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We resolve a controversy about reading fixations before word-skipping saccades which were reported as longer or shorter than control fixations in earlier studies. Our statistics are based on resampling of matched sets of fixations before skipped and nonskipped words, drawn from a database of 121,321 single fixations contributed by 230 readers of the Potsdam sentence corpus. Matched fixations originated from single-fixation forward-reading patterns and were equated for their positions within words. Fixations before skipped words were shorter before short or high-frequency words and longer before long or low-frequency words in comparison with control fixations. Reasons for inconsistencies in past research and implications for computational models are discussed
Neuronal activity in area LIP is correlated with the perceived direction of ambiguous apparent motion (Z. M. Williams, J. C. Elfar, E. N. Eskandar, L. J. Toth, & J. A. Assad, 2003). Here we show that a similar correlation exists for small eye movements made during fixation. A moving dot grid with superimposed fixation point was presented through an aperture. In a motion discrimination task, unambiguous motion was compared with ambiguous motion obtained by shifting the grid by half of the dot distance. In three experiments we show that (a) microsaccadic inhibition, i.e., a drop in microsaccade frequency precedes reports of perceptual flips, (b) microsaccadic inhibition does not accompany simple response changes, and (c) the direction of microsaccades occurring before motion onset biases the subsequent perception of ambiguous motion. We conclude that microsaccades provide a signal on which perceptual judgments rely in the absence of objective disambiguating stimulus information.
As Chinese is written without orthographical word boundaries (i.e., spaces), it is unclear whether saccade targets are selected on the basis of characters or words and whether saccades are aimed at the beginning or the centre of words. Here, we report an experiment where 30 Chinese readers read 150 sentences while their eye movements were monitored. They exhibited a strong tendency to fixate at the word centre in single-fixation cases and at the word beginning in multiple-fixation cases. Different from spaced alphabetic script, initial fixations falling at the end of words were no more likely to be followed by a refixation than initial fixations at word centre. Further, single fixations were shorter than first fixations in two-fixation cases, which is opposite to what is found in Roman script. We propose that Chinese readers dynamically select the beginning or centre of words as saccade targets depending on failure or success with segmentation of parafoveal word boundaries.
Bei N = 101 Arbeitnehmern verschiedener Berufe wurden mit der Experience Sampling Method (ESM) eine Woche lang Daten zum Flow-Erleben, zu Glück/Zufriedenheit und zur Zielausrichtung laufender Aktivitäten erhoben (N = 4603 Messungen). Die Daten wurden mit GLMM-Analysen ausgewertet. Auch bei der jetzt vollständigen Erfassung aller Flow-Komponenten mit der FKS bestätigte sich das „Paradoxon der Arbeit“, wonach während der Arbeit höhere Flow-Werte, aber niedrigere Werte für Glück/Zufriedenheit auftreten als jeweils in der Freizeit. Während der Arbeit waren Aktivitäten häufiger auf die Erreichung von Zielen ausgerichtet als während der Freizeit. Die Zielausrichtung wirkte auf Flow vs. Glück/Zufriedenheit signifikant verschieden. Während der Arbeit hat die Zielausrichtung auf Flow einen stark positiven Effekt, auf Glück/Zufriedenheit jedoch nicht. Im Freizeitbereich war der Effekt von Zielausrichtung auf Glück/Zufriedenheit sogar negativ. Das „Paradoxon der Arbeit“ lässt sich partiell als Effekt der Zielausrichtung verstehen.
In alphabetic writing systems, saccade amplitude (a close correlate of reading speed) is independent of font size, presumably because an increase in the angular size of letters is compensated for by a decrease of visual acuity with eccentricity. We propose that this invariance may (also) be due to the presence of spaces between words, guiding the eyes across a large range of font sizes. Here, we test whether saccade amplitude is also invariant against manipulations of font size during reading Chinese, a character-based writing system without spaces as explicit word boundaries for saccade-target selection. In contrast to word-spaced alphabetic writing systems, saccade amplitude decreased significantly with increased font size, leading to an increase in the number of fixations at the beginning of words and in the number of refixations. These results are consistent with a model which assumes that word beginning (rather than word center) is the default saccade target if the length of the parafoveal word is not available.
Effects of frequency, predictability, and position of words on event-related potentials were assessed during word-by-word sentence reading in 48 subjects in an early and in a late time window corresponding to P200 and N400. Repeated measures multiple regression analyses revealed a P200 effect in the high-frequency range also the P200 was larger on words at the beginning and end of sentences than on words in the middle of sentences (i.e., a quadratic effect of word position). Predictability strongly affected the N400 component; the effect was stronger for low than for high- frequency words. The P200 frequency effect indicates that high-frequency words are lexically accessed very fast, independent of context information. Effects on the N400 suggest that predictability strongly moderates the late access especially of low-frequency words. Thus, contextual facilitation on the N400 appears to reflect both lexical and post- lexical stages of word recognition, questioning a strict classification into lexical and post-lexical processes.
