Language, problem solving and executive function

Transcript

RyanTry this in your head. Picture the word green, printed in bright red ink. Your job is to say the color of the ink, not the word. Ready? Red. Easy enough once. Now imagine a whole page of them, fast.

SoheeAnd you'd feel yourself slow down, and catch a few errors. Your brain wants to read the word. Something has to hold that back.

RyanWelcome to EPPP Prep, the podcast. I'm Ryan.

SoheeI'm Sohee. That holding back is executive function, and we'll end there. But first, language and problem solving, the rest of this knowledge statement on elements of cognition.

RyanThe OpenStax psychology textbook defines language as a communication system that uses words and systematic rules to organize those words, to transmit information between people. While language is a form of communication, not all communication is language.

SoheeLanguage has two components: a lexicon, its words, or vocabulary, and grammar, the rules used to convey meaning with the lexicon.

RyanThen the units. A phoneme is a basic sound unit of a language, like the sounds ah and eh. Different languages have different sets of phonemes.

SoheePhonemes combine into morphemes, the smallest units of language that convey meaning. The word I is both a phoneme and a morpheme.

RyanAnd two parts of grammar. Semantics is how we derive meaning from morphemes and words. Syntax is how words are organized into sentences.

SoheeNow acquisition, and a famous debate. B. F. Skinner proposed that language is learned through reinforcement. Noam Chomsky criticized that, arguing the mechanisms of language acquisition are biologically determined.

RyanThe evidence the textbook cites: language develops without formal instruction and follows a very similar pattern in children across very different cultures. That suggests a biological predisposition to acquire language.

SoheeAnd there appears to be a critical period. The ability to acquire language is maximal early in life, and generally, as people age, learning and mastering new languages gets harder.

RyanThe sad, famous case is Genie. In 1970 a social worker in the Los Angeles area found a thirteen-year-old girl who'd spent over a decade in extreme neglect and abuse, with virtually no social interaction. She couldn't stand, chew solid food or speak.

SoheeAfter she was removed, Genie built an impressive vocabulary fairly quickly. But she never mastered the grammatical aspects of language. Perhaps missing the critical period kept her from fully acquiring it.

RyanBabies start early. They can discriminate the sounds of all human languages at first. But by about one year old, they can only discriminate the phonemes used in the languages around them.

SoheeAfter the first few months comes babbling, repeated single syllables. And babies raised around sign language babble with their hands.

RyanA first word usually comes between one year and eighteen months, then a one-word stage, where one word can carry a larger meaning. Cookie can mean that's a cookie, or I want a cookie.

SoheeThen rapid growth, and a revealing kind of mistake, overgeneralization: extending a language rule to an exception. Those two gooses. Three mouses.

RyanPause and think. A three-year-old says, I goed to the park and I runned fast. Is that a sign of a problem?

SoheeNot by this account. It's overgeneralization of the add-e-d past-tense rule. The child clearly understands the rule, and is still learning the exceptions.

RyanNext, does language shape thought? Edward Sapir and Benjamin Lee Whorf proposed that language determines thought. Researchers have since called that view too absolute, pointing out a lack of empirical support.

SoheeA softer idea is that language may influence thought. Mandarin speakers sometimes describe time vertically, and with vertical priming they were faster at recognizing temporal relationships between months.

RyanBut the Dani of Papua New Guinea have only two color words, one for light and one for dark, and they distinguished colors as well as English speakers, who have eleven color terms.

SoheeAnd in the brain, two areas to know cold. Broca's area, in the frontal lobe, is essential for language production. Damage there brings great difficulty producing language.

RyanWernicke's area, in the temporal lobe, is important for speech comprehension. Damage there leaves people unable to understand language.

SoheeNow problem solving. An algorithm is a problem-solving formula with step-by-step instructions that produce the same result every time, like a detailed recipe.

RyanA heuristic is a general problem-solving framework, a mental shortcut, a rule of thumb. It saves time and energy, but it isn't always the best way to make a rational decision.

