A new study led by University of Birmingham professors has revealed for the first time how our bodies go into stress mode when we hear incorrect grammar.
Professors Dagmar Divjak, Professorial Research Fellow in Cognitive Linguistics and Language Cognition at the University of Birmingham, and Petar Milin, Professor of Psychology of Language and Language Learning, discovered a direct correlation between instances of bad grammar and subjects’ Heart Rate Variability (HRV) for the study.
“The results of this study bring into focus a new dimension of the intricate relationship between physiology and cognition. This relationship has been studied using techniques ranging from eye-tracking over electro-encephalography to brain imaging. But the relation between language cognition and the autonomic nervous system (ANS) has so far received less attention,
Professor Divjak, principal investigator of the study, said.
Heart Rate Variability
The intervals between subsequent heartbeats are captured by heart rate variability. When someone is relaxed, their heartbeats tend to be irregularly spaced out, but when they are under stress, they become more regular.
The new study reveals a statistically significant reduction in HRV in response to grammatical violations. This reduction reflects the extent of the grammatical violations, suggesting that the more errors a person hears, the more regular their heartbeat becomes — a sign of stress.
The sympathetic (SNS) and parasympathetic (PNS) neural systems make up the autonomic nervous system. In short, when faced with a threat or perceived danger, the sympathetic nervous system triggers the body’s ‘fight or flight’ response, while the parasympathetic nervous system regulates the’rest and digest’ or ‘feed and breed’ responses.
“Our findings show that this system, too, responds to cognitive demands, and this suggests that cognitive effort reverberates through the physiological system in more ways than previously thought,”
said Divjak.
Implicit Language Knowledge
This study by Divjak, Professor Milin of the University of Birmingham, and Dr. Hui Sun, a postdoctoral researcher working on the project at the time, provides the first proof that HRV can function as a gauge of implicit linguistic knowledge.
Your knowledge about your first language is largely implicit, i.e., learning your mother tongue did not require you to sit and study, and using it does not require much, if any, thought. This also means that you will find it hard to pin down what exactly is right or wrong about a sentence and, even worse, explain why that is so, especially if you’ve not had formal language training,”
Divjak explained.
Assessing someone’s linguistic abilities accurately, regardless of age or physical or cognitive abilities, is important for many questions pertaining to core areas of life relating to cognition, including brain health.
“This study provides us with a new method for tapping into aspects of cognition that are not directly observable. This is particularly valuable in work with language users who are unable to verbally express their opinion due to young or old age, or ill health,”
he concluded.
Abstract
Over the past decades, focus has been on developing methods that allow tapping into aspects of cognition that are not directly observable. This includes linguistic knowledge and skills which develop largely without awareness and may therefore be difficult or impossible to articulate. Building on the relation between language cognition and the nervous system, we examine whether Heart Rate Variability (HRV), a cardiovascular measure that indexes Autonomic Nervous System activity, can be used to assess implicit language knowledge. We test the potential of HRV to detect whether individuals possess grammatical knowledge and explore how sensitive the cardiovascular response is.
41 healthy, British English-speaking adults listened to 40 English speech samples, half of which contained grammatical errors. Thought Technology’s 5-channel ProComp 5 encoder tracked heart rate via a BVP-Flex/Pro sensor attached to the middle finger of the non-dominant hand, at a rate of 2048 samples per second. A Generalised Additive Mixed Effects Model confirmed a cardiovascular response to grammatical violations: there is a statistically significant reduction in HRV as indexed by NN50 in response to stimuli that contain errors. The cardiovascular response reflects the extent of the linguistic violations, and NN50 decreases linearly with an increase in the number of errors, up to a certain level, after which HRV remains constant.
This observation brings into focus a new dimension of the intricate relationship between physiology and cognition. Being able to use a highly portable and non-intrusive technique with language stimuli also creates exciting possibilities for assessing the language knowledge of individuals from a range of populations in their natural environment and in authentic communicative situations.
Reference:
- Dagmar Divjak et al. Physiological responses and cognitive behaviours: Measures of heart rate variability index language knowledge. Journal of Neurolinguistics (2023). DOI: 10.1016/j.jneuroling.2023.101177
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