scholarly journals Genetics of Cognition: Outline of a Collaborative Twin Study

Twin Research ◽  
2001 ◽  
Vol 4 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Margie Wright ◽  
Eco De Geus ◽  
Juko Ando ◽  
Michelle Luciano ◽  
Danielle Posthuma ◽  
...  
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
The Netherlands ◽  
Cognitive Ability ◽  
Processing Speed ◽  
Twin Study ◽  
Memory Task ◽  
Inspection Time ◽  
Phenotypic Correlation ◽  
Spatial Span

AbstractAmultidisciplinary collaborative study examining cognition in a large sample of twins is outlined. A common experimental protocol and design is used in The Netherlands, Australia and Japan to measure cognitive ability using traditional IQ measures (i.e., psychometric IQ), processing speed (e.g., reaction time [RT] and inspection time [IT]), and working memory (e.g., spatial span, delayed response [DR] performance). The main aim is to investigate the genetic covariation among these cognitive phenotypes in order to use the correlated biological markers in future linkage and association analyses to detect quantitativetrait loci (QTLs). We outline the study and methodology, and report results from our preliminary analyses that examines the heritability of processing speed and working memory indices, and their phenotypic correlation with IQ. Heritability of Full Scale IQ was 87% in the Netherlands, 83% in Australia, and 71% in Japan. Heritability estimates for processing speed and working memory indices ranged from 33–64%. Associations of IQ with RT and IT (−0.28 to −0.36) replicated previous findings with those of higher cognitive ability showing faster speed of processing. Similarly, significant correlations were indicated between IQ and the spatial span working memory task (storage [0.31], executive processing [0.37]) and the DR working memory task (0.25), with those of higher cognitive ability showing better memory performance. These analyses establish the heritability of the processing speed and working memory measures to be used in our collaborative twin study of cognition, and support the findings that individual differences in processing speed and working memory may underlie individual differences in psychometric IQ.

scholarly journals Individual Differences in Prospective Memory Offloading in Laboratory and Naturalistic Settings

2021 ◽  
Author(s):  
Hunter Ball ◽  
Philip Peper ◽  
Durna Alakbarova ◽  
Sam Gilbert ◽  
Gene Arnold Brewer
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Cognitive Ability ◽  
Prospective Memory ◽  
High Ability ◽  
Memory Ability ◽  
Multiple Measures ◽  
Good Working

The current study examined whether offloading prospective memory (PM) demands onto the environment through the use of reminders eliminates PM differences typically seen between individuals that have poor or good working memory ability. Over two laboratory sessions scheduled one week apart, participants completed three versions of a PM offloading task with and without the use of reminders, along with multiple measures of working memory. Participants also generated a list of naturalistic intentions to fulfill between sessions and were given an intention to email the experimenter every day. They later indicated which intentions were completed with and without the use of reminders. Consistent with prior research, high working memory participants did better in both laboratory and naturalistic settings when having to rely on their own memory. Critically, however, working memory ability was no longer predictive of performance with the use of reminders. Participants with lower working memory also offloaded more often that high ability participants, but this was not optimally calibrated to actual PM performance. These findings suggest that offloading may be particularly beneficial for those with poor cognitive ability. The theoretical and applied ramifications of these findings are discussed.

scholarly journals Contralateral Delay Activity Tracks Fluctuations in Working Memory Performance

2018 ◽  
Vol 30 (9) ◽  
pp. 1229-1240 ◽  
Author(s):  
Kirsten C. S. Adam ◽  
Matthew K. Robison ◽  
Edward K. Vogel
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Memory Load ◽  
Memory Performance ◽  
Memory Task ◽  
Memory Storage ◽  
Alpha Power ◽  
Working Memory Load ◽  
Contralateral Delay Activity ◽  
Trial Performance

Neural measures of working memory storage, such as the contralateral delay activity (CDA), are powerful tools in working memory research. CDA amplitude is sensitive to working memory load, reaches an asymptote at known behavioral limits, and predicts individual differences in capacity. An open question, however, is whether neural measures of load also track trial-by-trial fluctuations in performance. Here, we used a whole-report working memory task to test the relationship between CDA amplitude and working memory performance. If working memory failures are due to decision-based errors and retrieval failures, CDA amplitude would not differentiate good and poor performance trials when load is held constant. If failures arise during storage, then CDA amplitude should track both working memory load and trial-by-trial performance. As expected, CDA amplitude tracked load (Experiment 1), reaching an asymptote at three items. In Experiment 2, we tracked fluctuations in trial-by-trial performance. CDA amplitude was larger (more negative) for high-performance trials compared with low-performance trials, suggesting that fluctuations in performance were related to the successful storage of items. During working memory failures, participants oriented their attention to the correct side of the screen (lateralized P1) and maintained covert attention to the correct side during the delay period (lateralized alpha power suppression). Despite the preservation of attentional orienting, we found impairments consistent with an executive attention theory of individual differences in working memory capacity; fluctuations in executive control (indexed by pretrial frontal theta power) may be to blame for storage failures.

scholarly journals Individual Differences in Processing Speed and Working Memory Speed as Assessed with the Sternberg Memory Scanning Task