Manipulations of presentation time have a long history in research on the development of memory, with a number of paradoxical results deriving from methodological shortcomings as well as from insufficient theoretical specifications. After a look at some of the problems in earlier research, a psychophysics approach to investigate episodic memory functions is presented in which criterion-referenced manipulation of presentation time is used to estimate the effects of experimental manipulations and the effects of individual differences. Criterion'referenced presentation time (CRPT), defined as the time required to score at an a priori specified level of accuracy, is interpreted as a preliminary indicator of internal processing time. CRPTs are shown to be valid predictors of traditional measures of memory accuracy. Moreover, an extension of this psychophysics approach yields estimates of complete condition-specific timeaccuracy functions and of function-specific processing times (plus other parameters) for individual subjects. It is argued that both from a cognitive and a developmental perspective it is often advantageous to trade experimental equivalence in presentation times for functional equivalence in accuracy of performance; this applies not only to episodic memory processes.
Earlier testing-the-limits research on age differences in cognitive plasticity of a memory skill was extended by 18 additional assessment and training sessions to explore whether older adults were able to catch up with additional practice and improved training conditions. The focus was on the method of loci, which requires mental imagination to encode and retrieve lists of words from memory in serial order. Of the original 37 subjects, 35 (16 young, ranging from 20 to 30 years of age, and 19 older adults, ranging from 66 to 80 years of age) participated in the follow-up study. Older adults showed sizable performance deficits when compared with young adults and tested for limits of reserve capacity. The negative age difference was substantial, resistant to extensive practice, and applied to all subjects studied. The primary origin for this negative age difference may be a loss in the production and use of mental imagination for operations of the mind.
Gedächtnistraining im Alter
(2000)
In this paper we present an approach to recover the dynamics from recurrences of a system and then generate (multivariate) twin surrogate (TS) trajectories. In contrast to other approaches, such as the linear-like surrogates, this technique produces surrogates which correspond to an independent copy of the underlying system, i. e. they induce a trajectory of the underlying system visiting the attractor in a different way. We show that these surrogates are well suited to test for complex synchronization, which makes it possible to systematically assess the reliability of synchronization analyses. We then apply the TS to study binocular fixational movements and find strong indications that the fixational movements of the left and right eye are phase synchronized. This result indicates that there might be one centre only in the brain that produces the fixational movements in both eyes or a close link between two centres.
In this paper, we present an approach to recover the dynamics from recurrences of a system and then generate (multivariate) twin surrogate (TS) trajectories. In contrast to other approaches, such as the linear-like surrogates, this technique produces surrogates which correspond to an independent copy of the underlying system, i.e. they induce a trajectory of the underlying system visiting the attractor in a different way. We show that these surrogates are well suited to test for complex synchronization, which makes it possible to systematically assess the reliability of synchronization analyses. We then apply the TS to study binocular fixational movements and find strong indications that the fixational movements of the left and right eye are phase synchronized. This result indicates that there might be only one centre in the brain that produces the fixational movements in both eyes or a close link between the two centres.
How preview space/time translates into preview cost/benefit for fixation durations during reading
(2013)
Eye-movement control during reading depends on foveal and parafoveal information. If the parafoveal preview of the next word is suppressed, reading is less efficient. A linear mixed model (LMM) reanalysis of McDonald (2006) confirmed his observation that preview benefit may be limited to parafoveal words that have been selected as the saccade target. Going beyond the original analyses, in the same LMM, we examined how the preview effect (i.e., the difference in single-fixation duration, SFD, between random-letter and identical preview) depends on the gaze duration on the pretarget word and on the amplitude of the saccade moving the eye onto the target word. There were two key results: (a) The shorter the saccade amplitude (i.e., the larger preview space), the shorter a subsequent SFD with an identical preview; this association was not observed with a random-letter preview. (b) However, the longer the gaze duration on the pretarget word, the longer the subsequent SFD on the target, with the difference between random-letter string and identical previews increasing with preview time. A third patternincreasing cost of a random-letter string in the parafovea associated with shorter saccade amplitudeswas observed for target gaze durations. Thus, LMMs revealed that preview effects, which are typically summarized under preview benefit, are a complex mixture of preview cost and preview benefit and vary with preview space and preview time. The consequence for reading is that parafoveal preview may not only facilitate, but also interfere with lexical access.
We question the assumption of serial attention shifts and the assumption that saccade programs are initiated or canceled only after stage one of word identification. Evidence: (1) Fixation durations prior to skipped words are not consistently higher compared to those prior to nonskipped words. (2) Attentional modulation of microsaccade rate might occur after early visual processing. Saccades are probably triggered by attentional selection.
