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Psycholinguistics/Development of Speech Perception

Introduction
Speech perception is the process by which humans are able to interpret and understand the sounds used in language. It is about how we recognize speech sounds and how we use this information to understand spoken language.Researchers have studied how infants learn speech. It is evident that different languages use different sets of speech sounds and infants must learn which sounds their native language uses, and which ones it does not. As we ponder children's development of speech perception more carefully, we will see how children are able to do this. In many studies, psychologists have suggested that certain sound categories are genetically-specified while others have determined that infants may be able to learn the sound categories of their native language through passive listening, using a process called "statistical learning". Psychologists use three different techniques,sucking, heart rate, and head turn, to demonstrate if infants detect changes in phonetic features. These techniques also measure boredom and/or preferences for certain sounds and toys. Furthermore, this chapter will explain how infants are able to distinguish more categories of speech sounds than adults. Newborns are able to distinguish between many of the sounds of human languages, but by about 12 months of age, their abilities weaken. As they age, there would be a need for different techniques to determine infants' abilities in speech perception.

A time line of Speech Perception and Production

The figure was proposed by Kuhl et. al in 2004 to show how the changes that occur in speech perception and production in typically developing infants during their first year of life. It presents how a child begins to process basic linguistic units, including phonological features, phonemes, and syllables during the auditory input and articulatory output of spoken language. As seen in the figure, infants discriminate phonetic contrasts of all languages until they are 5-months old. While 3 months, they can produce non-speech and vowel-like sounds. As they are 6 months old, they are introduced to statistical learning (distributional frequencies) and they have preference to language-specific perception for vowels. At 7 months old, they start making 'canonical babbling' and by 8 months, they detect typical stress pattern in words resulting from statistical learning (transitional probabilities). At 9 months old, they recognize language specific sound combinations and by 10 months, they produce language specific speech production. When infants are 11 months old, the consonant perception in foreign language declines and there is an increase in their native language consonant perception. This time line is complete when the infant turns one year old. At this point, many infants produce their first words.

Prelinguistic Speech Perception
Although most children begin producing language, some still cannot produce speech sounds when they are just turning one year old. Developmentalists therefore make inferences about how preverbal children learn to discriminate speech sounds that they heard in their environments. There has been evidence indicating that newborn infants have had exposure to at least some characteristics of native language while still in the womb, a procedure that would allow developmentalists to test neonates and understand how this is possible. DeCasper and Fifer(1980) found that newborns less than one day old preferred hearing their mother's voice over listening to an unfamiliar female voice, suggesting that prenatal auditory experience is involved. These researchers showed that newborns would suck more when hearing their mother's voice compared to a stranger's voice. They also undertook further research asking pregnant women to read a specific passage aloud everyday for the last six weeks of their pregnancy and reread the same passage as well as a novel passage to their newborn infants. Infants were tested to see if there was a preference for the familiar passage over the new one. The babies who were read the passages before birth showed preference for the familiar passage whereas babies who were not read any passage did not show any preference at all. These are all examples of research demonstrating a preference for one type of speech over another. Each new investigation provides some additional phonetic evidence indicating that infants can discriminate. There are different procedures that can be used for testing speech perception capabilities in young infants, and what they can perceive at very young age. These include high amplitude sucking, visual habituation, and the conditioned head turning procedures.

HIGH AMPLITUDE SUCKING PROCEDURE
Sucking is one of the few activities over which infants have good motor control. Infants are born with a sucking reflex and in the first months of their lives they suck not only for food but for any object they can get in their mouth. One of the techniques used to measure newborn's perceptual abilities is called "High Amplitude Sucking". It is an ideal technique since sucking behaviour is easily conditioned. It was found by Siqueland and DeLucia(1969)and it used visual reinforcement to condition infant's sucking. The strength of sucking was controlled by the brightness of a visual display, and they showed that 4 month olds can learn the contingency between sucking and presentation of light. In another study, infants are hooked up to a device that records how vigorously they are sucking on an artifical nipple to receive formula. The sucking response here is a good indicator of the infants' arousal level, since sucking rates increase when there are changes in environmental stimuli. For example, an infant will increase their sucking rates to a novel stimuli and decrease their rates if the stimuli is continuously repeated( habituation), indicating a shift in arousal via sucking rate. In 1971, a study by Eimas et al. assessed 1-4 month old infants abilities to discriminate between /ba/ versus /pa/ stimuli. They presented infants with between category shift sounds such as /ba/and /pa/, and the control group with within category shift sounds such as /ba/ and /ba/. Results showed that infants increased their sucking rate after the between category shift and not after the within category shift. This study demonstrates that infants, like adults, can perceive speech in a categorical manner, and this technique therefore can be profitably used to describe discrimination abilities in very young infants.

THE VISUAL HABITUATION
The visual habituation procedure has been used to test many aspects of infant visual perception. Werker. et al (1994) proved it more sensitive than many other behavioural techniques for revealing infant's discrimination capabilities. Infant's ability to categorise stimuli can also be assessed using this method, and performance in habituation tasks can be used as a predictor of information processing capacity. The procedure is based on the infant's novelty preference and thus his/her visual attendance to a display when it is new. When an infant is presented to the same display it will become familiar and it will no longer be novel and therefore an infant's time will decline and the experimenter can infer that habituation has occurred. An infant, at this point, will be presented to novel stimuli and watched to see if they can discriminate the old display and therefore their looking time will increase. An infant is usually seated in a dim testing room with little to interest them. A red flashing light is used to attract infant's attention to the screen. The trial begins as the experimenter determines that the infant is looking at the screen. The infant in this study can both be presented repeatedly with visual and auditory stimuli which can be the syllable (/da/). In the fully infant-controlled version of this procedure, as long as the infant continues to look at the visual displayed on the screen, the infant hears the familiarisation stimulus(1994). When the infant looks away from the screen, the experimenter signals the computer to end the trial and both visual and auditory stimuli are turned off (1994). At this point, the red light is turned on and the cycle begins again. This procedure is found to be relatively easy to implement, and the experimenter can be trained quickly, and to test the whole session. It also capitalises on an infant's tendency to look at a visual stimulus in the presence of an interesting auditory stimulus.

HEAD TURN TECHNIQUE(Visually Reinforced Infant Speech Discrimination)
A third way to obtain evidence of sound preference is through the Head Turn Technique. Researchers suggest that infants are born with the ability to discriminate the universal set of phonetic contrasts and that experience with a specific language serves to narrow infants' discriminatory capabilities. This was based on the research of infants using High Amplitude Sucking Technique and it was also based on research of adults using labelling tasks. They found that the tasks used for testing infants were more sensitive and that there was a difference in methodology, rather than a difference in perceptual sensitivity between infants and adults. Therefore, it was decided that a procedure was required that could be adapted with only minor modifications for testing people from infancy through adulthood. This technique therefore is one of the most versatile procedures for testing people of different ages. One version of the procedure is for early infants where it tests for habituation simply by recording how the newborn reacts to new stimuli. Another procedure tests the older infant's (ages from 6 months to 1 year of age) tendency to listen to something new or to look at something interesting, like a moving toy. The infant learns to turn his/her head to a sound or to a change in sounds. The infant will always initially be more interested, meaning that they will pay more attention to the word if they notice something familiar about it than a word they are not familiar with at all. The study follows that an infant sits on the caregiver's lap across the table from an experimental assistant and he/she is shown brightly coloured toys to keep their attention and interest. The initial sound is played repeatedly and then changed, at which point the moving toy is presented. When the baby makes a correct head-turn, the moving toy is displayed and the assistant smiles and praises the infant. When there is an incorrect head-turn, there is no reinforcement.

