Chapter 2 The Brain Ideas about brain parallel ideas about machines 1500s: brain is hydraulic pump 1900: brain is switchboard 1950: brain is serial processing computer Present: brain is parallel processing computer Neurons Dendrites receive info from other neurons Axons pass info to other neurons Synapses Cocaine Cocaine doesn't allow dopamine to be reabsorbed. It builds up and produces pleasure. LSD Serotonin also passes between the synapses. LSD replaces it because it is similar. Ecstasy Antidepressants Antidepressants keep serotonin from being reabsorbed. Lack of serotonin causes depression. Neurons Are at rest until they receive neurotransmitters from other neurons Once they get enough they are activated When activated, inhibitory neurons reduce activity in other neurons Excitatory neurons increase activity in other neurons The strength of the connection between neurons varies Learning Neurons make new connections between each other The strength of the connections between neurons changes Learning Neurons make new connections between each other The strength of the connections between neurons changes Does this really explain it? It is so complex we can't really understand it Memory Patterns of connections and strengths of connections encode memory The same neuron may be involved in millions of memories. Computers don't store things this way. They run out of memory Mirror Neurons Monkeys had electrode on neurons that control hand and mouth movements When monkeys moved mouth and hands the electrons fired When monkeys watched person pick up food and eat, the same neurons fired Mirror Neurons In fMRI studies a part of the brain that moves the hand show activation when the hand is moved. It also shows activation when watching someone else's hand move Mirror Neurons Speculation that people with autism have problems with mirror neurons Apraxia Brain damage that affects area involved in muscle movement Top down, bottom up Top-down: information at higher levels influences processing at lower levels (use past experience to discover pattern) Bottom-up: lower levels of processing occur without help from higher levels (use features and clues in stimulus to find pattern) Top down, bottom up Bottom uplooking at each word or sound in order to understand language Top-downusing context in order to understand what someone is saying Tip of tongue phenomenon Same ambiguous symbol interpreted differently What do you see? What are the words? EAT GOAT LIFE Top down or bottom up? Experiment 2 groups One heard story about sailors The other hear story about violence They were asked to identify this word: Experiment 2 groups One heard story about sailors The other hear story about violence They were asked to identify this word: ROPE Top down or bottom up? Experiment Words cut out of recorded conversation They were presented individually to people Only 50% correctly identified The same words were understood in the conversation with no problem Miller & Isard1963 Three types of sentence: a)Semantically & syntactically OK strings: Accidents kill motorists on the highways b)Semantically anomalous, syntactically OK strings: Accidents carry honey between the house. c)Syntactically anomalous strings: Around accidents country honey the shoot. Listeners had to identify a word masked by a hissing sound (white noise) Performance accuracy: (a) better than (b) better than (c) => Top-down influence from the semantic level Phoneme Restoration Warren & Warren (1970) One phoneme was obscured by a cough (*); subjects, subjects fill in the missing sound and are not aware of it. It was found that the *eel was on the axle. (wheel) It was found that the *eel was on the shoe. (heel) It was found that the *eel was on the orange. (peel) It was found that the *eel was on the table. (meal) Top-down influence from the semantic level on sound identification fi yuo cna raed tihs, yuo hvae a sgtrane mnid too. Cna yuo raed tihs? Olny 55 plepoe out of 100 can. i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dsenot mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghi t pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt! if you can raed tihs forwrad it. Mispronuncia tion Detection Marslen-Wilson & Welsh (1978) (mispronunciation detection in a shadowing task) Listeners had to repeat back text with some mispronunciations in it In a highly predictable context listeners were unlikely to repeat a mispronounced sound as it was (rather they restored an intended pronunciation) Example As rain from Hurricane Rita threatened to once again flood the city, the Army Corps of Engimeers was racing to patch New Orleans' fractured levee system while residents were forced to decide yet again whethel to stay or go. Forecasters said the storm that swiped Florida on Tuesday could strengthen to a Catedory 4 and hit Texas by the end of the week. But a slight turn to the right was possible and engimeers feared additioral rain could swamp the city's levees. Language is automatic Say color of the word you see Language is automatic Say color of the word you see Table Language is automatic Say color of the word you see Green Language is automatic StroopTest (discovered by John Ridley Stroopin 1935) Interpretation: the Stroop effect emphasizes the interference that automatic processing of words has on the more mentally "effortful" task of just naming the colors Gender Differences Males have larger brains (6-8% larger) Females have greater cortical complexity in some areas of the brain Corpus callosum is larger in females May help incorporate emotion and language Gender Differences Gray matter: information processing White matter: information transfer (multitasking?) Who is better at L2? Payne et al looked at gender differences but held the following constant: a. Age of acquisition b. Working memory capacity c. Number of L2 classes taken, d. English reading comprehension Everyone took a Spanish comprehension test Who is better at L2? Results: Women were better on L2 comprehension test than meneven when all the above were held constant Is language innate? Linguists versus psychologists Linguists (Chomsky) argued that there is a language acquisition device (LAD) in the mind, preprogrammed before birth to learn language, that allows any human to learn a (native) language with similar success Psychologists said prove it Linguists couldnt Linguists vs. psychologists Psychologists say language is like any other skill Linguists say language is special Psychologists are looking for proof that differences in some skills means better able to learn language Linguists are trying to prove that other skills and language are not linked. So--Psychologists say things like memory influence the ability to learn language.