TY  - JOUR
A1  - Schütt, Heiko Herbert
A1  - Rothkegel, Lars Oliver Martin
A1  - Trukenbrod, Hans Arne
A1  - Reich, Sebastian
A1  - Wichmann, Felix A.
A1  - Engbert, Ralf
T1  - Likelihood-based parameter estimation and comparison of dynamical cognitive models
JF  - Psychological Review
N2  - Dynamical models of cognition play an increasingly important role in driving theoretical and experimental research in psychology. Therefore, parameter estimation, model analysis and comparison of dynamical models are of essential importance. In this article, we propose a maximum likelihood approach for model analysis in a fully dynamical framework that includes time-ordered experimental data. Our methods can be applied to dynamical models for the prediction of discrete behavior (e.g., movement onsets); in particular, we use a dynamical model of saccade generation in scene viewing as a case study for our approach. For this model, the likelihood function can be computed directly by numerical simulation, which enables more efficient parameter estimation including Bayesian inference to obtain reliable estimates and corresponding credible intervals. Using hierarchical models inference is even possible for individual observers. Furthermore, our likelihood approach can be used to compare different models. In our example, the dynamical framework is shown to outperform nondynamical statistical models. Additionally, the likelihood based evaluation differentiates model variants, which produced indistinguishable predictions on hitherto used statistics. Our results indicate that the likelihood approach is a promising framework for dynamical cognitive models.
KW  - likelihood
KW  - model fitting
KW  - dynamical model
KW  - eye movements
KW  - model comparison
Y1  - 2017
U6  - https://doi.org/10.1037/rev0000068
SN  - 0033-295X
SN  - 1939-1471
VL  - 124
IS  - 4
SP  - 505
EP  - 524
PB  - American Psychological Association
CY  - Washington
ER  - 
TY  - JOUR
A1  - Chandra, Johan
A1  - Krügel, André
A1  - Engbert, Ralf
T1  - Modulation of oculomotor control during reading of mirrored and inverted texts
JF  - Scientific Reports
N2  - The interplay between cognitive and oculomotor processes during reading can be explored when the spatial layout of text deviates from the typical display. In this study, we investigate various eye-movement measures during reading of text with experimentally manipulated layout (word-wise and letter-wise mirrored-reversed text as well as inverted and scrambled text). While typical findings (e.g., longer mean fixation times, shorter mean saccades lengths) in reading manipulated texts compared to normal texts were reported in earlier work, little is known about changes of oculomotor targeting observed in within-word landing positions under the above text layouts. Here we carry out precise analyses of landing positions and find substantial changes in the so-called launch-site effect in addition to the expected overall slow-down of reading performance. Specifically, during reading of our manipulated text conditions with reversed letter order (against overall reading direction), we find a reduced launch-site effect, while in all other manipulated text conditions, we observe an increased launch-site effect. Our results clearly indicate that the oculomotor system is highly adaptive when confronted with unusual reading conditions.
KW  - human behaviour
KW  - psychology
KW  - eye-movement control
KW  - e-z reader
KW  - ideal-observer model
KW  - fixation locations
KW  - landing positions
KW  - saccade generation
KW  - cognitive-control
KW  - dynamical model
KW  - decision-theory
KW  - attention
Y1  - 2019
U6  - https://doi.org/10.1038/s41598-020-60833-6
SN  - 2045-2322
VL  - 10
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  -