Download 13 May 2003: Introduction to Animal Behavior • Why study Animal

13 May 2003: Introduction to Animal
Behavior
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Why study Animal Behavior?
History of Animal Behavior
Levels of analysis
Tools & methods
Why study Animal Behavior?
• behavior is central to understanding all
aspects of the animal’s biology: it occurs at
the interface of ecology, physiology, and
evolution
• changes in behavior are good warning signs
of environmental degradation
• behavior can have significant economic
importance
Why study Animal Behavior?
• understanding behavior is critical for
improving animal welfare
• consideration of behavior can improve
effectiveness of wildlife conservation
efforts
• behavior offers solutions to human social
problems
History of Animal Behavior
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Pre-Darwinian views of animal behavior
Charles Darwin’s contribution
Classical ethology
Behaviorism (Comparative psychology)
Behavioral ecology
Sociobiology
History of Animal Behavior
Darwin’s contributions
Origin of Species (1859)
• Darwin suggests that intricate behavior
patterns could have evolved from simpler
behaviors via the action of natural selection
and not have spontaneously arisen via
supernatural creation
History of Animal Behavior
Descent of Man (1871)
• Darwin looks for evidence of human-like
mental abilities in animals
• He presents his hypothesis of mental
continuity
– The animal mind and human mind are points on
a continuum, they do not differ qualitatively.
• This launches the science of ‘comparative
psychology’.
History of Animal Behavior
Darwin’s contributions
Origin of Species (1859)
• According to Darwin, if instincts have
evolved, then:
more primitive species should show simpler
behavior sequences
we ought to be able to find gradations in
behavior among related species
History of Animal Behavior
Darwin’s contributions
• He suggested that studying animals could
teach us about ourselves.
• He believed that the expression of emotion
in man and animals represents a continuum.
• He presented the first systematic, rigorous
attempt to study comparative animal
behavior and its evolution.
Classical ethology
• The study of the mediation, ecology, and
evolution of behavior; originally pursued by
zoologists in Europe and North America.
• Complex behavior usually the expression of
mindless circuits of sign stimuli, innate
releasing mechanism (IRM), and fixed
action patterns (FAP)
• Behavior should be studied in natural
environment, as much as possible
• Differences between species reflect natural
selection, and are therefore interesting.
Classical ethology
Jacob von Uexkull (1864-1944)
• Animals perceive only limited portions of
the total environment with their sense
organs and central nervous systems.
• Umwelt: the sensory-perceptual world of an
animal
Classical ethology
Karl von Frisch (1886-1982)
• honey bee dance language: animal symbolism
Classical ethology
Konrad Lorenz
• imprinting
• hydraulic model of motivation
Classical ethology
Niko Tinbergen
• Experimental ethology, levels of analysis
Ethological terms
• Displacement behavior
• Intention movement
Ethogram
• complete inventory
or descriptive catalog
of the motor patterns
exhibited by
members of a
particular species
Behaviorism (comparative psychology)
• emphasized behavioral plasticity: learning most animals can learn many things
– Originated among philosophers and
psychologists in the United States.
– even complex behavior is forged from simple
stimulus-response interactions
Behaviorism (comparative psychology)
• animal enters the laboratory as a clean slate,
and the animal’s current state is irrelevant
• a single small set of rules governs all
learning in all animals
• species differences are insignificant
– studying one species = studying all species
• law of equipotentiality
Behaviorism (comparative psychology)
Lloyd Morgan
• Morgan’s canon
– “In no case may we interpret an action as the
outcome of the exercise of a higher physical
faculty if it can be interpreted as the outcome of
the exercise of one which stands lower in the
psychological scale.” (Occam’s razor, or the
Law of Parsimony)
– all responses are conditionable to all stimuli
• emphasized need for non-anthropomorphic
approach
Behaviorism (comparative psychology)
Edward Thorndike
Behaviorism (comparative psychology
Ivan Pavlov
• stressed systematic, replicable experiments
rather than anecdotes and observation
• trial and error learning
– no deduction, via Thorndike ‘puzzle box’
• documented role of reinforcement
• species-independent laws of learning
• classical conditioning
Behaviorism (comparative psychology)
B.F. Skinner
• Skinner box
• if we cannot observe a direct behavioral
response, there is no point in pondering
‘mental events’ (e.g., consciousness,
emotions)
Pros of Behaviorism & Classical Ethology
Behaviorism
Classical Ethology
• strong grounding in
• enormous
evolutionary theory
enhancement of
scientific rigor
• contributed the
ethogram to the study
• established many basic
of animal behavior
laws of learning that
are good predictors of • studied a diversity of
animals’ interactions
animal taxa and
with their
behavioral phenomena
environments
Cons of Behaviorism & Classical Ethology
Behavioral ecology
Behaviorism
• dogmatic focus on
environmental
influence
– due largely to study of
only a few species in
arbitrary situations
• not grounded in
evolutionary theory
• unrealistic view of
nervous system
Classical Ethology
• overlooked much
behavioral plasticity
due to excessive focus
on ‘instincts’
• unrealistic view of the
nervous system
• examines the ways in which animals
interact with their environments, and the
adaptive value of behavior (ultimate
questions).