2009 ◽  
Vol 40 (3) ◽  
pp. 315-326 ◽  
Author(s):  
Anna A. E. Vinkhuyzen ◽  
Sophie van der Sluis ◽  
Dorret I. Boomsma ◽  
Eco J. C. de Geus ◽  
Danielle Posthuma
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Processing Speed ◽  
Memory Scanning ◽  
Scanning Task

scholarly journals Individual Differences and Long-term Consequences of tDCS-augmented Cognitive Training

2017 ◽  
Vol 29 (9) ◽  
pp. 1498-1508 ◽  
Author(s):  
Benjamin Katz ◽  
Jacky Au ◽  
Martin Buschkuehl ◽  
Tessa Abagis ◽  
Chelsea Zabel ◽  
...  
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Cognitive Training ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Memory Task ◽  
Memory Training ◽  
Direct Current Stimulation ◽  
Sham Condition

A great deal of interest surrounds the use of transcranial direct current stimulation (tDCS) to augment cognitive training. However, effects are inconsistent across studies, and meta-analytic evidence is mixed, especially for healthy, young adults. One major source of this inconsistency is individual differences among the participants, but these differences are rarely examined in the context of combined training/stimulation studies. In addition, it is unclear how long the effects of stimulation last, even in successful interventions. Some studies make use of follow-up assessments, but very few have measured performance more than a few months after an intervention. Here, we utilized data from a previous study of tDCS and cognitive training [Au, J., Katz, B., Buschkuehl, M., Bunarjo, K., Senger, T., Zabel, C., et al. Enhancing working memory training with transcranial direct current stimulation. Journal of Cognitive Neuroscience, 28, 1419–1432, 2016] in which participants trained on a working memory task over 7 days while receiving active or sham tDCS. A new, longer-term follow-up to assess later performance was conducted, and additional participants were added so that the sham condition was better powered. We assessed baseline cognitive ability, gender, training site, and motivation level and found significant interactions between both baseline ability and motivation with condition (active or sham) in models predicting training gain. In addition, the improvements in the active condition versus sham condition appear to be stable even as long as a year after the original intervention.

scholarly journals Is baseline pupil size related to cognitive ability? Yes (under proper lighting conditions).

2020 ◽  
Author(s):  
Jason S. Tsukahara ◽  
Randall W Engle
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Cognitive Ability ◽  
Pupil Size ◽  
Large Scale ◽  
Fluid Intelligence ◽  
Functional Organization ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Lighting Conditions

We found that individual differences in baseline pupil size correlated with fluid intelligence and working memory capacity. Larger pupil size was associated with higher cognitive ability. However, other researchers have not been able to replicate our 2016 finding – though they only measured working memory capacity and not fluid intelligence. In a reanalysis of Tsukahara et al. (2016) we show that reduced variability on baseline pupil size will result in a higher probability of obtaining smaller and non-significant correlations with working memory capacity. In two large-scale studies, we demonstrated that reduced variability in baseline pupil size values was due to the monitor being too bright. Additionally, fluid intelligence and working memory capacity did correlate with baseline pupil size except in the brightest lighting conditions. Overall, our findings demonstrated that the baseline pupil size – working memory capacity relationship was not as strong or robust as that with fluid intelligence. Our findings have strong methodological implications for researchers investigating individual differences in task-free or task-evoked pupil size. We conclude that fluid intelligence does correlate with baseline pupil size and that this is related to the functional organization of the resting-state brain through the locus coeruleus-norepinephrine system.

scholarly journals Cognitive impairment from early to middle adulthood in patients with affective and nonaffective psychotic disorders

2019 ◽  
Vol 50 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Josephine Mollon ◽  
Samuel R. Mathias ◽  
Emma E. M. Knowles ◽  
Amanda Rodrigue ◽  
Marinka M. G. Koenis ◽  
...  
Keyword(s):  
Working Memory ◽  
African American ◽  
Cognitive Impairment ◽  
Executive Function ◽  
Cognitive Functioning ◽  
Cognitive Ability ◽  
Processing Speed ◽  
Psychotic Disorders ◽  
General Cognitive Ability ◽  
Middle Adulthood

AbstractBackgroundCognitive impairment is a core feature of psychotic disorders, but the profile of impairment across adulthood, particularly in African-American populations, remains unclear.MethodsUsing cross-sectional data from a case–control study of African-American adults with affective (n = 59) and nonaffective (n = 68) psychotic disorders, we examined cognitive functioning between early and middle adulthood (ages 20–60) on measures of general cognitive ability, language, abstract reasoning, processing speed, executive function, verbal memory, and working memory.ResultsBoth affective and nonaffective psychosis patients showed substantial and widespread cognitive impairments. However, comparison of cognitive functioning between controls and psychosis groups throughout early (ages 20–40) and middle (ages 40–60) adulthood also revealed age-associated group differences. During early adulthood, the nonaffective psychosis group showed increasing impairments with age on measures of general cognitive ability and executive function, while the affective psychosis group showed increasing impairment on a measure of language ability. Impairments on other cognitive measures remained mostly stable, although decreasing impairments on measures of processing speed, memory and working memory were also observed.ConclusionsThese findings suggest similarities, but also differences in the profile of cognitive dysfunction in adults with affective and nonaffective psychotic disorders. Both affective and nonaffective patients showed substantial and relatively stable impairments across adulthood. The nonaffective group also showed increasing impairments with age in general and executive functions, and the affective group showed an increasing impairment in verbal functions, possibly suggesting different underlying etiopathogenic mechanisms.

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