Levels of Organization and Causation
1) Tinbergen: Four Unifying Questions
a) Causation (Mechanism)
b) Survival Value
c) Ontogeny
d) Evolution
2) Levels of Organization
a) Composition
b) Interactions
3) Time Scale
a) Composition
b) Interactions
4) Scientific Perspectives and Organization
5) Causation
a) Aristotle’s Four Causes
(1) Material Cause
(2) Efficient Cause
(3) Formal Cause
(4) Final Cause
b) A Reformulation of Aristotle’s Four Causes
(1) Material Cause => Composition
(2) Efficient Cause => Proximate
(3) Cause Formal Cause => Organization
(4) Final Cause => Function
(a)
System Function
(b)
Evolutionary adaptive function
6) Army Ants
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1. Tinbergen: Four Unifying Questions
Nikolaas Tinbergen was interested in developing a unified methodological and
theoretical approach (though he doesn’t explicitly say this) for the study of animal
behavior. In particular, he thought the perspective should be biological.
Tinbergen was writing in a context that is considerably different from today, but
what he had to say was very forward looking, even beyond where we are today as I
will try to explain.
The context in which he was writing was one the one hand, naturalistic observation
stemming from the 19th century and the emergence of experimental approaches to
behavior. These experimental approaches had two main sources. The experiments
by Konrad Lorenz and the development of laboratory experimental approaches to
learning with the newly emerging behaviorist approach. The latter he viewed as
introducing artificialities.
Tinbergen defined ethology as the study of movement or behavior patterns with a
method (or as implied in his writing a coherent theoretical approach). At the time
(and perhaps still today), ethology or the study of animal behavior was more a
collection of approaches, questions, and methods rather than a coherent discipline.
What it lacked was unifying questions, methods, and theoretical approaches. Thus,
his paper “On the aims and methods of ethology” aimed to outline such an
approach organized around four major questions originating from biology.
The first three of these questions he credits to Huxley and the last to himself:
a.
b.
c.
d.
Causation (Mechanism),
Survival Value (fitness),
Evolution, and
Ontogeny.
For Tinbergen, these four questions provided the theoretical core for the study of
behavior from a biological point of view. These questions are not independent, but
intertwined as we will see and they have implications for the kinds of research that
should characterize the field of animal behavior.
These four questions are aimed add answering the most fundamental question of
ethology (or animal behavior):
Why do animals behave as they do? (p. 411).
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Tinbergen recognized that the traditional observational and descriptive approach to
the study of behavioral patterns, while necessary was not sufficient to answer this
fundamental question, much less the four organizing questions above.
He recognized that experimental analysis was necessary—an I would add today,
we need more precise quantitative and dynamic theories of behavior to answer
Tingbergen’s fundamental question. It is, however, essential detailed descriptions
of behavioral patterns to proceed with both experimental and theoretical analysis.
c. Causation
Behavior is not just events, but patterns of events that like organs can have
functions, can be selected for, evolve, and develop. Underlying these patterns are
mechanisms and it is important to remove subjectivity and anthropomorphism from
mechanistic explanations.
Theoretical/Experiential Perspectives
The problem of perspective comes in when, for example, we study behavioral
patterns of nest building or fighting and assume that independent mechanisms
underlie our observed patterns. The problem is that we do not know the
complexity and interconnectedness of underlying mechanisms. Cutting up
behavior patterns by the perspectives (e.g., studying foraging behavior or social
behavior) we adopt may impose our own categories on behavior, which in turn
may distract us from seeing connections and the full complexity of the behavior
machinery (mechanisms) that generate the patterns of behavior we observe and
want to explain.
Behavior machinery:
This is fundamental contribution of Tinbergen around which all four
organizing questions revolve. It is the recognition that complex mechanisms
underlie the behavioral patterns we see. This machinery is not entirely different
and arbitrarily from species to species, which means that, in principle, we can
study the detailed similarities and differences between complex mechanisms
underlying behavior in different species and why eliminating one such mechanism
or component thereof may shed light on the behavior machinery in other animal
systems (see evolution below).
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The potential commonality of behavior machinery across species does not imply
behavior is innate in any of its traditional senses, but rather—in more modern
terminology—is emergent from these multi-level complex mechanisms.