Phonological Development
In speech perception, categorization represents the ability to group perceptually distinct sounds in the same category. Unlike computers, infants can classify as similar phonetic units spoken by different talkers, at different rates of speech and in different contexts (Jay, 2003).

Categorical Perception

An early discovery about the nature of the innate skills that infants bring to the task of phonetic learning and about the timeline of early learning is called "categorical perception". Kuhl et. al (1994) describe categorical perception as the tendency for adult listeners of a particular language to classify the sounds used in their languages as one phoneme or another, showing no sensitivity to intermediate sounds. It is focused on the discrimination of the acoustic events that distinguish the phonetic units. In speech, at the age of one month, infants can discriminate between /b/ and /p/ syllables and /ba/ and /pa/. There are two tasks that are involved in demonstrating categorical perception. These are called "identification and discrimination" (Kuhl et al,1994). Experimentally we determine categorical perception both by using identification tasks such as 'was that sound a /pa/ or a /ba/?' and with discrimination tasks such as distinguishin two sounds. Perfect categorical perception occurs when specific conditions are met. For example, if the identification function changes abruptly along the continuum, the discrimination function shows a peak in accuracy at the boundary between categories, with performance at or near chance within category, and also if the discrimination functions are perfectly predictable from the identification probabilities (Scott. et al).

Voice Onset Time (VOT)
Voice Onset Time (VOT) is the length of time that passes between when a stop consonant is released and when voicing, the vibration of the vocal folds, begins. For example, /b/ is perceived if the VOT of the bilabial consonant is less than 25ms, but when the VOT is between 25 and 60 ms then the consonant /p/ is perceived (Jay, 2003). Children, like adults, after varying the VOT tables, showed poor discrimination with a phoneme category but good discrimination across phoneme boundaries. Using the High Amplitude Sucking Technique, it was suggested that children habituate to sounds within a category. They would however increase their sucking rate when the sounds shift categories (/b/ to /p/), meaning that there was a novel stimuli, a dishabituation.

Critical VOT Times also vary between languages. In "Perception of Speech from sound to meaning" written by Moore. et al, a cross language study of syllable initial stops identified an important phonetic correlation of voicing contrasts, namely, the VOT. They found that stops in initial position tend to occur within three VOT sub ranges across languages: long negative VOTs that preceds the articulator release by more than 45 ms, short positive VOTs that follows the release by no more than 20ms, and long positive VOTs that follows the release by more than 35ms. These three VOT sub ranges illustrated that languages select two adjacent ones to implement their voicing contrasts. An example to this would be the Spanish and Dutch speakers when they use long negative VOTs for their voiced category and short positive VOTs for their voiceless category, whereas for English and Cantonese speakers, it is used in opposite way. This indicates that for all of these language groups, VOT perception is categorical in the sense that listeners show sharp identification boundaries between the categories relevant for their language, relatively good disrimination of stimulus pairs that straddle category boundaries, and relatively poor discrimination of stimulus pairs drawn from the same voicing category. This study also examined infants from a Spanish speaking environment and found that they showed enhanced discrimination of VOT differences, going back and forth with the Spanish or English voicing boundaries, and it was also found the same for infants from an English-speaking environment (Moore.et al, 2009).

Nonhumans and Categorical Perception
A child's ability to discriminate phonemes does not only rely on specific perceptual skills, such as speech sounds, but also on non speech sounds. In "Listening to Speech" written by Greenberg. et al, researchers investigated non humans ability perceiving language categorically. The study found that chincillas label and discriminate voiced /b/,/d/,/g/ from voiceless /p/,/t/,/k/ stop consonants in a fashion remarkably like that found for human listeners with the same stimuli, exhibiting categorical perception. In this study we see a phoneme boundary effect for /p/ and /b/, which is the property of mammalian audition the language uses, and it proves that categorical perception is not only unique to humans since we know language, but to nonhumans as well (Greenberg. et al, 2006). The researchers also argued that Kuhl's formulation of the native language magnet theory, suggesting that gross phonetic categories that are seperated by natural boundaries and produced by general auditory processes are common among related species, is best supported by the chinchilla study above (2006).

Statistic Learning
Kuhl et al describe statistical learning as the "Acquisition of knowledge through the computation of information about the distributional frequency with which certain items occur in relation to others, or probabilistic information in sequences of stimuli, such as the odds (transitional probabilities) that one unit will follow another in a given language." One of the studies in "The Psychology of Language" written by Timothy B. Jay (2003), examined statistical learning in 8 month old infants. They were presented to two minutes of tape recorded randomly combined 'words' in a single stream of speech (2003). Later in the study, they were either presented to these same 'words' or to 'nonwords' made up of the same syllables but in different orders. They found that infants listened longer to the nonwords than they did to the words, indicating that infants prefers novel stimuli over to familiar ones (2003). They knew the difference between them by learning the statistical probabilities of syllables in the words such as /tu/ is followed by /pi/. On the other hand, the nonwords had different transitional probabilities, even though the syllables in the words and nonwords were the same illustrating that infants were counting the statistical frequency of one particular syllable's being followed by another (2003). This study therefore reveals that infants can learn language and they can do it by using the statistical learning strategy.

Patricia Kuhl and Native Language Magnet Theory
It is Patricia Kuhl who proposed the Native Language Magnet Theory (NLM) of speech development to account for the influence of linguistic environment on speech perception. NLM specify three phases in this development. In phase 1, the initial state, infants are capable of differentiating human speech in all languages, and these abilities derive from their general auditory processing mechanisms rather than from a speech-specific mechanism. In phase 2, infants’ sensitivity to the distributional properties of linguistic input produces phonetic representations based on the distributional ‘modes’ in ambient speech input. In phase 3, the distortion of perception, which is the perceptual magnet effect, produces facilitation in native and a reduction in foreign language phonetic abilities. The research done by Goodman& Nisbaum (1994) focuses on the developmental transition from an infants' universal phonetic capacity to their native phonetic discrimination. These findings reveal that the child up to 1 months old have the ability to perceive difference in phonemes that adults cannot perceive. Infants are ready to learn any human language but their perceptual abilities adjust to their native speech environment within the first year.

Motherese
Kuhl. et al identify motherese as a slower, more stressed, simplified, and repetitive version of an adult sentence in the native language. When we talk to infants, we use this special language which has a unique acoustic signature that promotes infants' processing of speech. When compared to adult-directed speech, child-directed speech (motherese) is slower, has a higher average pitch, and contains exaggerated pitch contours. In child-directed speech, prosodic cues tend to be exaggerated in the kind of speech that is directed toward learning speech sounds. Likewise, motherese helps infants to analyze the structure of speech by highlighting boundaries between important units, such as words and clauses. Study examined women speaking either English, Russian, or Sweedish and their voices were recorded while they spoke to another adult or to their young infants. The research analyses illustrated that the vowel sounds (the /i/ in 'see' and the /a/ in 'saw' and the /u/ in 'Sue') in child-directed speech were more clearly articulated, because women were exaggerating all of the acoustic components of vowels which benefited the infants (Kuhl et al 1994). In contrast, in adult-directed speech, there did not find any emphasis in the articulation. Motherese has also been documented in a variety of cultures and across a typologically diverse set of languages, including sign language (1994).

