peter gärdenfors the role of cooperation in the evolution of human communication
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Peter Gärdenfors
The role of cooperation in the evolution of human communication
SEDSU project
Stages in the Evolution and Development of Sign Use
Work done in collaboration with Ingar Brinck and Mathias Osvathat Lund University
Hominin ancestors
What makes human thinking so unique?
Levels of Levels of cognition cooperation
Levels ofcommunication
Prospective cognition
• ”Mental time travel” representing future needs and events
• Involving ”detached” representations, suppressing current sensations
• Unique in humans? (the Bischof-Köhler hypothesis)
• Long ranging life style of hominins promoted prospective cognition
Oldowan tools ≈ 2.5 Mya
Main components of the Oldowan culture
• Manufacturing and use of stone tools
• Transport of artefacts (at least the stone tools)
• Transport of pieces of carcasses
• Use of accumulation spots
• Division of labor (?)
Plummer (2004): ”Flaked stones and old bones”, Yearbook of Physical Anthropology
Homo transportens
Intersubjectivity: Components of a ”theory of mind”
• Understanding the emotions of others
• Understanding the desires of others
• Understanding the attention of others
• Understanding the intentions of others
• Understanding the beliefs of others
Representing the beliefs of others: False belief tasks
0. Subjects are three- to five-year-old children.1. The children are first shown a Smarties tube and then asked what they think is in it. All the children reply “Smarties” (or “sweets”). 2. When the tube is opened it is found to contain pencils. 3. Then the tube is closed. 4. The children are now asked what a friend, who has not yet seen what is in the tube, will say that it contains. 5. The three-year-olds generally answer “pencils” whereas most of the older children say “Smarties.”
Levels of Levels of cognition cooperation
Levels ofcommunication
Levels of cooperation
• Ingroup vs. outgroup behaviour
• Reciprocal altruism
Reciprocalaltruism
I scratch your back - you scratch mine
Modeled by iterated prisoners’ dilemmas Building up trust between two individuals
Levels of cooperation
• Ingroup vs. outgroup behaviour
• Reciprocal altruism
• Cooperation about future goals
• Indirect reciprocity (the good Samaritan)
QuickTime och enTIFF (okomprimerat)-dekomprimerare
krävs för att kunna se bilden.
Building a reputation
Nowak & Sigmund, 2005
Type of cooperation Cognitive demands Communicative demandsIngroup coperation Recognition of group member NoneReciprocal altruism(attitudinal reciprocity)
Individual recognition, minimalmemory, reacting to the desiresof others
None
Cooperation about futuregoals
Individual recognition, memory,prospective planning, valuecomparison, intersubjectivityincluding joint intentions
Symbolic communicationProtolanguage
Indirect reciprocity Individual recognition, (episodic)memory, slow temporaldiscounting, reacting to theemotions and intentions of others
Symbolic communicationLanguage with syntax forroles
Commitment andcontract
Individual recognition, memory,prospective planning, jointbeliefs
Symbolic communicationProtolanguage
Cooperation based onconventions
Intersubjectivity that allowscommon knowledge
None, but enhanced bysymbolic communication
Table 1: The cognitive and communicative demands of different forms of cooperation.
Connections between cooperation, cognition and communication
Levels of Levels of cognition cooperation
Levels ofcommunication
Basic levels of communication
Type of sign (Peirce)
• Signal (index)
• Icon
• Symbol
Type of communication• Most animal communication• Mimesis• Language
– Protolanguage (Tarzan)– Language with syntax
Communicating about our inner worlds
Why humans evolved symbolic communication
(1) The Oldowan culture constituted an ecological niche containing evolutionary forces that fostered prospective cognition.
(2) Prospective cognition made cooperation about future goals beneficial for the hominins.
(3) Protolanguage is an efficient way of solving problems concerning cooperation about future non-existent goals.
Symbols are required for communication about future goals
• If the goal is present, then signaling is sufficient.
Joint attention to a referent
Joint attention to a referent
Future goal
• If the goal is present, then signaling is sufficient.
• If the communicated goal is not present, detached representations are required. Iconic miming may work, but only if the signaler and receiver have sufficient common knowledge about the goal.
• If the communicated goal is a novel entity that does not yet exist, combinatorial symbols (protolanguage) are required.
• Dessalles: Protolanguage can describe scenes.• Explains why no other species uses symbols.
Symbols are required for communication about future goals
Building a reputation
Nowak & Sigmund, 2005
Indirect reciprocity requires language with (minimal) syntaxCommunication concerning reputation
requires: • Reference to individuals in their absence • Express that “x was good to y” and “y was
bad to x”• Express that “y has bad reputation”• Involves marking roles, which is done by
syntax
Two hypotheses concerning the evolution of language
• Protolanguage is an efficient system for cooperation about future goals
• Language with syntax is an efficient system for maintaining indirect reciprocity
Possible archaeological evidenceFor prospective cooperation:• Division of labor• Big game hunting• Large dwellings• Marriage (Deacon)
For indirect reciprocity:• Indications that reputation has social impact
Peter Gärdenfors
The role of cooperation in the evolution of human communication
Representing the emotions of others: Empathy
• Empathy: perception of emotion in another activates the same emotion in the receiver
• Evidence for empathy in mammals• Speculation: depends on mirror neurons• Chimpanzees exhibit consolation behaviour • Cognitive empathy: subjects understand the
emotions of others without having the emotion themselves
Representing the attention of others
• Children at 6 months can follow the gaze of their mother if she turns her head
• At 12 months they can follow the gaze of their mother if she just moves her eyes
• At 18 months they can follow the gaze of their mother if she looks outside their field of vision (requires allocentric representation of space)
• Chimps can also follow gazes in an allocentric way
Representing the intention of others
Understanding the pursuit of goals:• Experiments where an adult (1) deliberately
avoids handing over or (2) fails to hand over a reward (a toy or food)
• Children from 9 months and chimps react differently to (1) and (2), i.e. to whether the failure was deliberate or not
• Is this sufficient to claim that chimps represent the intentions of others?
How to avoid prisoners’ dilemmas
• Iterated games (trust can be built up)• ”Guilt aversion” (Charness and
Dufvenberg 2006) changes outcomes of a prisoners’ dilemma - increases cooperation
• Presumes understanding desires• May explain egalitarianism in human
(hominin) societies