Executive Function Index (EFI) performance in nonclinical individuals with high levels of autistic traits.

This study examined the ability of the Executive Function Index (EFI) to detect differences in executive functioning amongst participants with varying levels of subclinical autistic symptoms as quantified by the Autism Spectrum Quotient (ASQ). Participants were a nonclinical college subject sample classified as displaying either Low (0-15 ASQ score, n = 182) ASQ traits or High (16 or higher ASQ score, n = 91) ASQ traits. Participants were given the ASQ (Baron-Cohen et al., 2001) and the EFI (Spinella, 2005 ). High ASQ subjects were significantly impaired (p's < .04) on the Motivation/Drive (EFI-1) and Organization (EFI-4) subscales of the EFI, as compared to the Low ASQ subjects. However, no High/Low ASQ group differences were observed for EFI-2 (Impulse Control), EFI-3 (Empathy), EFI-5 (Planning) subscales or the EFI-Total Score (p's > .12), although these differences were in the predicted direction (High ASQ < Low ASQ). Use of the EFI as a measure of executive function performance in nonclinical ASQ trait individuals requires further study and may not be sensitive enough of an instrument to assess EF in nonclinical populations with autistic traits.

Dynamical age differences among coeval star clusters as revealed by blue stragglers.

Globular star clusters that formed at the same cosmic time may have evolved rather differently from the dynamical point of view (because that evolution depends on the internal environment) through a variety of processes that tend progressively to segregate stars more massive than the average towards the cluster centre. Therefore clusters with the same chronological age may have reached quite different stages of their dynamical history (that is, they may have different 'dynamical ages'). Blue straggler stars have masses greater than those at the turn-off point on the main sequence and therefore must be the result of either a collision or a mass-transfer event. Because they are among the most massive and luminous objects in old clusters, they can be used as test particles with which to probe dynamical evolution. Here we report that globular clusters can be grouped into a few distinct families on the basis of the radial distribution of blue stragglers. This grouping corresponds well to an effective ranking of the dynamical stage reached by stellar systems, thereby permitting a direct measure of the cluster dynamical age purely from observed properties.

Two distinct sequences of blue straggler stars in the globular cluster M 30.

Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. 'Blue stragglers' are stars massive enough that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for their formation: mass transfer between binary companions and stellar mergers resulting from direct collisions between two stars. Recently the binary explanation was claimed to be dominant. Here we report that there are two distinct parallel sequences of blue stragglers in M 30. This globular cluster is thought to have undergone 'core collapse', during which both the collision rate and the mass transfer activity in binary systems would have been enhanced. We suggest that the two observed sequences are a consequence of cluster core collapse, with the bluer population arising from direct stellar collisions and the redder one arising from the evolution of close binaries that are probably still experiencing an active phase of mass transfer.

The cluster Terzan 5 as a remnant of a primordial building block of the Galactic bulge.

Globular star clusters are compact and massive stellar systems old enough to have witnessed the entire history of our Galaxy, the Milky Way. Although recent results suggest that their formation may have been more complex than previously thought, they still are the best approximation to a stellar population formed over a relatively short timescale (less than 1 Gyr) and with virtually no dispersion in the iron content. Indeed, only one cluster-like system (omega Centauri) in the Galactic halo is known to have multiple stellar populations with a significant spread in iron abundance and age. Similar findings in the Galactic bulge have been hampered by the obscuration arising from thick and varying layers of interstellar dust. Here we report that Terzan 5, a globular-cluster-like system in the Galactic bulge, has two stellar populations with different iron contents and ages. Terzan 5 could be the surviving remnant of one of the primordial building blocks that are thought to merge and form galaxy bulges.

Creativity, unique designs, and schizotypy in a nonclinical sample.

The present study examined whether creativity and novel design construction differ in 60 individuals who scored low and high (based on a median split) on a measure of schizotypy. Groups differed on one measure, total designs made, but not on creativity.

Severity of bulimic symptoms is the best predictor of interference on an emotional Stroop paradigm.

