Notes + assignments + book summary of Behavioural Biology
Assignment 16 november (Lecture 2)
Self organisation:
- Implies that a pattern at a global level (macropattern like flocks) emerges from the
interactions among the lower level units (microlevel like interaction between starlings)
Interactions between the individuals depend on: attraction, alignment and avoidance
- Lower level units behave according to local information and simple rules only
- The emergent, complex pattern (change/complexity/density of shape) is more than the
sum of the components (rules of individuals). Because only the behaviour of the individuals
doesn’t say anything about the shape or shape changes of the flocks.
- Emergent properties arise unexpectedly
Foraging in Ants
Ants are indeed marking their path, they leave a drop of pheromone when they walk.
What if you have 2 the same food resources, at the same distance towards the nest, what
will the ants do?
First there is no difference, the amount of ants to the left food resource equals the amount
of ants to the right food resource. Then there can me a bifurcation, phase transition, where a
couple of ants accidently switch to the left/right source and then they leave marks over
there so the other ants will follow the path with more marks so they are all going to that one
resource and it gets even marked stronger.
The advantage of asymmetric exploitation is that a heavily marked path is more easy and
they can defend themselves better against other colonies and predators. In this case there is
no leader, no cognition so its clearly self organization.
Dominance style in primate society’s
There is a dominance hierarchy between primates. How to become dominant?
- Conventional (quality of individual)
- Self organization (chance and self-reinforcing effects of winning and losing, winner-loser
,effect (because of hormones the chance of winning again after winning is higher than losing
after winning))
There are 2 dominance styles
- Despotic: steep hierarchy, dominants have easier access to resources than subordinates
- Egalitarian: weak hierarchy, group members have equal access to resources
In societies there are different traits when the hierarchy is steep or weak.
In steep societies the average distance, attack asymmetry, male migration, female choice
etc. is higher. This will be in practical:
Each individual has a
capacity to win what we call
its DOM value.
1 there are 8
individuals in this
case so at first they
all get the number 8.
2 when they meet
they consider their
attack, they only attack if they think they will win
3 if its relative dominance value is larger than their random value between 0 and 1 it
thinks it will win
4 if it wins their dominance value will be updated (increases), if it loses it will
decrease
, This is damped positive feedback, because if someone wins after many times losing, the
effect is bigger than if some wins after many times winning.
In Behavioural measurement you study:
- Who interacts with whom
- Dominance hierarchy (differentiation)
Coefficient of Variation (CV) of dominance values: high CV is high differentiation
The average dominance index is the proportion of winning per individual averaged over all
its opponents
Less aggression can be because the hierarchy is set (chickens) or because there is more
distance between the individuals because of all the earlier fights
- Spatial structure (average distance among
individuals, centrality of dominants)
This is a pattern you see at high intensity
aggression.
Dominants never flee, the subordinates
flee again and again.
This pattern is not centripetal instinct
(higher survival in the center) but because
of dominance.
Assignment 16 november (Lecture 2)
Self organisation:
- Implies that a pattern at a global level (macropattern like flocks) emerges from the
interactions among the lower level units (microlevel like interaction between starlings)
Interactions between the individuals depend on: attraction, alignment and avoidance
- Lower level units behave according to local information and simple rules only
- The emergent, complex pattern (change/complexity/density of shape) is more than the
sum of the components (rules of individuals). Because only the behaviour of the individuals
doesn’t say anything about the shape or shape changes of the flocks.
- Emergent properties arise unexpectedly
Foraging in Ants
Ants are indeed marking their path, they leave a drop of pheromone when they walk.
What if you have 2 the same food resources, at the same distance towards the nest, what
will the ants do?
First there is no difference, the amount of ants to the left food resource equals the amount
of ants to the right food resource. Then there can me a bifurcation, phase transition, where a
couple of ants accidently switch to the left/right source and then they leave marks over
there so the other ants will follow the path with more marks so they are all going to that one
resource and it gets even marked stronger.
The advantage of asymmetric exploitation is that a heavily marked path is more easy and
they can defend themselves better against other colonies and predators. In this case there is
no leader, no cognition so its clearly self organization.
Dominance style in primate society’s
There is a dominance hierarchy between primates. How to become dominant?
- Conventional (quality of individual)
- Self organization (chance and self-reinforcing effects of winning and losing, winner-loser
,effect (because of hormones the chance of winning again after winning is higher than losing
after winning))
There are 2 dominance styles
- Despotic: steep hierarchy, dominants have easier access to resources than subordinates
- Egalitarian: weak hierarchy, group members have equal access to resources
In societies there are different traits when the hierarchy is steep or weak.
In steep societies the average distance, attack asymmetry, male migration, female choice
etc. is higher. This will be in practical:
Each individual has a
capacity to win what we call
its DOM value.
1 there are 8
individuals in this
case so at first they
all get the number 8.
2 when they meet
they consider their
attack, they only attack if they think they will win
3 if its relative dominance value is larger than their random value between 0 and 1 it
thinks it will win
4 if it wins their dominance value will be updated (increases), if it loses it will
decrease
, This is damped positive feedback, because if someone wins after many times losing, the
effect is bigger than if some wins after many times winning.
In Behavioural measurement you study:
- Who interacts with whom
- Dominance hierarchy (differentiation)
Coefficient of Variation (CV) of dominance values: high CV is high differentiation
The average dominance index is the proportion of winning per individual averaged over all
its opponents
Less aggression can be because the hierarchy is set (chickens) or because there is more
distance between the individuals because of all the earlier fights
- Spatial structure (average distance among
individuals, centrality of dominants)
This is a pattern you see at high intensity
aggression.
Dominants never flee, the subordinates
flee again and again.
This pattern is not centripetal instinct
(higher survival in the center) but because
of dominance.