We question the assumption of serial attention shifts and the assumption that saccade programs are initiated or canceled only after stage one of word identification. Evidence: (1) Fixation durations prior to skipped words are not consistently higher compared to those prior to non-skipped words. (2) Attentional modulation of microsaccade rate might occur after early visual processing. Saccades are probably triggered by attentional selection
Factorial experiments in research on memory, language, and in other areas are often analyzed using analysis of variance (ANOVA). However, for effects with more than one numerator degrees of freedom, e.g., for experimental factors with more than two levels, the ANOVA omnibus F-test is not informative about the source of a main effect or interaction. Because researchers typically have specific hypotheses about which condition means differ from each other, a priori contrasts (i.e., comparisons planned before the sample means are known) between specific conditions or combinations of conditions are the appropriate way to represent such hypotheses in the statistical model. Many researchers have pointed out that contrasts should be "tested instead of, rather than as a supplement to, the ordinary 'omnibus' F test" (Hays, 1973, p. 601). In this tutorial, we explain the mathematics underlying different kinds of contrasts (i.e., treatment, sum, repeated, polynomial, custom, nested, interaction contrasts), discuss their properties, and demonstrate how they are applied in the R System for Statistical Computing (R Core Team, 2018). In this context, we explain the generalized inverse which is needed to compute the coefficients for contrasts that test hypotheses that are not covered by the default set of contrasts. A detailed understanding of contrast coding is crucial for successful and correct specification in linear models (including linear mixed models). Contrasts defined a priori yield far more useful confirmatory tests of experimental hypotheses than standard omnibus F-tests. Reproducible code is available from https://osf.io/7ukf6/.
I. Introduction A. Theoretical Framework and Selection of Tests B. Related Studies of Reading Disability Subtypes C. Overview of Specific Questions and Article Outline II. Selection criteria nd performance on standardized measures III. Group differences between disabled and normal readers A. Phonetic Memory B. Picture-Naming Speed and Automatic Responses to Print C. Phonological and Orthographic Skill D. Easy Regular and Exception Word Reading E. Difficult Regular and Exception Words IV. Individual diferences in reading disability A. Phonological Skill, Orthographic Skill, and the Regularity Effect B. Phonological Skill, Orthographic Skill, and Spelling Errors V. Eye movement reading style A. The "Plodder-Explorer" Dimension of Eye Movement Reading Style B. Eye Movements, Coding Skills, and Spelling Ratings C. Verbal Intelligence and the Plodder-Explorer Dimension D. Eye Movements in a Nonreading Task and the "Visual-Spatial" Subtype VI. Distribution and etiology of reading disabilities A. Distribution Issues B. Etiology of Reading Disabilities VII. Summary and new directions in research
Protanopie, deuteranopic and tritanopic neutral points were computed by determining the wavelength of light that produced the same quantal-catch ratio in the photopigments as that produced by a broad-band light of specified color temperature (range: 2 800—6 600 K). The Vos-Walraven primaries were used as photopigment absorption spectra that were screened by varying densities of ocular (0.5—2.5 at 400 nm) and macular (0.0—1.0 at 460 nm) pigmentation. The computations were carried out in 1 nm steps for the wavelength range of 380 to 720 nm. Most of the empirically determined mean, neutral-point loci in the literature were predicted from these computations to within 1—2nm when average ocular and macular pigment densities were used. The neutral-point range associated with the extreme values of the prereceptoral screening pigments was up to 25 nm for protanopes and deuteranopes and up to 13 nm for tritanopes.
There has been a substantial increase in the percentage for publications with co-authors located in departments from different countries in 12 major journals of psychology. The results are evidence for a remarkable internationalization of psychological research, starting in the mid 1970s and increasing in rate at the beginning of the 1990s. This growth occurs against a constant number of articles with authors from the same country; it is not due to a concomitant increase in the number of co-authors per article. Thus, international collaboration in psychology is obviously on the rise.
There has been a substantial increase in the percentage for publications with co-authors located in departments from different countries in 12 major journals of psychology. The results are evidence for a remarkable internationalization of psychological research, starting in the mid 1970s and increasing in rate at the beginning of the 1990s. This growth occurs against a constant number of articles with authors from the same country; it is not due to a concomitant increase in the number of co-authors per article. Thus, international collaboration in psychology is obviously on the rise.
There has been a substantial increase in the percentage for publications with co-authors located in departments from different countries in 12 major journals of psychology. The results are evidence for a remarkable internationalization of psychological research, starting in the mid 1970s and increasing in rate at the beginning of the 1990s. This growth occurs against a constant number of articles with authors from the same country; it is not due to a concomitant increase in the number of co-authors per article. Thus, international collaboration in psychology is obviously on the rise.
