1. In a method for developing an individual's capacity to form and utilize accurate mental images of data to which the subject has been previously exposed, the steps comprising: a. providing an electronically generated visual display of an environment simultaneously including a plurality of distinctive datum references within the displayed environment which may be acted upon by the subject; b. providing data processing means with data storage means containing predetermined information relative to said datum references of said display including (i) a first condition of each said datum reference to be acted upon, (ii) an instruction for action on each such datum reference to be acted upon, said instruction requiring at least two dimensions of action upon the datum reference, and (iii) at least a second condition of each such datum reference to be representing the result of at least two dimensions of action upon each such datum reference acted upon and following proper execution of the instruction with respect thereto; c. providing means for manipulation by the subject coupled to said data processing means to electronically record in said data storage means the action to change said datum references of said visual display; d. highlighting at least one of said datum references of said display and providing an instruction to the subject requiring an action with said manipulatable means to change at least said one of the highlighted datum references of said visual display, said action requiring at least two dimensions of manipulation with said manipulation means as to each such datum reference acted upon; e. electronically recording at least two dimensions of the actions of the subject on the hightlighted datum references in response to the instruction to change any highlighted datum references of said visual display; f. comparing the recorded dimensions of the subject's action on the appropriate datum reference with the predetermined dimensions for change in condition of such datum reference in proper response to the given instruction; and g. presenting to the subject the results of such comparison.