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Reading requires the orchestration of visual, attentional, language-related, and oculomotor processing constraints. This study replicates previous effects of frequency, predictability, and length of fixated words on fixation durations in natural reading and demonstrates new effects of these variables related to previous and next words. Results are based on fixation durations recorded from 222 persons, each reading 144 sentences. Such evidence for distributed processing of words across fixation durations challenges psycholinguistic immediacy-of-processing and eye-mind assumptions. Most of the time the mind processes several words in parallel at different perceptual and cognitive levels. Eye movements can help to unravel these processes.
A paradigm for the determination of time-accuracy functions (TAFs) for individual participants is introduced for two pairs of tasks differing in cognitive complexity, that is, word scanning vs cued recognition and figural scanning vs figural reasoning. TAFs can be used to test dissociations of cognitive processes beyond scale-related ambiguities of ordinal interactions. The approach is applied to examine the cognitive-aging hypothesis that a single slowing factor can account for interactions between adult age and cognitive task complexity. Twenty young and 20 old adults participated in 17 sessions. Presentation times required for 75, 87.5, and 100% accuracies were determined for each task with a variant of the psychophysical method of limits. Accuracy was fit by negatively accelerated functions of presentation time. State-trace analyses showed that different slowing factors are required for high- and low-complexity tasks. Relations to speed-accuracy and performance-resource functions are discussed.
Content: 1 Introduction 2 Theoretical background - Expertise and Reserve Capacity - Testing-the-Limits and Research on Expertise - Cognitive Processes and Knowledge - Age Comparisons of Peak Performance - Advantages of Constructed Versus Naturally Acquired Expertise - Hypotheses Related to Aging and Expertise: Toward Magnification and Identification of Age Differences and Aging-Sensitive Components 3 Theory-guided synthesis of memory expertise - Theoretical Framework - Procedure - Subjects - Results 4 Adaptivity testing of expert memory - Increasing Task Difficulty Within an Extant System - Selective Componential Interference - Toward the Study of Compensatory Processes 5 Conclusions
Computational models such as E-Z Reader and SWIFT are ideal theoretical tools to test quantitatively our current understanding of eye-movement control in reading. Here we present a mathematical analysis of word skipping in the E-Z Reader model by semianalytic methods, to highlight the differences in current modeling approaches. In E-Z Reader, the word identification system must outperform the oculomotor system to induce word skipping. In SWIFT, there is competition among words to be selected as a saccade target. We conclude that it is the question of competitors in the “game” of word skipping that must be solved in eye movement research.
This research has three interrelated foci: (i) engineering and testing a cognitive model of expert memory, (ii) the study of intellectual reserve capacity and (iii) the use of a testing-the-limits methodology to magnify and delineate age differences in limits of reserve capacity. The assumption is that age differences are magnified if studied at high levels of expertise or task difficulty. Results from age-comparative point training studies in expert memory are reported. Both young and elderly subjects reached high levels of skilled memory, confirming the model. However, despite this sizeable reserve capacity, when compared to IQ-eguivalent young adults, superior elderly showed decline in upper limits of function.
Investigated the range and limits of cognitive reserve capacity as a general approach to the understanding of age differences in cognitive functioning. Testing-the-limits is proposed as a research strategy, Data are reported from 2 training studies involving old (65 to 83 years old) and young adults (19 to 29 years old). The training, designed to engineer an expertise in serial word recall, involved instruction and practice in the Method of Loci. Substantial plasticity was evident in pretest to posttest comparisons. Participants raised their serial word recall several times above that of pretest baseline. Age-differential limits in reserve capacity were evident in amount of training gain but not in responses to conditions of increased test difficulty (speeded stimulus presentation). Group differences were magnified by the training to such a degree that age distributions barely overlapped at posttests. Testing-the-limits offers promise in terms of understanding the extent and nature of cognitive plasticity.
We investigate the cognitive control in polyrhythmic hand movements as a model paradigm for bimanual coordination. Using a symbolic coding of the recorded time series, we demonstrate the existence of qualitative transitions induced by experimental manipulation of the tempo. A nonlinear model with delayed feedback control is proposed, which accounts for these dynamical transitions in terms of bifurcations resulting from variation of the external control parameter. Furthermore, it is shown that transitions can also be observed due to fluctuations in the timing control level. We conclude that the complexity of coordinated bimanual movements results from interactions between nonlinear control mechanisms with delayed feedback and stochastic timing components.
We examined relations between eye movements (single-fixation durations) and RSVP-based event-related potentials (ERPs; N400’s) recorded during reading the same sentences in two independent experiments. Longer fixation durations correlated with larger N400 amplitudes. Word frequency and predictability of the fixated word as well as the predictability of the upcoming word accounted for this covariance in a path-analytic model. Moreover, larger N400 amplitudes entailed longer fixation durations on the next word, a relation accounted for by word frequency. This pattern offers a neurophysiological correlate for the lag-word frequency effect on fixation durations: Word processing is reliably expressed not only in fixation durations on currently fixated words, but also in those on subsequently fixated words.
Mathematical models have become an important tool for understanding the control of eye movements during reading. Main goals of the development of the SWIFT model (Engbert, Longtin, & Kliegl, 2002)were to investigate the possibility of spatially distributed processing and to implement a general mechanism for all types of eye movements we observe in reading experiments. Here, we present an advanced version of SWIFT which integrates properties of the oculomotor system and effects of word recognition to explain many of the experimental phenomena faced in reading research. We propose new procedures for the estimation of model parameters and for the test of the model’s performance. A mathematical analysis of the dynamics of the SWIFT model is presented. Finally, within this framework, we present an analysis of the transition from parallel to serial processing.
Past research suggests that age differences in measures of cognitive speed contribute to differences in intellectual functioning between young and old adults. To investigate whether speed also predicts age-related differences in intellectual performance beyond age 70 years, tests indicating 5 intellectual abilities—speed, reasoning, memory, knowledge, and fluency—were administered to a close-to-representative, age-stratified sample of old and very old adults. Age trends of all 5 abilities were well described by a negative linear function. The speed-mediated effect of age fully explained the relationship between age and both the common and the specific variance of the other 4 abilities. Results offer strong support for the speed hypothesis of old age cognitive decline but need to be qualified by further research on the reasons underlying age differences in measures of speed.