Prosody
The role of prosody in the acquisition of language in general and in the development of speech perception in particular is fundamental for developmentalists. Empirical research suggests that prosody may help infants to segment speech and to help locate grammatical units. Boundaries between important grammatical units such as clauses and phrases are often marked by changes in variables related to prosody, including changes in pitch contour, increases in syllable duration, and pausing. It is Hirsh-Pasek et al (1987) who first examined whether infants respond to prosodic marking of clausal units in fluent speech. They initially collected speech samples of a mother talking to her 18-month old infant. They chose passages from were 15 to 20 seconds long and modified these passages by inserting 1 second pauses in them in one of two ways. The pauses were either inserted between the two successive clauses, coincident versions, or they were between two words within each clause, non coincident versions. They hypothesized that if infants are sensitive to prosodic marking of clausal units, then they will listen longer to the versions with pauses coinciding with the clause boundaries than those versions with the noncoincident pauses (1987). The procedure used in this test was the Head Turn Technique and there were groups of 6 to 9 month-old infants. They both displayed significant listening preferences for the coincident versions, concluding that the sensitivity to prosodic markers of clausal units is present in infants as young as 6 months (1987).

Critical Period for Learning Speech
Communication, by means of sound, are innate for animals and requires no experience to be correctly produced. Humans, on the other hand, require extensive postnatal experience to produce and decode speech sounds that are the basis of language. Language acquisition during the critical periods require hearing and practicing abilities in deaf children. While most babies begin producing speechlike sounds at about 7 months(babbling), naturally deaf infants show distinct deficits in their early vocalizations and such individuals fail to develop language if not provided with an alternative form of symbolic expression (Fitzpatrick D. et al, 2001). If these deaf children are exposed to sign language at an early age however, they begin to “babble” with their hands just as a hearing infant babbles audibly. This suggests that regardless of the modality early experience shapes language behaviour. There are other children who have acquired speech but lost their hearing right before puberty. These children also suffer a significant decline in spoken language, because they are unable to hear themselves talk and thus lose the opportunity to refine their speech by auditory feedback (2001). An example of a pathological case is given in a situation where a girl was raised by deranged parents until the age of 13 under conditions of almost total language deprivation. Despite the training later in her development, she was never able to learn more than the fundamental levels of communication, which led the researchers to support the importance of early language experience. If children can learn a language normally at young age, and as they become adults in the future, they are able to retain their ability to speak and comprehend language even if a significant amount of time has passed without exposure or speaking. The normal acquisition of human speech in other words is subject to a critical period: The process is sensitive to experience or deprivation before puberty and is determined by similar experience or deprivation in adulthood (2001).

During an individual's early life, the phonetic structures of the language they hear shapes both the perception and production of speech. Very young infants can perceive and discriminate between differences in all speech sounds and are not innately biased towards the characteristics of phonemes of any particular language. This universal appreciation however does not continue. For example, the phonetic distinction between /r/ and /l/ sounds in English is not present in Japanese language and therefore, Japanese speakers cannot reliably distinguish between them. Nonetheless, 4-month-old Japanese infants were tested using two procedures, the Head Turning and Sucking Technique, and showed that they can make this discrimination as reliably as 4-month-olds raised in English-speaking household (2001). By 6 months of age however infants begin showing specific preferences for phonemes in their native language over those in foreign languages, and by the end of their first year they no longer respond to phonetic elements other than their native languages. The ability to perceive these phonemic contrasts, the fact that children can learn to speak a second language without an accent and with fluent grammar, continues for several more years until about age 7 or 8. The performance later on declines gradually no matter what the extent of practice or exposure (2001). Interestingly, the “baby-talk” or “motherese” emphasizes phonetic distinctions compared to normal speech among adults. Thus, learning language during the critical period for its development entails an amplification and reshaping of innate biases by appropriate postnatal experience (2001).

Summary
Infant's first perception of speech starts in the utero. It is filtered and the mother's voice is the most familiar sounds of all other sounds. Many studies illustrate that one day old infants prefer mother's voice to other female voices and they also show preference for stories frequently heard while still in the utero. This indicates that infants are sensitive to prosody (Mehler et al, 1988). For example, when a baby is born, their preference of hearing their native language eventually becomes higher than other foreign languages. Infants detect contrasts from non-native language before they turn one year old and they lose this ability afterwards. We learned that infants as young as 4 weeks show categorical perception and it is revealed that this is not only unique to humans but also to non humans to have categorical perception. Infants also have pattern abstraction capabilities where 6 month-olds can perceptually 'sort' novel instances of phonemes into categories. They can detect similarity across different voices, intonation contours, and phonological (co-articulary) contexts.

Path Kuhl is one of the only scientists who emphasize substantially on development of speech perception and production. In 1992, she introduced the phenomenon called 'perceptual magnet effect', which demonstrated that as a second language is acquired, the brain gradually groups sounds according to their similarity with phonemes in the native language. Many of the thousands of human languages and dialects use different repertoires of speech elements called 'phonemes' to produce spoken words. For example, when asked to categorize a continuous spectrum of artificial phonemes between /r/ and /l/, native English speakers, but not Japanese speakers, tend to perceive sounds that sound as either /r/ or /l/. She also introduced a type of speech used in child directed speech called 'the motherese'. It has a slower rate, an exaggerated stress and prolonged vowel sounds used by mothers to communicate with their infants. Motherese has instructive meaning that it conveys knowledge for infants during their critical period of language acquisition.

In summary, it may seem deceptively simple to acquire language however researchers have struggled to explain the initial phases of how exactly infants can do this. At all levels, language learning is constrained, meaning that perceptual, social and neural factors affect what can be learned, how, and when. Identifying these constraints on infant learning and how they reflect innate knowledge will be a continuing focus in the next decade.

Learning Exercises
 PART 1: MATCHING TECHNIQUES

''There are a couple of the discussed procedures in the chapter that may be used concurrently to perceive speech in infants. Please select the proper one from the following that best corresponds with the three examples below and explain why: (A) Visual Habituation Technique, (B) The Head Turn Technique, (C) High Amplitude Sucking Technique''

1.In one study, researchers examine what differences infants can make in speech sounds and how they begin to respond to the differences between them. They also observe what kind of information infants can remember from these different sounds. In order to do this study, they use one of the techniques mentioned above. In your opinion, which technique for this infant language study should be used and how will it function?

2.In another study, researchers examine how interesting different speech stimuli are to infants. By comparing infants’ preferences among two or more stimuli types, researchers can determine if infants are sensitive to the relevant properties that differentiate the stimuli. They also examine in this study how long infants can remember words once they are familiarized with it. In your opinion, regarding the procedure of this study, which technique will be most suitable to observe infant’s attention to the stimuli and how will it function?

3.In the last study, researchers examine infants understanding of word meanings and their discrimination between them. This technique shows parents how important it is to know that before their infant starts to say their first words, they are be able to comprehend some of the words that they hear. Therefore, in your opinion, what technique determines infants’ ability to discriminate between these words via visual and auditory stimuli and how will it function?

 PART 2: COMPREHENSION

Upon reviewing the chapter which consists of information about Development of Speech Perception, write a short answer essay to the questions below:

Question #1: After watching the video clip provided here| Baby Talk: Stimulation Speech and Development, how would you define motherese? Also give an example from the chapter and other research articles on the importance of child-directed speech for infants’ language acquisition.

Question #2: What is categorical speech perception and when does it arise in infants?. Which of the techniques discussed in the chapter is best to illustrate the use of categorical speech in infants? Include the important dimension in speech perception such as ' The Voice onset Time' while answering the question.

 PART 3:TRUE OR FALSE

Upon reviewing the chapter above, decide which statements are true and which are false and explain why in either case:

1.Deaf children are incapable to develop language and therefore it is impossible for them to bable in any sort of way.

