Seeing the Fisher<Emphasis Type="Italic">Z</Emphasis>-transformation

Since 1915, statisticians have been applying Fisher'sZ-transformation to Pearson product-moment correlation coefficients. We offer new geometric interpretations of this transformation.     

Four studies extending the utility of the Schwartz Outcome Scale (SOS-10)

The Schwartz Outcome Scale (SOS-10; Blais et al., 1999) is a brief, cost free, and easy to administer assessment device designed to measure a broad domain of psychological health. The 4 studies using the SOS-10 reported here extend the initial reliability and validity studies beyond psychiatric patients in a hospital setting to examine (a) test-retest reliability in a college student population, (b) concurrent validity with college students using an indirect technique assessing maladjustment, (c) concurrent validity with college counseling center clients using a self-report measure of client distress, and (d) sensitivity to treatment changes with outpatient clients. These studies lend further support for using the SOS-10 as a measure of psychological well-being and as an outcome measure in varied settings.     

Multisensory temporal order judgments: when two locations are better than one

In Experiment 1, participants were presented with pairs of stimuli (one visual and the other tactile) from the left and/or right of fixation at varying stimulus onset asynchronies and were required to make unspeeded temporal order judgments (TOJs) regarding which modality was presented first. When the participants adopted an uncrossed-hands posture, just noticeable differences (JNDs) were lower (i.e., multisensory TOJs were more precise) when stimuli were presented from different positions, rather than from the same position. This spatial redundancy benefit was reduced when the participants adopted a crossed-hands posture, suggesting a failure to remap visuotactile space appropriately. In Experiment 2, JNDs were also lower when pairs of auditory and visual stimuli were presented from different positions, rather than from the same position. Taken together, these results demonstrate that people can use redundant spatial cues to facilitate their performance on multisensory TOJ tasks and suggest that previous studies may have systematically overestimated the precision with which people can make such judgments. These results highlight the intimate link between spatial and temporal factors in determining our perception of the multimodal objects and events in the world around us.     

The role of intent and harm in judgments of prejudice and discrimination

Four experiments examined how an actor's intent and the harm experienced by a target influence judgments of prejudice and discrimination. The presence of intent increased the likelihood that participants judged an actor as prejudiced and the actor's behavior as discriminatory. When intent was uncertain, harm influenced judgments of the behavior, which in turn influenced judgments of the actor, and participants were more cautious in their judgments about an actor than an actor's behavior. Harm also played a stronger role in targets' than observers' judgments. Understanding the role of intent and harm on perceptions of prejudice can help explain variations in targets' versus observers', and possibly targets' versus actors', judgments of discrimination and prejudice.     

Visual identification and spatial location in Alzheimer's disease

Twelve patients with Alzheimer's disease (AD) and 15 healthy elderly control subjects were shown sets of luminance-defined letters, texture-defined letters, luminance-defined squares, and texture-defined squares. They were asked to name the letters or point to the target square on each page. The stimuli were graded into four levels of difficulty based on the amount of contrast between the figure and the background. Performance was measured in terms of the maximum level of difficulty at which the participant correctly identified or located the three figures. Contrary to expectations, no significant difference was found between the performance of AD patients and control subjects on texture discrimination tasks vs. luminance discrimination tasks. However, results indicate that AD patients are impaired in performing a task requiring them to locate a texture-defined target of known shape in a noisy background field. By contrast, AD patients show no significant deficit in a task requiring them to locate a texture-defined shape in a known location. This argues that the observed deficit in the location task is not due to a failure in the system that discriminates target texture from background texture (since both location and identification tasks require the same textural discriminations), but rather to an impairment of the system responsible for "finding things" (i.e., locating known targets at unknown locations). This observation suggests that AD patients may suffer selective damage to the dorsal "Where" pathway, which is responsible for localizing objects in space.     

ERP evidence for the time course of graphic, phonological, and semantic information in Chinese meaning and pronunciation decisions

Two words that varied in their relationship were presented sequentially to Chinese readers who made meaning and pronunciation decisions. In the meaning task, they decided whether the words had the same meaning. In the pronunciation task, they decided whether the words had the same pronunciation. In both tasks, the word pairs represented 1 of 4 relationships: graphically similar, homophonic, semantically related, or unrelated. Event related potentials (ERP) recordings made from the onset of the 2nd word suggested a temporal unfolding of graphic, phonological, and semantic effects. Specifically, graphically-related pairs produced a smaller P200 in the pronunciation task and a smaller N400 in the meaning task. Homophones produced reduced N400 component with bilateral sources in the meaning task.     

Modeling memory decline in older adults: the importance of preclinical dementia, attrition, and chronological age

This longitudinal study examined memory loss in a sample of 391 initially nondemented older adults. Analyses decomposed observed memory loss into decline associated with preclinical dementia, study attrition, terminal decline, and chronological age. Measuring memory as a function of only chronological age failed to provide an adequate representation of cognitive change. Disease progression accounted for virtually all of the memory loss in the 25% of the sample that developed diagnosable dementia. In the remainder of the sample, both chronological age and study attrition contributed to observed memory loss. These results suggest that much of memory loss in aging adults may be attributable to the progression of preclinical dementia and other nonnormative aging processes that are not captured by chronological age.