What we need • Language evolution theories need to be: – Evolutionarily plausible: Consistent with fossil Language Evolution: and archeological record; with knowledge of our ancestor’s lives and structure – Consistent with what we know about language Neurological, cognitive, social? – Consistent with what we know about anatomy, including neuroanatomy MU! – Computationally plausible: Consistent with some functional understanding of language Symbols as representational flexibility Symbols as representational flexibility • As we have been discussing, symbolism is a • Insofar as this is true, language evolution may be way of increasing representational underlain by many non-linguistic incremental adaptations, each of which introduces a (perhaps very flexibility (of removing stimuli [‘goads’] slight) increase in freedom in representation: in the from the environment, and bringing them number of ways we can look at things inside) • Anything that helps us look at things in a new way (modulates our behavioral pesponses) increases • Representational flexibility may be useful in potential adaptivity AND also brings us closer to ‘true’ many many ways, many of which are not symbolism linguistic per se i.) The Merkwelt ii.) The Umwelt • A factor that is tied in more directly to representational flexibility • Jakob von Uexkull (1934): A Stroll through the Worlds of is the ability to detect those stimuli that can be used for adaptive Animals and Men: A Picture Book of Invisible Worlds. purposes (the size of the creature's Umwelt, [German for environment] in von Uexkull's terms) • The merkwelt is the set of all environmental factors that are significant for a species, whether or not they are actually • The umwelt is the set of stimuli that are actually perceived by an perceptible: the set of things it might care about, if only it entity: its subjective universe knew about them; the objective universe that impinges on existence “Everything that falls under the spell of an Umwelt is altered and reshaped until it has become a useful meaning-carrier; otherwise • We would say that the merkwelt is a species' context: the more it is totally neglected.” (Uexküll, 1982) complex the creature’s contextual sensitivity, the more complex its structure 1 What changes a subjective universe? iii.) Stimulus flexibility • A creature’s Umwelt will vary not only between species due to different perceptual sensitivities, but also within any individual. • The number of possible ways detectable • This is a function of at least four factors which may co-evolve: stimuli can combine to produce different • a.) the sensitivity and number of channels of the organism's sensory system (sensory sensitivity) behaviors • b.) the organism's degree of attentional control – Think of the blue light and the buzzer, again: (attentional control); To the extent that the meaning of a thing is • c.) an ability to store and recall the stimuli (stimulus memory capacity); modulated by another thing, the complexity a • d.) The store of cultural knowledge available creature needs to represent is multiplied iv.) Behavioral flexibility v.) Response generalizability • The number and complexity of alternative actions they can • The extent of each animal's ability to re-use produce in response to any given stimulus set an action which has been appropriate for • This is in turn a function of: • a.) an ability to generate more complex and/or more one situation in another situation where it numerous behaviors (behavioral productive might also be appropriate capacity) • We might see this as freedom from external • b.) an ability to store and retrieve those behaviors (behavioral memory capacity); context, or (equally precisely) as increasingly portability of context vi.) Social learning ability A mixed bag! • The extent of an animal's ability to increase its Umwelt size, stimulus flexibility, behavioral flexibility, and response • Insofar as all these factors may contribute to an generalizability by observing its conspecifics or other animals increasing enrichment of representational • This is itself a function of: flexibility, all may underlie language and its – a.) the number of opportunities it has to interact with any conspecific (companionship probability) evolution – b.) the number of different conspecifics with which it has an • Language is the culmination of a great deal of opportunity to interact (group size) selective pressure for ‘specializing at being a – c.) flexibility in its ability to map between modalities- for non-specialist’ example, from seeing to producing a behaviour, and from hearing to producing a sound (cross-modal flexibility) 2 vii.) Social learning pressures Theory of mind • Worden (and others) focus on factors related to the problems • One way to be good is to be able to ‘read the minds’ of others: to which are posed when a highly complex animal is living in an understand their thoughts (and so predict their future behavior) increasingly complex social world from their current behavior • In many primate societies, those who navigate the social • This requires: hierarchy the best get to send their genes down to the next – i.) Recognizing and tracking individuals generation – ii.) Representing abstract and complex social relationships – So there is selective pressure to be good (= sexual and and situations which involve specific individuals therefore reproductive rewards for being good) at such – iii.) Learning and representing causal relationships (or, at navigation least, reliable regularities) in those relationships in order to be good at: – iv.) Predicting future developments Theory of mind is language-like Theory of mind is language-like • Theory of mind shares some properties with • It is self-contextualizing: What is important is not marked language: by where it happens, but how it happens. • It is emotionally complex, and – It is structured: Specific individuals with specific • It requires that emotional impact be separated from its attributes interact in rule-governed ways behavioral consequences – It is complex and open-ended: Many thing can happen • Mapping the actions of others requires syntax-like – It is discrete-valued: Identity, kinship etc. are discrete structured semantics, marking person, number, time, on- – It is extended in space and time: Requiring memory for goingness, place, subject, and object specifics of previous interactions • Many semantic regions (and primary language areas) overlap with the ventral (lower) pre-frontal cortex that is – It is dependent on many sensory modalities associated with theory of mind Be wary of singular explanations! • Humans like singular ‘causal’ lines of effect, that account for a large part of the variance in an outcome • Natural selection can (and formally does) work with parallel lines of effect that each account for small amounts of varance in an outcome • We need to be wary of evolutionary explanations that put all the explanatory burden on one adaptation • However, the evolution of human social complexity plausibly interacts to a large degree with the historical emergence of human language 3.