2. In Kuhl’s Native Language Theory, Phase three is when the infants' sensitivity to the distributional properties of linguistic input produces phonetic representations. Experience accumulates and the representations most often activated begin to function as perceptual magnets for other members of the category.

3.Regarding the three phases from Native Language Magnet Theory, it is predicted that better native phonetic perception at 7 months of age will have accelerated language development at between 14 and 30 months whereas better non-native performance at 7 months will have slower language development at 14 and 30 months.

4.Jean-Philippe is 5 months old and he can already detect typical stress pattern in words resulting from statistical learning (transitional probabilities).

5. A study found that 8 month old infants can learn language by using the statistical learning strategy, and they do it by differentiating between the statistical probabilities of syllables in the words they learned and the transitional probabilities of syllables in the nonwords(created by words but put in different orders).

Follow the link to the answers


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Talk:Educational Media Awareness Campaign/Physics/POTD 3

Shouldn't the second line refer to "products of nuclear fission"?? Wikiain 02:10, 8 January 2011 (UTC)


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User:Cbrousseau

Claire Brousseau

Claire Brousseau, a born-and-raised Haligonian, is a fourth-year undergraduate student, completing a double major in psychology and biology at Dalhousie University in Halifax, Nova Scotia. Upon graduation, Claire will be applying for the health sciences program at Dalhousie, with the hopes of studying respiratory therapy, and eventually completing the anaesthesia assistant program. Claire's favorite areas of study in psychology include language and development in children, and she hopes to further her knowledge and enthusiasm for these topics in Psycholinguistics 3190 this term. Claire is very excited about the idea of Wikiversity, and is looking forward to contributing to such a great knowledge base. She hopes this project will help other psychology students in the future.

Claire is looking forward to combining her studies with one of her favorite things: MUSIC! She is eager to begin learning more about the connections and interactions between language and music, and is excited about her term in Psycholinguistics with Dr. Newman. The process will be documented through weekly blogs as the project develops. Read on below to see the latest!

Visit the class' main page to see how everyone's progressing:
 * Psycholinguistics - Winter, 2011

January 10 - 14
Unlike many of the students in this class, I have never taken a course strictly devoted to language before, and frankly, I LOVE it! The courses I have taken that got me interested in linguistics were mostly centered around language acquisition and changes through the various stages of development. Now that I am being exposed to all of the history that led to the theories I had been taught, I am finally able to put my previous knowledge into context and perspective.

It was amazing to learn about so many different types of languages, cultures, and even species (as we saw with Kanzi), and how they communicate. For example, I had never realized that even sign language is different depending on where you live. I think, like many people, I had fallen into the fallacy of believing that it was essentially a "universal" language. I also found it so fascinating when Dr. Newman told us that we can't "see" a colour (for example, a shade between green and blue) if we don't have a word for it. I remember being completely boggled by this idea. How can we not SEE a colour that exists?? I think this was meant to reinforce the idea that a person would not see the colour "burnt sienna" if they didn't have that word to describe it...they might instead see it as a light brown or dark orange colour. No one can categorize something if their vocabulary doesn't have a category name for it.

My lingering questions from this weeks lectures were related to some of the more "simplistic" languages that we learned about (although I also learned this week that NO language is simple!!). The Toki Pona language, with so few words (symbols) and sounds is meant to create more using less. It also aims to create a happier atmosphere, where negative thoughts are almost impossible to express. To me, the whole idea of creating such a language sounds like it could be a psychology course within itself, but I was wondering whether the creators have achieved what they wished to accomplish? Are people who communicate through Toki Pona happier people, and is this actually related to use of the language itself, or simply because these people are open to such a way of life? It's an interesting concept, I just wonder whether people who are used to such a rich language would be able to simplify their vocabulary so drastically. Secondly, I was fascinated by the idea that we have so many different words that describe the exact same thing (where other languages would just use one word). How did it happen that some languages grew and branched off so much more extensively, while others stayed very basic, using only the words needed to convey their meaning. Our language has become so flowery, and new words are always being created as society (and even pop culture) changes, though I suppose some words are being "lost" for the same reason. Why did we feel the need to create 10 different words to describe snow, when one works perfectly well for other languages?

Needless to say I am on the edge of my seat, and am thoroughly enjoying the class. I am excited to start looking into more in-depth information about my chapter topic as well: combining language and music!

January 17 - 21
Needless to say, I am NOT a neuroscientist. I find the "brain stuff" a bit like trying to find your way around New York City for the first time: there's so much going on so quickly, it's very easy to get lost. I am, however, very interested in how we can use lesions or injuries to very specific areas of the brain in order to see what function these areas serve. This is fascinating considering that you can't exactly go around lesion-ing peoples' brains, it is simply an area that we study as the opportunities present themselves. This adds to the impressiveness of the amount of research that HAS been done and how much we know!

I have always been interested in the research on Broca's and Wernicke's area(s). Although it is not as simple as "speech perception vs. speech production" it is still a very good relationship that non-neuroscientists can enjoy! I know that double dissociations have been used to show how the two affect different areas and processes in the brain, but I am wondering whether anyone has ever found a way to "repair" these areas at all? I know brain damage is very dangerous and usually life-altering or lethal, but it would be interesting to see someone who had damaged one of these two areas, and showed some degree of healing. I think this would be so great to see if they were permanently disabled in functions of language, or whether some of these abilities would recover WITH the damaged areas. Maybe my lack of knowledge about the brain is showing here, but that would be so amazing to see someone try to completely learn to talk, or understand language again, as if they were an infant. Knowing that learning a second language as an adult is much more difficult, they may have a much harder time grasping the language than an infant would as well.

Perhaps it is possible, or purely my imagination but it would make a great movie! Until next week...

January 24 - 28
I am always fascinated by speech perception in general. Even as early as my intro psych class, professors have taught us that languages are much easier to learn as a young child, before neural connections have been completed, strengthened and pruned. I think it is incredible that children are able to learn two or even more languages at a time in development when we ask a lot (in terms of learning and growth) of these children.

While researching for another class, I learned a lot about imitation in children. We performed a study that included requiring the children to imitate certain words (both real and nonsense) after being asked to do so by both a live and a televised model. Though (as we were expecting), children performed better when imitating a live model, I was amazed at how many children were able to imitate both, let alone imitate at all in some cases. These children were as young as 12 months, up to age 3.5 years. This requires children to receive the language we are sending them (asking them to imitate), processing this language, and responding accordingly (being able to produce these same speech sounds themselves). The fact that children can do this in one, two, or even more languages is incredible. The interesting thing to note was where letters may be switched during repetition. For example "go" was sometimes replaced by "doh" when repeated back, or "wiggle" with "wipple" or "wickle".

It is also interesting how children are able to generalize when learning to speak. They know that adding "-ed" to a word usually makes it past tense, so we often hear them say "I goed to the store" instead of "went". I don't know a lot about sign language (although it is something I have always wanted to learn), but I wonder if the language rules for generalizing are the same? My understanding is that many times a single sign represents a whole word (instead of having to spell each word in a sentence). Would changing the word for play to played be the same thing required to change the word stay to stayed? If so, do these children ever experience the same problems with tense as we see in spoken language? I know that the processing would not be affected too drastically as that occurs in the brain, but the actual production step of the language processing...would that be affected in the same way?

