Publications by authors named "Hasker P Davis"

The present study focuses on the role of frequency bias and expected value on the learning processes driving performance on the Iowa Gambling Task (IGT) in individuals between 5 and 89 years of age. As in previous studies, children performed poorly on the IGT, were increasingly influenced by frequency of losses during learning, and constantly changed their decisions. Decision-making strategies changed after childhood from erratic behavior to more consistent strategies that promoted expected value of deck choices.

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Objectives: To investigate the concurrent validity of the Saint Louis University Mental Status examination (SLUMS) by comparing the ability of the Mini-Mental State Examination (MMSE) and the SLUMS to predict performance on standard neuropsychological measures of memory and executive functioning.

Design: Cross-sectional.

Setting: University-based research clinic.

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Unlabelled: BACKGROUND/STUDY CONTEXT: Previous tests of the relationship between subjective organization during encoding, aging, and recall have produced inconsistent findings. The present study investigates subjective organization and the acquisition and recall of verbal material across the life span (from 5 to 89 years of age) using two measures, the intertrial repetition paired frequency (PF) measure and the unidirectional subjective organization (SO) measure.

Methods: Participants (N = 2656) were administered a version of the Rey Auditory Verbal Learning Test, including a delayed recall trial.

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Older adults have been shown to exhibit a positivity effect in processing of emotional stimuli, seemingly focusing more on positive than negative information. Whether this reflects purposeful changes or an unintended side effect of declining cognitive abilities is unclear. For the present study, older adults displaying a wide range of cognitive abilities completed measures of attention, visual, and verbal memory; executive functioning and processing speed; as well as a socioemotional measure of time perspective.

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Temporal processing, or processing time-related information, appears to play a significant role in a variety of vital psychological functions. One of the main confounds to assessing the neural underpinnings and cognitive correlates of temporal processing is that behavioral measures of timing are generally confounded by other supporting cognitive processes, such as attention. Further, much theorizing in this field has relied on findings from clinical populations (e.

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Unlabelled: BACKGROUND/STUDY CONTEXT: An emotion recognition task that morphs emotional facial expressions from an initial neutral expression to distinct increments of the full emotional expression was administered to 482 individuals, 20 to 89 years of age.

Methods: Participants assessed six basic emotions at 25%, 50%, 75%, and 100% of the full facial expression.

Results: Participants in the three oldest age groups (60s, 70s, and 80s) demonstrated decreased performance for the recognition of the fear, anger, and sad emotions.

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The present study aimed to investigate changes in facial expression recognition across the lifespan, as well as to determine the influence of fluid intelligence, processing speed, and memory on this ability. Peak performance in the ability to identify facial affect was found to occur in middle-age, with the children and older adults performing the poorest. Specifically, older adults were impaired in their ability to identify fear, sadness, and happiness, but had preserved recognition of anger, disgust, and surprise.

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In previous research, older adults responded to mortality salience (MS) with increased tolerance, whereas younger persons responded with increased punitiveness. One possible explanation for this is that many older adults adapt to challenges of later life, such as the prospect of mortality, by becoming more flexible. Recent studies suggest that positively oriented adaptation is more likely for older adults with high levels of executive functioning.

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Latent growth models were applied to data on multitrial verbal and spatial learning tasks from two independent studies. Although significant individual differences in both initial level of performance and subsequent learning were found in both tasks, age differences were found only in mean initial level, and not in mean learning. In neither task was fluid or crystallized intelligence associated with learning.

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This study examined the contributions of general slowing and task-specific deficits to age-related changes in Stroop interference. Nine hundred thirty-eight participants aged 20 to 89 years completed an abbreviated Stroop color-naming task and a subset of 281 participants also completed card-sorting, simple reaction time, and choice reaction time tasks. Age-related increases in incongruent color-naming latency and card-sorting perseverative errors were observed.

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Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been associated with reproductive strategies.

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The current study examined the contributions of general slowing and frontal decline to age differences in fluid intelligence. Participants aged 20-89 years completed Block Design, Matrix Reasoning, simple reaction time, choice reaction time, Wisconsin Card Sorting, and Tower of London tasks. Age-related declines in fluid intelligence, speed of processing, and frontal function were observed.

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Aging is associated with changes in automatic processing of task-irrelevant stimuli, and this may lead to functional disturbances including repeated orienting to nonnovel events and distraction from task. The effect of age on automatic processing of time-dependent stimulus features was investigated by measurement of the auditory mismatch negativity (MMN) in younger (18-23) and older (55-85) adults. Amplitude of MMN recorded during a paradigm involving low-probability deviation in interstimulus interval (from 500 ms to 250 ms) was found to be reduced in the older group at fronto-central sites.

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The contributions of working memory, inhibition, and fluid intelligence to performance on the Tower of Hanoi (TOH) and Tower of London (TOL) were examined in 85 undergraduate participants. All three factors accounted for significant variance on the TOH, but only fluid intelligence accounted for significant variance on the TOL. When the contribution of fluid intelligence was accounted for, working memory and inhibition continued to account for significant variance on the TOH.

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Memory performance by four age groups (30-45 years, 46-60 years, 61-75 years, and 76-90 years) was compared on a multi-trial verbal recall task with 20-minute and 1-day delay free recall and recognition trials. The rate of acquisition across 5 learning trials was similar for all ages except the youngest group whose performance was constrained by a ceiling effect. The level of acquisition achieved was less in the two oldest groups.

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