• J.R. Krebs, N.B. Davies
Levels of analysis:
Tinbergen’s 4 questions
Sociobiology
• applies the principles of evolutionary
biology to the study of social behavior in
animals
– a synthesis of behavioral ecology and the study
of social organisms which relies heavily on the
comparative approach
• Proximate:
– What are the mechanisms that cause the
behavior?
– How does the behavior develop?
• Ultimate:
– Why - what is the survival (& reproductive)
value of the behavior?
– How did the behavior evolve?
• E.O. Wilson
– Sociobiology: the new synthesis
Methods, tools, and concerns in the
scientific study of animal behavior
• science is only one way of ‘knowing’
– other ways include religion, art, etc.
• science is based on two assumptions
– physical reality exists
– there are physical explanations for events.
• science is a systematic way of seeking, but
never finding, truths
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Methods and tools: strong inference
(hypothesis testing) method
begin with an observed, described
phenomenon
state the questions clearly.
create natural explanations for the
phenomenon (hypotheses), including a null
hypothesis
generate testable predictions/outcomes from
the explanations/hypotheses; if possible
generate mutually exclusive predictions
Methods and tools: strong inference method
Methods and tools: strong inference method
• whenever possible, avoid predictions which
support the hypothesis in favor of
predictions which would falsify the
hypothesis
• test the hypotheses
– disproof is stronger than proof.
– collect data and compare it to the predictions
• reject the hypotheses that did not predict the
observed data
• continue until only one hypothesis not
rejected
– then test this one!
Methods and tools: strong inference method
Methods and tools: strong inference method
• example: Timothy Clutton-Brock (& others)
• observation
– sentinel behavior among meerkats (Suricata
suricata)
– individual meerkats appear to take turns at
sentinel duty, watching out for predators and
giving an alarm call if one is seen.
Methods and tools: strong inference method
• question
– Why (in adaptive sense) do meerkats take turns
at sentinel duty?
• H1: because sentinels can save the lives of relatives,
sentinal duty & warning is favored by kin selection.
• H2: reciprocal altruism (I scratch your back...)
• H3: sentinel behavior is selfish, warning is cheap
Methods and tools: strong inference method
• H1: because sentinels can save the lives of
relatives, behavior is favored by kin
selection
– P1: group members closely related
nope, group members not closely related, on average
P2: sentinel more frequently when near close
relatives
nope, individuals sentinel when near completely
unrelated animals
therefore, H1 is not true.
Methods and tools: strong inference method
• H2: reciprocal altruism (I scratch your
back...)
P1: group members serve sentinel duty
in regular order, they take turns...
nope, no regular order of sentinel duty
therefore, H2 is not true
Methods and tools: strong inference method
• H3: selfish behavior is selfish, warning is
cheap
P1: sentinel only when full & don’t need to eat
Yep
P2: sentinel behavior is not risky
Yep
P3: perform sentinel behavior whether alone or in a
group
Yep
P4: perform sentinel behavior when in group and no
one else on guard
Yep
therefore, H3 is not rejected
Methods and tools: design of an animal
behavior study
• Will the study describe a phenomenon or test hypotheses?
– If the latter, clearly define the behavior.
– Identify the independent and dependent variables, and the control
groups (if necessary).
• Which of Tinbergen’s four questions will be addressed?
Methods and tools: design of an animal
behavior study
• Will the study be performed in a laboratory or field
setting?
lab concerns
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animal procurement (captured v. bred)
housing and care
experimental conditions
experimental techniques
• How will the variables be measured/codified?
• What will be the study species?
• What is the level of investigation?
Methods and tools: design of an animal
behavior study
• lab experimental techniques
Classical conditioning apparatus
Methods and tools: design of an animal
behavior study
• lab experimental techniques
Skinner box
Methods and tools: design of an animal
behavior study
• lab experimental techniques
Thorndike puzzle box
Methods and tools: design of an animal
behavior study
• Will the study be performed in a laboratory or field
setting?
– field concerns:
• non-invasive
– data collection methods
» ad libitum
» zero-one
» scan
» focal animal survey (FAS)
• invasive?
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how to be minimally invasive
how to identify individuals, if necessary
how to find/track animals
experimental techniques
data collection & recording tools
legal & ethical concerns
• external validity
– How well can you generalize from your results?
• How well do your results represent the ‘real world’?
• internal validity
– How well can you replicate your results?
• How well can you establish cause & effect?
• impact the smallest number of animals as possible
• detect and reduce animal stress & pain
• weigh the potential gain in knowledge against the
consequences to the individual animals and populations
• use the appropriate control groups, test sequences, and
statistical analysis
• consider different Umwelts