Madison Chaos & Complex Systems Seminars

Fall 2002 Seminars

All seminars are Tuesday at 12:05 pm in 4274 Chamberlin except as noted.

Short List


Abstracts

September 10, 2002

Behavior as an Emergent Phenomenon

Larry Shapiro, UW Department of Philosophy

Researchers in artificial intelligence and cognitive psychology have standardly portrayed the mind as like a function that takes sensory stimuli as input and produces behavior as output.  Recent work on emergent behavior offers an alternative to this conception of mind.  In this talk I illustrate emergence and discuss the challenge it presents to more traditional work in cognitive science.


September 17, 2002

Climatic changes inferred from Lake Mendota ice records

Dale Robertson, US Geological Survey and Clarence Clay, UW Department of Geology

Ice cover records for a lake, such as the number of days of ice cover, represent an integration of nearby weather conditions and, therefore, can be used as a climatic indicator. Lake Mendota has the longest uninterupted ice records available for any lake in North America, dating back to 1855. In this talk, we discuss the techniques used to examine this record for long-term changes and interannual variability, and examine the climatic causes of these changes and variability in ice duration.

ARIMA analyses are used to demonstrate long-term changes in ice duration. Most of the change in these records occurred rather abruptly around 1890 and since 1980 rather than as a long-term monotonic change. The days of ice cover have the appearance a of a random time series of geophysical data. The Wiener optimum prediction "filter" method was run on the data. If the random time series goes along as expected, the predicted value at the next time step is close to the actual data point. Large errors or unpredicted changes are a "signal" that the system has changed at that time step. We will also give the results of the variogram method of estimating fractal dimensions. Superposed epoch analyses are then used to demonstrate that consistent annual anomalies occur during El Niño events.  The long-term changes found for Lake Mendota are consistent with those found for many lakes throughout the Northern Hemisphere; however, the changes found during El Niño events varies throughout the Northern Hemisphere.

Selected Readings:

Robertson, D. M., R. A. Ragotzkie, and J. J. Magnuson. 1992. Lake ice records used to detect historical and future climatic changes. Climatic Change 21:407-427.

Robertson, D.M., Wynne, R.H., and Chang, W.Y.B., 2000, Variability in ice cover across the northern hemisphere during the 1900's associated with El Nino events, Proceedings of the International Limnological Society, SIL, Dublin, Ireland, August, 1998.

Magnuson, J.J., Robertson, D.M., Wynne, R.H., Benson, B.J., Livingstone, D.M., Arai, T., Assel, R.A., Barry, R.G., Card, V., Kuusisto, E., Granin, N.G., Prowse, T.D., Stewart, K.M., and Vuglinski, V.S., 2000, Historical Trends in Lake and River Ice Cover in the Northern Hemisphere, Science, Vol. 289, No. 5485, p. 1743-1746.


September 24, 2002

The incompatibility of explanatory theories regarding the benefits of modern medicine and the benefits of psychotherapy

Bruce E. Wampold, UW Department of Counseling Psychology

The hallmark of modern medicine is specificity, which stipulates that the specific ingredients in medications are responsible for the benefits derived.  Specificity is established through the randomized double-blind placebo control group design (indeed,  the superiority of the drug to a placebo is required for FDA approval).  Moreover, specificity is supported by demonstrating theoretical mediated actions (i.e., the hypothesized physiological changes precede symptom reduction).  Proponents of a medical model of psychotherapy claim specificity as well.  Although psychotherapy has been found to be remarkably efficacious, the preponderance of the evidence shows that psychotherapy does not work specifically.  That is, the hypothesized mechanisms are not causal to the benefits.  A meta-theory of psychotherapy that emphasizes the healing context is consistent with the research evidence.


October 1, 2002

Mathematical models of love and happiness (Part 2)

Clint Sprott, UW Department of Physics

In February 2001 I described a two-dimensional, linear, continuous-time, dynamical model of the love/hate relationship between two individuals.  I described the rich dynamics of this simple model and suggested some nonlinear extensions and models of love triangles with chaotic solutions.  In this talk, I will describe a related linear model for the time evolution of one's happiness in response to external stimuli (hedonics).  I will show how the models are related and will discuss some implications for psychotherapy and for a personal philosophy of life. An important implication of the happiness model is that one cannot expect to be either exclusively happy or exclusively unhappy over long periods.  A similar response can occur with love/hate.  Also, one's subjective feelings are more volatile and often opposite to those perceived by others.

This talk is available as a PowerPoint Presentation and in HTML format.


October 7, 2002 (Special lecture, Monday, 7:30 pm in the Memorial Union Theater)

A new kind of science

Stephen Wolfram, Wolfram Research

Stephen Wolfram, developer of Mathematica and a pioneer in the study of cellular automata, will discuss the subject of his new book "A New Kind of Science" in this special evening lecture.