Regarding Lorenz’s third postulate that we need to emphasize complex internal
mechanisms of behavior, which today include the neurosciences and genomics is
important, but incomplete. We also must consider the context of behavior, which
includes environmental and social contexts, which can occur at multiple levels of
organization.
b. Survival Value:
“Has anyone an idea why so many birds flock more densely when attacked by a
bird of prey?” (p. 417) —this was a question Tinbergen asks of one of his
professor’s but was dismissed.
Today we can begin to answer this complex question by appealing to selforganizing behavior and its potential consequences for predator detection and
capture mechanisms.
Tinbergen pointed out the importance of investigating the functions of behavior
patterns and the complex mechanism that produced them. These functions
causally act to increase the survivability of the organism and its ability to
reproduce.
Tinbergen recognized that investigating functional questions about behavioral
patterns was a very difficult task. Not all behavioral patterns may have functions
and there are many behavioral patterns that we have no idea whether they have a
function or not (see Gould and Lewontin).
He recognized that the analysis of the survival value (fitness) was crucial for
making natural selection an empirical theory. We should be able to assess and
analyze behavioral patterns and their mechanistic role in fitness to make evolution
by natural selection clearly a testable and predictive theory.
c. Ontogeny
Tinbergen defined ontogeny as “Change of behaviour machinery during
development.” (p. 424). This is not the same as change of behavior during
development, but rather change in the mechanisms that generate behavioral
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patterns during development. Thus, ontogeny is the study of the development of
the mechanisms of behavior during development.
Because the behavioral machinery is complex, there will be components of the
machinery that appear more innate and others that result more from the
environment and learning. It is a mistake, according to Tinbergen, to try to isolate
the components of the complex behavioral mechanism and attempt to assign innate
or environmental sources to these components in isolation. Tinbergen believed
that strictly reductive and categorical approaches would fail to explain the
development of the behavioral machinery of complex behavioral patterns.
Finally, it is also important to ask about the survival value of the behavior
machinery at different stages of development—further illustrating how these
questions are not independent.
d. Evolution
“Evolutionary study has, of course, two major aims: the elucidation
of the course evolution [phylogeny] must be assumed to have taken,
and the unraveling of its dynamics [the mechanisms operating that
produce evolution].” (p. 428).
In ethology, the first aim is found in the study of comparative behavior;
investigating similarities and differences in behavioral patterns [and presumably
behavioral machinery] using other tools such as structural relationships and now,
genomic approaches.
The second aim, the study of dynamics focuses on:
(1) genetic influences on behavior or better heritable genetic differences—it may
be more complicated than this with cultural inheritance and environmental
inheritance.
(2) the other is the study of selection for behavior by studying its survival value.
Number (2) can illuminate the complex selection forces acting on an organism,
which have implications for future evolution and may be extrapolated to the past.
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2. Levels of Organization
Video: Fall webworms
a. Composition
One meaning of the term Levels is composition: A thing X is at a higher level
of organization than a thing Y if X is composed of Ys (and possibly other things).
For example, cells are at a higher level of organization then DNA molecules,
because among other subcellular structures, cells are composed of DNA.
Galaxi es
Planets
E cosystems
Societies
Groups, Populations
Multicellular O rganisms
Cells
Subcellular
Structu
resDNA
Proteins,
Subatomic
Par ticles
Compositional Levels do not reveal how the components at one level interact
to produce the behavior and characteristics of organization at a higher level. Thus,
for example, merely knowing that a group is composed of individuals of a
particular species (e.g., army ants, wild dogs, or humans), tells us very little about
the social structure of the group or how the individuals develop in the context of
the group.
1.B. Levels: Interactions
Another meaning of Levels is the number, strength, and kinds of interactions
among components at different levels of composition. The interactions of
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components at a given level constitute levels of organization. Organization
and complex organization often emerge from simple interactions of
components as we saw with fall webworms and as we will see with
army ants below.
However, complex systems are not limited to interactions (i.e., interactional
complexity) to components at one level of compositional. For example, Oxytocin,
a peptide hormone, is involved in the organizational process of birth and nursing in
mammals and social behavior, but there are many other physiological processes
and behavioral interactions required for these organizational processes to occur.
The particular function of a hormone such as oxytocin on the state and
environment of an organism, i.e., its context or the situation. Vasopressin, a
peptide hormone closely related to oxytocin is best known for regulating kidney
function. If the vasopressin gene is defective, mammals such as rats will develop
diabetes insipidus. However, it also plays a role in social behavior and anxiety. It
may also modulate early sensorimotor development, making it a prime candidate
for playing a role in autism.
