News and ViewsOn the uniqueness of humankind: is language working memory the final piece that made us human?
Section snippets
The enhanced working memory (EWM) hypothesis
Recently, Frederick Coolidge and Thomas Wynn have developed an appealing hypothesis according to which a single additive genetic mutation might have increased working memory capacity in our species. As a consequence of this enhanced working memory (EWM), modern mind would emerge (Coolidge and Wynn, 2001, Coolidge and Wynn, 2005, Wynn and Coolidge, 2004). This change would have been modest and added to the abilities already possessed by pre-modern populations, who would nevertheless have
The central executive: nothing new under the sun
My comments about enhancement of the central executive capacity as the place where EWM could have occurred are in fact implicit in Coolidge and Wynn's proposal. These authors have already noticed that considering this component as part of working “memory” is in fact incidental, and that its description is far from different than the one used for executive functions. This has the advantage of being in line with many classical proposals on what “made us human” (Eccles, 1989, Russell, 1996,
The language processor
In contrast, the alternative of EWM as specific to the phonological loop is the most appealing and original suggestion in Coolidge and Wynn's proposal. But it is here where additional problems may lie. These authors confer to this slave system a steep leading role in the appearance of the syntax processes that convert our language in an outstanding attribute.
Indeed, Baddeley and Logie (1999; see also Baddeley, 2003) suggested that the phonological loop may be the bottleneck of language
The limited resources of the language processor and the number of active neurons
In several studies of event-related brain electrical potentials (ERP), it has been shown that good language comprehenders (either as measured by the Reading Span Test or by performance measures) display larger amplitudes of certain ERP components reflecting syntax processing than do bad comprehenders (e.g., King and Kutas, 1995, Vos et al., 2001). It has also been shown that these ERP components notably reduce in amplitude when parallel demands on certain linguistic working memory operations
Final comment: EWM specific only to the language processor?
If working memory were defined as the number of neurons that can be activated simultaneously, the dichotomy between the phonological loop (or, rather, the language processor) and the central executive as the locus for EWM as proposed by Coolidge and Wynn could be academic. Instead, EWM could have occurred in overall terms; that is, it was the number of neurons that can be activated simultaneously which was enhanced, regardless of whether these neurons belong to one or another partition within
Acknowledgements
The author wishes to thank Frederick Coolidge, Thomas Wynn, Juan Luis Arsuaga, and Diego Martín-Loeches for their helpful and valuable comments to improve the manuscript.
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A socio-cognitive framework for designing interactive IR systems: Lessons from the Neanderthals
2008, Information Processing and ManagementModern cognition in the absence of working memory: Does the working memory account of Neandertal cognition work?
2007, Journal of Human EvolutionCitation Excerpt :The relationship between phonological storage and other cognitive processes is clearly laid out, and it is obvious that phonological storage per se is not a unique access route for subsequent language processing or cognition and therefore is unlikely to constitute the “bottleneck” claimed within the EWM hypothesis. Language is supported by multiple cognitive processors, the increasing coordination of which might prove a more fruitful basis for the evolution of the spoken word than enhancement of a single component (cf. Aboitiz et al., 2006; Martín-Loeches, 2006). Wynn and Coolidge (2004) rightly pointed to the dangers of assuming that the behavioral sequelae of brain damage are the same as the sequelae of restricted phonological storage, although if brain damage has the functional effect of restricting phonological memory, then it is difficult to see how the preserved behavioral capabilities of brain-damaged patients can fail to tell against the idea that phonological working memory is the necessary cognitive antecedent to behavioral flexibility.
The effect of enhanced working memory on language
2006, Journal of Human EvolutionUses and abuses of the enhanced-working-memory hypothesis in explaining modern thinking
2010, Current AnthropologyBeyond symbolism and language: An introduction to supplement 1, working memory
2010, Current Anthropology