Across languages, brains process abstract and concrete words differently

Philosophical differences.
Philosophical differences.
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For the past century, philosophers have deliberated over the distinction between abstract and concrete concepts, and how to define each category. Thirty years ago, neuroscientists entered the fray, showing that the brain processes abstract and concrete words differently. Though we know there’s a difference, we still don’t know how, exactly, the brain responds to abstract versus concrete words.

Last week, a review of neuroimaging studies published in the Journal of Neurophysiology highlighted evidence that suggests different areas of the brain process abstract versus concrete words. And our understanding of concrete words, which are shaped by sensory experiences, seems to be dependent on the areas of the brain involved in processing sensory experiences.

In this framework, “concrete” words are those referring to material objects and those that can be experienced through the senses, such as “tree,” “person,” or “book.” These are distinguished from abstract words, such as “love” and “happiness,” which are not defined by physical characteristics and tend to be more emotional.

Axel Cleeremans, cognitive scientist from the Université Libre de Bruxelles who was not involved in the study, says that the different processes in the brain reflect the fact that these types of words are fundamentally different. “There’s a lot of features in common among concrete words that are not shared by abstract words,” he says. “If you hear ‘truth’ or ‘wisdom,’ there’s no imagery related with that.”

The newly published review analyzed three 2018 neuroimaging studies in three different languages. In one English-speaking study, participants had to answer questions about concrete words. Some questions referred to concrete visual characteristics (such as “is it round?”) while others referred to abstract questions (such as “is it living?”) The researchers found that the parahippocampal cortex, an area of the brain that surrounds the hippocampus in the temporal lobe and is used for memory formation, was only activated for the abstract questions.

A separate study on Chinese-speaking subjects found that the inferior frontal gyrus, a part of the prefrontal cortex associated with language processing, and the middle temporal gyrus, a part of the temporal lobe involved in retrieving word meaning, worked together to process information about abstract words. A third study, of Italian-speakers, found that the inferior frontal gyrus was activated in when participants were asked to distinguish between abstract and concrete words.

Taken together, the studies show that abstract and concrete words are processed by different specific areas in the brain. And, crucially, the areas of the brain involved in relating to physical objects also seem to be involved in understanding the words that describe physical objects. “It’s not like we just happen to find abstract meanings here and concrete meanings there, it’s more like: This makes sense,” says David Plaut, psychology professor at Carnegie Mellon University, who also wasn’t involved in the study. “The meanings are anchored to the kinds of processing that underlie our learning of [these words] as children and adults. The idea that meaning representations are built on top of either sensory-motor processing for concrete concepts, or language and emotion-related processing for abstract concepts makes a lot of sense.”

We’re still unravelling precisely how the brain responds differently to abstract versus concrete words. But based on these studies, the differences between abstract and concrete concepts are not simply theoretical.