Name: CARTA: 言語はどのように進化するのか？脳の中の言語 (CARTA: How Language Evolves: Language in The Brain)
Uploaded: 2021-01-14T05:43:15.000Z
Duration: 1 h 24 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

基礎受動態

- [automated message] This UCSD TV program is presented by University of California

Television. Like what you learn? Visit our website, or follow us on Facebook and

Twitter to keep up with the latest programs.

- [male] We are the paradoxical ape, bi-pedal, naked, large brain, long the

master of fire, tools, and language, but still trying to understand ourselves.

Aware that death is inevitable, yet filled with optimism. We grow up slowly. We hand

down knowledge. We empathize and deceive. We shape the future from our shared

understanding of the past. CARTA brings together experts from diverse disciplines

to exchange insights on who we are and how we got here. An exploration made possible

- [Evelina] Thanks very much for having me here. So today, I will tell you about the

language system and some of its properties that may bear on the question of how this

system came about. I will begin by defining the scope of my inquiry, because

people mean many different things by language. I will then present you some

evidence, suggesting that our language system is highly specialized for language.

Finally I will speculate a bit on the evolutionary origins of language.

So linguistic input comes in through our ears or our eyes. Once it's been analyzed

perceptually, we interpret it by linking the incoming representations toward our

stored language knowledge. This knowledge, of course, is also used for generating

utterances during language production. Once we've generated an utterance in our

heads, we can send it down to our articulation system. The part that I focus

on is this kind of high-level component of language processing.

This cartoon shows you the approximate locations of the brain regions that

support speech perception, shown in yellow, visual letter and word recognition

in green. This region is known as the visual word-form area. Articulation in

pink and high-level language processing in red.

What differentiates the high-level language processing regions from the

perceptual and articulation regions is that they're sensitive to the

meaningfulness of the signal. So for example, the speech regions will respond

just as strongly to foreign speech as they respond to meaningful speech in our own

language. The visual word-form area responds just as much to a string of

consonants as it does to real words. The articulation regions can be driven to a

full extent by people producing meaningless sequences of syllables.

But in contrast, the high-level language-processing system or network, or

sometimes I refer to it just as the language network for short, cares deeply

about whether the linguistics signal is meaningful or not.

In fact, the easiest way to find this system in the brain is to contrast

responses to meaningful language stimuli, like words, phrases, or sentences. Some

control conditions like linguistically degraded stimuli.

The contrast I use most frequently is between sentences and sequences of

non-words. A key methodological innovation that laid the foundation for much of my

work was the development of tools that enable us to define the regions of the

language network, functionally at the individual subject level, using contrasts

like these. Here, I'm showing you sample language regions in three individual

brains. This so-called functional localization approach has two advantages.

One, it circumvents the need to average brains together, which is what's done in

the common approach, and it's a very difficult thing to do because brains are

quite different across people. Instead, in this approach, we can just average the

signals that we extract from these key regions of interest.

The second advantage is that it allows us to establish a cumulative research

enterprise, which I think we all agree is important in science, because comparing

results across studies and labs is quite straightforward if we're confident that

we're referring to the same brain regions across different studies. This is just

hard or impossible to do in the traditional approach, which relies on very

coarse anatomical landmarks, like the inferior frontal gyrus or the superior

temporal sulcus, which span many centimeters of cortex and are just not at

the right level of analysis. So what drives me and my work is the

desire to understand the nature of our language knowledge and the computations

that mediate language comprehension and production. However, these questions are

hard, especially given the lack of animal models for language. So for now, I settle

on more tractable questions. For example, one, what is the relationship between the

language system and the rest of human cognition? Language didn't evolve, and it

doesn't exist in isolation from other evolutionarily older systems, which

include the memory and attention mechanisms, the visual and the motor

systems, the system that supports social cognition, and so on. That means that we

just can't study language as an isolated system. A lot of my research effort is

aimed at trying to figure out how language fits with the rest of our mind and brain.

The second question delves inside the language system, asking, "What does its

internal architecture look like?" It encompasses questions like, "What are the

component parts of the language system? And what is the division of labor among

them, in space and time?" Of course, both of those questions

ultimately should constrain the space of possibilities for how language actually

works. So they place constraints on both the data structures that underlie language

and the computations that are likely performed by the regions of the system.

Today, I focus on the first of these questions. Okay. So now onto some

evidence. So the relationship between language and the rest of the mind and

brain has been long debated, and the literature actually is quite abundant with

claims that language makes use of the same machinery that we use for performing other

cognitive tasks, including arithmetic processing, various kinds of executive

function tasks, perceiving music, perceiving actions, abstract conceptual

processing, and so on. I will argue that these claims are not

supported by the evidence. Two kinds of evidence speak to the relationship between

language and other cognitive systems. There is brain-imaging studies,

brain-imaging evidence, and investigations of patients with brain damage. In fMRI

studies, we do something very simple. We find our regions that seem to respond a

lot to language, and then we ask how do they respond to other various

non-linguistic tasks. If they don't show much of a response, then we can conclude

that these regions are not engaged during those tasks. In the patient studies, we

can evaluate non-linguistic abilities in individuals who don't have a functioning

language system. If they perform well, we can conclude that the language system is

not necessary for performing those various non-linguistic tasks. So starting with the

fMRI evidence, I will show you responses in the language regions to arithmetic,

executive function tasks, and music perception today. So here are two sample

regions, the regions of the inferior frontal cortex around Broca's area and the

region in the posterior middle temporal gyrus, but the rest of the regions of this

network look similar in their profiles. The region on the top is kind of in and

around this region known as Broca's area, except I don't use that term because I

don't think it's a very useful term. In black and gray, I show you the responses

字幕リスト動画再生

CARTA: 言語はどのように進化するのか？脳の中の言語 (CARTA: How Language Evolves: Language in The Brain)

language

sentence

child

kind