January 31 - February 4
This was a short week, so our only lecture focused on morphology. As an elective I am taking an introductory anthropology course as well, and I was pleasantly surprised to find that this week's material focused on "language". I was really interested to compare the social/anthropological perspectives on language to those of a psychologist/linguist. We talked about many of the same topics covered in some of our introductory classes (in less detail of course), and I was even able to share what we'd learned about Toki Pona with the professor. Though some of the views and ideas were very similar in both classes, I did notice some interesting differences in the way that each approached or viewed some of the fieldwork. For example, linguists are often trying to create concrete structural "rules" (in a sense) that they can apply across various situations (or at least that is my initial observation, and from our morphology lecture). This allows us to learn about a new idea once and generalize our previous knowledge when we see a similar situation the next time instead of having to re-learn the same thing (similar to the idea of mental schemas). Anthropologists, on the other hand, do NOT seem to like to impose any sorts of rules at all...they are solely interested in observing the patterns or changes that take place naturally, and studying about why or how this occurred. They like to use differences in languages across cultures to make observations about how these differences may affect how different people view the world. My question that arose this week relates to this very idea of comparing the study of languages in two different disciplines. Our anthropology professor proposed the idea that "modern linguistics aims to be DESCRIPTIVE, not PRESCRIPTIVE" (Radice, 2011). In my opinion, this is very much the way that anthropologists approach language studies. They like to stand back and watch the changes that society experiences in languages, and observe what cultural changes may have caused these. Linguists seem to be a little more "prescriptive" though. I'm not entirely sure that the statement holds entirely true for psycholinguistics. In looking at morphology, there certainly ARE rules that we are expected to follow! In that sense linguistics DOES seem a bit prescriptive, as well as descriptive. It is like a description of the prescription of language. I was just thinking about what the two sides would say, or how they would feel about such a statement?

February 7 - 11
The majority of my energy in psycholinguistics this week was directed towards researching my textbook chapter assignment. As I said earlier, I do not claim to be a neuroscientist. Much of the neuroscience aspect of this course, and project, is new information to me. I do find it very interesting, and it helps put a biological context to the psychology of what I've learned in other classes, though it can be hard to wrap my head around at times. This week I was fascinated with how much similarity there is between the brain systems used in processing music as are used in processing language (as my topic implies). Though specific areas of the brain can be "isolated" for different aspects of processing (hearing, production, etc.) they all essentially need to come together as one in order for the whole process to function properly (though we can see some functioning, with certain deficits present, after brain damage has occurred). One question was left with me through this week though. As a biology student, I am always wondering about how these processes would be seen in other organisms with similar, but slightly less complex brain systems. Biologists often try experiments on much simpler organisms, as long as the systems are close enough to ours that the results could still be generalized to human systems as well. I began to wonder what the simplest brain system that could process music AND language would be. It would likely not be a matter of understanding, but more a matter of observing actual brain activity, which implies a certain level of processing. Would this require a brain system with ALL of the parts used in human brains when processing language and music? Or, could brain activity be seen with only certain parts used in humans (or more simplistic versions of these structures)? I think it would be a really interesting research project to see the level of processing in very simple brain systems, and see what the minimal requirements for brain structures would be, or if processing could take place without all of these structures, just to a lesser degree. This may have been researched in the past, so I will continue to look throughout my research on the subject.

February 14 - 18 (and Break Week!! February 21-25)
This reflection is following a week of class, and a week off for spring break, which was mostly directed towards reading up, and preparing for the peer edit portion of the class project. The section that I reviewed was on Language and the Brain, and as I have said (surely many times) I am not a neuroscientist, so I am continually learning more and more about the brain and how it works through this class and the term project. It is so fascinating to see how the brain works under "normal" circumstances, but when you factor in language deficits (like aphasias, dyslexia, or problems like deafness or blindness), it is even more amazing to see how the brain adapts to overcome these problems. I learned about the different methods of viewing the brain through the various imaging techniques, which I have been exposed to in different biology classes, but was still interested to see in another context. I am familiar with these techniques, having worked in a medical clinic and constantly receiving reports and scans that were performed on various individuals. I know that each of these techniques are used under different circumstances. Each has its own benefits as well as risks. For example, CAT scans are commonly used, but involve radiation, whereas fMRI scans are safer and more widely available. Given all of the techniques available to us, and how far we have come in terms of our technological advances, it is still possible for mistakes to occur, or for things to be missed. In some cases, patients may have illnesses (maybe tumors or cancer) that are misread, or missed by the scans altogether. Luckily this is not a common occurrence, but at this stage, having come so far and having greatly refined these techniques, it's a wonder we have not managed to avoid or overcome these problems. My question is, what should be the next step? Is there some information that we still can't quite get from any of these techniques, where perhaps a newer technique needs to be developed? Is there any way to minimize the human error, and hopefully eliminate the mechanical error?

February 28 - March 4
I find the idea of speech errors very interesting. Obviously I make them all the time (as it is a very common mistake), and I have heard them many times from other people, but I never really knew about, or understood the underlying processes. I think my all-time favorite one (and my favorite "non-word") is stummy. It is a perfect example of sometimes our brain can be moving faster than our mouths, or vice versa, and all of a sudden we are saying something very different than what we intended. I think that each speech error (addition, deletion, exchange, anticipation, etc) is so interesting, each for their own reason. I find it really funny that sometimes I make these exact same mistakes when typing. I don't mean making simple typing mistakes, but actually typing out the words that we would say when we make speech errors (anticipation for example). I know that typing includes a whole new set of issues, when we get into motor skills and deficits or errors, but it still seems to be much more than coincidence. I began to wonder whether the brain processes that take place when we make speech production errors are similar, or the same as when we type these same words (ex: clarefully vs carefully, or platic vs plastic). Are the processes in our mind the same, or is it a simple case where our fingers can't keep up with what our brains want us to say or type? Regardless, I think that both cases are just another way which our brains keep us guessing, and another terrific example of the wonders of neuroscience!

March 7 - 11
I attended a music production this weekend, and some of the songs got me thinking about my topic for my text chapter. As I had discovered (and have mentioned on my "Music and Language" page), music is a culturally-based form of entertainment. When we listen to a piece of music, we often feel some tunes and melodies sound more "correct" and more enjoyable than others. Certain combinations of notes, rhythms, and songs are more likely to become popular in our culture than others. These songs, however, may NOT be the same combinations or tunes that would be most popular in other cultures. At the concert I attended, there were two or three songs that I really enjoyed, and the music sounded so wonderful, but there were two other songs that I could not get into at all. I found they strayed hugely from what we would consider "typical" music, and I felt that the sequences of notes didn't seem to go together properly at all! I was astonished that I could perceive any music (which is meant to be a form of expression) as "wrong", but I found myself almost immediately enjoying, or strongly disliking the tunes. I began to wonder what it was about our cultural knowledge of "correct" melodies that was making me feel this way. Is it simple exposure that makes us prefer some music over others? Do we get used to hearing certain types of music from a young age, so the familiarity gives us a sense of comfort, and anything outside of this is uncomfortable to our ears? Or is it more biologically-based, where genetics plays a role in how we react to music? Does reproduction within certain areas create differences in music preferences around the world, and genes come into play? Do our ears link up to certain neural networks that are created to allow us to remember the music we hear as children, and the infrequently used pathways get pruned away, leaving us feeling less favorable about these combinations of tones? All of these questions seem very important to my topic, and I have always simply accepted the cultural basis of music to be true without looking any further. I would like to research all of these questions this week to help enhance my knowledge of language and music.

