Programming of saccades to double-step targets in scene viewing: A test of assumptions present in the CRISP model
R. Calen Walshe, Antie Nuthmann · eScholarship (California Digital Library) · 2013
Several computational models explaining fixation durations in scene viewing (Nuthmann, Smith, Engbert, & Henderson, 2010) and in reading (Engbert, Nuthmann, Richter, & Kliegl, 2005;Reichle, Pollatsek, Fisher, & Rayner, 1998) assume that saccade programming is completed in two stages: an initial, labile stage that is subject to cancellation and an subsequent, non-labile stage in which the program can no longer be cancelled.This distinction is motivated by findings from doublestep experiments that used much simpler situations than scene viewing or reading.Here, we adopt a classic double-step paradigm to a scene-viewing context.In a Static condition targets are presented to the left or right of a central fixation cross along a horizontal axis while in a Scene condition targets are presented in a gaze contingent manner along a trajectory defined by the location of recent fixations.We found evidence in support of the claims that saccade cancellation occurs within a naturalistic scene-viewing context and that saccade cancellation can account for increases in observed fixation duration distributions.The duration of the non-labile stage was estimated to be longer in the Scene condition compared to the Static condition.