Results from these meta-analyses were consistent with the results of our individual experiments. Altogether, our results suggest that participants respond based on retrieval fluency rather than source-specifying information.

Measuring working memory in the Spanish population: Validation of a multiple shortened complex span task.

Working memory plays a key role in cognition as it is a major predictor of a wide range of higher order abilities and behaviors typical to daily life. Shorter versions of the complex span tasks (CSTs) have been recently developed, allowing for the reduction of test administration time without affecting validity and reliability in the measurement of working memory capacity (WMC). However, these short versions have not been validated for the Spanish-speaking population. The present work aimed to validate an English version of the shortened CSTs into Spanish in a sample of 325 university students (40% female; mean age = 21.04; SD = 2.80). Cronbach's coefficient alpha was computed for each complex span task as an index of internal consistency. Validity evidence was evaluated by comparing participants' scores on the three shortened complex span tasks (operation span, symmetry span, and rotation span) with two measures of reasoning ability (Raven's Advanced Progressive Matrices and Number Series) and using confirmatory factor analysis. Results indicated that the short version of the Spanish complex span has satisfying qualities for assessing WMC in a sample of university students, which is an initial step toward providing a valid and standardized method for assessing WMC in the Peninsular Spanish-speaking population. (PsycINFO Database Record

Do the effects of working memory training depend on baseline ability level?

There is a debate about the ability to improve cognitive abilities such as fluid intelligence through training on tasks of working memory capacity. The question addressed in the research presented here is who benefits the most from training: people with low cognitive ability or people with high cognitive ability? Subjects with high and low working memory capacity completed a 23-session study that included 3 assessment sessions, and 20 sessions of training on 1 of 3 training regiments: complex span training, running span training, or an active-control task. Consistent with other research, the authors found that training on 1 executive function did not transfer to ability on a different cognitive ability. High working memory subjects showed the largest gains on the training tasks themselves relative to the low working memory subjects-a finding that suggests high spans benefit more than low spans from training with executive function tasks. (PsycINFO Database Record

Nonprobative photos rapidly lead people to believe claims about their own (and other people's) pasts.

Photos lead people to believe that both true and false events have happened to them, even when those photos provide no evidence that the events occurred. Research has shown that these nonprobative photos increase false beliefs when combined with misleading suggestions and repeated exposure to the photo or target event. We propose that photos exert similar effects without those factors, and test that proposition in five experiments. In Experiment 1, people saw the names of several animals and pretended to give food to or take food from each. Then people saw the animal names again, half with a photo of the animal and half alone, and decided whether they had an experience with each. The photos led people to believe they had experiences with the animals. Moreover, Experiments 2-5 provided evidence that photos exerted these effects by making it easier to bring related thoughts and images to mind-a feeling that people mistook as evidence of genuine experience. In each experiment, photos led people to believe positive claims about the past (but not negative claims), consistent with evidence that feelings of ease selectively increase positive judgments. Experiment 4 also showed that photos (like other manipulations of ease) bias people's judgments broadly, producing false beliefs about other people's pasts. Finally, in Experiment 5, photos exerted more powerful effects when they depicted unfamiliar animals, and thus could most help bring information to mind. These findings suggest that nonprobative photos can distort the past without other factors that encourage false beliefs, and that they operate by helping related thoughts and images come to mind.

Working memory capacity accounts for the ability to switch between object-based and location-based allocation of visual attention.

Bleckley, Durso, Crutchfield, Engle, and Khanna (Psychonomic Bulletin & Review, 10, 884-889, 2003) found that visual attention allocation differed between groups high or low in working memory capacity (WMC). High-span, but not low-span, subjects showed an invalid-cue cost during a letter localization task in which the letter appeared closer to fixation than the cue, but not when the letter appeared farther from fixation than the cue. This suggests that low-spans allocated attention as a spotlight, whereas high-spans allocated their attention to objects. In this study, we tested whether utilizing object-based visual attention is a resource-limited process that is difficult for low-span individuals. In the first experiment, we tested the uses of object versus location-based attention with high and low-span subjects, with half of the subjects completing a demanding secondary load task. Under load, high-spans were no longer able to use object-based visual attention. A second experiment supported the hypothesis that these differences in allocation were due to high-spans using object-based allocation, whereas low-spans used location-based allocation.

Shortened complex span tasks can reliably measure working memory capacity.