March 14 - 18
I LOVED the lecture on gestures this week, because (for as long as I can remember), people who constantly gesture while they talk have been absolutely fascinating to me. These "hand-talkers" seem (usually) completely oblivious to the fact that their hands are going a mile a minute, as if independant from the rest of their body!! I think I took interest in this phenomenom from an early age because my mom is a typical hand-talker. I was interested to realize how many cultural (as well as universal) gestures, or "emblems", there are. As with my topic of language and music, many of these are cultural, but within that culture the gestures would be readily recognized. There are also people (or "icons") who act the same way as emblems or symbols do, representing a whole concept or idea. It is so amazing to consider! Again, like my topic of music, I realized that gesturing has a beat, or rhythm of a sort, and we tend to gesture along with the emphasis of our speech. It gives our language and gestures a song-like quality.

Again, I was so taken with the ideas of Anomia and Tip-of-the-tongue state. It was said that restricting gesturing during TOT state led to less successful retrievals. I began to wonder whether people who gesture a lot begin to rely on their gesturing to jog their memories and remember what they're saying. Perhaps if you have a tendency to use a lot of hand gestures, you are relying on these gestures more than people who don't tend to use their hands when talking. I wonder if restricting "hand-talkers" hands (and preventing gesturing) during regular speech and conversations would actually CAUSE more TOT state, and more errors in speech. It would be a really interesting experiment to try. Maybe even people who don't think they gesture a lot would be surprised to find how hard it would be to try to talk without gesturing at all.

March 21 - March 25
This week, I was particularly impressed with the guest lecture we had about aphasias. I had no idea that aphasia was so prevalent in society (~10,000 new cases a year was the figure stated), and as the lecturer theorized, this could be due to the fact that aphasia affects communication abilities, obviously making it nearly impossible for victims to advocate as is seen with other illnesses. I also didn't realize that aphasia could affect people so young (sometimes as young as 18 years old). It is so sad to think about the devastating effects this would have on the person's life, as well as the lives of their family.

The thing I was particularly impressed with was being able to actually see videos of aphasia victims. I have learned about Non-fluent (expressive), and Fluent (receptive) aphasias in other psychology classes, but always had a bit of a hard time visualizing what this would actually look like. It was so helpful to see videos of actual aphasia sufferers, and how they act and interact, as well as try to cope with the problem. The lecture also touched on some of the aggressive therapy options which were fascinating. Most of the recovery that is going to take place will happen in the first year, although some gains can be made after that (they just seem to be less significant and much less rapid). I was wondering whether (as a therapist) it would be "easier" to treat patients with non-fluent, or fluent aphasia. I am sure that each comes with its own set of challenges, but whether one was more difficult? Also, whether (on average) more significant overall recovery was seen in non-fluent or in fluent aphasia patients?

I wasn't as familiar with the type of aphasia known as "Global Aphasia", where the victim has both expressive AND receptive difficulties. This was the most amazing video we saw, as the patient essentially had one phrase which he used to communicate every idea (and even those were very limited). In my mind it seemed a little bit like having a baby to talk to, because they speak a different "language", don't understand what you're saying to them (aside from non-verbal cues), and have trouble expressing themselves, though they seem to be able to understand what they want to say. It must be very frustrating to lose someone to this type of aphasia. I was wondering how you would treat a person like this, or whether you would have to basically start from scratch (as you would with a very young child learning to communicate? Cna they ever reach a point where they are able to speak more words, and understand others again? Why is it that sometimes global aphasia will resolve itself into non-fluent or fluent aphasia, and other times it won't?

March 28 - April 1
This week, we have been debating...and I LOVE it! It is great to see some of the major issues in psycholinguistics, and to hear the most compelling arguments for each side. I am also learning a lot about some of the chapter topics that I was less familiar with, which is very interesting too!

One of the most interesting things that I have gotten from the debates thus far (my group included), is that if you boil each topic down to it's bare essentials, they all seem to come down to whether we should standardize one particular method to use for every person, or whether we should allow different groups to operate differently. For ebonics: should all children learn English, or should some schools teach ebonics as well? Should we use Fast ForWord in schools, or are there other programs that may work better? Should children with cochlear implants use only oral communication, or should some be able to use total communication as well? In my mind, it seems that for each debate, one group wants one method, while the other group is advocating for a "to each their own" method.

I began thinking about what sort of headway was being made in the real-wold applications of these debates? Who gets to make these decisions? Should it be the government, the family, the children, the community, the country? Likely these questions would be well assessed in an ethics class, but the implications of each do come up throughout the debates. I found myself having a hard time imagining saying that, in one case, a particular method should be standardized and used for everyone, but in another case, everyone should make their own individual decisions on what works best for them. These are the types of things that come up though, as certain situations and circumstances are different than others. However, for the ebonics debate, Dr. Newman mentioned that this had been an issue when we were younger, so I did wonder what the result of that debate had ultimately been (as it was never hinted at). I know the cochlear implant debate is still very evenly divided as well. Clearly, these are hot-topic issues, and the ethical repercussions of each decision is a very interesting (as well as complicated) point to consider. For example, should cost be an issue in cases with great benefits? What are the physical or emotional risks?

April 4 - 8 (THE END!!)
This will be my last blog post, and the end of my semester in Psycholinguistics.

If I'm being completely honest, I originally took this class because it fulfilled my last requirement to graduate. Now, as I write my last assignment for the course, I can confidently say it was my favorite course of the semester, and quite possibly the whole year! I came in knowing nothing about linguistics, and having a very minimal neuroscience background, and (quite frankly) I was terrified, and dreading what my fate in this course would be.

My one criticism of the psychology courses at Dalhousie would be that they cater to students who are really good at writing exams. Most (though not all) of my psych courses are graded on nothing more than 2 or 3 (4 if you're really lucky), multiple choice exams. Speaking as a student who feels much more confident in submitting smaller assignments spaced throughout the year, I am far from fond of the set-up. I was so excited when Dr. Newman announced that our project would be a wikiversity page. I loved the format of the class, and I felt that I learned more in this course, and with this design of grading than I have in courses with a few exams. Though our chapters focused on one area, we were still required to learn about the other areas through lectures, debates, guest lectures and learning exercises. We also had to familiarize ourselves with another chapter for our peer review. My one question is....what about next year?? Perhaps the students will edit our chapters, or complete our learning exercises?? It would certainly be interesting to hear how Dr. Newman decides to shape the course for the next group!

Through this semester, the class taught me how to draw links across topics (within this course), as well as to make connections about things we'd learned here and similar topics we'd covered in other courses (I impressed many Anthropology classmates when I told them about the language of Toki Pona!). The learning exercise forced me to look beyond the obvious information, and to try to draw conclusions by looking across many different fields. How do you teach someone, while also furthering their understanding so they will really remember the material?? (maybe Dr. Newman was giving us a taste of how he feels!)

Overall, I could not be happier with my experience in this class. The grade I receive will truly reflect the amount of work I put into the class, and how much I learned (as opposed to how well I memorized the material and can write a multiple choice exam). I haven't had the opportunity to debate in many of my other classes, and I was a bit resistant to the idea at first, but I thought it was a fantastic way to learn about the real-world arguments in the field!

Thank you, Dr. Newman. I am recommending this class to any upcoming psychology students!

title: User:Cbrousseau


title: File:Crossprodfig7.svg


text:
Fibroblasts

A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.

Background information
Fibroblasts and fibrocytes are two states of the same cells, the former being the activated state, the latter the less active state, concerned with maintenance. Currently, there is a tendency to call both forms fibroblasts. The suffix "blast" is used in cellular biology to denote a stem cell or a cell in an activated state of metabolism. Fibroblasts are morphologically heterogeneous with diverse appearances depending on their location and activity. Though morphologically inconspicuous, ectopically transplanted fibroblasts can often retain positional memory of the location and tissue context where they had previously resided, at least over a few generations.