OBJECTIVE: The goal of the current study was to further investigate whether an emotional Stroop effect exists among patients with bulimia nervosa. METHOD: Performances of 30 female controls, 30 females with subclinical eating disordered symptoms, and 30 females diagnosed with bulimia nervosa were compared on an emotional Stroop color naming task using stimuli separated into three areas of concern (eating, weight, and shape words). RESULTS: Results indicated that overall the three groups differed significantly on the emotional Stroop task, with the interference latency for disorder salient words progressively increasing as the severity of bulimic symptoms increased. Severity of bulimic symptoms was the best predictor of interference on the emotional Stroop paradigm. DISCUSSION: Results provide further evidence that interference on the emotional Stroop is uniquely related to the symptoms of bulimia nervosa and bear credence to the possibility of its use as an additional tool in the diagnosis of bulimia nervosa.

Effects of emotional state on lexical decision performance.

The effect of emotional state on lexical processing was investigated. Subjects were randomly assigned to either a happy or sad mood condition. Emotional state was then induced by listening to 8 min of classical music previously rated to induce happy or sad moods. Response times and error rates were analyzed in a lexical decision task involving sad words, happy words, and pseudowords. Results suggest that emotion aided the participants in responding to emotion-congruent stimuli. The sad group responded faster than the happy group to sad words and the happy group responded faster than the sad group to happy words. Results are discussed with regard to information processing and emotion.

Lexical properties of the Boston Naming Test stimuli: age differences in word naming and lexical decision latency.

Two experiments examined the lexical properties of the word representations of the Boston Naming Test (BNT; Kaplan, Goodglass, & Weintraub, 1983) stimuli and whether these properties differentially influenced performance of young and older adults in a speeded word naming task and a lexical decision task. The lexical properties of the word representations examined were familiarity, number of letters, frequency of the word's occurrence, and number of syllables. The results of Experiment 1 indicated that the process of lexical access was similar in young and older adults and provided the first examination of lexical properties of the BNT stimuli in a speeded naming situation. The purpose of Experiment 2 was to reexamine the questions raised in Experiment 1 using a lexical decision task. The results of the analysis in Experiment 2 indicated that age was a significant predictor of performance on the lexical decision task. None of the other predictors contributed significantly to the regression equation.

The relationship between cognitive ability and positive and negative priming in identity and spatial priming tasks.

The authors examined whether stimulus activation and inhibition in the identity priming task are related to the temporal lobe, and whether these processes in the spatial priming task are related to the parietal lobe. Forty participants performed spatial and identity positive and negative priming tasks, the Vandenberg Mental Rotation task, and the Digit Span task. Both men and women showed significant positive and negative priming in the identity and spatial tasks with no gender difference. The magnitude of identity positive priming was predicted by the Digit Span task, and the magnitude of spatial positive priming was predicted by the mental rotation task. Only women showed a correlation between spatial ability and spatial negative priming. The results are partially consistent with the dorsal-ventral model of cognitive inhibition.

Individual differences in information-processing rate and amount: implications for group differences in response latency.

Research on group differences in response latency often has as its goal the detection of Group x Treatment interactions. However, accumulating evidence suggests that response latencies for different groups are often linearly related, leading to an increased likelihood of finding spurious overadditive interactions in which the slower group produces a larger treatment effect. The authors propose a rate-amount model that predicts linear relationships between individuals and that includes global processing parameters based on large-scale group differences in information processing. These global processing parameters may be used to linearly transform response latencies from different individuals to a common information-processing scale so that small-scale group differences in information processing may be isolated. The authors recommend linear regression and z-score transformations that may be used to augment traditional analyses of raw response latencies.

The effect of importance level, delay, and rate of forgetting on prose recall in multiple sclerosis.