This long-awaited work from one of of the world's most respected scientists presents a series of dramatic discoveries never before made public.  Starting from a collection of simple computer experiments -- illustrated by striking computer graphics -- he shows how the unexpected results force a whole new way of looking at the operation of our universe.

Wolfram uses his approach to tackle a remarkable array of fundamental problems in science, from the origins of apparent randomness in physical systems, to the development of complexity in biology, the ultimate scope and limitations of mathematics, the possibility of a truly fundamental theory of physics, the interplay between free will and determinism, and the character of intelligence in the universe.

More information is available at http://wolframscience.com/


October 8, 2002

Measuring unanticipated brain responses using functional magnetic resonance imaging

Beth Meyerand, UW Department of Medical Physics

Functional magnetic resonance imaging (fMRI) is a noninvasive medical imaging technique that can be used to measure the brain's response to stimuli. Most forms of fMRI data analysis require prior knowledge of the expected response of the brain to the stimuli. In this talk, I will describe recent fMRI analysis methods that do not require apriori information. I will also compare and contrast the results of these analysis with standard techniques.


October 15, 2002

Modeling nature with mathematics

David Albers, UW Department of Physics

In most fields of science, mathematical models are constructed and used as analogies to phenemena under investigation without considering the qualitative behavior of the functions used in the model.  In this talk I will discuss problems that occur when assuming that such mathematical models accurately represent nature, preliminary results regarding the qualitative space of functions, and how we can more carefully relate problems in nature to the mathematics we hope to use to represent those problems.


October 22, 2002

The Flight of the  frisbee,  aerobie, and the boomerang

Martin Olsson, UW Department of Physics

We discuss a class of recreational objects that depend on both aerodynamic and gyscopic principles.  The combination of  aerodynamic forces and precession of a spinning body can produce remarkable results and help us to understand flying discs and the return of the boomerang.


October 29, 2002

Climate and weather: Questions from chaos

John Young, UW Department of Atmospheric and Oceanic Sciences

The earth's climate is a forced dissipative system, affected by boundary conditions which are both naturally varying and human-induced. Weather systems swirl about the climate state in unpredictably chaotic patterns which interact with the climate. In our seminar, I will first summarize some aspects of observed atmospheric behavior and the nonlinear prediction laws which we use to study it. Then, we will have a group discussion.

Some candidate questions for discussion are:
- Can we distinguish between climate and weather? Are low order systems useful?
- Can we distinguish between human-induced global warming and natural variability?
- How does chaotic weather affect climate regimes? Are strange attractors relevant?
- Are there predictable components in low frequency climate variability?
- How do we go about classifying the behavior of complex chaotic climate systems?


November 5, 2002

Predator-prey dynamics for rabbits, trees, and romance

Clint Sprott, UW Department of Physics

The Lotka-Volterra equations represent a simple nonlinear model for the dynamic interaction between two biological species in which one species (the predator) benefits at the expense of the other (the prey). With a change in signs, the same model can apply to two species that compete for resources or that symbiotically interact. However, the model is not structurally stable, since persistent time-dependent (oscillatory) solutions occur for only a single value of the parameters.

This talk considers structurally stable variants of the Lotka-Volterra equations with arbitrarily many species solved on a homogenous two-dimensional grid with coupling between neighboring cells. Interesting, biologically-realistic, spatio-temporal patterns are produced. These patterns emerge from random initial conditions and thus exhibit self-organization. The extent to which the patterns are self-organized-critical (spatial and temporal scale-invariant) and chaotic (positive Lyapunov exponent) will be examined.

The same equations, without the spatial interactions, can be used to model romantic relationships between individuals. Different romantic styles lead to different dynamics and ultimate fates.

This talk is available as a PowerPoint Presentation, in HTML format, and in condensed written format.


November 12, 2002

Not happy? Just wait! Age differences in daily psychological distress during adulthood

David Almeida, UW Institute on Aging

When are the best years of life? At what point in the life span is well-being at its peak? One way to answer these questions is to examine age difference in the experience of psychological distress as indexed by negative emotions such as sadness, hostility, and anxiety. Using daily reports from a sample of twins, I will assess biological and environmental influences on mean level and intraindividual fluctuations in psychological distress. Results suggest that genetic influences on mean level psychological distress decrease across adulthood.  For all age groups, daily fluctuations in distress were influenced most by environmental factors.  These findings are discussed in terms of a "set point" theory of emotion.


November 19, 2002

Consciousness: What it is and what is takes to make it

Giulio Tononi, UW Department of Psychiatry

If one wants to make a machine conscious, what ingredients should one put in? Asking this question is not only of some practical significance; it is also an excellent way of testing one’s understanding of how the only machine that can surely generate consciousness – namely our brain - is capable of doing it. Obviously, an answer can be given only in the light of some theoretical notion of what consciousness is.
The theoretical approach we have developed maintains that consciousness is integrated information. High information content is an essential feature of conscious experience, in the precise sense that each conscious state is selected out of an immense repertoire of possible ones. Moreover, this information is integrated - conscious experience is a unified whole that cannot be subdivided into independent components. Note that the availability of a large amount of integrated information over a short period of time has obvious adaptive advantages.

