Lesson 2: The Science of Behavior - Some History and Principles Flashcards
anthropodomorphism
- Literally means “human-shaped”
- The practice of giving animals human characteristics
natural selection
Differential survival and/or
reproduction of individuals
that differ in their traits
- Charles Darwin, On the Origin of
Species (1859)
If a particular variation is more advantageous, then individuals with that
variation will reproduce better (be selected for naturally) than other
individuals and so pass more of their genes on to the next generation.
we know how natural selection affects behavior: Trinidaninan Guppies
In Trinidad & Tobago, guppy populations vary in predation pressure
- upstream: low predation
- downstream: high predation
Fish from high-predation sites have different physical and hysiological characteristics compared to low-predation sites. These might help deal with predators
- Are less brightly colored (harder to see)
- Reach sexual maturity at a younger age
(less risk of being prey before
reproducing) - Produce more, smaller offspring (more
chances to pass genes to next
fish from high-predation sites also show behavioral differences:
- Swim in larger, tighter schools
- Stay farther away from suspected predators and inspect them more often
experiment: trinidadian guppies
200 guppies from high-predation
site transferred upstream to low-predation site
result: trinidadian guppies
Within 11 years (about 30-
60 generations), the manipulated
population evolved schooling and
predator inspection behaviors
more similar to low-predation
populations than to the ancestral
high-predation population
classical ethology
study of how behavior is adaptive
comparative psychology
based on the idea that behavior evolved so it can be compared between other species
classical ethologists were influenced by the new ideas of natural selection. They wanted to understand how behavior made the anima “fit” for its environment
as a result: they concentrated on field work and inherited behaviors that were clearly subject to natural selection
Example of the contributions of the Classical Ethologists:
Fixed Action Pattern” Egg retrieval in the greylag
fixed action pattern features:
- Stereotyped
- Triggered by sign
stimulus - Plays out to completion
Chain-reaction FAPs
Several fixed action patterns
can be strung together creating
very complex behaviors
triggering territorial behavior in sticklebacks
- as long as the models had an eye and a red belly – they were showing territorial behavior
FAP: grey goose
mamma had to keep doing the action to completion – whenever she notice her egg, or something resembling the sort was out of her nest – she had to do the rolling action to completion
chain-reation FAPs: stickleback courtship behavior
- female with eggs
- male responds with zigzag swim and swims
- female follows
- male shows nest entrance and female enters nest
- male then prods females tale while making trembling movements
female spawns and leaves; male then enters the nest and also spawns
Another contribution of ethologists: Manipulation of
environment to understand mechanism (Tinbergen)
- Manipulation: visual cues around nest were
changed after wasp had left vicinity - Result: returning wasps followed the visual cue searched first in area with pine cones
Another contribution of ethologists: Manipulation of environment to understand mechanism (Tinbergen)
Manipulation: “Cue conflict” experiment: scent vs vision
Result: returning wasps followed the visual cue:
searched first in area with pine cones
Comparative Psychologists
- Used animals as models for human
behavior, especially learning. The word
‘comparative’ meant that we could learn
about humans by comparing them to animals - Pioneered the use of ‘controlled
environments’ to reduce variability; did
mostly lab work so could create those
controlled environments
a classic contribution: classical conditioning
A regular and measurable unlearned
response to an ordinary stimulus becomes
associated with a neutral stimulus –
something really unrelated to the
response. So the response is now a
‘conditioned reflex’
behaviorism
- Regarded animal behavior as
primarily controlled by conditioned
reflexes - So behavior was dependent on
previous experiences – basically the
environment that the animals grew up
in - Skinner boxes: Chambers designed
to create a very controlled physical
environment so that during testing the
only differences were in the
rewards/punishments offered when
nature vs. nurture
Because ethologists and comparative
psychologists tended to focus on different
aspects of behavior, there came to be
opposing views on the relative importance of
genes (nature) and environment (nurture) in
determining behavior
Begging in black-headed gulls has four
steps:
- Chick approaches parent
- Opens and closes beak several times
- Chick turns its own head, positions own
bill & grasps parent’s bill - Chick pushes up with body and pulls down
with bill
This whole process works as a releaser to get
parents to feed the chick. But if chick
fumbles, the parents try harder to get the
chick to beg properly
Begging in black-headed gulls was
regarded as an innate behavior and a fixed
action pattern:
Observations suggested that
- Triggered by sign stimulus (releaser) of
parental arrival - all chicks did this in the same way
(stereotyped) - Seemed to play out to completion though
were no experimental manipulations to
verify
Why don’t all chicks beg correctly from
the beginning?
Nature argument: they are genetically
programmed to beg in a certain way but
physically too weak right after hatching –
must mature first
Nurture argument: they need
experience, that is, they need to learn how
to position their heads to beg properly
chicks begging - manipulation
Manipulation: Raised some
chicks in incubators without a
chance to beg (hand fed) and
allowed others to be raised by
parents
Then had the chicks beg from
a fake parent (stuffed gull)
