No abstract

Working memory is a construct of primary relevance to many areas of psychology. Two types of tasks have been used to measure working memory, primarily in different research areas: Complex span tasks are commonly used in behavioral studies in the cognitive and individual-differences literature, whereas n-back tasks have been used more frequently in cognitive neuroscience studies investigating the neural underpinnings of working memory. Despite both categories of tasks being labeled as "working memory" measures, previous empirical studies have provided mixed evidence regarding the shared amount of overlapping processes between complex span and n-back tasks. The present meta-analysis showed that the complex span and n-back tasks are weakly correlated, although significant heterogeneity across studies was observed. A follow-up analysis of unpublished data indicated that the sample composition affects the relationship between the complex span and n-back tasks, following the law of diminishing returns. Finally, a separate meta-analysis indicated that the simple span and n-back tasks are correlated to the same extent as are the complex span and n-back tasks. The present findings indicate that the complex span and n-back tasks cannot be used interchangeably as working memory measures in research applications.

Fine motor skills like typing involve a mapping problem that trades Fitts' law against Hick's law. Eight fingers have to be mapped onto 26 keys. Movement time increases with distance, so Fitts' law is optimized by recruiting more fingers. Choice difficulty increases with the number of alternatives, so Hick's law is optimized by recruiting fewer fingers. The effect of the number of alternatives decreases with consistent practice, so skilled typists achieve a balance between Fitts' law and Hick's law through learning. We tested this hypothesis by comparing standard typists who use the standard QWERTY mapping consistently with nonstandard typists who use fewer fingers less consistently. Typing speed and accuracy were lower for nonstandard typists, especially when visual guidance was reduced by removing the letters from the keys or covering the keyboard. Regression analyses showed that accommodation to Fitts' law (number of fingers) and Hick's law (consistency) predicted typing speed and accuracy. We measured the automaticity of typing in both groups, testing for hierarchical control in 3 tasks: word priming, which measures parallel activation of keystrokes, keyboard recall, which measures explicit knowledge of letter locations, and hand cuing, which measures explicit knowledge of which hand types which letter. Standard and nonstandard typists showed similar degrees of hierarchical control in all 3 tasks, suggesting that nonstandard typists type as automatically as standard typists, but their suboptimal balance between Fitts' law and Hick's law limits their ability to type quickly and accurately. (PsycINFO Database Record

No abstract

Associations are formed among the items in a sequence over the course of learning, but these item-to-item associations are not sufficient to reproduce the order of the sequence (Lashley, 1951). Contemporary theories of serial order tend to omit these associations entirely. The current paper investigates whether item-to-item associations play a role in serial order, specifically focusing on whether these associations influence how typists order their keystrokes. To address this question, participants completed variants of the spin list learning procedure (Ebenholtz, 1963). In these experiments, participants practiced typing nonword anagram sequences, and the order of the letters between anagrams was manipulated. Between half of the anagram sequences, both absolute and relative letter order were made inconsistent by scrambling the letters according to a balanced Latin square. For the other half, the letters were instead spun, making absolute order inconsistent but keeping relative order consistent. Learning was faster for anagram sequences with consistent relative order (Experiment 1). Practice on spun sequences with consistent relative order transferred to unpracticed sequences with the same relative order (Experiment 2). Transfer to unpracticed sequences did not depend on the absolute position of the letters in the unpracticed sequences (Experiment 3). However, transfer disappeared if letter order was reversed (Experiment 4). These results suggest that typing does make use of item-to-item associations, at least when associative interference is minimized. Although not sufficient, item-to-item associations are a necessary component of serial order in typing. (PsycINFO Database Record