Measuring children's sustained selective attention and working memory: validity of new minimally linguistic tasks.

This study introduces visual tasks using nonlinguistic stimuli that measure sustained selective attention (SSA) and working memory (WM), two constructs foundational to learning and associated with developmental disorders in children. Using an argument-based approach to validation, we examine whether each task (a) measures distinct constructs, (b) shows internal consistency, (c) captures a range of performance, and (d) relates to development as indexed by age. Participants included 71 children, ages 4-10, of whom 12 had parental concern for language/learning. The SSA task presented spatial locations within a long and uninteresting task, following the continuous performance task paradigm. The WM task presented paired location sequences of increasing length, incorporating key elements of the n-back and complex span paradigms. Controlling for age, tasks were found to be minimally associated with each other (r = .26), suggesting related but distinct constructs. Internal consistency was high, with split-half reliability of .94 (SSA) and .92 (WM); the stability of these estimates was supported by bootstrapping simulations. Task performance was evenly distributed, with minimal floor or ceiling effects within this age range. Performance was positively related to age (SSA r = .49; WM r = .53). Exploratory correlations with a measure of parental concern were significant for SSA but not WM. The results show that these new tasks can be used to measure children's SSA and WM in a visual domain with minimal linguistic influence. These tasks capture developmental changes in the early school years. Further investigation can examine their utility for classifying children with developmental disorders.

Resurrecting urban sunflowers: Phenotypic and molecular changes between antecedent and modern populations separated by 36 years.

Resurrection experiments provide a unique opportunity to evaluate phenotypic and molecular evolution in response to environmental challenges. To understand the evolution of urban populations of Helianthus annuus, we compared plants from 36-year-old antecedent seed collections to modern seed collections from the same area using molecular and quantitative genetic approaches. We found 200 differentially expressed transcripts between antecedent and modern groups, and transcript expression was generally higher in modern samples as compared to antecedent samples. Admixture analysis indicated gene flow from domesticated to modern populations over time. After a greenhouse refresher generation, one antecedent-modern population pair was grown under two water availability (well-watered and drought) and temperature (ambient and elevated by 2.8°C) conditions reflecting historical and contemporary climates. Overall, 78% (7 out of 9) of traits differed between the antecedent and modern populations, with modern individuals displaying some trait changes that are coherent with climate changes expectations and some trait changes in the direction of crop varieties. Phenotypic selection analysis showed that modern trait values were often favoured by selection, especially in environmental treatments resembling modern conditions. Trait heritability in the antecedent population was five times as high as in the modern population, on average. In addition, phenotypic plasticity for some traits, such as flowering phenology, was present in the antecedent population but absent in the modern population. The combination of phenotypic and molecular information suggests that evolution has been influenced by crop-wild introgression, adaptive processes and drift. We discuss these results in the context of continued evolution in response to anthropogenic factors.