Kognitive Komplexität
(1996)
Kognitive Plastizität und altersbedingte Grenzen am Beispiel des Erwerbs einer Gedächtnistechnik
(1989)
Die Bedeutung kognitiver Entwicklungskapazität (Plastizität) und ihrer altersabhängigen Grenzen für Theorien kognitiven Alters wird thematisiert. Für kognitive Basisprozesse wird erwartet, daß die durch Training umgesetzte Entwicklungskapazität älterer Menschen zwar ausreicht, die Ausgangsleistung junger Erwachsener zu übertreffen, daß aber aufgrund altersbedingter Grenzen der Entwicklungskapazität nur sehr wenige ältere Erwachsene das Leistungsniveau trainierter junger Erwachsener erreichen werden. Am Beispiel eines Gedächtnistrainingsprogrammes zur Erhöhung der Merkfähigkeit für Wortlisten werden zwei Forschungsstrategien vorgestellt: (a) das Training von sehr leistungsfähigen älteren Erwachsenen und (b) Längsschnitt-Einzelfall-Studien. Die experimentellen Befunde bestätigten die theoretischen Erwartungen. Zwar waren die Leistungen der besten älteren Erwachsenen etwa doppelt so hoch wie die untrainierter junger Erwachsener, aber die durch das Training aufgedeckten Altersverluste konnten auch in bis zu 75 weiteren Übungsstunden nicht behoben werden.
Gedächtnishöchstleistungen sind auch im Alter möglich. Dies konnte am Beispiel der »Methode der Orte« experimentell bestätigt werden. Hierbei hat sich gezeigt, daß das Gehirn über große kognitive Kapazitätsreserven verfügt. In einer speziellen Testmethode (»testing the limits«) zeigt sich aber im Hochleistungsbereich, trotz der grundsätzlichen Plastizität, ein altersbezogenes Nachlassen der Gedächtnismechanik. Offenbar gibt es biologische Grenzen in der Schnelligkeit der menschlichen Vorstellungskraft. Vielleicht gelingt es auf der Grundlage dieser Erkentnnis, einen zuverlässigen Markierungsindikator für das hirnphysiologische Altern zu finden. Daraus könnten sich auch neue Methoden zur Früherkennung von Demenzen ableiten lassen.
Semantic processing from parafoveal words is an elusive phenomenon in alphabetic languages, but it has been demonstrated only for a restricted set of noncompound Chinese characters. Using the gaze-contingent boundary paradigm, this experiment examined whether parafoveal lexical and sublexical semantic information was extracted from compound preview characters. Results generalized parafoveal semantic processing to this representative set of Chinese characters and extended the parafoveal processing to radical (sublexical) level semantic information extraction. Implications for notions of parafoveal information extraction during Chinese reading are discussed.
The complexity of eye-movement control during reading allows measurement of many dependent variables, the most prominent ones being fixation durations and their locations in words. In current practice, either variable may serve as dependent variable or covariate for the other in linear mixed models (LMMs) featuring also psycholinguistic covariates of word recognition and sentence comprehension. Rather than analyzing fixation location and duration with separate LMMs, we propose linking the two according to their sequential dependency. Specifically, we include predicted fixation location (estimated in the first LMM from psycholinguistic covariates) and its associated residual fixation location as covariates in the second, fixation-duration LMM. This linked LMM affords a distinction between direct and indirect effects (mediated through fixation location) of psycholinguistic covariates on fixation durations. Results confirm the robustness of distributed processing in the perceptual span. They also offer a resolution of the paradox of the inverted optimal viewing position (IOVP) effect (i.e., longer fixation durations in the center than at the beginning and end of words) although the opposite (i.e., an OVP effect) is predicted from default assumptions of psycholinguistic processing efficiency: The IOVP effect in fixation durations is due to the residual fixation-location covariate, presumably driven primarily by saccadic error, and the OVP effect (at least the left part of it) is uncovered with the predicted fixation-location covariate, capturing the indirect effects of psycholinguistic covariates. We expect that linked LMMs will be useful for the analysis of other dynamically related multiple outcomes, a conundrum of most psychonomic research.
Messung von Blickbewegungen
(2006)
We compared effects of covert spatial-attention shifts induced with exogenous or endogenous cues on microsaccade rate and direction. Separate and dissociated effects were obtained in rate and direction measures. Display changes caused microsaccade rate inhibition, followed by sustained rate enhancement. Effects on microsaccade direction were differentially tied to cue class (exogenous vs. endogenous) and type (neutral vs. directional). For endogenous cues, direction effects were weak and occurred late. Exogenous cues caused a fast direction bias towards the cue (i.e., early automatic triggering of saccade programs), followed by a shift in the opposite direction (i.e, controlled inhibition of cue-directed saccades, leading to a 'leakage' of microsaccades in the opposite direction). (C) 2004 Elsevier Ltd. All rights reserved