Neuropsychological Performance in Gulf War Era Veterans: Motivational Factors and Effort

Assuming that the underlying etiology of unexplained health-related symptoms in returning Gulf War (GW) veterans is multifactorial, the possible role of feigning or exaggeration of symptoms is worth consideration as a contributing factor. The present study assessed the relationship between motivation to perform well during neuropsychological assessment and objective neuropsychological test performance. Motivation was measured as the score on a visual memory task (Test of Memory Malingering, TOMM) of low difficulty. Participants included 77 veterans from the cohorts of GW- (n = 58) and Germany-deployed (n = 19) GW-era veterans described in two other papers in this issue who were administered the TOMM. Most veterans earned perfect or near-perfect scores on the TOMM (48–50/50). Scores 47 were associated with lower scores on neuropsychological tasks assessing attention, executive functions, and memory. Variability in test performance within and between tasks measuring similar functions was also found in participants with lower TOMM scores.     

Stroop dilution depends on the nature of the color carrier but not on its location

Stroop dilution is the reduction of the Stroop effect in the presence of a neutral word. It has been attributed to competition for attention between the color word and neutral word, to competition between all stimuli in the visual field, and to perceptual interference. Five experiments tested these accounts. The critical manipulation was whether the color to be named was carried by the color word or the neutral word. Neutral words diluted the Stroop effect when they were the color carrier, but not when the color word was the color carrier. We argue that Stroop dilution is due to attentional competition between the color word and neutral word, with priority given to the color carrier.     

Emergent perceptual features in the benefit of consistent stimulus-response mappings on dual-task performance

Duncan (1979) examined all combinations of compatible and incompatible stimulus-response mappings for two spatial three-choice tasks in the psychological refractory period paradigm. Performance was better when the mappings for the tasks were consistent than when they were not, even when both mappings were incompatible. He attributed the benefit for the consistent incompatible mapping to an emergent choice between mappings when they are inconsistent that slows performance. Consistent incompatible mappings also may benefit from emergent perceptual features. The present study examined the role of emergent perceptual and mapping-choice features in two experiments that used pairs of two-choice tasks. Results similar to Duncan’s were obtained with visual stimuli mapped to keypresses at short (stimulus onset asynchrony) SOAs. However, the benefit of the consistent incompatible mapping condition over the inconsistent mapping conditions was eliminated at an SOA of 1,000 ms. Furthermore, this benefit was not evident when the stimuli were auditory for Task 1 and visual for Task 2. With two-choice tasks, the benefit for consistent mappings apparently is due primarily to an emergent perceptual feature.     

Stroop-like serial position effects in color naming of words and nonwords

Color-naming latencies to noncolor words and nonwords were faster when the onset or final phoneme of the displays corresponded to the onset or final phoneme of the color response. For example, for displays printed in red, the word rack and nonword rask, which share the initial onset phoneme with the response, led to faster naming than did the control word chap and nonword chup. Conversely, when the onset or final phoneme of the displays matched the onset or final phoneme of a conflicting color response (e.g., rack printed in blue), latencies were longer than to control items. Facilitation effects were stronger than interference effects, and the onset phoneme facilitation effect was augmented by coloring only the initial letter in the display. It is hypothesized that nonlexical processes that govern the translation of print to speech may be a source of facilitation in Stroop-like tasks, whereas lexical processes are more likely to contribute to interference.     

Laudan's normative naturalism: a useful philosophy of science for psychology

Logical positivism, widely regarded as the received epistemology of psychology in the first half of the 20th century, was supplanted in the 1960s by various postpositivistic, relativistic philosophies of science, most notably that of Kuhn. Recently, Laudan, a major figure in the philosophy of science, developed a novel approach called normative naturalism that provides an alternative to positivism and relativism. His central thesis is that the two are not always on opposite ends of a continuum but rather have many assumptions in common. This article brings Laudan's important views to the attention of psychologists and describes some of the unique implications of these views for the conduct of research and theory in psychology. These implications, which follow from a number of closely reasoned pragmatic arguments, include more realistic and appropriate evaluation of theory and methodology than has been suggested by logical positivism or relativism.     

Multiple spatial correspondence effects on dual-task performance

Three dual-task experiments were conducted to examine whether the underadditive interaction of the Simon effect and stimulus onset asynchrony (SOA) on Task 2 performance is due to decay. The experiments tested whether the reverse Simon effect obtained with an incompatible stimulus-response (S-R) mapping would show an overadditive interaction with SOA, as predicted by R. De Jong, C.-C. Liang, and E. Lauber's (1994) dual-process model. Tone or letter identification tasks with vocal or keypress responses were used as Task 1. Task 2 was keypresses to arrow direction (or letter identity in Experiment 1). For all experiments, the normal Simon effect showed an underadditive interaction with SOA, but the reverse Simon effect did not show an overadditive interaction. The results imply that the dual-process model is not applicable to the dual-task context. Multiple correspondence effects across tasks implicate an explanation in terms of automatic S-R translation.     

Spatial Stroop interference occurs in the processing of radicals of ideogrammic compounds

In this study, we investigated whether the meanings of radicals are involved in reading ideogrammic compounds in a spatial Stroop task. We found spatial Stroop effects of similar size for the simple characters (“up”) and (“down”) and for the complex characters (“nervous”) and (“nervous”), which are ideogrammic compounds containing a radical or , in Experiments 1 and 2. In Experiment 3, the spatial Stroop effects were also similar for the simple characters (“east”) and (“west”) and for the complex characters (“state”) and (“spray”), which contain and as radicals. This outcome occurred regardless of whether the task was to identify the character (Exps. 1 and 3) or its location (Exp. 2). Thus, the spatial Stroop effect emerges in the processing of radicals just as it does for processing simple characters. This finding suggests that when reading ideogrammic compounds, (a) their radicals’ meanings can be processed and (b) ideogrammic compounds have little or no influence on their radicals’ semantic processing.     

The Satisfaction with Life Scale in Adolescent Samples: Measurement Invariance across 24 Countries and Regions,Age, and Gender

Measurement of adolescent life satisfaction across cultures has not received much attention in previous empirical research. The present study evaluated measurement invariance of the Satisfaction with Life Scale (SWLS) among adolescents in 24 countries and regions (N = 22,710; age range = 13–19 years; 53% female). A single-factor model with residual covariance between a pair of items tapping past life satisfaction fitted well in 19 countries and regions and showed a partial metric invariance. In a subset of nine countries and regions, partial scalar invariance was supported. Partial metric invariance across all 24 countries and regions was achieved when custom model modifications in five countries and regions were included. Three SWLS items showed evidence of noninvariance across cultures. The measurement model was found to operate similarly across gender and age. Our findings suggest that caution is needed when using the SWLS for measuring life satisfaction among adolescents from different cultures.