I suspect that "Orientation" could be a latent factor for some measurable faculties, including directed (split) attention, facility, acuity, sophistication, etc in perceptual and cognitive processing of bimodal sensory input..
Dear colleague, have you tried the Sensation Seeking Scale (Eysenck & Zuckerman, 1978)? In case you don't know it, this test assesses individual differences in terms of sensory stimulation preferences. So there are people who prefer a strong stimulation and display a behavior that manifests a greater desire for sensations and there are those who prefer a low sensory stimulation. The scale is a questionnaire designed to measure how much stimulation a person requires and the extent to which they enjoy the excitement. Zuckerman hypothesized that people who are high sensation seekers require a lot of stimulation to reach their Optimal Level of Arousal. When the stimulation or sensory input is not met, the person finds the experience unpleasant.
Evidences suggest that high sensation seekers prefer new, complex and sophisticated stimulus...
Thanks for the tip Anna - I notice this scale has been used in research on music perception (e.g. Rentfrow & Gosling 2003 which I knew, Saarikallio 2007 which I didn't) so it seems very relevant - - I now have some more reading to do!