Neuronal Recycling Hypothesis: 1. Beginning of the story

2009/12/12 at 9:30 pm | Posted in Cognition, Language, Research, Teaching, Thought | Leave a comment

Almost a decade ago, I nearly engaged in the study of the number sense because of Stanislas Dehaene‘s wonderful introduction. This year he collected his and other reading researchers’ findings into the book “Reading in the Brain“. He attempts to build a theory covering the recent understanding across the behavioral experiments, the computational modeling, and the neuroscience on the reading.

I’d like to say his book is absolutely the best recommendation for the students who are searching the entry to the research of reading. His major claim atop all the topics in this book emphasizes the reading as the crystal of neural systems and cultures during generations of evolution. The core of his “neural recycling hypothesis” directs to that the reading capacities possessed by the modern human have been equipped in human gene pool generations ago. Since the first literature system was created, a variety of perished and alive cultures have developed the potential of these “language genes”. Every language loaded one reading culture in the world have a diverse variation on the spectrum of “phonological transcoding“. Inside the brains of these language users, the accumulated studies have revealed an “universal neural circuit” installed with a small accommodation  for the cultural specificity. This is the first branch of evidence supporting the universal basis of the human languages. Dehanas’ second support come from the single cell studies of primate vision. The words that could be encoded by the readers’ brain of a language have the “perceptual advantage” which could easily activate the specific neurons in the human and apes brains.

These are the brief story of the first three chapters of this book and the keystone of the “neuronal recycling”. Realizing this hypothesis is helpful to wave the recent top reading studies together. On the other hand, the first three chapters illustrate Dehanas’ perspectives on the human cognition and culture: nature is priority to nurture; natural constraints decide the development of culture; the neural circuit serving human language have been matured thounds of years ago. You should be familiar with these perspectives if you have routinely recieved  the news of the evolutional psychology, which have been criticized from the ontological to the empidemic problems. I will do a series of critical thinking on Dehanas’ perspectives in the following articles.

Greek Nonword Reading

2009/09/05 at 7:39 pm | Posted in Cognition, Research | Leave a comment

This presentation deeply connects with the orthography-to-phonology correspondence issue which has been broadly investigaged in English literatures but infrequently cared in the other lanaguages. Protopapas was interested in a graphophonemic case of Greek, his native language, that might be stored as a form of cateograical rule in Greek readers’ mind. In addition to 95% of feedforward consistent graphophonemic correspondences, the /i/ in the syllable strucute CiV could be pronunceable or read palatally. Protopapas attempt to confirm wheather the the pronunciation of nonwords reflect the regular rules compromised the real words. This observation would be evident when the nonwords were generally pronunced as /i/ or palatal in consideration of the neighborhood aspects. In the final part, they failed to isolate the regular reading of CiV words and proposed an argument to rethink the theoretical implications of DRC model.

In Protopapas’ corpus survey, there are 79,825 CiV words (by type and by token) which could be pronunced /i/ or palatal. Because it is impossible to figure out which pronunciation pattern is “regular”, he decide the major pronuciation type of a CiV sequence by the type and token frequency (2:1).  The principle of DRC would predict both kinds of pronuciations would be the “regular reading” of CiV words: the reading pattern will be consistent with the default pronunciation of source words or the majority pronunciation. His study firstly classifies the CiV words into four groups according to the source words pronunciation ( /i/ or palatal) and the group majority pronuciation (/i/ versus palatal). Then ecah word generates two pronunceable nonwords: one had one letter modified and the other had several letters modified (In his presented case, the letter sequence mapping CiV keeps contant). Therefore, the final stimuli list had 8 groups of 20 nonwords and 40 unrecognizable nonwords from the CiV words without clear major pronunciation pattern (conflict between type and token).

The primary results are the response rates of /i/ for these critical nonwords. The analysis showed no effect of the number of replaced letters, but this factor interact with the other two factors. For the nonwords similar to the source words, the response rate of /i/ is related to the source word pronunciation rather than the group majority pronunciation. However, this tendency was reversed for the nonwords dissimilar to the source words. This means that the pronuncing Greek words may have no determinatic influence from the GPC rules.

I leave three questions and comments for his study:

Q1: why did not he analyze the effect of source word frequency? Is that because the error rates are the only data for his analysis?

Q2: Their analysis focused on the pronunciation of /i/. Did they consider the consistency between the pronunciation pattern and the source word pronunciation?

Q3: Reaction times of reading these nonwords have no difference among these conditions. Why did not they design an experiment for the source words? This may offer a clear picture for their interpretation.

This study also generate some ideas I can test in the Chinese study:

1.  The tendency to read nonwords aloud might rely on the clearest orthography-phonology mapping aspects embedded in the word forms.

2. There will be a solid argument about nonword reading if we have a acceptable findings about real words reading.

3. The theoretical thinking of Chinese character reading should consider the aspects about the phonetics.

After Inaugural Day

2009/01/24 at 8:48 pm | Posted in Cognition, Psychologist, Research, Thought | Leave a comment

January, 20, 2009 is a day remarked the coming of new era for the American people. This year I also experienced the change within the research society I am contacting. At the day after the inaugural day, the top science journal “Nature” published a paper that will challenge the basic assumption accepted by every researchers depending on functional magnetic resonance imaging (fMRI). Dr. Sirotin and Dr. Das proposed the evidence that, in addition to the neural activity, a novel preparatory mechanism in the primates brain bring additional change to blood volume. I wonder the respond of my friends using fMRI as their research responds to this study. This news, in my opinion, is not totally bed for the future of cognitive neuroscience. This is the other opportunity for us to admit the complicated nature of the brain and to think of the bold but naive intention to build the link between brain and mind. The novel mechanism revealed by this study might be a caution for the optimistic views of building the link between behavior and brain function without sufficient understanding of behavioral facts.

The other change I am watching is the raising of the new perspective to the psycholinguists’ analytic tools. In the psycholinguistic studies, the generality of the empirical evidence is constrained by the variation of participants’ performance and the variation of stimuli property. For a group of stimuli with the same property according to a experimental definition, each stimuli usually generate a random effect within a wide variation. This situation increases the difficulty to conclude the effect of stimuli property based on the collected data. For a very long time, psycholinguists like to use by-item analysis for the confirmation of the observed effects. With the thousands of data accumulated, more and more psycholinguists have a thought if this analytic tool is really helpful to make conclusions. We might be expanding the frontier with an inaccurate compass. Keeping this awareness is what we should take care hour and hour in doing the psycholinguistic studies. Further reading about this issue is in the last volume of journal of memory and language, 2008.

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