Before Robert’s third birthday, he and I played with Duplo blocks. We built  simple structures by lining  the blocks along the edges of the base or stacking them on top of each other.  To make those structures  a little more interesting I began to  alternate blocks.  White, red, white red.  Soon, Robert followed building white and red towers or white and red paths.  It seemed  such an easy task to learn  that there was no point of practicing it over next year or year and a half.  During that year, Robert was practicing matching by color, matching identical pictures, or matching pictures of the same, but differently looking,  objects. (For instance, differently looking tables.) .   When he was already four and a half years old, I noticed that he couldn’t complete a simple ABABA pattern.  So I brought back Duplo blocks assuming that Robert would recognize the task he had already mastered 18 months before and build the tower alternating white and red blocks. But he was unable to do that.  He placed red on red and white on white.  The paths could be all white or all red. Moreover, this time, I was unable to teach Robert to alternate colors  I tried many times and failed.  ( In the end I used Robert’s strong urge to match by color by having him to match the path I built with alternating colors.  Later, a friend of mine advised me to use a kindergarten level computer program where the skill of  completing patterns was taught by matching the pictures in the top row by placing identical ones in the row below. When the identical matching was completed, the pictures from lower row were immediately transported to the top row to extend the pattern.)

When I realized that Robert could not alternate blocks by colors, I began to doubt my memory.  Could Robert really complete white and red pattern before?  Did I make it up? How could he unlearn the skill that came to him so easily before?  Where his resistance to alternating colors came from?  Did too many months of  identical matching resulted in Robert’s strong conviction that this is the only way to go?

I can only hypothesize why Robert lost the skill he had.  Yet I strongly believe that had I continued working with Robert on varying the tasks presented to him, he might have not developed this rigidity in thinking. If the matching of “same with same” were interspersed with practicing patterns, the learning of a new skill might take longer but the “unlearning” might not happen.