SoheeThe textbook lists when we reach for heuristics: too much information, limited time, an unimportant decision, very little information, or when a heuristic just happens to come to mind. Working backward from the goal, and breaking a big task into small steps, are two useful ones.

RyanAnd two classic pitfalls. A mental set is persisting with an approach that worked in the past but clearly isn't working now. Like pushing on a locked door when three others are open.

SoheeFunctional fixedness is a type of mental set where you can't see an object being used for anything other than its designed purpose. Duncker's classic task gave people a candle, a book of matches and a box of thumbtacks, and asked them to attach the candle to the wall so it wouldn't drip on the table.

RyanAnd functional fixedness isn't just an industrialized-world thing. Research with the Shuar of Ecuador found it in nonindustrialized cultures too.

SoheeNow executive function. Adele Diamond's review describes executive functions as a family of top-down mental processes needed when you have to concentrate and pay attention, when going on automatic would be ill-advised, insufficient or impossible.

RyanThere's general agreement on three core executive functions. Inhibition, working memory and cognitive flexibility. And from them, higher-order functions like reasoning, problem solving and planning are built.

SoheeInhibition, or inhibitory control, has two parts. Self-control, resisting temptations and not acting impulsively. And interference control, which includes selective attention and cognitive inhibition.

RyanSelective attention is what lets you screen out all but one voice at a cocktail party. And remember our ink colors. On incongruent Stroop trials, a color word printed in a different ink, people are slower and make more errors when they must name the ink.

SoheeOther inhibition measures Diamond lists include the Flanker task and go/no-go tasks.

RyanWorking memory involves holding information in mind and mentally working with it. Diamond separates it from short-term memory, which is just holding information in mind. They cluster on separate factors and rely on different neural systems.

SoheeAnd working memory comes in two types by content: verbal, and nonverbal or visual-spatial. That lines up with Baddeley and Hitch's model, which has a phonological loop and a visuospatial sketchpad under a central executive.

RyanThe third, cognitive flexibility, builds on the other two and comes later in development. It includes changing perspectives, spatially or interpersonally, thinking outside the box, and adjusting to changed demands. It's the opposite of rigidity.

SoheeIts classic test is the Wisconsin Card Sorting Task, one of the classic tests of prefrontal cortex function. Cards can be sorted by color, shape or number, and the person has to figure out the rule from feedback, then switch when the rule changes.

RyanPause and think. A patient keeps sorting cards by color, even after being told several times that his sorts are now wrong. Which executive function is struggling?

SoheeCognitive flexibility, the ability to shift sets. And notice the family resemblance to mental set from problem solving, sticking with what used to work.

RyanWhy it matters clinically: Diamond notes executive functions are impaired in many mental disorders, including addictions, attention-deficit hyperactivity disorder, depression, obsessive-compulsive disorder and schizophrenia.

SoheeAnd stress, lack of sleep, loneliness or lack of exercise each impair executive functions. The hopeful part: executive functions are trainable and can be improved with practice.

RyanSo the exam angles. Phoneme versus morpheme. Semantics versus syntax. Skinner versus Chomsky. Broca's for production, Wernicke's for comprehension. Algorithm versus heuristic. Mental set and functional fixedness. And the three core executive functions with their tasks: Stroop for inhibition, Wisconsin Card Sorting for flexibility.

SoheeLet's recap. Language is a lexicon plus grammar, built from phonemes and morphemes, with semantics for meaning and syntax for order.

RyanChomsky argued for a biological predisposition and there seems to be a critical period, as Genie's grammar suggests. Overgeneralization shows rule learning. Language may influence thought, but strict determinism is too absolute.

SoheeAlgorithms guarantee a result, heuristics are shortcuts. Mental set and functional fixedness block solutions.

RyanExecutive functions: inhibition, working memory and cognitive flexibility, with reasoning and planning built on top.

SoheeAnd Diamond's point about sleep, stress, loneliness and exercise isn't just trivia. It's study advice. Protect your sleep and your breaks. Your executive functions will thank you.

RyanTry a few practice questions, and we'll see you next time on EPPP Prep.

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