Human Behaviour!
• Human characteristics
Homo sapiens:
– Widest geographic range
– Anatomy
• Largest relative brain size
• Unique obligatory bipedal locomotion
• Loss of body hair
– Behaviour
• Highly social
• Continuous (non-seasonal) sexual activity
• Many different mating systems (& norms)
• Highly sophisticated verbal and non-verbal
communication
Human behaviour:
Ethologists and ecologists in 1960s & 70s
• Can we apply theories underlying the evolutionary and proximate
causes of ‘animal’ behaviour to our own species ?
• Is human psychology [merely] the result of Darwinian processes ?
• Once this idea was born, it began to generate many complex
problems and controversies
E. O Wilson:
• First biologist tried to unite
the fields of animal
behaviour, ecology and
human social sciences
• Used evolutionary principles
• Took a reductionist
standpoint – attempted to
quantify certain behaviours in the same way that animal behaviours
are reduced to simple elements
• Called the new science: sociobiology
Sociobiology: nature vs. nurture?
, The core debate
• Wilson questioned the ubiquitous role of cultural (nurture)
influences on human behaviour, personality and emotions
• Denied the concept of tabula rasa (clean slate) i.e.
that individuals are born with no innate mental content, and that
knowledge of the world develops solely from experiences and
sensory perceptions (nurture over nature)
Sociobiology: the consequences
Vehement and entrenched debate
• Offended the left
• Offended the right
• Re-ignited the nature vs. nurture debate
• Accused of providing justification for racism, sexual discrimination,
and eugenics (beliefs and practices that aim to improve the genetic
quality of the human population)
Debates continue today… although it is clear that evolutionary biology
does make fundamental contribution to understanding human behaviour
• Human behaviour from an evolutionary
perspective
– Foraging
Foraging behaviour in the Ache
• e.g. the Ache nomadic foragers in Paraguay
• Live in bands (3-160 people)
• Men hunt
• Women & children collect (e.g., fruits, plants and insects)
• Diet: meat (56%, ↑ calories), honey (18%), plants & insects
(26%)
Can optimal foraging theory predict food choice?
Prediction: unprofitable food (prey) i.e. with low calorific return
per hour, should be ignored
-Optimal foraging theory predicts how animals behave when searching for
food (trade-offs between costs and benefits)
• Human characteristics
Homo sapiens:
– Widest geographic range
– Anatomy
• Largest relative brain size
• Unique obligatory bipedal locomotion
• Loss of body hair
– Behaviour
• Highly social
• Continuous (non-seasonal) sexual activity
• Many different mating systems (& norms)
• Highly sophisticated verbal and non-verbal
communication
Human behaviour:
Ethologists and ecologists in 1960s & 70s
• Can we apply theories underlying the evolutionary and proximate
causes of ‘animal’ behaviour to our own species ?
• Is human psychology [merely] the result of Darwinian processes ?
• Once this idea was born, it began to generate many complex
problems and controversies
E. O Wilson:
• First biologist tried to unite
the fields of animal
behaviour, ecology and
human social sciences
• Used evolutionary principles
• Took a reductionist
standpoint – attempted to
quantify certain behaviours in the same way that animal behaviours
are reduced to simple elements
• Called the new science: sociobiology
Sociobiology: nature vs. nurture?
, The core debate
• Wilson questioned the ubiquitous role of cultural (nurture)
influences on human behaviour, personality and emotions
• Denied the concept of tabula rasa (clean slate) i.e.
that individuals are born with no innate mental content, and that
knowledge of the world develops solely from experiences and
sensory perceptions (nurture over nature)
Sociobiology: the consequences
Vehement and entrenched debate
• Offended the left
• Offended the right
• Re-ignited the nature vs. nurture debate
• Accused of providing justification for racism, sexual discrimination,
and eugenics (beliefs and practices that aim to improve the genetic
quality of the human population)
Debates continue today… although it is clear that evolutionary biology
does make fundamental contribution to understanding human behaviour
• Human behaviour from an evolutionary
perspective
– Foraging
Foraging behaviour in the Ache
• e.g. the Ache nomadic foragers in Paraguay
• Live in bands (3-160 people)
• Men hunt
• Women & children collect (e.g., fruits, plants and insects)
• Diet: meat (56%, ↑ calories), honey (18%), plants & insects
(26%)
Can optimal foraging theory predict food choice?
Prediction: unprofitable food (prey) i.e. with low calorific return
per hour, should be ignored
-Optimal foraging theory predicts how animals behave when searching for
food (trade-offs between costs and benefits)