Memory deficits are frequently seen in patients with multiple sclerosis (MS). The focus of this study was to examine semantic encoding and the rate of forgetting in MS patients. The prose passages of the Wechsler Memory Scale Logical Memory subtest were used to examine MS patients' semantic sensitivity to the idea units of a story. The stories were divided into high, medium, and low idea units, reflecting their overall importance to the meaning of the story. MS patients recalled fewer idea units than controls, but both groups favored the main ideas relative to the nonessential details at both the immediate and delayed recall of the passages. Likewise, MS patients forgot information at a much faster rate than controls. Implications of this faster forgetting rate in MS patients are discussed from an applied setting.

An analysis of the "eveningness-morningness" dimension in "depressive" college students.

BACKGROUND: Circadian variability in depression has not been well characterized with respect to the "eveningness-morningness" dimension. METHODS: The "eveningness-morningness" dimension, as measured by the Home and Ostberg questionnaire, was examined among a student population (n = 1617) that was named as "depressive". Three depression scales (BDI, GDS-SF, and CESD) were used to determine "depressiveness". The Horne and Ostberg questionnaire was used to measure the degree of "eveningness-morningness". It was hypothesized that there would be negative and significant correlations between the scores on the Horne and Ostberg questionnaire and the depression scales. Consequently, it was expected that there would be a significantly higher number of evening types than the morning types among the participants identified as "depressives". RESULTS: There were significant, negative correlations between the Horne and Ostberg questionnaire scores and the responses on the 3 depression scales (for BDI r= -.174, GDS-SF r= -.182, CESD r = -.176, all p < .001). Also, a significantly higher incidence of evening types than of the morning types among the "depressive" students was found (chi2 = 11.18, p < .01). LIMITATIONS: It is uncertain to what extent these data generalize to clinical populations. CONCLUSIONS: "Depressive" college students are more likely to be evening types.

Age and the allocation of attention across the time course of word recognition.

Younger and older adults performed lexical decisions on ambiguous words, unambiguous words, and pseudowords, and simultaneously responded to an auditory probe presented at stimulus onset asynchronies (SOAs) of 90, 180, or 270 ms. For both age groups, lexical decisions and probe responses were faster for ambiguous words than for unambiguous words, and slowest for pseudowords. For the older adults, but not the younger adults, lexical decisions were slower when the probe was presented (the dual-task condition), compared with a control condition in which the lexical decision was performed alone. The older participants also showed slower tone-detection responses in the dual-task condition than when the tone was presented alone. For all participants, proportional tone-detection times (compared with tones in isolation) decreased with increasing SOA, but this decrease was less pronounced in the older group. Finally, the time between responses in the dual-task condition was longer for older than for younger adults. The results indicate that word meaning influences the allocation of attention similarly for younger and older adults, but that older adults suffer a cost and become disproportionately slower in processes related to response coordination and output.

The role of vocabulary ability during visual word recognition in younger and older adults.

The role that vocabulary ability plays in adult age differences in word recognition was investigated. In Experiment 1, 44 older adults (ages 61-93 years) were compared with 44 younger adults (ages 18-39 years) on a standard lexical-decision task, with ambiguous words, unambiguous words, and pseudowords serving as stimuli. In Experiment 1, the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981) vocabulary performance was uncontrolled across the younger and older adults, and the older adults had higher WAIS-R scores. There was no Group x Stimulus interaction. In Experiment 2, the data from the same 44 older adults were compared with data from a new sample of 44 younger adults (ages 18-44). Both groups were then matched on WAIS-R performance. Results revealed a significant Group x Stimulus interaction. Reaction time differences between the younger and older groups on the ambiguous words and unambiguous words were identical. The differences in reaction times for words and pseudowords were greater in the older adults. The importance of vocabulary ability during word recognition and lexical processing is discussed.

Frontal lobe deficits in domestic violence offenders.