If the notion of consciousness as integrated information is to be scientifically productive, as well as testable, one needs clearly defined concepts and corresponding measures. For this purpose, we have developed measures aimed at characterizing the degree to which a set of elements can integrate information. The main one is a general, information-theoretical definition of integrated informa-tion, called complexity. This measure, which is based on the amount of information that can be exchanged between bipartitions of subsets of elements, can be used to determine whether a subset of elements consti-tutes an integrated complex, as well as how many different states are available to it. Using simplified models, it can be shown that complexity constitutes an objective measure of the extent to which functionally specialized parts work together in an integrated fashion.

A key advantage of having a measure of integrated information is that it makes it possible to test the relationship between consciousness and integrated information in exemplary cases. At present, it seems most useful to begin where the distinctions are most obvious. Consider two basic contrasts. The first one is between two portions of the brain - the thalamocortical system and the cerebellum  – which differ dramatically in their ability to give rise to conscious experience. The cerebellum has an estimated 50 billion neurons, against an estimated 30 billion for the thalamocortical system. It has probably as many connections, similar neurotransmitters and neuromodulators and, just as the thalamo-cortical system, it receives multiple sensory inputs. However, while many areas of the thalamocortical system are each essential for a different aspect of conscious experience, the entire cerebellum can be removed without significant changes in conscious experience. This simple contrast indicates that the generation of conscious experience is not merely a property of numbers of neurons and connections, of neurochemical diversity, or of biological intricacy.

A second illuminating contrast has to do with the neural activity within the thalamocortical system when we are awake and conscious vs. when we are asleep and unconscious, specifically during dreamless sleep. The anatomical organization of the thalamocortical system obviously does not change between sleep and waking, and we now know that the amount of neural activity is not substantially different, except that during deep sleep it is highly synchro-nized. We suggest that the reason the thalamocortical system can generate conscious experience and the cerebel-lum (or other parts of the brain) cannot is that the former is organized in such a way as to integrate a large amount of information, while the latter is not. Similarly, we predict that during deep sleep, while the anatomy and the amount of neuronal firing do not change appreciably, the amount of integrated information should markedly decrease.

In principle, these predictions can be tested empirically, e.g. through neuroimaging experiments. While such experiments are essential for validating the proposed concepts, they have several limitations in terms of the available spatial and temporal resolution as well as in terms of what manipulations are feasible. An equally important avenue to validate these concepts is to develop large-scale simulations of brain circuits in which all the rele-vant parameters are precisely known and every possible manipulation can be performed. Moreover, such a synthetic approach can provide guidelines about the requirements for developing an architecture endowed with conscious expe-rience in a machine.

Selected References:

1.  Tononi, G., Complexity and coherency: integrating information in the brain. Trends in Cognitive Sciences, 1998. 2:474-484.
2.  Tononi, G. and G.M. Edelman, Consciousness and complexity. Science, 1998. 282:1846-51.
3.  Edelman, G.M. and G. Tononi, A Universe of Consciousness: How matter becomes imagination. 2000, New York: Basic Books.
4.  Tononi, G., Information measures for conscious experience. Arch. Ital. Biol., 2001, 139:367-71.
5.  Tononi, G., Galileo e il fotodiodo. 2003, Roma, Laterza.


November 26, 2002

Illustrating sensitivity of short-term weather forecasts to initial condition errors

Michael Morgan, UW Department of Atmospheric and Oceanic Sciences


December 3, 2002

Health care dynamics

George Pasdirtz, UW Division of Information Technology

State Space Dynamic Mode (SSDM) models allow multivariate time series to be decomposed into a mixture of trend, cyclical and residual components. SSDM models provide an alternative implementation of concepts such as edge of chaos, path dependence, lock in, sensitivity to initial conditions and state-space complexity.

SSDM models are also well suited to quantitative historical analysis: dynamic system equations capture evolutionary forces, measurement equations account for low-quality historical statistics, policy variables capture the role of government and phenomenological components help where theory is unavailable.

This talk will analyze the growth of the US Health Care sector in the 20th century particularly concentrating on price movements from 1900-1950. A SSDM model is estimated from historical data and then simulated to (1) pose historical counterfactual experiments (what would price trends have been without particular government policy regimes) and (2) to evaluate the model statistically.


December 10, 2002

A dialogue on David Bohm's "On Dialogue"

Introduced by Myrna Casebolt & Robin Chapman

Bohm proposes that the act of dialog could create and deepen our shared understanding of the world, in contrast to the act of discussion, which entrenches our separate positions and creates winners and losers. What do seminar participants think? The article may be found at http://sprott.physics.wisc.edu/Chaos-Complexity/dialogue.pdf or picked up at the seminar talks.  See also http://www.muc.de/~heuvel/dialogue/.