Hierarchical control and skilled typing: Evidence for word-level control over the execution of individual keystrokes.

Abstract

Routine actions are commonly assumed to be controlled by hierarchically organized processes and representations. In the domain of typing theories, word-level information is assumed to activate the constituent keystrokes required to type each letter in a word. We tested this assumption directly using a novel single-letter probe technique. Subjects were primed with a visual or auditory word or a visually presented random consonant string and then probed to type a single letter from the prime or another randomly selected letter. Relative to randomly selected letters, probe responses were speeded for first, middle, and last letters contained in visual and auditory word primes but not for middle and last letters contained in random consonant primes. This suggests that word-level information causes parallel activation of constituent keystrokes, consistent with hierarchical processing. The role of hierarchical processing in typing and routine action is discussed.Keywords: typing, hierarchical processing, performance, routine, motor control Everyday tasks and routines are structured hierarchically with higher level goal completion resting on the completion of component subgoals. For example, the higher level goal of hammering a nail involves several lower level strokes of the hammer on the head of the nail until the nail head is flush with the board. Theories of routine action commonly assume that the hierarchical structure of tasks is reflected in the cognitive processes and representations mediating task performance (Miller, Galanter, & Pribram, 1986), whereby higher level goal representations control the unpacking and execution of constituent lower level goal representations. In the present experiments, we sought to test how higher level goals interact with lower level goals in the domain of skilled typing. In particular, typing models assume that word-level representations activate keystroke execution processes for each letter in the word in parallel. In three experiments, we developed a novel singleletter probe technique to test this assumption of parallel activation in skilled typists.Typing is a compelling example of the ability to fluently and rapidly coordinate intention with performance (Shaffer, 1976). The intention to type and perform keystrokes is argued to be organized hierarchically with higher level intentions to type words and sentences controlling lower level processes through which words are converted into ordered keystrokes (Shaffer, 1975). We have elaborated on these assumptions in our inner-outer loop theory of typing (Logan & Crump, 2009). We characterized the outer loop as receiving input from the world in the form of written or spoken language and generating a series of words that are passed individually to the inner loop. The inner loop receives words as input, translates each word into keystrokes corresponding to each letter, and then executes them. Our previous work focused on the role of attention and monitoring during keystroke execution to investigate the assumption that outer and inner lo...

Typing pictures: Linguistic processing cascades into finger movements

“…Alternatively it may be that, consistent with suggestions from previous literature (e.g., Crump & Logan, 2010b;, orthographic word-forms are retrieved in advance of response initiation, but the lexical-orthographic predictors we considered may play little or no role in these retrieval processes. The effects of these variables may instead act during response execution on control system processes that come in to play after a motor program has already been selected.…”

“…For example, Crump and Logan (2010b) presented word or pseudoword primes before a probe letter. Touch typists were instructed to type the probed letter.…”

Attention to the hands disrupts skilled typewriting: The role of vision in producing the disruption

“…One possibility is that keystrokes are prepared in parallel although they are executed serially (Crump & Logan, 2010a;Logan, Miller, & Strayer, 2011;Rumelhart & Norman, 1982). Often, the movement for the next keystroke begins before the movement for the current keystroke finishes (Flanders & Soechting, 1992).…”

“…Typists know but do not know which hand types which letter. The resolution to this paradox is to propose a hierarchical control system in which different parts of the hierarchy know different things (also see Crump & Logan, 2010a, 2010bLiu et al, 2010;Shaffer, 1976).…”

Pushing typists back on the learning curve: Contributions of multiple linguistic units in the acquisition of typing skill.

“…However, typing rate is little influenced when skilled typists type a text in which the orders of words in sentences are scrambled, suggesting that sentences (and units above sentences) are not important in skilled typewriting. Therefore, theories of skilled typewriting are concerned with how typing behavior is controlled at the level of words and the levels below words (Crump & Logan, 2010b;Logan & Crump, 2011;Rumelhart & Norman, 1982). Logan and Crump (2011) proposed a two-loop theory of skilled typewriting, which assumes two nested control loops that divide labor between word-and letter-level processes (see Figure 1A).…”