T-61.186 Special course in language technology
September 29

Session notes: the article by Amy Perfors

New concepts

Baldwin effect: The selection of genes that strengthen the genetic basis of a variant of the phenotype.

Genetic assimilation: a phenotypic variant that depends on environmental triggering becomes genetically determined. Any trait that eases the costs of behavioural adaptation to new conditions is favoured by Baldwinian selection; if something makes the learning of a behavioural adaptation quicker, more reliable, or more efficient, it will add to the reproductive success of its carrier. 

Spandrel: a phenotypic feature that is not been selected for, i.e. is not an adaptation itself but rather a byproduct of another. The term, although not the conept itself, originates in a classic article by Gould and Lewontin (The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme, 1978). The term 'Panglossian' refers to a character from Voltaire's Candide, Dr. Pangloss. The doctor claimed, for example, that humans have noses so that they could wear spectacles. Modified spandrels: if a structure that has originally been a spandrel gains an adaptive function and starts to affect selection, it becomes a modified spandrel.

Discussion points

Simulations: Perfors notes that in Kirby's ILM model, the emergence of recursive compositional syntax is strongly favoured by the learning algorithm used by the agents; this is demonstration of the danger of incorporating assumptions in the models and then presenting them as findings.
Simulations II: Can something really be learned from simulations? Can something be proven with simulations?
Deacon and coevolution: Perfors seems to have misread (section 4.38) Deacon. One of the main arguments of the The Symbolic Species (1997) concerns the Baldwinian coevolution of language and the brain. Deacon does say, however, that grammar cannot be among the genetically determined features of the brain, and this is contradicted by the simulations cited by Perfors in this section.

Debates

Gradualism vs. saltationism (punctuated equilibria): did the language ability or abilities of Homo sapiens develop gradually or was there a sudden leap (caused by a macromutation, genetic drift in a small population or something else)?
Exaptations: did the language ability develop as an exaptation of some other function, for example some other cognitive function?
Exclusiveness between cognitive functions: what, if any, parts of the language ability are unique to language and not used by other cognitive functions?
Exclusiveness between species: what, if anything, is the qualitative difference between human language ability and that of other species?
Nativism vs. non-nativism: which parts of the language ability are genetically coded and therefore innate? Which parts can be explained with cultural evolution? What is the role of coevolution in the emergence of language?

Semiotic terms

In semiotics, there are three kinds of relationships between the signifiers (signs) and the signified (the referents of the signs):
1) iconic: the sign looks/sounds/etc. like the referent; e.g. a picture of a cigarette is an iconic sign of the cigarette.
2) indexical: there's a causal relationship between the sign and its referent; e.g. smoke is an indexical sign of fire.
3) symbolic: the relationship between the sign and its referent are arbitrary; e.g. letters are arbitrary symbols for sounds.

Miscellaneous about animal communication

Currently, most researchers in the field agree only about two instances of compositional communication in the wild, namely bee dance and human language. There are many theories about other such communication systems, e.g. with bottlenose dolphins and chimpanzees, but at the moment none of them is considered accepted fact. It should be noted that some close relatives of humans, such as bonobos and chimpanzees, have acquired considerable linguistic abilities after being reared by humans, but such cases have not been encountered in the wild. At the moment it seems that other primates apart from humans do not use complex syntactic communication systems among each other in their natural environments.

Communication systems capable of coding an infinite range of meanings need a compositional syntax and, in practise, a system of learned arbitrary symbols. The use of arbitrary symbols is not rare in the animal kingdom, but the use of learned arbitrary symbols seems to be rarer. (Pavlovian conditioning as a source of signifier-signified relationships?)

Honeybees: Honeybees communicate with each other about food sources by dancing. The dance has a compositional structure, with a separate element for at least the distance and the direction of a food source (the quality of the source may be signalled with hormones). The speed of waggling reveals the distance (the more rapid the waggle, the closer the food source), and the direction is signalled by the angle of the center route of the dance in relation to the sun (Apis florea, dwarf honeybee) or to gravity (Apis dorsata, giant honeybee); Apis cerana and A. mellifera use the second option, because their nests are not open, unlike those of the A. florea and A. dorsata. If the food source is very close, a simple round dance is used.

Bottlenose dolphins: The dolphins use at least one learned symbolic signal, their unique name. It is learned as an infant. Appears also with some other cetaceans. According to some theories, dolphins have a highly developed syntactic communication system.

Vervet monkeys: Vervets have different alarm calls for snakes, eagles and leopards. They are genetically determined, not learned, but they are still arbitrary symbols.