Programma
Voorzitter: Cor van Dijkum
Loet
Leydesdorff
Amsterdam
University
The
dynamic analysis of structural change in the organization of the sciences
requires methodologically the integration of multivariate and time-series
analysis. Structural change—e.g., interdisciplinary development—is often an
objective of government interventions. Recent developments in multi-dimensional
scaling (MDS) enable us to distinguish the stress originating in each
time-slice from the stress originating from the sequencing of time-slices, and
thus to locally optimize the trade-offs between these two sources of variance
in the animation. Furthermore, visualization programs like Pajek and Visone
allow us to show not only the positions of the nodes, but also their
relational attributes like betweenness centrality. Betweenness centrality in
the vector space can be considered as an indicator of interdisciplinarity.
Using this indicator, the dynamics of the citation impact environments of the
journals Cognitive Science, Social Networks, and Nanotechnology
are animated and assessed in terms of interdisciplinarity among the disciplines
involved.
Validating Complex Signal Analyses of Human
Cognition by Simulating Well Known Dynamical Systems:
Promises and Pitfalls
Fred Hasselman
Ralf Cox
Radboud University (Nijmegen)
Recently
techniques based on Takens’ embedding theorem have been successfully used to
analyse data from psychological experiments. Many of the studies show promising
results for instance in the fields of language development, human postural
control, ERP experiments, problem solving, dyadic interactions, tremors in
Parkinson’s disease and rhythmical aiming movements.
Takens’
theorem (1981) allows for the reconstruction of the phase space of a complex
dynamical system based on the measurement of just one variable of the system.
Takens has shown that the reconstructed phase space will be topologically
equivalent to the phase space of the original system. Recurrence Quantification
Analysis is usually conducted on this reconstructed phase space, which enables
a quantification of the complexity of the system in terms of stationarity,
determinism, entropy and sensitivity on initial conditions. One reason why
these analyses are interesting for psychology is that there are no restrictions
on the data, as is the case with analyses based on the Gauss-Markov theorem. Or
are there?
Of
course there is the theoretical assumption that humans should be studied as a
complex system. Several authors have taken the presence of 1/f noise in many
cognitive tasks as a sign that we are dealing with a complex self-organising
system. Its mere presence is however not enough to make this claim. Moreover,
many of the studies use well known dynamical systems such as the Lorenz system
to show that RQA measures are able to detect order-chaos and chaos-chaos
transitions and then look for similar changes in RQA measures retrieved from
their own data. I will address the promises and pitfalls of this approach by
discussing several recent studies which combine fractal analysis, complex
signal analysis and simulation.
Suggested reading:
Kello,
C.T., Beltz, B.C., Holden, J.G., & Van Orden, G.C. (2007). The emergent
coordination of cognitive
function. Journal of Experimental
Psychology: General,
136,
551-568.
Richardson, D.C., Dale, R.,
& Kirkham, N.Z. (2007). The art of conversation is
coordination: Common ground
and the coupling of eye movements during
dialogue. Psychological Science 18 , 407–413
Schinkel, S.,
Marwan, N. & Kurths, J. (2007). Order patterns recurrence
plots in the
analysis of ERP data. Cognitive Neurodynamics, 1, 4, 317-325.
Shockley, K., Santana, M-V.,
Fowler, C. (2003). Mutual interpersonal postural
constraints are involved in
cooperative conversation. Journal of
Experimental
Psychology:
Human Perception and Performance, 29, 326-323.
Stephen, D.G., Dixon, J.A.,
& Isenhower, R.W. (2008). Dynamics of representational
change: Entropy, action, and
cognition. Manuscript submitted for publication.
Wijnants, M.L.,
Bosman, A.M.T., Hasselman, F., Cox, R.F.A., & Van Orden, G.C.
(2008).
1/f
scaling fluctuation in movement time: Temporal structure changes
with massed practice. Manuscript submitted for publication in
NLDPS.
Non-Linear Models for the Feedback between GP and Patients
Cor van Dijkum, Niek Lam
Department of Methodology and Statistics
Faculty of Social Sciences,
Utrecht University
The Netherlands
c.j.vandijkum@uu.nl
William Verheul, Jozien Bensing
Netherlands
Institute for Health Services Research
Otterstraat 118 – 124
3513 CR Utrecht
The Netherlands
W.verheul@nivel.nl
Abstract
How can we model the interaction between a medical
doctor and a patient that takes into account the dynamics and non-linearity of
the communication? To answer this question we use a dataset of 101 hypertension
(video-taped) consultations in Dutch General Practice.
We develop causal hypotheses about the relations
between variables that are important for the communication. A non-linear model is builded with the aid
of the software STELLA that expresses those causal relations. Thereafter we
explore with the more mathematical software MatLab how such a model of coupled
logistic equations behaves, especially concerning coupled patterns of chaos and
order. Thereby we focus on phenomena such as synchronization and
selforganization in the process of communication.