Аннотация
As any cognitive task, visual search involves a number of underlying
processes that cannot be directly observed and measured. In this way,
the movement of the eyes certainly represents the most explicit and
closest connection we can get to the inner mechanisms governing this
cognitive activity. Here we show that the process of eye movement during
visual search, consisting of sequences of fixations intercalated by
saccades, exhibits distinctive persistent behaviors. Initially, by
focusing on saccadic directions and intersaccadic angles, we disclose
that the probability distributions of these measures show a clear
preference of participants towards a reading-like mechanism (geometrical
persistence), whose features and potential advantages for
searching/foraging are discussed. We then perform a Multifractal
Detrended Fluctuation Analysis (MF-DFA) over the time series of jump
magnitudes in the eye trajectory and find that it exhibits a typical
multifractal behavior arising from the sequential combination of
saccades and fixations. By inspecting the time series composed of only
fixational movements, our results reveal instead a monofractal behavior
with a Hurst exponent H approximate to 0.7, which indicates the presence
of long-range power-law positive correlations (statistical persistence).
We expect that our methodological approach can be adopted as a way to
understand persistence and strategy-planning during visual search.
