Transcript Document

Hierarchical Theory (HT) is the theory of scaled systems; really focuses
on levels of analysis an they relate to understanding a complex system
http://en.wikipedia.org/wiki/File:Hierarchical_Model.jpg
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A hierarchical data model is a data model in which the data is organized into a
tree-like structure.
Not all structure in nature is hierarchically organized, depending on the study
objectives, or variable of concern
HT Levels
Hierarchical Structure: a landscape is hierarchically structured. It can be
divided, or decomposed, into discrete components, while this landscape is a
component of larger system.
Maslow's Hierarchy of Needs
http://web.utk.edu/~gwynne/maslow.HTM
Abraham Maslow is known for establishing the theory of a hierarchy of needs, writing that human beings are motivated
by unsatisfied needs, and that certain lower needs need to be satisfied before higher needs can be satisfied. Maslow
studied exemplary people such as Albert Einstein, Jane Addams, Eleanor Roosevelt, and Frederick Douglas rather than
mentally ill or neurotic people. This was a radical departure from two of the chief schools of psychology of his day:
Freud and B.F. Skinner. Freud saw little difference between the motivations of humans and animals. We are supposedly
rational beings; however, we do not act that way. Such pessimism, Maslow believed, was the result of Freud's study of
mentally ill people. "The study of crippled, stunted, immature, and unhealthy specimens can yield only a cripple
psychology and a cripple philosophy" (Motivation and Personality). Skinner, on the other hand, studied how pigeons
and white rats learn. His motivational models were based on simple rewards such as food and water, sex, and avoidance
of pain. Say "sit" to your dog and give the dog a treat when it sits, and-after several repetitions--the dog will sit when
you command it to do so. Maslow thought that psychologists should instead study the playfulness, affection, etc., of
animals. He also believed that Skinner discounted things that make humans different from each other. Instead, Skinner
relied on statistical descriptions of people.
Maslow's hierarchy of needs was an alternative to the depressing
determinism of Freud and Skinner. He felt that people are
basically trustworthy, self-protecting, and self-governing. Humans
tend toward growth and love. Although there is a continuous
cycle of human wars, murder, deceit, etc., he believed that
violence is not what human nature is meant to be like. Violence
and other evils occur when human needs are thwarted. In other
words, people who are deprived of lower needs such as safety
may defend themselves by violent means. He did not believe that
humans are violent because they enjoy violence. Or that they lie,
cheat, and steal because they enjoy doing it.
According to Maslow, there are general types of needs
(physiological, safety, love, and esteem) that must be satisfied
before a person can act unselfishly.
Other Examples:
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Catalog in a library
Political and religion hierarchies
Organizations of a company
Geography
Program planning
Species classification (from
Kingdom to species)
Wildlife habitat
Landscape structure (e.g., roads
in different parts of a landscape,
or different grades)
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Other Examples:
http://www.fs.fed.us/land/ecosysmgmt/ecoreg1_home.html
Ecoregions of the United States
Map of the world's ecozones
Violet: Nearctic
Green: Palearctic
Orange: Afrotropic
Red: Indomalaya
Olive: Australasia
Brown: Neotropic
Oceania, Antarctic not shown
http://en.wikipedia.org/wiki/Ecozone
Wavelet Transform of Species Richness
LOW
HIGH
(A) Pine Barrens
1 5 0 0
1000
1 0 0 0
500
5 0 0
0
0
500
1500
2000
2500
YA2
Distance Along Transect (m)
H2
PA
SPB
H1
OPB
CC
JPO SPB
1000
3000 0
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MA
YA2
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OPB
Resolution (m)
1500
BOPB
Wavelet Variance
http://www.isss.org/hierarchy.htm
Hierarchy: in mathematical terms, it is a partially ordered set. In less austere
terms, a hierarchy is a collection of parts with ordered asymmetric relationships
inside a whole. That is to say, upper levels are above lower levels, and the
relationship upwards is asymmetric with the relationships downwards.
Hierarchical levels: levels are populated by entities whose properties
characterize the level in question. A given entity may belong to any number of
levels, depending on the criteria used to link levels above and below. For
example, an individual human being may be a member of the level i) human, ii)
primate, iii) organism or iv) host of a parasite, depending on the relationship of
the level in question to those above and below.
