One more example of cognitive psychological experimentation before we move on. This experiment demonstrates the mandatory nature of spreading activation and the way it instantly gets everywhere and affects everything. It illustrates, specifically, the Stroop effect. Again, you are sitting in front of a screen and again, stimuli appear on the screen. Some are words, some are line drawings. These stimuli are coloured, and your task is to press the appropriate button to indicate whether they are, say, green or red. You are specifically asked not to read any words which may appear, you are only to indicate the colour in which the stimulus appears (red or green). OK. The word CAR appears in red and you press the red button. A red house appears and you press the red button. The word HOUSE appears, written in green script, so you press the green button. The word RED appears, written in green script, so you press … the green button. This last task takes you significantly longer, because, of course, you are absolutely unable to avoid processing the stimulus and reading the word RED to meaning. This extraneous, but apparently relevant, information, naturally enough, interferes with your ability to respond straightforwardly to the colour green, so you hesitate and either take longer or make an error. You read the stimulus to meaning mandatorily and even though you had not intended to, and when you reach its meaning you find it contradicts the decision you were in the process of making as to the colour of the stimulus. The result is confusion and delay.
We have bitten the bullet. Since literacy undeniably takes place in the brain, particularly in its cerebral cortex, we have examined that organ and its processes and procedures unflinchingly. Much cognitive psychology was there, in fact.
We have seen that the cortex is made up of billions of ‘little grey cells’ arranged in columns which are, themselves, arranged in modules according to function. We have seen some of the anatomy of language management as performed in the left hemisphere, and the various mental lexicons where language is stored in different codes – phonemic, graphemic, semantic and various ‘motor’ codes. We saw that the mind may read through simultaneous top-down and bottom-up cascading analysis.
Since, as we saw, our neurons are so amazingly numerous and so extravagantly interconnected it follows that copious spreading activation is a pronounced and mandatory feature of mind. Processing, we saw, is parallel and distributed, it happens instantaneously, all over the brain at the same time. Different aspects of everything are considered simultaneously in differently specified areas all over the cortex. We have, as a result, formidable computing clout.
Cascading feature analysis, probably based on neural nets recognition and association units, allows our proactive minds to reach decisions very fast and accurately even with little information, and even with incomplete, degraded or distorted information. We very easily identify stuff, probably by the application of a small selection of feature ‘questions’ and by accepting the conclusion even if only approximate. We probably read by top-down and bottom-up cascading analysis of features and probabilities. The unit of text we actually seek to identify is, though, in usual circumstances, a whole word rather than individual letters, although the identification of a word also involves the recognition, at some level and to some degree, of the letters within it.
We have now reached the point at which we may begin to take all this theory out into the real world and apply it there. We start by examining the ‘reading wars’ in the light of all this cognitive psychology.