1. A method comprising: maintaining a set of visual stimuli, each of the visual stimuli being associated with an identified emotional reaction that is likely to be elicited in a subject to whom the stimulus is presented, identifying to a subject, by computer through a user interface, a context with which emotional reactions are to be associated; after identifying the context to the subject, presenting, to the subject, by a computer through a presentation interface, the visual stimuli to the subject, including, for each visual stimulus: presenting the visual stimulus for a limited period of time having a predefined duration of more than 500 milliseconds and less than 1000 milliseconds, the duration of the limited period of time being enforced by computer and being sufficiently brief as to limit or prevent cognitive processing of the visual stimulus by the subject, ending the presenting of the visual stimulus at the end of the limited period of time, providing a grace period immediately following the end of the limited period of time, the grace period having a predefined duration of up to 300 milliseconds during which none of the visual stimuli is presented, the duration of the grace period being enforced by computer, and presenting a subsequent visual stimulus at the end of the grace period; by a computer, receiving a response, by the subject, to at least one of the visual stimuli during a response period including the first limited period of time and the grace period, the response of the subject to a particular visual stimulus representing a emotional reaction of the subject to the particular visual stimulus in relation to the context; by a computer, storing information that represents the pre-cognitive emotional reaction of the subject to each of the at least one visual stimuli for which a response was received; and by a computer, determining, based on at least some of the stored information, one or more dominant emotional characteristics of the subject in relation to the context.