Level of organization: this type of level fits into its hierarchy by virtue of set of
definitions that lock the level in question to those above and below. For example,
a biological population level is an aggregate of entities from the organism level of
organization, but it is only so by definition. There is no particular scale involved in
the population level of organization, in that some organisms are larger than some
populations, as in the case of skin parasites.
http://www.isss.org/hierarchy.htm
Level of observation: this type of level fits into its hierarchy by virtue of relative scaling
considerations. For example, the host of a skin parasite represents the context for the
population of parasites; it is a landscape, even though the host may be seen as belonging
to a level of organization, organism, that is lower than the collection of parasites, a
population.
The criterion for observation: when a system is observed, there are two separate
considerations. One is the spatiotemporal scale at which the observations are made. The
other is the criterion for observation, which defines the system in the foreground away
from all the rest in the background. The criterion for observation uses the types of parts
and their relationships to each other to characterize the system in the foreground. If
criteria for observation are linked together in an asymmetric fashion, then the criteria
lead to levels of organization. Otherwise, criteria for observation merely generate isolated
classes.
The ordering of levels: there are several criteria whereby other levels reside above lower
levels. These criteria often run in parallel, but sometimes only one or a few of them apply.
Upper levels are above lower levels by virtue of: 1) being the context of, 2) offering
constraint to, 3) behaving more slowly at a lower frequency than, 4) being populated by
entities with greater integrity and higher bond strength than, and 5), containing and
being made of - lower levels.
http://www.isss.org/hierarchy.htm
Nested and non-nested hierarchies: nested hierarchies involve levels which
consist of, and contain, lower levels. Non-nested hierarchies are more
general in that the requirement of containment of lower levels is relaxed.
For example, an army consists of a collection of soldiers and is made up of
them. Thus an army is a nested hierarchy. On the other hand, the general at
the top of a military command does not consist of his soldiers and so the
military command is a non-nested hierarchy with regard to the soldiers in
the army. Pecking orders and a food chains are also non-nested hierarchies.
Duality in hierarchies: the dualism in hierarchies appears to come from a
set of complementarities that line up with: observer-observed, processstructure, rate-dependent versus rate-independent, and part-whole. Arthur
Koestler in his "Ghost in The Machine" referred to the notion of holon,
which means an entity in a hierarchy that is at once a whole and at the same
time a part. Thus a holon at once operates as a quasi-autonomous whole
that integrates its parts, while working to integrate itself into an upper level
purpose or role. The lower level answers the question "How?" and the
upper level answers the question, "So what?”
http://www.isss.org/hierarchy.htm
Constraint versus possibilities: when one looks at a system there are two
separate reasons behind what one sees. First, it is not possible to see something
if the parts of the system cannot do what is required of them to achieve the
arrangement in the whole. These are the limits of physical possibility. The limits
of possibility come from lower levels in the hierarchy. The second entirely
separate reason for what one sees is to do with what is allowed by the upper
level constraints. An example here would be that mammals have five digits. There
is no physical reason for mammals having five digits on their hands and feet,
because it comes not from physical limits, but from the constraints of having a
mammal heritage. Any number of the digits is possible within the physical limits,
but in mammals only five digits are allowed by the biological constraints.
Constraints come from above, while the limits as to what is possible come from
below. The concept of hierarchy becomes confused unless one makes the
distinction between limits from below and limits from above. The distinction
between mechanisms below and purposes above turn on the issue of constraint
versus possibility. Forget the distinction, and biology becomes pointlessly
confused, impossibly complicated chemistry, while chemistry becomes unwieldy
physics.
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Any level of a biological system is composed of interacting components and
limited by a) potential behaviors of components (the lower levels) and b)
environmental constraints (imposed by higher levels);
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Concept of constraints is really the key to understanding hierarchies;
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One level is composed of smaller interacting units and is itself a component of
a larger unit or higher level in the hierarchy;
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Each level is considered to operate at distinct spatial (and temporal) scales,
and is constrained by the behavior of the levels above and below i.e., a level
can have a scale but a level is not a scale;
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The upper levels provide context, i.e., are constant at lower levels (e.g., whale
is constant context of its cells); this unresponsiveness leads to the constraint of
the lower levels (i.e., it’s a passive rather than active limitation): the upper
level is a parameter for the variable behavior of the lower level;
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In a hierarchy of empirical levels of observation, levels are ordered according
to the spatial and frequency characteristics of the entities that occupy each
level;
Why is HT useful?
