Download Copyright Message Recap: Where we got to and where we

22/07/2016
Copyright Message
Recap: Where we got to and where we’re going
 Historical themes in motivation
 Mechanistic  hard-wired/genetic
 Appetitive  Learning
 Rational  Cognition/agency
 Unit organisation
 Material presented in rough order of phylogenetic development or
complexity
 Mechanistic Approaches to Motivation pre-Darwin
 1600's: Descartes' dualism: Body is mechanistic, mind is not
 1700's-1800's: Explosion of study in anatomy/physiology
 Mid 1800's: Darwin...
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Darwinian evolution - Controversies & abuses
 Widely accepted scientifically as best
account of the origin of physiological
characteristics in biology
Charles Darwin (1809-1882)
 Controversy in Darwin's time
 Naturalistic explanation of source of life and
species
 Questioned separation of humans and animals
 Common ancestor
 Controversy after Darwin's time
 Francis Galton’s ‘eugenics’
 ‘Social Darwinism’: ‘Survival of the fittest’
applied to social/political theory
 Side-stepping the controversies
 Evolutionary theory = multiple, discrete claims
Evolutionary theory: Theoretical claims
 Heredity
 Many biological processes driven by proteins
 Proteins coded for by DNA
 Section of DNA coding for a protein = gene
 Genes (and resulting traits) passed from parents to children
 Variation
 Passing of genes from parent  child not perfect
 Main sources of genetic variation


Mutations
Sexual reproduction: e.g. ‘crossing over’ during meiosis (formation of
gametes)
 Therefore: Child's genes (and thus physical/psychological characteristics)
similar but not identical to parents.
Evolutionary theory: Logical claims
 Reproductive survival
 If gene(s)  traits which increase likelihood of that gene passing to next
generation, those genes+traits will continue across generations.
 Genes that code for traits increasing probability that


The organism will reproduce successfully
Other organisms carrying same gene will successfully reproduce
 Selection
 Offspring differ slightly from parents and siblings
 Individual with reproductively advantageous trait over others in its
generation will pass that trait onto more offspring
 Over successive generations, that trait will become dominant in the
population
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Artificial and Natural Selection
 Artificial Selection
 Selective breeding to target specific
traits
 Traits 'artificially' selected for passing
onto next generation
 Natural Selection
 Environment is the selector
 Environmental change drives
evolutionary change
 (Sexual Selection)
 Covered later...
Example: The Peppered Moth
 Peppered Moth (Biston betularia betularia)
Time
Habitat trees
Dominant moth
colour
Pre-industrial
revolution
Light-barked,
lichen-covered
Light, speckled
colour
During industrial
revolution
Blackened by soot
Dark
Post-industrial
revolution
Light-barked,
lichen-covered
Light, speckled
colour
Example: Evolution in viruses and bacteria
 Short generational turn-over time = high rate of evolution
 Laboratory mouse: sexual maturity in 6-8 weeks
 Drosophila (fruit fly): 7-9 days or longer, depending on
environmental temperature
 ‘Model organisms’
 Studied because…



Simple analogues
Cheap and easy to raise/maintain
Short life-spans and developmental turn-over
 Bacteria and viruses: replicate in minutes
 Drug resistance…
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VIDEO: Virus evolution
VIDEO
Virus evolution
SOURCE
Evolution, Episode 1. Darwin's Dangerous Idea (SBS, 2001-11-11)
Early instinct theorists: James
 Followed from Darwin…
 Most behaviours are instinctual
 Human behaviour can be explained through
William James (1842-1910)
instincts
 Human instincts
 All animal instincts plus many human ones:


20 physical instincts: e.g. sucking,
locomotion, etc.
16 mental instincts: rivalry, curiosity,
pugnacity, sociability, sympathy, shyness,
hunting, secretiveness, fear, cleanliness,
acquisitiveness, modesty, constructiveness,
jealousy, play, parental love.
 Not all behaviour is instinctive:

Reflexes  Instincts  Learning
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Early instinct theorists: McDougall
 Instincts include…
 Parental care, sympathy, combat, self-
assertion, curiosity, submission, food seeking,
mating, repulsion, constructiveness, escape,
appeal, gregariousness.
William McDougall (1871-1938)
 All instincts consist of:
 Cognitive component: Knowing of an object
that can satisfy the instinct
 Affective component: The feeling (emotion)
that the object arouses
 Conative component: Striving toward or away
from the object
 That is: Teleological (purposive) view:
 Assumes awareness
 Anthropomorphic
Criticisms of the early instinct theories
 Critiqued by e.g. Kuo (1921), Tolman (1923)
 Vague/crude definitions
 Uncertain relationship to learning (are responses fixed or not?)
 Does 'instinct' = all behaviour (e.g. McDougall), or a specific subset (e.g.
James)
 Level of automaticity: McDougall's teleological approach vs James' more
mechanistic approach
 Vague definition  overuse of the concept...
 Overuse: Everything is an instinct 
 How many are there?
 Nominal fallacy



Naming X does not explain X
Self-confirming
Very common fallacy in psychology.
Classical ethologists
 Konrad Lorenz, Niko Tinbergen
 Evolution, development and




Nikolaas “Niko”
Tinbergen (1907-1988)
Konrad Lorenz
(1903-1989)
function of behaviour
Primarily instinctual behaviours
Detailed naturalistic observational
records before behavioural
interpretation
Careful labelling and description
of core components of instincts
Behaviour explained by build-up
and release of ‘energy’
 Criticisms
 Distinction between learned and instinctive behaviours still unclear
 Concept of ‘energy’ criticised by some as unnecessary
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Modern ethological approaches
 Behavioural ecology
 Evolution of behaviour
 Includes: E.g. predator-prey relationships, resource competition amongst
conspecifics, group membership, aggressive and sexual behaviours, parental
care.
 Mostly studying innate, but sometimes learned.
 Cognitive ethology
 How animals interpret information (study of the 'animal mind')
 Neuro-ethology
 Neural underpinnings of reflexive/instinctual behaviours
 Evolutionary psychology
 Genetic mechanisms of human behaviour.
 "The analysis of the human mind as a collection of evolved mechanisms, the
contexts that activate those mechanisms, and the behavior generated by those
mechanisms" (Buss, 1999, p.47)
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