The role of strategies in the development of memory span assessed by running probes

The running memory span task and the fixed memory span task were administered to children aged 7 to 13 years under conditions which made them directly comparable. A probe task, consisting of a short string of digits embedded in a block of longer strings, was also used. The running probe task was argued to be a better measure of strategy-free span than the standard running task. The probe task showed age differences as great as with the fixed span task, and span was reduced by only about half an item over all ages. It is therefore concluded that strategies are not responsible for memory span development over this age range

Information-Processing Demands of Transitive Inference

The information-processing demands of transitive inference problems were investigated with a probe reaction-time (RT) secondary task. Two versions of a primary task were used: the standard three-term inference problem and a matched verification task that did not require premise integration. In the first two experiments the premise and target-matching components of the primary task were presented sequentially. For the transitive inference task, probe RT was especially slow when the probe occurred during the second premise phase, but no such effect was found with the matched verification task. This implies that premise integration imposed an increased load on processing resources. A third experiment showed that the processing demand associated with premise integration also occurred with simultaneous presentation. Other variations in problem form (e.g., premise markedness, negation, and pivot search) did not influence probe RT, although they are known to affect solution time. Thus, solution time and measures of processing load may be independent

Set-size effects in primary memory: An age-related capacity limitation?

Set size was varied as a factor in the primary memory paradigm developed by Wickens and colleagues (Wickens, Moody, & Dow, 1981; Wickens, Moody, & Vidulich, 1985). In Experiment 1, using adults and teenagers, no proactive interference (PI) was observed at set size 4, consistent with previous research, but PI was observed at set size 10. In Experiment 2, with adults, PI was observed at set sizes 6, 8, and 10, but not at set size 4. These results are consistent with the hypothesis that sets of more than 4 items overload primary memory, so that some items have to be retrieved from secondary memory. In Experiment 3, 8- to 9-year-olds were used with set sizes of 2 and 4. Proactive interference was observed with the larger, but not with the smaller, set. This suggests that primary memory was overloaded by 4 items at this age, indicating that its capacity increases with age

The development of memory and processing capacity.

The assumption of some developmental theories that short‐term memory is the workspace of higher cognitive processes, and consequently that span measures processing capacity, is claimed to be inconsistent with the working memory literature. 4 experiments, using children aged 5 to 12 years, contrast this theory with a model in which short‐term memory and the processing space component of working memory are at least partly distinct. Experiments 1 and 2 varied processing load, holding duration constant. The processing load manipulation had little effect on recall of a short‐term memory preload. Experiments 3 and 4 failed to support the prediction that the greater processing efficiency of older children would be associated with slower loss of information from short‐term memory. Although counting and rehearsal rates increased with age, and correlated with span, they did not predict the rate of loss of memory preload due to intervening counting. The data suggest that effects obtained with short‐term memory span do not provide clear indications of overall working memory development, because short‐term memory span and the processing space component of working memory entail distinct systems

Facial asymmetry in parents of children on the autism spectrum

First published: 16 September 2021Greater facial asymmetry has been consistently found in children with autism spectrum disorder (ASD) relative to children without ASD. There is substantial evidence that both facial structure and the recurrence of ASD diagnosis are highly heritable within a nuclear family. Furthermore, sub-clinical levels of autistic-like behavioural characteristics have also been reported in first-degree relatives of individuals with ASD, commonly known as the ‘broad autism phenotype’. Therefore, the aim of the current study was to examine whether a broad autism phenotype expresses as facial asymmetry among 192 biological parents of autistic individuals (134 mothers) compared to those of 163 age-matched adults without a family history of ASD (113 females). Using dense surface-modelling techniques on three dimensional facial images, we found evidence for greater facial asymmetry in parents of autistic individuals compared to age-matched adults in the comparison group (p = 0.046, d = 0.21 [0.002, 0.42]). Considering previous findings and the current results, we conclude that facial asymmetry expressed in the facial morphology of autistic children may be related to heritability factors. Lay Abstract: In a previous study, we showed that autistic children presented with greater facial asymmetry than non-autistic children. In the current study, we examined the amount of facial asymmetry shown on three-dimensional facial images of 192 parents of autistic children compared to a control group consisting of 163 similarly aged adults with no known history of autism. Although parents did show greater levels of facial asymmetry than those in the control group, this effect is statistically small. We concluded that the facial asymmetry previously found in autistic children may be related to genetic factors.Diana Weiting Tan, Syed Zulqarnain Gilani, Maryam Boutrus, Gail A. Alvares, Andrew J. O. Whitehouse, Ajmal Mian, David Suter, Murray T. Mayber

Spatial working memory and arithmetic deficits in Nonverbal learning difficulties (NLD) children

Visuospatial working memory and its involvement in arithmetic were examined in two groups of 7- to 11-year-olds: one comprising children described by teachers as displaying symptoms of nonverbal learning difficulties (N = 21), the other a control group without learning disabilities (N = 21). The two groups were matched for verbal abilities, age, gender, and sociocultural level. The children were presented with a visuospatial working memory battery of recognition tests involving visual, spatial-sequential and spatial-simultaneous processes, and two arithmetic tasks (number ordering and written calculations). The two groups were found to differ on some spatial tasks but not in the visual working memory tasks. On the arithmetic tasks, the children with nonverbal learning difficulties made more errors than controls in calculation and were slower in number ordering. A discriminant function analysis confirmed the crucial role of spatial-sequential working memory in distinguishing between the two groups. Results are discussed with reference to spatial working memory and arithmetic difficulties in nonverbal learning disabilities. Implications for the relationship between visuospatial working memory and arithmetic are also considered