Words

Researchers identify brain regions that encode words, grammar, story

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Some people say that reading “Harry Potter and the Sorcerer’s Stone” taught them the importance of friends, or that easy decisions are seldom right. Carnegie Mellon University scientists used a chapter of that book to learn a different lesson: identifying what different regions of the brain are doing when people read.

Researchers from CMU’s Machine Learning Department performed functional magnetic resonance imaging (fMRI) scans of eight people as they read a chapter of that Potter book. They then analyzed the scans, cubic millimeter by cubic millimeter, for every four-word segment of that chapter. The result was the first integrated computational model of reading, identifying which parts of the are responsible for such subprocesses as parsing sentences, determining the meaning of words and understanding relationships between characters.

As Leila Wehbe, a Ph.D. student in the Machine Learning Department, and Tom Mitchell, the department head, report today in the online journal PLOS ONE, the model was able to predict fMRI activity for novel text passages with sufficient accuracy to tell which of two different passages a person was reading with 74 percent accuracy.

“At first, we were skeptical of whether this would work at all,” Mitchell said, noting that analyzing multiple subprocesses of the brain at the same time is unprecedented in cognitive neuroscience. “But it turned out amazingly well and now we have these wonderful brain maps that describe where in the brain you’re thinking about a wide variety of things.”

Wehbe and Mitchell said the model is still inexact, but might someday be useful in studying and diagnosing reading disorders, such as dyslexia, or to track the recovery of patients whose speech was impacted by a stroke. It also might be used by educators to identify what might be giving a student trouble when learning a foreign language.

“If I’m having trouble learning a new language, I may have a hard time figuring out exactly what I don’t get,” Mitchell said. “When I can’t understand a sentence, I can’t articulate what it is I don’t understand. But a brain scan might show that the region of my brain responsible for grammar isn’t activating properly, or perhaps instead I’m not understanding the individual words.”


Researchers at Carnegie Mellon and elsewhere have used fMRI scans to identify activation patterns associated with particular words or phrases or even emotions. But these have always been tightly controlled experiments, with only one variable analyzed at a time. The experiments were unnatural, usually involving only single words or phrases, but the slow pace of fMRI—one scan every two seconds—made other approaches seem unfeasible.

Wehbe nevertheless was convinced that multiple cognitive subprocesses could be studied simultaneously while people read a compelling story in a near-normal manner. She believed that using a real text passage as an experimental stimulus would provide a rich sample of the different word properties, which could help to reveal which are associated with these different properties.

“No one falls asleep in the scanner during Leila’s experiments,” Mitchell said.

They devised a technique in which people see one word of a passage every half second—or four words for every two-second fMRI scan. For each word, they identified 195 detailed features—everything from the number of letters in the word to its part of speech. They then used a algorithm to analyze the activation of each cubic centimeter of the brain for each four-word segment.

Bit by bit, the algorithm was able to associate certain features with certain regions of the brain, Wehbe said.

“The test subjects read Chapter 9 of Sorcerer’s Stone, which is about Harry’s first flying lesson,” she noted. “It turns out that movement of the characters—such as when they are flying their brooms – is associated with activation in the same brain region that we use to perceive other people’s motion. Similarly, the characters in the story are associated with activation in the same brain region we use to process other people’s intentions.”

Exactly how the brain creates these neural encodings is still a mystery, they said, but it is the beginning of understanding what the brain is doing when a person reads.

“It’s sort of like a DNA fingerprint—you may not understand all aspects of DNA’s function, but it guides you in understanding cell function or development,” Mitchell said. “This model of reading initially is that kind of a fingerprint.”

A complementary study by Wehbe and Mitchell, presented earlier this fall at the Conference on Empirical Methods in Natural Language Processing, used magnetoencephalography (MEG) to record brain activity in subjects reading Harry Potter. MEG can record activity every millisecond, rather than every two seconds as in fMRI scanning, but can’t localize activity with the precision of fMRI. Those findings suggest how words are integrated into memory—how the brain first visually perceives a word and then begins accessing the properties of the word, and fitting it into the story context.