Functional frontal lobe deficits were examined in 38 men who committed domestic violence and 38 control participants. Dependent measures that examine frontal lobe deficits, including the Wisconsin Card Sorting Test (D. A. Grant & E. A. Berg, 1948), the Stroop Color-Word Test (J. R. Stroop, 1935), and Trails B (R. M. Reitan & L. A. Davidson, 1974), were used. The prediction that men who commit domestic violence would perform more poorly on neuropsychological measures related to frontal lobe deficits was only partially supported. A discriminate analysis was significant (p < .05), explaining approximately 7% of the variance; Trails B was the only contributor to that equation. The men who committed battery took significantly longer to complete Trails B than the control participants, suggesting that the men who committed battery may not have been as good as the control participants at inhibiting the competing response and therefore took longer to complete the task. The groups did not significantly differ on the other neuropsychological measures.

The effect of moderate levels of simulated altitude on sustained cognitive performance.

Previous work has documented cognitive deficits at high altitudes (15,000-25,000 ft), but there is controversy for lower altitudes. This study looked at the effects of moderate altitudes--12,500 ft and 15,000 ft--on short-term memory in comparison to 2,000 ft. Seventy-two student pilots and instructors were first administered the Vocabulary, Digit Span, and Digit Symbol subtests from the Wechsler Adult Intelligence Scale-Revised, the Vandenberg Mental Rotation Test, and the near-contrast sensitivity portion of the Vistech VCTS 6000 chart. Participants then spent 1 1/2 hr at their designated altitude for cognitive testing. Participants performed a 30 min vigilance task while listening to an audiotape with instructions to recall radio calls prefaced by their assigned call sign. Half of the radio calls were high memory loads (at least 4 pieces of information), and half were low memory loads (no more than 2 pieces of information). No effects of altitude were found in performance on the Vigilance task. However, for readbacks of high memory load, significant deficits in recall were observed at 12,500 ft and 15,000 ft, whereas no effect of altitude was observed on recall of readbacks with low memory loads. These results indicate that, at altitude, short-term memory was exceeded for the readbacks requiring a larger amount of information to be recalled, and that cognitive deficits are found at lower altitudes than previously observed.

Cross-modal semantic and homograph priming in healthy young, healthy old, and in Alzheimer's disease individuals.

Two experiments are reported that explore the influence of strength of the prime-target relationship on the observed priming effects in young, healthy old, and individuals diagnosed with dementia of the Alzheimer type (DAT). In Experiment 1, participants were auditorily presented primes (FURNITURE) and after varying delays presented visual targets that were (1) high-strength related (e.g., SOFA), (2) low-strength related (e.g., RUG), or (3) unrelated control words (e.g., COW or DEER). The results indicated that the DAT individuals produced relatively larger priming effects that both the young and the healthy old, but these data could be accommodated by increases in effect size due to general slowing of response latencies. In Experiment 2, the same cross-modal priming paradigm was used with ambiguous words presented as primes (e.g., BANK) and either high-dominant (e.g., MONEY) or low-dominant (e.g., RIVER) words as targets. The results of Experiment 2 produced a qualitatively distinct pattern of priming that indicated DAT individuals only produced priming for high-dominant targets and not for low-dominant targets, whereas, the healthy control groups produced equivalent priming for both high- and low-dominant targets. The discussion focuses on the implication that these results have for the interpretation of semantic priming effects, in general, along with implications for the apparent semantic memory loss in DAT individuals.

The role of speed of processing, inhibitory mechanisms, and presentation order in trail-making test performance.

The roles of speed of processing, inhibition, and presentation order in the Trail Making Test (TMT) performance were examined. One-hundred ten undergraduates performed the TMT (1/2 received order Part A-Part B, 1/2 received order Part B-Part A) and also completed computerized tests of inhibitory functioning and speed of processing. Neither speed of processing nor inhibitory functioning affected TMT performance. However, order of presentation significantly affected TMT performance. Presentation order is an important variable to consider in TMT performance.

Institutional Review Board issues related to special populations.

The present article begins with an introduction to the role of Institutional Review Boards (IRBs) in research activities in general and proceeds to issues IRBs face with relation to special populations, including children and terminally ill individuals, as well as developmentally disabled and cognitively impaired persons. A historical overview of research with these special populations is included, and the report concludes with a real-world example of how IRB-related issues with developmentally disabled and cognitively impaired individuals are discussed and resolved.