The prevalence of synaesthesia depends on early language learning

According to one theory, synaesthesia develops, or is preserved, because it helps children learn. If so, it should be more common among adults who faced greater childhood learning challenges. In the largest survey of synaesthesia to date, the incidence of synaesthesia was compared among native speakers of languages with transparent (easier) and opaque (more difficult) orthographies. Contrary to our prediction, native speakers of Czech (transparent) were more likely to be synaesthetes than native speakers of English (opaque). However, exploratory analyses suggested that this was because more Czechs learned non-native second languages, which was strongly associated with synaesthesia, consistent with the learning hypothesis. Furthermore, the incidence of synaesthesia among speakers of opaque languages was double that among speakers of transparent languages other than Czech, also consistent with the learning hypothesis. These findings contribute to an emerging understanding of synaesthetic development as a complex and lengthy process with multiple causal influences.     

The relationships between quantity‐number competencies,working memory,and phonological awareness in 5‐ and 6‐year‐olds

In this study, the interdependencies among phonological awareness, verbal working memory components, and early numerical skills in children 1 year before school entry are addressed. Early numerical skills were conceptualized as quantity‐number competencies (QNC) at both basic (QNC Level 1) and advanced (QNC Level 2) levels. In a sample of 1,343 children aged 5 and 6, structural equation modelling provided support for the isolated number words hypothesis (Krajewski & Schneider, 2009, J. Exp. Child Psychol., 103, 516–531). This hypothesis claims that phonological awareness contributes to the acquisition of QNC Level 1, such as learning the number word sequence, but not of QNC Level 2, which requires the linkage of number words to quantities. In addition, phonological awareness relied on verbal working memory, especially with regard to the phonological loop, central executive, and episodic buffer. The results were congruent with the idea that phonological awareness mediates the impact of verbal working memory on QNCs. The relationships between verbal working memory, phonological awareness, and QNCs were comparable in monolingual and bilingual children.     

Memory for goals: an activation‐based model

Goal‐directed cognition is often discussed in terms of specialized memory structures like the “goal stack.” The goal‐activation model presented here analyzes goal‐directed cognition in terms of the general memory constructs of activation and associative priming. The model embodies three predictive constraints: (1) the interference level, which arises from residual memory for old goals; (1) the strengthening constraint, which makes predictions about time to encode a new goal; and (3) the priming constraint, which makes predictions about the role of cues in retrieving pending goals. These constraints are formulated algebraically and tested through simulation of latency and error data from the Tower of Hanoi, a means‐ends puzzle that depends heavily on suspension and resumption of goals. Implications of the model for understanding intention superiority, postcompletion error, and effects of task interruption are discussed.     

Attentional focus effects on joint covariation in a reaching task

Adopting an external focus of attention (EF) has been found beneficial over internal focus (IF) for performing motor skills. Previous studies primarily examined focus of attention (FOA) effects on performance outcomes (such as error and accuracy), with relatively less emphasis on movement coordination. Given that human movements are kinematically and kinetically abundant (Gefland & Latash, 1998), FOA instructions may change how motor abundance is utilized by the CNS. This study applied the uncontrolled manifold analysis (UCM) to address this question in a reaching task. Healthy young adults (N = 38; 22 ± 1 yr; 7 men, 31 women) performed planar reaching movements to a target using either the dominant or nondominant arm under two different FOA instructions: EF and IF. Reaching was performed without online visual feedback and at a preferred pace. Joint angles of the clavicle-scapula, shoulder, elbow, and wrist were recorded, and their covariation for controlling dowel endpoint position was analyzed via UCM. As expected, IF led to a higher mean radial error than EF, driven by increases in aiming bias and variability. Consistent with this result, the UCM analysis showed that IF led to higher goal-relevant variance among the joints (V_ORT) compared to EF starting from the first 20% of the reach to the end. However, the goal-irrelevant variance (V_UCM)—index of joint variance that does not affect the end-effector position—did not show FOA effects. The index of stability of joint coordination with respect to endpoint position (ΔV) was also not different between the EF and IF. Consistent with the constrained action hypothesis, these results provide evidence that IF disrupted goal-relevant joint covariation starting in the early phases of the reach without affecting goal-irrelevant coordination.