In a study published in Science Advances, Stuart K. Watson and colleagues investigate the ability of monkeys, apes, and humans to process nonadjacent dependencies in language. Nonadjacent dependencies are relationships between words or phrases in a sentence that are not adjacent to each other, such as in the sentence “The dog that chased the cat barked loudly.”
To test this ability, the researchers used a novel experimental paradigm that involved training the subjects to associate certain sequences of sounds with specific outcomes. The subjects were then presented with novel sequences of sounds that contained nonadjacent dependencies, and their ability to recognize these dependencies was assessed.
The results of the study showed that all three groups of subjects were able to recognize nonadjacent dependencies in the novel sequences of sounds. However, there were some differences in performance between the different groups. Specifically, the monkeys and apes had more difficulty with more complex nonadjacent dependencies, while the humans were able to process even the most complex dependencies with high accuracy.
These findings suggest that the ability to process nonadjacent dependencies in language may be present in a wide range of primate species, including humans. However, there may be some differences in the level of complexity that different species are able to handle.
The study also has implications for our understanding of the evolution of language. Nonadjacent dependencies are a key component of human language, and the ability to process them may have been a crucial step in the evolution of language from simpler communication systems. By showing that this ability is present in other primate species, the study suggests that the ability to process nonadjacent dependencies may have evolved earlier than previously thought.
Watson and colleagues provide important insights into the cognitive abilities of different primate species and sheds light on the evolutionary origins of language. The findings of this study could have important implications for the development of language-related interventions for individuals with language impairments, as well as for the design of artificial intelligence systems that can process natural language.
For a detailed account read the original paper.
Stuart K. Watson et al. 2020. Nonadjacent dependency processing in monkeys, apes, and humans. Science Advances 6 (43): eabb0725; doi: 10.1126/sciadv.abb0725