Measures of working memory capacity (WMC), such as complex span tasks (e.g., operation span), have become some of the most frequently used tasks in cognitive psychology. However, due to the length of time it takes to complete these tasks many researchers trying to draw conclusions about WMC forgo properly administering multiple tasks. But can the complex span tasks be shortened to take less administration time? We address this question by splitting the tasks into three blocks of trials, and analyzing each block's contribution to measuring WMC and predicting fluid intelligence (Gf). We found that all three blocks of trials contributed similarly to the tasks' ability to measure WMC and Gf, and the tasks can therefore be substantially shortened without changing what they measure. In addition, we found that cutting the number of trials by 67 % in a battery of these tasks still accounted for 90 % of the variance in their measurement of Gf. We discuss our findings in light of administering the complex span tasks in a method that can maximize their accuracy in measuring WMC, while minimizing the time taken to administer.

People with easier to pronounce names promote truthiness of claims.

When people make judgments about the truth of a claim, related but nonprobative information rapidly leads them to believe the claim--an effect called "truthiness". Would the pronounceability of others' names also influence the truthiness of claims attributed to them? We replicated previous work by asking subjects to evaluate people's names on a positive dimension, and extended that work by asking subjects to rate those names on negative dimensions. Then we addressed a novel theoretical issue by asking subjects to read that same list of names, and judge the truth of claims attributed to them. Across all experiments, easily pronounced names trumped difficult names. Moreover, the effect of pronounceability produced truthiness for claims attributed to those names. Our findings are a new instantiation of truthiness, and extend research on the truth effect as well as persuasion by showing that subjective, tangential properties such as ease of processing can matter when people evaluate information attributed to a source.

Building false memories without suggestions.

People can come to remember doing things they have never done. The question we asked in this study is whether people can systematically come to remember performing actions they never really did, in the absence of any suggestion from the experimenter. People built LEGO vehicles, performing some steps but not others. For half the people, all the pieces needed to assemble each vehicle were laid out in order in front of them while they did the building; for the other half, the pieces were hidden from view. The next day, everyone returned for a surprise recognition test. People falsely and confidently remembered having carried out steps they did not; those who saw all the pieces while they built each vehicle were more likely to correctly remember performing steps they did perform but equally likely to falsely remember performing steps they did not. We explain our results using the source monitoring framework: People used the relationships between actions to internally generate the missing, related actions, later mistaking that information for genuine experience.

Repetition, not number of sources, increases both susceptibility to misinformation and confidence in the accuracy of eyewitnesses.

Are claims more credible when made by multiple sources, or is it the repetition of claims that matters? Some research suggests that claims have more credibility when independent sources make them. Yet, other research suggests that simply repeating information makes it more accessible and encourages reliance on automatic processes-factors known to change people's judgments. In Experiment 1, people took part in a "misinformation" study: people first watched a video of a crime and later read eyewitness reports attributed to one or three different eyewitnesses who made misleading claims in either one report or repeated the same misleading claims across all three reports. In Experiment 2, people who had not seen any videos read those same reports and indicated how confident they were that each claim happened in the original event. People were more misled by-and more confident about-claims that were repeated, regardless of how many eyewitnesses made them. We hypothesize that people interpreted the familiarity of repeated claims as markers of accuracy. These findings fit with research showing that repeating information makes it seem more true, and highlight the power of a single repeated voice.

Reproducibility of a scoring system for computed tomography scanning in cystic fibrosis.

INTRODUCTION: Computerized tomography (CT) scanning shows promise as an outcome surrogate for cystic fibrosis (CF) lung disease progression. The scoring system used to convert the CT image to numeric data is an essential determinant of the performance of CT scanning. METHODS: Three radiologists independently scored 16 high-resolution CT scans performed on children in the Wisconsin CF Neonatal Screening Project. The test scans were selected to provide a broad range of disease severity. The scoring system provided subscores for the presence and severity of 5 findings of CF lung disease. The sum of the subscores provided a total score. The CT scans were then read again by each of the radiologists at least 11 months later. Using Mixed Effects Linear Model Analysis, the sources of error (scan-to-scan variation, interrater variance, and intrarater variance) were calculated. RESULTS: For the total score, the scan-to-scan variation was 14.48, interrater variance was 0.28, and intrarater variance was 0.45, with an overall reproducibility of 95%. The square root of scan-to-scan variance, a measure of sensitivity, was 3.81. Evaluation of the subscores showed higher reproducibility for bronchiectasis and hyperinflation (95% and 88%, respectively). The bronchiectasis score was more sensitive than the air-trapping score (1.46 vs. 0.89). DISCUSSION: This system was developed to provide a reproducible method that could be used to evaluate the lobar location, severity, and extent of a broad spectrum of CT features of CF lung disease, especially in children. This study demonstrates that the overall score is both sensitive to variation in the severity of lung disease and reproducible.