Memory Limits Give Rise to Open Ended Language Abilities

Summary: How we remember sequences helps give rise to language like systems of reusable structural patterns, a new study reports.

Source: Cornell.

A hallmark of human language is our ability to produce and understand an infinite number of different sentences. This unique open-ended productivity is normally explained in terms of “structural reuse”; sentences are constructed from reusable parts such as phrases. But how languages come to be composed of reusable parts in the first place is a question that has long puzzled researchers in the language sciences.

A study published in PLoS ONE led by Cornell psychology professor Morten H. Christiansen provides new insight into this age-old question by simulating cultural evolution in the lab. The results demonstrate how basic limitations on how we remember sequences can give rise to a language-like system of reusable structural patterns, when amplified across generations of learners.

Christiansen and colleagues used human learners to simulate cultural evolution through a process of “iterated learning.” Inspired by the classic game of telephone, the study involved taking the output from one participant and using it as the input for the next one, and so on for a total of 10 “generations” of learners. Sitting in front of a computer, each participant was exposed to a set of consonant strings under the guise of a memory experiment and then subsequently asked to recall them. The recalled strings then became the set of strings that the next participant had to learn.

Whereas the initial set of strings seen by the first participants contained no reusable structure, the repeated cycle of memorization and recall resulted in increased structural reuse.

Image shows people talking.
The results demonstrate how basic limitations on how we remember sequences can give rise to a language-like system of reusable structural patterns, when amplified across generations of learners. NeuroscienceNews.com image is for illustrative purposes only.

“Our subsequent statistical comparisons with linguistic corpora revealed that the patterns of reuse observed in the final generation of learners were similar to what is observed in natural language,” said Christiansen. “This suggests that basic cognitive limitations on how we learn sequences can lead to the emergence of a language-like system of reusable structural patterns.”

The results of the study by Christiansen and colleagues speak to the long-standing debate over the fundamental nature of our linguistic abilities and how they evolved in our species. If basic limitations on memory can explain the emergence of structural reuse in human language, then it suggests that at least this aspect of human language may not require specific biological adaptations. Instead, it highlights the importance of cultural transmission in the evolution of language, as already noted by Charles Darwin in “The Descent of Man.”

About this memory and language research article

The study, “Sequence memory constraints give rise to language-like structure through iterated learning,” is co-authored by Hannah Cornish, University of Stirling, U.K.; Rick Dale, University of California-Merced; and Simon Kirby, University of Edinburgh, U.K.

Source: George Lowery – Cornell
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Full open access research for “Sequence Memory Constraints Give Rise to Language-Like Structure through Iterated Learning” by Hannah Cornish, Rick Dale, Simon Kirby, and Morten H. Christiansen in PLOS ONE. Published online January 24 2017 doi:10.1371/journal.pone.0168532

Cite This NeuroscienceNews.com Article

[cbtabs][cbtab title=”MLA”]Cornell “Memory Limits Give Rise to Open Ended Language Abilities.” NeuroscienceNews. NeuroscienceNews, 27 January 2017.
<https://neurosciencenews.com/language-memory-limits-6022/>.[/cbtab][cbtab title=”APA”]Cornell (2017, January 27). Memory Limits Give Rise to Open Ended Language Abilities. NeuroscienceNew. Retrieved January 27, 2017 from https://neurosciencenews.com/language-memory-limits-6022/[/cbtab][cbtab title=”Chicago”]Cornell “Memory Limits Give Rise to Open Ended Language Abilities.” https://neurosciencenews.com/language-memory-limits-6022/ (accessed January 27, 2017).[/cbtab][/cbtabs]


Abstract

Sequence Memory Constraints Give Rise to Language-Like Structure through Iterated Learning

Human language is composed of sequences of reusable elements. The origins of the sequential structure of language is a hotly debated topic in evolutionary linguistics. In this paper, we show that sets of sequences with language-like statistical properties can emerge from a process of cultural evolution under pressure from chunk-based memory constraints. We employ a novel experimental task that is non-linguistic and non-communicative in nature, in which participants are trained on and later asked to recall a set of sequences one-by-one. Recalled sequences from one participant become training data for the next participant. In this way, we simulate cultural evolution in the laboratory. Our results show a cumulative increase in structure, and by comparing this structure to data from existing linguistic corpora, we demonstrate a close parallel between the sets of sequences that emerge in our experiment and those seen in natural language.

“Sequence Memory Constraints Give Rise to Language-Like Structure through Iterated Learning” by Hannah Cornish, Rick Dale, Simon Kirby, and Morten H. Christiansen in PLOS ONE. Published online January 24 2017 doi:10.1371/journal.pone.0168532

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