Gr oup s, Populations
Multicellular
Organisms
Proteins, DNA
Subatom ic
Pa rticles
Galaxi es
Planets
Societies
Cells
Subcellular
Structur es
Simple
E cosystems
Complex
Inter actions
The figure above is a rather rough ordering of different systems in terms of the
levels of complexity of their interactions. Note, for example, that although
galaxies are at a very high level of composition (i.e., they are composed of many
different kinds of things) they are at a low of interactional complexity. That is,
many of the things that a galaxy is composed of do not directly interact other than
overall gravitational forces. For example planets and any living things that may be
on them have negligible influences on the organization of galaxies—of course
galaxies are composed of complex systems, it is just that they are not complex
systems by virtue of being composed of complex systems.
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A. Composition ! Interactions
If we plot systems in terms of their compositional level versus their interactional
level, we see that there is not a simple relationship between the two.
Confusing these two levels can and has led to oversimplifications of the
relationships between behavior and development, genes and development, and
evolution and development.
Later we will see that these two levels have different meanings of Causation
associated with them.
Composition
Galaxi es
Planets
Ecosystems
Societies
Gr oups, Populations
M ulticellular O rganisms
Cells
Subcellular
Structures
Proteins, DNA
Subatom ic
Pa rticles
Interactions
2.A. Time Scale ! Composition
When we look at the time scale of processes, we see that compositional level and
time scale are closely correlated (the figure below is only an approximate
representation of the relationship).
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Composition
Galaxi es
Planets
E cosystems
Societies
Gr oup s, Populatio ns
Multicellular
Organisms
Cells
Subcellular
Structures
Proteins, DNA
Subatom ic
Pa rticles
Time Scale
2.B. Time Scale: Interactions
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It a myth about the relationship that development and evolution occur on on strictly
different time scales, thus one can study one type of system relatively
independently of the other as Tinbergen concluded.
3. Scientific Perspectives and Organization
Earlier I said that the function of a hormone such oxytocin depended on the state of
an organism (e.g., whether it is pregnant) and its environment (including social
context). From a researcher’s point of view, questions of function and mechanism
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lead to different views or perspectives of a system. Depending on how we
view a system can lead to considerably different ways of decomposing a system
that is at the same level of composition!
In the diagram above, Wimsatt illustrated different perspectives one may take in
studying a piece of granite and a fruitfully. In the case of the piece of granite,
taking different perspectives leaves us with the same, relatively simple description
of components. However, with the fruitfully, depending on the perspective and
questions asked, we get descriptions of complex systems, which differ according to
perspective.
4. Causation
By our ordinary meaning of causation, we understand the relationship between
cause and effect as one of conditions that bring about certain effects. For
example, throwing a ball and thereby breaking a window. The summation and
integration of excitatory and inhibitory postsynaptic potentials bring about action
potential in a neuron.
Causation in this sense is proximate, which means that the conditions bringing
about an effect are near their effects in space, time, and typically at the same
level of organization.
Aristotle, a famous ancient Greek philosopher, had a more general notion of
causation. He thought of causes as reasons or factors explaining the objects and
processes that exist in the world. For Aristotle there were four basic causes:
1. Material Cause: The material of which a thing is made.
2. Efficient Cause: The conditions that combine to produce an effect from a
cause.
3. Formal Cause: The shape, configuration or type of thing something is.
4. Final Cause: The purpose or end of a thing or process.
Aristotle held that anything could be explained in terms of these four causes. For
example, the material cause of a statue is the stone it is made of. Its efficient
cause is all the chiseling required to transform the stone into a shape or
configuration, its formal cause, which was the purpose or aim of the sculptor who
produced it, its final cause.
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There is a ring of truth to Aristotle’s four causes as explanations for why an artifact
is the way it is, but they require a modern reinterpretation in light of modern
science to apply behavioral explanation.
Indeed, there are modern ideas that correspond neatly to Aristotle’s four causes.
They are:
1. Composition: Composition corresponds very closely to Aristotle’s notion of
material cause. It is the components, entities and processes that compose a
system at some level of organization. For example, DNA, RNA, and Proteins
are among the components making up cells.
