Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Impact of Workplace Bullying on Emotional and Physical Well-Being: A Longitudinal Collective Case Study

Bullying and mobbing are occupational safety hazards pervasive in developed and developing countries. Our study aim was to determine whether bullying and mobbing caused poor health for a victim and a witness from the same workplace in western Canada. Longitudinal semistructured interviews were conducted in 2007 and 2008 with both parties. The interviews were transcribed, analyzed, and arranged into arrays using chronological ordering and time sequencing. The victim felt targeted because she represented a threat to the bully, with victim and witness experiencing negative health outcomes. The authors suggest that wellness programs should place greater emphasis on mental health promotion to discourage workplace bullying.     

Testing the dorsal stream attention hypothesis: Electrophysiological correlates and the effects of ventral stream damage

The roles of dorsal and ventral processing streams in visual orienting and conscious perception were examined in two experiments. The first employed high density EEG with source localization. The second comprised a neuropsychological case study. Visual orienting was assessed with an attention procedure, where peripheral letters cued participants towards a target location. In the perception procedure participants responded to the same letters by performing an explicit conscious discrimination. In Experiment 1, the peripheral letters elicited rapid dorsal stream activation in the attention procedure, and this activation preceded top-down enhancement of target processing in occipital cortex. In the perception procedure early ventral stream activation was seen. In addition, peripheral letters elicited an “early directing attention negativity” (EDAN) over parietal recording sites in the attention procedure, but not in the perception procedure. In Experiment 2, a patient with a bilateral ventral stream lesion but preserved dorsal stream function showed clear disruption to performance in the perception procedure, whilst exhibiting a normal visual orienting effect in the attention procedure. Taken together these findings (1) highlight the distinct roles of the dorsal and ventral streams in attention and perception, and (2) suggest how these streams might interact, via reentrant effects of attention on perceptual processing.     

The psychological puzzle of Sudoku

Sudoku puzzles, which are popular worldwide, require individuals to infer the missing digits in a 9 × 9 array according to the general rule that every digit from 1 to 9 must occur once in each row, in each column, and in each of the 3-by-3 boxes in the array. We present a theory of how individuals solve these puzzles. It postulates that they rely solely on pure deductions, and that they spontaneously acquire various deductive tactics, which differ in their difficulty depending on their “relational complexity”, i.e., the number of constraints on which they depend. A major strategic shift is necessary to acquire tactics for more difficult puzzles: solvers have to keep track of possible digits in a cell. We report three experiments corroborating this theory. We also discuss their implications for theories of reasoning that downplay the role of deduction in everyday reasoning.     

The COMT Val/Met polymorphism is associated with reading‐related skills and consistent patterns of functional neural activation

In both children and adults there is large variability in reading skill, with approximately 5–10% of individuals characterized as having reading disability; these individuals struggle to learn to read despite adequate intelligence and opportunity. Although it is well established that a substantial portion of this variability is attributed to the genetic differences between individuals, specifics of the connections between reading and the genome are not understood. This article presents data that suggest that variation in the COMT gene, which has previously been associated with variation in higher‐order cognition, is associated with reading and reading‐related skills, at the level of both brain and behavior. In particular, we found that the COMT Val/Met polymorphism at rs4680, which results in the substitution of the ancestral Valine (Val) by Methionine (Met), was associated with better performance on a number of critical reading measures and with patterns of functional neural activation that have been linked to better readers. We argue that this polymorphism, known for its broad effects on cognition, may modulate (likely through frontal lobe function) reading skill.     

Adult Age Invariance in Sentence Unitization

We examined age differences on a letter detection task that was performed on four-word sentences in order to examine how letter-level and word-level processing is integrated with sentence-level unitization. Sentence-level unitization is defined as the formation of a sentence-level code that delays access to letter-level or word-level codes. There was a consistent word-frequency disadvantage for both age groups in which it took longer to detect letters within high and medium high frequency words than in low frequency words. This finding suggested that word-level and letter-level input channels were involved in a parallel “horse race” to the central processor while simultaneously outputting codes to the sentence-level at the second tier of processing. The present data also revealed that both age groups showed a larger relative increase in reaction time for letter detection for the fourth word position compared to the third word position on syntactically “intact” sentences relative to syntactically “scrambled” sentences. These data indicated that both age groups formed sentence-level codes that made letter-level codes more difficult to access. Finally, older adults' data showed a larger cost than younger adults' data for scrambled sentences than for intact sentences. These results suggest that older adults are more reliant on a syntactical processor that facilitates the parafoveal preview during the reading of syntactically intact sentences. These data suggest that whereas there are age differences in the perceptual processing of letters and words, sentence unitization and syntactical processing remain intact with increasing adult age.     

The usefulness of the story recall test in patients with mild cognitive impairment and Alzheimer's disease

ABSTRACT

Background: The story recall test (SRT) is one of the most reliable neuropsychological assessments for evaluating verbal memory function in order to distinguish between individuals with normal aging, mild cognitive impairment (MCI), and Alzheimer's disease (AD). The SRT is analogous to the logical memory test in Wechsler Memory Scale-III, which has recently been developed and standardized to apply to older adults in Korea. The purpose of this study was to examine the usefulness of the SRT and its ability to discriminate between normal cognitive aging and patients with MCI or AD. Methods: One hundred and twelve patients with MCI, 97 patients with AD, and 53 healthy elderly adults participated in this study. The SRT was compared with the Clinical Dementia Rating (CDR), Global Deterioration Scale (GDS), Korean version of the Mini Mental State Examination (K-MMSE), and the Korean version of the Hopkins Verbal Learning Test (K-HVLT). Results: The SRT was well-correlated with the dementia rating scales and the K-HVLT. However, the sensitivity and specificity of the SRT was greatly influenced by the level of education of the subjects. Conclusions: The SRT is a sensitive measurement of verbal memory function that can be used in clinical settings to discriminate between normal memory functioning and the very early and moderate stages of AD in a Korean population. Moreover, it is important to recognize that the SRT is more appropriate for subjects with a high level of education rather than a low level of education to differentiate normal cognitive aging from MCI or AD.     

Reports of My Death Anxiety Have Been Greatly Exaggerated: A Critique of Terror Management Theory from an Evolutionary Perspective

Although terror management theory's proponents claim that it is an evolutionary theory of human behavior, its major tenets are implausible when examined carefully from a modern evolutionary perspective. We explain why it is unlikely that natural selection would have designed a “survival instinct” or innate “fear of death,” nor an anxiety-reduction system in general, or worldview-defense system in particular, to ameliorate such fears. We argue that results of mortality-salience experiments are better explained as by-products of a psychological system of coalitional computation that evolved for a variety of functions, including defense against other humans, that is activated by certain kinds of death-related thoughts.