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Provides guidelines for defining the functional components and of a
system and finding ways in which components of different scales
interact
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Requires explicit characterization of scaled relationships that exist
between pattern of interest and ecological determinants of the
pattern;
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Examples:
Spatial and temporal bounds of each pattern
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Order in which these patterns are nested
A SHORT ANNOTATED BIBLIOGRAPHY OF HIERARCHY THEORY
Koestler, Arthur. 1967. The ghost in the machine. Macmillan, New York. This is a long hard look at human social structure in hierarchical
terms. The notion of holon first occurs in this work. This is a classic work, but is easily accessible to the lay public.
Whyte, L.. L.., A. G. Wilson and D. Wilson (eds.). 1969. Hierarchical structures. American Elsevier, New York. This is a classic collection
of early scholarly works by some of the founders of hierarchical thinking.
Pattee, H.. H. (ed.) 1973. Hierarchy theory: the challenge or complex systems. Braziller, New York. This edited volume has some classic
articles by Pattee, Simon and others.
Allen, T. F. H. and T. B. Starr. 1982. Hierarchy: perspectives for ecological complexity. University Chicago Press. This book has a
significant ecological component but is much more generally about hierarchical structure. It is abstract and a somewhat technical treatment
but has been the foundation work for the application of hierarchy theory in ecology and complex systems theory at large.
Salthe, S. 1985. Evolving Hierarchical Systems: their structure and representation. Columbia University Press, New York. This book has
a strong structural bias, in contrast to the process oriented approach of Allen and the other ecologists in this bibliography. Salthe introduces
the notion of the Triadic, where there is a focus on 1) the system as both a whole above the levels below and 2) a part belonging to another
level above, 3) not forgetting the level of the structure itself in between. While much biological hierarchy theory takes an anti-realist point
view, or is at least reality-agnostic, wherein the ultimate reality of hierarchical arrangement is left moot, Salthe's version of hierarchy theory
is concerned with the ultimate reality of structure. The anti-realist view of structure is that it is imposed by the observer, and may or may
not correspond to any ultimate reality. If structure does correspond to ultimate, external reality, we could never know that to be so. Salthe's
logic is consistent but always takes a structural and ontological position.
O'Neill, R. V., D. DeAngelis, J. Waide and T. F. H. Allen. 1986. A hierarchical concept of ecosystems. Princeton University Press. This is a
distinctly ecological application of hierarchy theory, making the critical distinction between process functional ecosystem approaches as
opposed to population and community relationships. It is an application of hierarchy theory to ecosystem analysis.
Allen T. F. H. and T. Hoekstra. 1992. Toward a unified ecology. Columbia University Press. This book turns on hierarchy theory, but is
principally a book about ecology. It goes beyond the O'Neill et al book, in that it makes the distinction between many types of ecology
(landscape, ecosystem, community, organism, population, and biomes) on the one hand, and scale of ecology on the other hand. It ends with
practical applications of hierarchy theory and ecological management.
Ahl, V. and T. F. H. Allen. 1996. Hierarchy theory, a vision, vocabulary and epistemology. Columbia University Press. This slim a volume
is an interdisciplinary account of a hierarchy theory, and represents the shallow end of the pool. It is the primer version of Allen and Starr
1982. It is full of graphical images to ease the reader into a hierarchical perspective. It makes the distinction between levels of organization
and levels of observation. It takes a moderate anti-realist point of view, wherein there may be an external reality, but it is not relevant to the
discourse. We only have access to experience, which must of necessity involve observer values and subjectivity. There are examples from a
wide discussion of many disciplines. Included are examples from psychology, ecology, the law, political systems and philosophy. It makes
reference to the global and technological problems facing humanity, and offers hierarchy theory as one tool in the struggle. The summary of
hierarchy theory in the opening paragraphs above comes from this book.