2. Proximate Cause: Proximate cause also corresponds very closely to
Aristotle’s notion of efficient cause. These are the causal conditions specified
in mechanisms for how things work, such as the firing of a neuron, or hormonal
factors that modulate reproduction and maternal care of young.
3. Organization: Is one aspect of Aristotle’s notion of formal cause, namely
the idea of configuration. But, specifically we are primarily concerned with
the configuration of interactions. Interactions connect organization to
composition and proximate cause (Tinbergen’s behavior machinery).
A. Interactions are among components of a systems, and
B. Interactions are proximate causal relationships among
components.
4. Function: The notion of function is the biggest departure from Aristotle’s
system. Final causes assume a purpose for a component or system. This is fine
for ordinary human artifacts. A purpose of a table is to set things on, and this is
a reason for it existence, but final causes are neither testable nor explanations of
natural systems. Thus, in biology and psychology we replace Aristotle’s notion
of final cause with two related concepts of function. Functions in either sense
are understood in terms of their consequences.
A. System function: This is the role of a component in a system. For
example, a function of a neuron is to modulate action potentials. A
function the heart is to circulate blood. System functions depend on the
composition of components, their proximate causal interactions,
and how these interactions are organized (e.g., the configuration of
excitatory and inhibitory inputs into a neuron, branching nature of the
circulatory system).
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B. Evolutionary adaptive function: This is the role of a component in
the survival and reproduction of a system in a larger ecosystem or
environment. Typically, adaptive functions are ascribed to components
and characteristic of individuals, but they may apply to entities at other
levels of organization such as groups, ecosystems, and species. (Both of
these are inherent in Tinbergen’s notion of survival value.)
Army Ants
Army ants are an interesting example of the complexities of organization and the
different kinds of causes operating during development.
What makes this example especially interesting is that individual insects such as
ants are in many respects much “simpler” (this is a relative term, ants are
nevertheless quite complex systems) than birds or mammals in the complexity of
their nervous systems, their behavioral repertoires, and in their capacity to learn.
T. C. Schneirla studied army ants (Eciton hamatum and E. burchelli; other
websites 1, 2, 3) throughout the 1940s. Army ants are nomadic foraging social
insects. Unlike many other social ants, wasps and bees they do not build
permanent nests.
One of the more remarkable aspects of army ant social behavior is that individual
development is highly coupled with social behavior and individual development
drives social behavior.
Cycles of Behavior
Army ants (50,000-120,000 in a colony) exhibit daily or diurnal cycles of
functional activity. Functional activity includes daytime foraging (when light,
temperature and humidity are best), thermoregulation and climate control in the
bivouac. These functional cycles are largely under external control of the daily
light cycle, temperature and humidity conditions. These are external Zeitgebers.
They go through Nomadic and Statary phases of colony behavior that are tightly
coupled with development of offspring. Interestingly, these cycles are not driven
by external Zeitgebers but emerge from the individual interactions of workers,
new workers and pupae.
Notice that all four types of causes are present Schneirla’s representation.
! The Colony Functional Cycle refers to the functions performed by the
colony such as foraging and incubation, care and feeding of the next generation.
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! The Brood Cycle corresponds approximately to the notion of proximate
causation, though later we will distinguish types of proximate causal relations
that occur at different time scales such as ontogenetic causation.
! The Bivouac Situation and Condition corresponds to the compositional
notion of cause and how it changes over time. (We see the composition of a
bivouac and where the young are located in the center).
The Typical Raiding Pattern illustrates one aspect of the organization in
army ants, particularly, foraging search patterns, which are the result of simple
individual rules of behavior.
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How are these functional cycles, and synchronous reproduction and development
generated? According to Schneirla they are due to local interactions between
newly emerged workers and the current work force and subsequently reciprocal
interactions between workers and the developing brood.
1. Newly eclosed brood (first spike above threshold): Newly emerged
works increase the activity levels of old workers in the workers lick and
groom the newly emerged workers due to chemical signals.
2. Developing larvae (the second more gradual rise): Workers are attracted
in the presence of larva pheromones and nutritive secretions that the workers
ingest. Larva also become more active in the presence of workers, who feed
them. Activation of workers spreads throughout the colony.
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This process of behavioral excitation and activation of workers is not merely timed
by the length of time it takes the larva to develop. Increase activation stimulates
the nomadic phase, foraging activity is increased, increasing the food supply
needed for growth and maturation of larvae.
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