Embryologic origin
The main function of fibroblasts is to maintain the structural integrity of connective tissues by continuously secreting precursors of the extracellular matrix. Fibroblasts secrete the precursors of all the components of the extracellular matrix, primarily the ground substance and a variety of fibers. The composition of the extracellular matrix determines the physical properties of connective tissues. Like other cells of connective tissue, fibroblasts are derived from primitive mesenchyme. Thus they express the intermediate filament protein vimentin, a feature used as a marker to distinguish their mesodermal origin. However, this test is not specific as epithelial cells cultured in vitro on adherent substratum may also express vimentin after some time. In certain situations epithelial cells can give rise to fibroblasts, a process called epithelial-mesenchymal transition (EMT). Conversely, fibroblasts in some situations may give rise to epithelia by undergoing a mesenchymal to epithelial transition (MET) and organizing into a condensed, polarized, laterally connected true epithelial sheet. This process is seen in many developmental situations (e.g. nephron and notocord development).

Structure and function
Fibroblasts have a branched cytoplasm surrounding an elliptical, speckled nucleus having one or two nucleoli. Active fibroblasts can be recognized by their abundant rough endoplasmic reticulum. Inactive fibroblasts, which are also called fibrocytes, are smaller and spindle shaped. They have a reduced rough endoplasmic reticulum. Although disjointed and scattered when they have to cover a large space, fibroblasts when crowded often locally align in parallel clusters. Fibroblasts make collagens, glycosaminoglycans, reticular and elastic fibers, and glycoproteins found in the extracellular matrix. Growing individuals' fibroblasts are dividing and synthesizing ground substance. Tissue damage stimulates fibrocytes and induces the mitosis of fibroblasts. Unlike the epithelial cells lining the body structures, fibroblasts do not form flat monolayers and are not restricted by a polarizing attachment to a basal lamina on one side, although they may contribute to basal lamina components in some situations (e.g. subepithelial myofibroblasts in intestine may secrete the α-2 chain carrying component of the laminin which is absent only in regions of follicle associated epithelia which lack the myofibroblast lining). Fibroblasts can also migrate slowly over substratum as individual cells, again in contrast to epithelial cells. While epithelial cells form the lining of body structures, it is fibroblasts and related connective tissues which sculpt the "bulk" of an organism. The life span of a fibroblast, as measured in chick embryos, is 57 ± 3 days.

Secondary actions
Mouse embryonic fibroblasts (MEFs) are often used as "feeder cells" in human embryonic stem cell research. However, many researchers are gradually phasing out MEFs in favor of culture media with precisely defined ingredients of exclusively human derivation. Further, the difficulty of exclusively using human derivation for media supplements is most often solved by the use of "defined media" where the supplements are synthetic and achieve the primary goal of eliminating the chance of contamination from derivative sources.

title: Fibroblasts


text:
User talk:Wikiain

 Hello Wikiain, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

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title: User talk:Wikiain


text:
User talk:Bengisug

 Hello Bengisug, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

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title: User talk:Bengisug


text:
User talk:Jchetwynd

 Hello Jchetwynd, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

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Copyright issues
You did not place a copyright tag on File:CATSCAN.jpg when you uploaded it, and its copyright status is thus unclear. To prevent copyright violation, the file will be deleted after a week if it is still not suitably tagged. Thanks. S Larctia 11:55, 25 September 2011 (UTC)

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MaintenanceBot (discuss • contribs) 03:47, 11 November 2013 (UTC)

title: User talk:Jchetwynd


text: Template:Navbox subgroup

title: Template:Navbox subgroup


text: Template:V

title: Template:V


text:
Animals

Animals are heterotrophic eukaryotic organisms which ingest food. They are distinguished from fungi which absorb food. Heterotrophs obtain energy by catabolising organic matter biosynthesised by other organisms. They are distinguished from autotrophs (plants and chromista) which obtain metabolic energy from inorganic sources. Eukaryotic organisms are composed of nucleated cells. They are distinguished from prokaryotic organisms (eubacteria and archea) which are composed of non-nucleated cells.

Choanozoa are single celled animals. Metazoa are multicellular animals. Holozoa are animals which are either single celled or multicellular. Although amoebas and paramecia are motile and heterotrophic, they are not animals. Fungi are more closely related to animals than amoebas and paramecia are more closely related to plants than to animals.

Many animals, including humans, exhibit a bilateral symmetry. Bilateral animals have left and right halves which are mirror images of each other. Before the emergence of bilateral animals, sponges, ctenophorans, cnidarians, and placozoans split from the main animal lineage, but order of divergence is less than certain. Bilaterian animals consist of three clades: deuterostomia, lophotrochozoa, and ecdysozoa.

Also see
School:Zoology

title: Animals


text: User:Nushensia/Spanish

title: User:Nushensia/Spanish


text:
User talk:Vasanth ice

 Hello Vasanth ice, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

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title: User talk:Vasanth ice


text:
User talk:Minniezheng

 Hello Minniezheng, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

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title: User talk:Minniezheng


text:
Talk:Complex socio-ecological systems/System dynamics

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The Forrester and Sterman pieces offer a systems approach to thinking that will likely serve as the backdrop for the rest of the semester’s discussions. Having recently taken an ecological and general systems course, I’m much more comfortable assessing the ideas of the two authors, and yet I still have some reservations. I’ll get to those in a moment, but first I’ll add that I attended a talk last night given by prominent futurist Ray Kurzweil; I did not stay for the duration of the event. As a technologist, Kurzweil assumes that all developments and innovations in the world are exponentially faster, bigger, and therefore better than ever before. He states a tautology that because these developments are better, the world is better, and that the world will be bettered further by better technologies until we reside in a utopia of nanotech blood thinners and iPods that can adhere to your belly fat and shock you when you’ve eaten too much. Oh frabjous day! Or more syllogistically: cooler technologies equal democracy equal a better world. Very problematic indeed, as many scholars have noted (check out Evgeny Morozov’s The Net Delusion to uncover the darker side of blogging and social media).

Forrester, and to a greater extent Sterman, are more critical of this approach. In Forrester’s understanding of the finite capacity of urban environments, and indeed the world, he posits that the technologists of his era (Kurzweil was at MIT in the ‘60s, it should be noted) failed to understand that population growth and pollution will either have to be developed proactively or they will massively handicap our species’ ability to enjoy a decent quality of life sooner rather than later (his model outputs have the numbers). Sterman is slightly more sanguine (the ‘70s was the era when neo-Malthusianism was in vogue, after all), but he too bemoans the inability of the average, or above average as the case may be, person to understand concepts of stocks and flows, model assumptions (“all models are wrong”) and generative thinking based on an understanding of soft and hard variables. Indeed, Sterman represents a greater comfort with the reflexivity of systems thinking and the recognition that should feedbacks and reorganizations be acknowledged, as might be stated in “resiliencese,” there is much hope for us yet.

It’s hard to refute either’s premise that finite resources and space limit exponential growth, conceptualized as being perpetual in neo-classical economics. It is much easier to point out that many of the metrics that Forrester claims Malthus was correct about (turns out the latter was 4/5, apparently) are considered pretty faulty nowadays; that birth control overlaid against demographic patterns in the industrialized and developing world illustrate a consistent positive correlation, as one small example. And in Sterman’s assessment, while he goes at lengths to portray the faultiness in assigning so many assumptions to his models, and how each and everyone should develop a recognition of modeling and simulation to reach their potential, he falls into the trap that many systems thinkers can’t seem to crawl out of: If the world’s problems are so darn complex, and what is needed is a greater ability to adapt to that complexity at definable scales, then how do we possibly hope to manage any of this with national governance structures? Supernational? In some sense, Sterman is asking for a greater degree of comfort with uncertainty, but offers conflicting solutions on how best to deal with this complexity given the errant outputs of most models.

