Learning and Brain Plasticity

There is ongoing controversy regarding whether to emphasize instruction of the alphabetic principle (e.g. phonics) or instruction of whole words in the teaching of reading. We have begun to address these issues by examining behavioral changes in adults when learning to read a novel orthography with teaching of the alphabetic principle (i.e. letter instruction) or teaching of whole words. We have shown that letter instruction results in greater between session gains, suggesting that this form of instruction engages procedural learning mechanisms. We have also shown that letter instruction results in greater alphabetic knowledge, but that whole word instruction results in greater sensitivity to larger orthographic units such as the rime. Indeed, whole word instruction may foster the acquisition of word specific representations and allow for less generalization. Our studies have also revealed that learning depends on reading skill and phonological ability, highlighting the importance of considering pre-existing individual differences. Although we have conducted studies examining neural changes when adult English speakers are learning Chinese characters, our future work will employ artificial orthographies to examine developmental differences in learning mechanisms. One of the central questions in developmental science is whether development constrains the learning process – in other words do children learn differently than adults. Our guiding theoretical framework is that there should be relatively small developmental changes in implicit learning whereas there should be large changes in explicit learning because the latter relies on the later maturing prefrontal cortex. Our future work will also examine how these learning mechanisms are affected in developmental disorders, with the guiding hypothesis that the central deficit in children with dyslexia and language impairments may be in implicit compared to explicit learning.