Individual differences in trajectories of arithmetical development in typically achieving 5-to 7-year-olds

The arithmetical performance of typically achieving 5- to 7-year-olds (N = 29) was measured at four 6-month intervals. The same seven tasks were used at each time point: exact calculation, story problems, approximate arithmetic, place value, calculation principles, forced retrieval, and written problems. Although group analysis showed mostly linear growth over the 18-month period, analysis of individual differences revealed a much more complex picture. Some children exhibited marked variation in performance across the seven tasks, including evidence of difficulty in some cases. Individual growth patterns also showed differences in developmental trajectories between children on each task and within children across tasks. The findings support the idea of the componential nature of arithmetical ability and underscore the need for further longitudinal research on typically achieving children and of careful consideration of individual differences. (C) 2009 Elsevier Inc. All rights reserved.

Strategic development in exact calculation: Group and individual differences in four achievement subtypes

This longitudinal study sought to identify developmental changes
in strategy use between 5 and 7 years of age when solving exact
calculation problems. Four mathematics and reading achievement
subtypes were examined at four time points. Five strategies were
considered: finger counting, verbal counting, delayed retrieval,
automatic retrieval, and derived fact retrieval. Results provided
unique insights into children’s strategic development in exact calculation
at this early stage. Group analysis revealed relationships
between mathematical and/or reading difficulties and strategy
choice, shift, and adaptiveness. Use of derived fact retrieval by
7 years of age distinguished children with mathematical difficulties
from other achievement subtypes. Analysis of individual differences
revealed marked heterogeneity within all subtypes,
suggesting (inter alia) no marked qualitative distinction between
our two mathematical difficulty subtypes.

Individual Differences in Children’s Paths to Arithmetical Development

Cross-sectional and longitudinal data consistently indicate that mathematical difficulties are more prevalent in older than in younger children (e.g. Department of Education, 2011). Children’s trajectories can take a variety of shapes such as linear, flat, curvilinear and uneven, and shape has been found to vary within children and across tasks (J Jordan et al. 2009). There has been an increase in the use of statistical methods which are specifically designed to study development, and this has greatly improved our understanding of children’s mathematical development. However, the effects of many cognitive and social variables (e.g. working memory and verbal ability) on mathematical development are unclear. It is likely that greater consistency between studies will be achieved by adopting a componential approach to study mathematics, rather than treating mathematics as a unitary concept.

Individual differences in speech and language ability profiles in areas of high deprivation

Speech and language ability is not a unitary concept; rather, it is made up of multiple abilities such as grammar, articulation and vocabulary. Young children from socio-economically deprived areas are more likely to experience language difficulties than those living in more affluent areas. However, less is known about individual differences in language difficulties amongst young children from socio-economically deprived backgrounds. The present research examined 172 four-year-old children from socio-economically deprived areas on standardised measures of core language, receptive vocabulary, articulation, information conveyed and grammar. Of the total sample, 26% had difficulty in at least one area of language. While most children with speech and language difficulty had generally low performance in all areas, around one in 10 displayed more uneven language abilities. For example, some children had generally good speech and language ability, but had specific difficulty with grammar. In such cases their difficulty is masked somewhat by good overall performance on language tests but they could still benefit from intervention in a specific area. The analysis also identified a number of typically achieving children who were identified as having borderline speech and language difficulty and should be closely monitored

Freshwater pearl mussels show plasticity of responses to different predation risks but also show consistent individual differences in responsiveness

Animals often show behavioural plasticity with respect to predation risk but also show behavioural syndromes in terms of consistency of responses to different stimuli. We examine these features in the freshwater pearl mussel. These bivalves often aggregate presumably to reduce predation risk to each individual. Predation risk, however, will be higher in the presence of predator cues. Here we use dimming light, vibration and touch as novel stimuli to examine the trade-off between motivation to feed and motivation to avoid predation. We present two experiments that each use three sequential novel stimuli to cause the mussels to close their valves and hence cease feeding. We find that mussels within a group showed shorter closure times than solitary mussels, consistent with decreased vulnerability to predation in group-living individuals. Mussels exposed to the odour of a predatory crayfish showed longer closures than control mussels, highlighting the predator assessment abilities of this species. However, individuals showed significant consistency in their closure responses across the trial series, in line with behavioural syndrome theory. Our results show that bivalves trade-off feeding and predator avoidance according to predation risk but the degree to which this is achieved is constrained by behavioural consistency. © 2011 Elsevier B.V.

Validating the use of intrinsic markers in body feathers to identify inter‑individual differences in non‑breeding areas of northern fulmars

Many wildlife studies use chemical analyses to explore spatio-temporal variation in diet, migratory patterns and contaminant exposure. Intrinsic markers are particularly valuable for studying non-breeding marine predators, when direct methods of investigation are rarely feasible. However, any inferences regarding foraging ecology are dependent upon the time scale over which tissues such as feathers are formed. In this study, we validate the use of body feathers for studying non-breeding foraging patterns in a pelagic seabird, the northern fulmar. Analysis of carcasses of successfully breeding adult fulmars indicated that body feathers moulted between September and March, whereas analyses of carcasses and activity patterns suggested that wing feather and tail feather moult occurred during more restricted periods (September to October and September to January, respectively). By randomly sampling relevant body feathers, average values for individual birds were shown to be consistent. We also integrated chemical analyses of body feather with geolocation tracking data to demonstrate that analyses of δ13C and δ15N values successfully assigned 88 % of birds to one of two broad wintering regions used by breeding adult fulmars from a Scottish study colony. These data provide strong support for the use of body feathers as a tool for exploring non-breeding foraging patterns and diet in wide-ranging, pelagic seabirds.

Do Individual Differences in Emotion Regulation Mediate the Relationship Between Mental Toughness and Symptoms of Depression?

Mental Toughness (MT) provides crucial psychological capacities for achievement in sports,
education, and work settings. Previous research examined the role of MT in the domain of
mental health and showed that MT is negatively associated with and predictive of fewer
depressive symptoms in non-clinical populations. The present study aimed at 1) investigating
to what extent mentally tough individuals use two emotion regulation strategies: cognitive
reappraisal and expressive suppression; 2) exploring whether individual differences in
emotion regulation strategy use mediate the relationship between MT and depressive
symptoms. Three hundred sixty-four participants (M = 24.31 years, SD = 9.16) provided
self-reports of their levels of MT, depressive symptoms, and their habitual use of cognitive
reappraisal and expressive suppression. The results showed a statistically significant
correlation between MT and two commonly used measures of depressive symptoms. A small
statistically significant positive correlation between MT and the habitual use of cognitive
reappraisal was also observed. The correlation between MT and the habitual use of
expressive suppression was statistically significant, but the size of the effect was small. A
statistical mediation model indicated that individual differences in the habitual use of
expressive suppression mediate the relationship between MT and depressive symptoms. No
such effect was found for the habitual use of cognitive reappraisal. Implications of these
findings and possible avenues for future research are discussed.