Using ancient words like “attention” and “memory” Psychology will fail.

If fMRI had been invented in the 18th century, scientists would have used neuroimaging to find biological evidence of poetic talent, murderousness, and wit. So argues Russell Poldrack, psychologist and neuroscientist at Stanford University, who believes the words we use to conceive of mental states have always drastically distorted the science of psychology.

A century and a half ago, thinkers interested in the way the mind works would likely have framed their work using the 27 faculties conceived of by physiologist Franz Joseph Gall, whose theories were widely embraced at the time. If they had fMRI machines, they would have used them to find brain activity patterns correlated with these traits, Poldrack said in a paper on the subject. For example, evidence that the prefrontal cortex is less active in murderers could be taken as evidence for this murderous faculty. “Poetic talent” could be compared to attempt today to evaluate “generation of creative versus uncreative narrative,” which has been found to be linked to the right medial frontal cortex.

Gall’s faculty theory was part of his work on phrenology, a field notorious for its attempts to justify eugenics; the entire field was widely dismissed by the 20th century. Today, both psychologists and neuroscientists rely heavily on neuroimaging to describe the relationship between mind and brain. There’s no unified theory dominating these fields of study as there was in Gall’s time. Instead, scientists from both fields rely on everyday words—like “fear,” “conflict,” and “attention”—to describe mental processes and brain activity. Poldrack argues that these words create an ambiguous framework for studying psychology.

The problem, Poldrack says, is that we use each one of these ancient words to describe a variety of moods and behaviors. And when researchers rely on these baggy concepts in the lab, the scientific results are extremely messy.

Take the word “attention.” It dates from the 14th century, according to Merriam-Webster dictionary, and comes from the Latin attendere,meaning to attend or give attention to. Today, children are told to pay attention, national scandals receive a lot of attention, we might focus our attention on a particular puzzle or problem. When psychologists get their hands on the word, they often end up studying quite different things, all grouped under a somewhat arbitrary shared label.

“I don’t think we know what ‘attention’ is,” says Poldrack. “It’s a concept that’s so broad and over-used as to be meaningless. There’s lots of things people in psychology and neuroscience study that they call ‘attention’ that are clearly different things.”

Some psychologists measure attention by focusing on “visual selective attention,” which evaluates how quickly subjects respond to something happening in their visual field when they’ve been told to look for it there. Others use the concept as a frame for investigating people’s ability to “stay attentive” while driving down the road. “That’s completely different in the brain and we use the same word for it,” says Poldrack. The belief that two different things are the same because they use the same name is known as a “jingle fallacy.”

Then there are “jangle fallacies,” when two things that are the same are seen as different because they have different names. For example, “working memory” is used to describe the ability to keep information mind. It’s not clear this is meaningfully different from simply “paying attention” to particular aspects of information.

Scientific concepts should be operationalized, meaning measurable and testable in experiments that produce clear-cut results. “You’d hope that a scientific concept would name something that one can use to then make predictions about how it’s going to work. It’s not clear that ‘attention’ does that for us,” says Poldrack.

It’s no surprise “attention” and “memory” don’t perfectly map onto the brain functions scientists know of today, given that they entered the lexicon centuries ago, when we knew very little about the internal workings of the brain or our own mental processes. Psychology, Poldrack argues, cannot be a precise science as long as it relies on these centuries-old, lay terms, which have broad, fluctuating usage. The field has to create new terminology that accurately describes mental processes. “It hurts us a lot because we can’t really test theories,” says Poldrack. “People can talk past one another. If one person says I’m studying ‘working memory’ and the other people says ‘attention,’ they can be finding things that are potentially highly relevant to one another but they’re talking past one another.”

Other scientific fields have made similar shifts: “In order to be able to describe the world, physics had to move away from the concepts we’ve had for hundreds of years around Newtonian physics towards this new way of thinking about things,” says Poldrack. “Physicists [today], when they describe why things fall because of gravity, they’re not using those terms, they’re using math.”

Adopting a new, precise language needn’t mean psychology is irrelevant to everyday life. For example, few people understand complex physics, but the mathematical language of the field still describes our physical reality. “We may know what a quark is but most of us can’t really say anything beyond, ‘I think it’s involved in quantum mechanic,” says Poldrack. Ultimately, though, psychology can’t be a robust science without revising its terminology. “We need scientific language, not a folk language,” says Poldrack.