At least both are open to the idea that stocks and flows change over time, that complexity is fluid by its very nature but that it must be captured in some way, which is far more sound than some of the assertions of the Daedalian technologists. (Sam Schramski)

_____ My first reaction on starting the Forrester paper is to question the underlying assumption that the human mind is “not adapted to interpreting how social systems behave.” It strikes me that every time a group has created a new and unique form of government, the attempt is there to understand the social system and create a predictive and adaptive leadership to a social system. Perhaps my reaction is because I am not used to the terminology in social sciences, and regardless, my reaction really has little to do with the rest of the paper. I find the writer’s rhetoric distracting, however. I’m honestly not always certain if his point is more that models are useful, or that it sucks to live right now in the first half of the paper. I notice that in his figure 6, pollution and quality of life, after an initial building point (which seems to be to be directly in line with how economists think of resource extraction) follows an oscillating pattern much like predator/prey interactions, where a build in one component in a positive feedback loop (ultimately destabilizing) is followed by a lagging build in the other, until the second component has a controlling influence (negative feedback) on the first. I infer from this that there are possible positive feedbacks to quality of life that are controlled by the negative feedback of some environmental, here pollution, factor. I also find it interesting that population growth and capital investment also exhibit these oscillations. By the end of the paper, I assume his main message is that the use of models is good and necessary and all that. I would agree, but I’m surprised he doesn’t spend any time on the types of models and their usefulness for various situations. For example, we might be able to very tightly predict social behavior using black-box models (Briesh and Iacobucci 1995, Briesch and Rajagopal 2010, for the example of neural network models), but they aren’t necessarily useful in developing or analyzing hypotheses about a system because the underlying model behavior is not based on any theoretical framework. And the inverse being also true, where a model might be based on some pretty advanced theory and exhibit interesting behavior when variables are altered, but does a poor job of predicting anything.

For Sterman’s paper: “As systems thinkers, we must constantly strive to break down the false barriers that divide us…” I like that quote, very much. I’m given to think of Bob Costanza’s work and the economic concept of externalities. Except that to systems thinking, externalities aren’t external at all, they were simply unaccounted for. While those externalities, like environmental degradation, might not be a component of the corporate economic world, they’re certainly a part of the system that includes all economic activity, social behavior, and policy decisions. It makes me wish all economists were also systems thinkers. And I have to admit, I sometimes struggle with stocks and flows, just like his students. The paper also has me musing about questions of scale, and the boundaries of a system. While something I’ve thought about before, I feel it’s always useful to think about the scale of the boundaries we put on a system as dictated by the questions we ask. Sometimes an ecosystem approach is the best, and sometimes a landscape approach is better. It’s a mistake to dictate the boundaries before the question; the best science always seems to be done when the question drives the scale of the modeled (theoretical or otherwise) system. To link this paper back to the Scheffer paper from last week, it strikes me with his atmospheric C concentration example that he’s talking about thresholds in non-linear relationships, which are often difficult to place (i.e., quantify), and can result in precipitous regime shifts, i.e., alternative configurations for a state. That said, recent work has focused on a rise in variance and skew as being a precursor to an incipient regime shift, and therefore helps define thresholds (see Carpenter and Brock 2006 and Guttal and Jayaprakash 2008 for examples). Then in his section of “All decision are based on models…and all models are wrong” I’m struck that he’s really reminding scientists to act like scientists, and to not be dogmatic about their own models. Good advice to remember at all times.

On a final note, it’s interesting how writing style itself can dictate how much we like a paper. For example, I didn’t care for the Forrester paper because of style more than content, but based on Sterman’s paper, I think “here’s a person I’d love to have a beer with.”

DWatts 16:31, 13 January 2011 (UTC)
 * R.Briesch and D. Iacobucci, 1995. Using neural networks to compare theoretical models: An application to persuasive communications. American Marketing Association. 6: 177-302.
 * R. Briesch and P. Rajagopal. 2010. Neural networks applications in consumer behavior. J. of Consumer Psychology 20: 381-389.
 * S. Carpenter and W. Brock. 2006. Rising variance: a leading indicator of ecological transition. Ecology Letters 9: 311-318.
 * Guttal, V., and C. Jayaprakash. 2008. Changing skewness: an early warning signal of regime shifts in ecosystems. Ecology Letters 11:450-460.

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Sterman:

I had mixed reactions to this reading. On one hand, Sterman points out many things that make sense to me, such as 1) how our mental models shape our understanding of the society and environment; 2) How based on their mental models, people make truth-claims; 3) How boundaries, such as disciplinary boundaries, can limit one's understanding; 4) How human perception is limited; 5) How many truths are in the eyes of the beholder; 6) Importance of critical thinking - challenging one's models of thinking; 7) How we are shaped and shape the world (this sounds like C. Wright Mills arguments about using the sociological imagination, that is, understanding that we write our history, but our history is also written for us). 8) Importance of some concepts, such as flows, stock, nonlinearity, and time-lag to understand phenomena.

One the other hand, Sterman sounds over-optimistic about the systems thinking model, as if a systems thinking model would solve all problems. Sterman argues that there is policy resistance because people fail to understand complexity and think in terms of systems, that is, people have too narrow models. However, I am not sure how much understanding complexity would help reduce this problem. After all, isn't system thinking another model, and aren't all models wrong? Also, understanding complexity goes hand-in-hand with recognizing the limitations of the human mind.

Systems thinking does not sound empowering, because it adds lots of complexity. For example, recognizing that "we are both shaped by and shape the world" means that there are many things that we have little control over. On the other hand, the author rejects the type of reasoning that attributes causality to "unpredictable and uncontrolled" forces. These two arguments are contradictory.

I am left with the question of whether systems thinking help us make decisions. Some people might resist making truth claims because they recognize complexity and the limitations of our mental models. However, other people will make truth claims. And, for better or worse, the people who make truth claims are the ones that seem to be influencing policy-making. Sterman recognizes this tension. He points out that system thinking "cannot be an excuse for indecision."

Reading this article, I often felt that Sterman sounded like a social constructivist, who recognizes that knowledge is socially constructed, and that knowledge depends on each person's mental models. At other moments, I felt that he was a fundamentalist that argues that systems thinking is the only way, it is the only truth.

Sam: Thanks for sharing your thoughts about Ray Kurzweil. Kurzweil is among those who believe that technology will solve-all and that modernization is the only way. Often technology-believers fail to see that many of our current problems came about as a result of the advancement of technology.

flaleite 04:05, 14 January 2011 (UTC)

suggestions
Hello, the following is just a suggestion, nothing mandatory. I try to post remarks on identi.ca (which then sends to twitter) while reading. I'll add tag #cses to the notices, so it can be found easier: #cses (identi.ca) + #cses (twitter). Perhaps that stimulates collaboration? Let's see And if some are versed with wikis, would be great, if you can add some info to Wikipedia (e.g. ) or here at Wikiversity Erkan Yilmaz uses the Chat 16:51, 8 January 2011 (UTC)


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Sponges

Sponges (Phylum: Porifera) are asymmetric, multi-celled animals. They are sessile and aquatic, and lack nervous, digestive or circulatory systems. There is evidence in the literature to suggest that animals may have evolved a nervous system twice.

title: Sponges


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no:Mal:Taksoboks-kunstig-gruppe ru:Шаблон:Группа таксонов

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