Speed-accuracy tradeoff and its relationship to higher-order cognition

It is a simple idea that there is an adversarial relationship between how quickly one performs an action and how well that action is performed. This phenomenon, known as the speed-accuracy tradeoff (SAT), has received some attention in the literature, notably through modeling work beginning in the 1960’s. However, it has not been measured as a cognitive construct using latent variable analysis, as is common with other constructs such as working memory capacity (WMC), fluid intelligence (Gf), attentional control, task switching, memory updating, and so on. The goal of the present study is to address this gap in the literature. Specifically, I propose that the ability to appropriately implement speed and accuracy across different tasks is an important executive function strongly related to higher-order cognition. I tested this hypothesis by implementing tasks of SAT in a large-scale correlational study involving measures of other constructs, namely WMC and Gf. Results are mixed, there is evidence that SAT can be measured at the latent level and that this construct relates to higher-order cognition. However, the magnitude of this relationship is small, and trial-by-trial analyses suggest that lower ability individuals are also capable of adjusting performance to meet task demands.M.S

Change Detection as a Framework for Understanding Individual Differences in Attention Control and Allocation of Attention Across the Visual Field

Attention control is a domain-general ability that guides the control of thoughts and intentional behavior in a goal-driven manner and is a central concept to many models of human cognition. Our lab recently showed that attention control can be measured more reliably and validly with alternative tasks, one of which being selective visual arrays (rapid change detection with distracting stimuli). The present study was designed with two goals in mind: first, to extend this finding by further exploring the nature of attentional individual differences in visual arrays tasks, and second to use the visual arrays paradigm to investigate individual differences in how individuals allocate attention across the visual field. Five variants of visual arrays were administered to 210 participants from the Atlanta community along with a battery of other cognitive tasks. Results showed that the presence of distractors in visual arrays was the most important factor in scores producing attention-related individual differences. Further, variants that had more distractors and/or required spatial selection of targets, as opposed to feature selection, were more difficult and more strongly predictive of overall cognitive ability. On the other hand, (1) performance on supra-capacity vs. near-capacity array sizes were not differentially predictive of cognitive ability, (2) within the variants that required spatial selection of targets there were no substantive differences in performance as a function how the targets and distractors were arranged, and (3) there were no detectable meaningful differences in performance across different cue-to-stimulus intervals. In the discussion section I explore how and potentially why some of these results are consistent with my hypotheses whereas some were unexpected and thus contrast with findings from the literature. The overall conclusion is that the visual arrays paradigm is an attention control measure robust to a variety of manipulations.Ph.D

Noninvasive measurements of arterial stiffness: Repeatability and interrelationships with endothelial function and arterial morphology measures

Corey J Huck1, Ulf G Bronas1, Eric B Williamson1, Christopher C Draheim1, Daniel A Duprez2, Donald R Dengel1,31School of Kinesiology, University of Minnesota, Minneapolis, MN, USA; 2Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN; 3Research Service, Minneapolis Veterans Affairs Medical Center, Minneapolis, MN, USABackground: Many noninvasive arterial assessment techniques have been developed, measuring different parameters of arterial stiffness and endothelial function. However, there is little data available comparing different devices within the same subject. Therefore, the purpose of this study was to examine the repeatability and interrelationships between 3 different techniques to measure arterial stiffness and to compare this with forearm-mediated dilation.Methods: Carotid-radial pulse wave velocity was measured by the Sphygmocor (SPWV) and Complior (CPWV) devices, cardio-ankle vascular index (CAVI) was measured by the VaSera device, vascular structure and function was assessed using ultrasonography and evaluated for reliability and compared in 20 apparently healthy, college-aged men and women.Results: The intraclass correlation coefficient and standard error of the mean for the Sphygmocor (R = 0.56, SEM = 0.69), Complior (R = 0.62, SEM = 0.69), and VaSera (R = 0.60, SEM = 0.56), indicated moderate repeatability. Bland-Altman plots indicated a mean difference of 0.11 ± 0.84 for SPWV, 0.13 ± 1.15 for CPWV, and –0.43 ± 0.90 for CAVI. No significant interrelationships were found among the ultrasound measures and SPWV, CPWV, and CAVI.Conclusions: The three noninvasive modalities to study arterial stiffness reliably measures arterial stiffness however, they do not correlate with ultrasound measures of vascular function and structure in young and apparently healthy subjects.Keywords: Pulse wave velocity, intima-media thickness, flow-mediated dilatio

Chocolate, Air Pollution and Children's Neuroprotection: What Cognition Tools should be at Hand to Evaluate Interventions?

