ABSTRACT
Eye movement monitoring is partly physics not only with regard to its techniques but also with regard to its self awareness. Considering this, the high variance of data occurring in eye movement investigations is astonishing. But from a methodological point of view, the real problematic variance results from apparatus, procedures, identification programs, or from insufficiently trained or instructed subjects (the variance resulting from a reader’s reading intention, from the way in which a text is read, or from reading skill is higher than even the worst apparatus can produce). Observations repeatedly made under different experimental conditions convinced us that bioelectrical influences as well as micro-movements of the eyes depend very much on subjects’ actual and habitual activation level, and that applies also to eyelid blink-rate. Precautions actually taken to handle the problem are as well heterogeneous and consist mainly in: formulating very restricted hypothetical models and looking at their proof as a result; and enlarging the number of subjects.