Weird Word Salad: The Terminology of the Unexplained.

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Paranormal investigators say they look for evidence of paranormal activity. That phrase always confounded me. I don’t quite get it. What does it mean when someone says they have evidence of “paranormal activity”? And, how do you know it’s not normal activity that you just couldn’t ferret out?

There is a problem with how the word paranormal is used because it is often utilized in a way that is perhaps not consistent with the original intent.

Language evolves. Let me take a shot at unpacking some of these definitions about unexplained phenomena. See if it makes sense.

“Paranormal” and other terms for strange goings-on have changed over time. The wordparanormal was coined around 1920. It means “beside, above or beyond normal.” Therefore, it’s anything that isn’t “normal” — or, more precisely, it is used as a label for any phenomenon that appears to defy scientific understanding. Ok, right there is a tripping point. Whose scientific understanding? The observer who is calling it “paranormal”? If so, that is problematic as a theoretical physicist sees things a lot differently than a dentist or a police officer. So, it appears too subjective to be precise. Each person may have their own idea of what constitutes “paranormal activity”.

The term “paranormal” used to just mean extrasensory perception and psychic power but, since the 1970s in particular — thanks to TV shows and proliferation of the subject in popular culture — the term expanded in scope to include all mysterious phenomena seemingly shunned by standard scientific study. It was a convenient way to bring many similarly peculiar topics under one heading for ease of marketing. So today, it can include everything that sounds mysterious: UFOs, hauntings, monster sightings, strange disappearances, anomalous natural phenomena, coincidences, as well as psychic powers.

Not everyone agrees that fields of study such as UFOlogy or cryptozoology (Bigfoot, Loch Ness Monster and the like) should be considered paranormal but, if we think about the fact that after all this time, we have yet to document what these things actually are, that isbeyond normal. Therefore, paranormal (arguably).

What appears as paranormal could essentially one day become normal. This has happened before with meteorites and still mysterious but likely explainable earthquakes lights and ball lightning. Or, we might not have developed the right technology or made the philosophical breakthrough yet to provide an explanation for some seemingly paranormal events. Perhaps we may find an instrument that can measure whatever it is that results in “hauntings” of a particular type. (Notice that I didn’t say an instrument that detects ghosts — an important distinction.)

Contrasted with paranormal is “supernatural.” To say something is supernatural is to conclude that the phenomenon operates outside the existing laws of nature. We would call such phenomena miraculous, a result of religious, occult (or magical) forces that are outside of human doings. These forces don’t adhere to boundaries of nature, which are waived. Perhaps the entity decides not to be detectable, for example. When that happens, we can’t test it, capture it or measure it. We just broke science. Our understanding stops if the explanation allows for supernatural entities to suspend natural laws on a whim. We end up with a form of “[Insert entity name here] did it.” Game over.

Paranormal events can appear to be supernatural but that in no way is proof that they are. Some unaccounted for natural explanation can be the cause. There is really no way to have excluded all natural possibilities in an investigation. We just may not have all the information. So to say something is the result of “paranormal” or “supernatural” activity is faulty logic. It can appear to be but you can’t say that it is for sure.

If you look at older anomalistic literature, you’ll find the word “preternatural” — a perfectly cromulent word — in place of paranormal. It’s not used as much anymore but it denotes a situation where the phenomenon appears outside the bounds of what we consider normal. It’s not supernatural, just extraordinary.

An even better word to use for weird natural phenomena — like strange falls from the sky (frogs, fish, colored rain), mystery sounds and lights, odd weather phenomena, etc. (things that might also be called Fortean) — would be paranatural. Events seem beyond natural because they are rare, unusual and we can’t quite pinpoint how they happened, but we need not revoke natural laws to have them occur. It’s similar to preternatural but sounds more modern.

Sorry about the word salad in this post but terminology is rather important for effective communication in order to avoid being misunderstood. These various words reflect the degree to which you want to go beyond observable, experimentally derived evidence. They get progressively LESS likely to be the correct designation: Paranatural -> paranormal/preternatural -> supernatural (which we can’t actually “prove”).

Source: Huffing post