Speed–accuracy trade-off in skilled typewriting: Decomposing the contributions of hierarchical control loops.

Abstract

Typing performance involves hierarchically structured control systems: At the higher level, an outer loop generates a word or a series of words to be typed; at the lower level, an inner loop activates the keystrokes comprising the word in parallel and executes them in the correct order. The present experiments examined contributions of the outer-and inner-loop processes to the control of speed and accuracy in typewriting. Experiments 1 and 2 involved discontinuous typing of single words, and Experiments 3 and 4 involved continuous typing of paragraphs. Across experiments, typists were able to trade speed for accuracy but were unable to type at rates faster than 100 ms/keystroke, implying limits to the flexibility of the underlying processes. The analyses of the component latencies and errors indicated that the majority of the trade-offs were due to inner-loop processing. The contribution of outer-loop processing to the trade-offs was small, but it resulted in large costs in error rate. Implications for strategic control of automatic processes are discussed.Keywords: motor control, hierarchical processing, speed-accuracy trade-off, skilled performance, action sequence A major issue in studies of cognitive skill concerns the ways in which skilled performance can be controlled strategically. Skill is acquired through training, and the extensive training required to attain high levels of skill makes component processes highly automatic (Anderson, 1982;Fitts, 1964;Logan, 1988;Schneider & Shiffrin, 1977); practice makes them specialized, stereotyped, and inflexible. Paradoxically, expert skills are often robust and flexible, so they can be utilized in various task contexts (MacKay, 1982). The present study addresses this paradox, asking whether automatic processes can be controlled strategically. To this end, we investigated a basic form of strategic control in cognitive performance-the trade-off between speed and accuracy. We focused on typewriting, which is one of the most prevalent skills among college students in modern society (Logan & Crump, 2011). Hierarchical Control in Skilled TypingTypewriting is an ideal subject for investigation of skilled performance. College students typically have a semester of formal training in middle school and 10 to 11 years of experience in which they type every day (Logan & Crump, 2011). Typing is a complex skill: It involves selecting specific keys that correspond to the letters in a to-be-typed word, moving appropriate fingers to precise key locations, and executing keystrokes in the correct order. Skilled typists implement these processes rapidly without watching the fingers that they control (i.e., touch typing).Typewriting is an expression of language, and language has hierarchically nested structures: Texts contain sentences, sentences contain words, and words contain letters. Skilled typewriting involves hierarchically organized cognitive processes that address these levels of representation (Fendrick, 1937;Lashley, 1951;Logan & Crump, 2011;Shaffer, 1975;Sternberg, Knoll, &...

Frontal theta band oscillations predict error correction and posterror slowing in typing.

“…In fact, corrected errors in their study were associated with post-error speeding where post-error key-presses were found to be faster than pre-error key-presses. Our findings partially support their interpretation in that PES following uncorrected errors in the absence of inhibition of backspace was much smaller than those reported in studies where participants are not allowed to correct their errors (usually several hundred ms in Snyder et al, 2014;Wilbert & Haider, 2012;Yamaguchi et al, 2013, as opposed to the current PES of 39ms). However, we did find that PES was statistically significant even though our participants were free, and in fact encouraged, to use the backspace to correct their errors.…”

“…For example, if errors are more frequent during slower (or faster) than average speed typing, such a baseline would be more sensitive to 'local' changes in typing speed. When participants try to type faster than their usual typing speed (Yamaguchi, Crump, & Logan, 2013) or too slowly, their chances of making mistakes may increase.…”

Pushing typists back on the learning curve: Memory chunking in the hierarchical control of skilled typewriting.

“…On each trial, words and nonwords are presented well before a go signal that instructs typists to start typing. Thus, much of the outer-loop processing might have been completed when the go signal was presented (Yamaguchi, Crump, & Logan, 2013).…”

Watch what you type: The role of visual feedback from the screen and hands in skilled typewriting

“…Many studies have demonstrated dissociations between the two loops (e.g., Abrahamse, Ruitenberg, de Kleine, & Verwey, 2013;Crump & Logan, 2010a, b;Logan & Crump, 2009, 2010Snyder & Logan, 2013;Tapp & Logan, 2011;Verwey, 1999;Yamaguchi & Logan, 2014;Yamaguchi, Logan, & Li 2013b), but few studies have addressed how they work together to control typing (Yamaguchi, Crump, & Logan 2013a). The inner loop is subordinate to the outer loop (Logan & Crump, 2011), so inner-loop processes are subject to outer-loop processes.…”