1. A method of pattern learning, comprising the steps of: (a) entering a pattern having a feature to be learned on a primary retina of a pattern recognition apparatus comprising a plurality of basic recognizers, each basic recognizer including a plurality of recognition elements; (b) for each recognition element of each basic recognizer of said pattern recognition apparatus, if a learning cycle count is less than a learning constant and if the recognition element sees the pattern having the feature to be learned, incrementing by one a count of the number of patterns having the feature to be learned that have been seen by that recognition element; (c) for each recognition element of each basic recognizer of said pattern recognition apparatus, if said learning cycle count is greater than or equal to said learning constant, reducing said count of the number of patterns having the feature to be learned that have been seen by that recognition element as a factor of the number by a forgetting constant consisting of a positive number less than 1; (d) for each recognition element of each basic recognizer of said pattern recognition apparatus, if said learning cycle count is greater than or equal to said learning constant and if the recognition element sees the pattern having the feature to be learned, incrementing by one the count of the number of patterns having the feature to be learned that have been seen by that recognition element; (e) for each basic recognizer, setting said learning cycle count equal to the lessor of said learning cycle count plus one or said learning constant; and (f) for each basic recognizer of said pattern recognition apparatus, calculating an estimate of the average number of recognition elements that have seen a pattern having the feature to be learned.