1. A non-transitory, computer readable storage medium having computer readable instructions stored thereon that, when executed by a computer, implement a method for retrieving mental images of faces from a human brain, the method comprising: generating an initial human facial image on a screen, the initial human facial image including characteristics based on an initial description of a human face; measuring brain activity data from a brain scanner, the brain activity data being measured from a subject viewing the screen; varying the characteristics of the initial human facial image on the screen; detecting changes in the brain activity data measured from the brain scanner, the brain activity indicative of recognizing the human face; fixing certain characteristics that correspond to brain activity that indicated strong recognition of the certain characteristics to construct a final human facial image, constructing the final human facial image from the certain characteristics that have been fixed based on the brain activity that indicated strong recognition of the certain characteristics; and generating the final human facial image on the screen, the final human facial image including the certain characteristics that have been fixed; wherein varying characteristics of the initial human facial image on the screen comprises: varying a first facial characteristic and varying a second facial characteristic; wherein the fixing comprises: in response to varying the first facial characteristic that results in an increase of brain activity as indicated from the brain activity data, fixing, based upon the increase of the brain activity associated with the first facial characteristic, the first facial characteristic as part of the final human facial image on the screen; and in response to varying the second facial characteristic that results in an increase of brain activity as indicated from the brain activity data, fixing, based upon the increase of the brain activity associated with the second facial characteristic, the second facial characteristic as part of the final human facial image on the screen.