Edward titchener was concerned primarily with using introspection to search for the mind's elements

The answer is structure elements of the mind. His ideas on how the mind worked were profoundly influenced by Wundt's theory of voluntarism and his thoughts of Association and Apperception (the passive and active combinations of elements of consciousness). He tried to categorize the structures of the mind in the method a chemist breaks down chemicals into their constituent parts—water into hydrogen and oxygen, for instance. Hence, for Titchener, just as hydrogen and oxygen were structures, so were sensations and thoughts. He considered oxygen and hydrogen as the structures of a chemical compound, while sensations and thoughts as structures of the mind. 

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