Indexación: Web of ScienceMillions of children across the world are exposed to multiple sources of indoor and outdoor air pollutants, including high concentrations of fine particulate matter (PM2.5) and ozone (O-3). The established link between exposure to PM2.5, brain structural, volumetric and metabolic changes, severe cognitive deficits (1.5-2 SD from average IQ) in APOE 4 heterozygous females with >75 - <94% BMI percentiles, and the presence of Alzheimer's disease (AD) hallmarks in urban children and young adults necessitates exploration of ways to protect these individuals from the deleterious neural effects of pollution exposure. Emerging research suggests that cocoa interventions may be a viable option for neuroprotection, with evidence suggesting that early cocoa interventions could limit the risk of cognitive and developmental concerns including: endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, and metabolic detrimental brain effects. Currently, however, it is not clear how early we should implement consumption of cocoa to optimize its neuroprotective effects. Moreover, we have yet to identify suitable instruments for evaluating cognitive responses to these interventions in clinically healthy children, teens, and young adults. An approach to guide the selection of cognitive tools should take into account neuropsychological markers of cognitive declines in patients with Alzheimer's neuropathology, the distinct patterns of memory impairment between early and late onset AD, and the key literature associating white matter integrity and poor memory binding performance in cases of asymptomatic familial AD. We highlight potential systemic and neural benefits of cocoa consumption. We also highlight Working Memory Capacity (WMC) and attention control tasks as opened avenues for exploration in the air pollution scenario. Exposures to air pollutants during brain development have serious brain consequences in the short and long term and reliable cognition tools should be at hand to evaluate interventions.http://journal.frontiersin.org/article/10.3389/fphar.2016.00232/ful

Information sharing and willingness-to-pay for CBPP vaccine in rural Kenya

•Improved sharing of CBPP risk information increases CBPP vaccine up-take.•Demand increases by 1.5 and 2.3 per cent for improved access and information.•WTP for a 1 h reduction in travel duration is KES 54 (USD 0.52) per vaccine.•WTP for receipt of CBPP risk information is KES 52 (USD 0.67) per vaccine.•Controlling for attribute non-attendance improves model fit and estimates. The study estimates cattle owners' willingness-to-pay (WTP) for Contagious Bovine Pleuropneumonia (CBPP) vaccine in Samburu county, Kenya. Of particular policy relevance, the study presents findings on WTP for i) improved access to vaccines and ii) timely access to disease-risk information. The mean price for a CBPP vaccine was estimated at KES 66 (USD 0.64). This price relates to a CBPP vaccine that requires a 1.8 h commute, cattle owners' receipt of timely information that the CBPP disease risk is low-moderate and the vaccine lowers the risk of either tail-drop or post-vaccine abortion. The conditional WTP for mean travel duration and high-risk information are similar at KES 53.9 and KES 51.5. The marginal effect on demand for a 1 h additional travel duration and provision of CBPP disease risk information was estimated as a 1.5 per cent reduction and 2.3 increase. The results of this study indicate that cattle owners value greater levels of knowledge concerning the changing risk profile of CBPP in their community and improved access to CBPP vaccination services. Enhanced engagement with cattle owners concerning CBPP would likely result in a greater utilisation of available CBPP vaccines, conditional on the perceived CBPP disease risk

Range-wide Phylogeographic Analysis of the Spotted Frog Complex (\u3ci\u3eRana luteiventris\u3c/i\u3e and \u3ci\u3eRana pretiosa\u3c/i\u3e) in Northwestern North America

The dynamic geological and climatic history of northwestern North America has made it a focal region for phylogeography. We conducted a range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) across its range in northwestern North America to understand its evolutionary history and the distribution of clades to inform conservation of R. pretiosa and Great Basin R. luteiventris, candidates for listing under the US Endangered Species Act. Mitochondrial DNA sequence data from a segment of the cytochrome b gene were obtained from 308 R. luteiventris and R. pretiosa from 96 sites. Phylogenetic analysis revealed one main R. pretiosa clade and three main R. luteiventris clades, two of which overlapped in southeastern Oregon. The three R. luteiventris clades were separated from each other by high levels of sequence divergence (average of 4.75–4.97%). Two divergent clades were also uncovered within the Great Basin. Low genetic variation in R. pretiosa and the southeastern Oregon clade of R. luteiventris suggests concern about their vulnerability to extinction

Characterization of 14 microsatellite DNA markers for the tropical forest tree Virola surinamensis (Rol.) Warb. (Myristicaceae)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74408/1/j.1755-0998.2009.02667.x.pd

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

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