Spatial frequency filtering and the direct control of fixation durations during scene viewing

Abstract

The present study employed a saccade-contingent change paradigm to investigate the effect of spatial frequency filtering on fixation durations during scene viewing. Subjects viewed grayscale scenes while encoding them for a later memory test. During randomly chosen saccades, the scene was replaced with an alternate version that remained throughout the critical fixation that followed. In Experiment 1, during the critical fixation, the scene could be changed to high-pass and low-pass spatial frequency filtered versions. Under both conditions, fixation durations increased, and the low-pass condition produced a greater effect than the high-pass condition. In subsequent experiments, we manipulated the familiarity of scene information during the critical fixation by flipping the filtered scenes upside down or horizontally. Under these conditions, we observed lengthening of fixation durations but no difference between the high-pass and low-pass conditions, suggesting that the filtering effect is related to the mismatch between information extracted within the critical fixation and the ongoing scene representation in memory. We also conducted control experiments that tested the effect of changes to scene orientation (Experiment 2a) and the addition of color to a grayscale scene (Experiment 2b). Fixation distribution analysis suggested two effects on the distribution fixation durations: a fast-acting effect that was sensitive to all transsaccadic changes tested and a later effect in the tail of the distribution that was likely tied to the processing of scene information. These findings are discussed in the context of theories of oculomotor control during scene viewing.

Predicting eye-movement characteristics across multiple tasks from working memory and executive control

“…A common explanation for the relationship between WM span and Tau is that increases in the tail of the fixation duration distribution reflect lapses of attention; WM span has been implicated in attentional control processes, with higher span individuals more able to maintain focus on a task and less likely to mind-wander (see, e.g., McVay & Kane, 2012b, who examined the relationship between mind-wandering and WM span directly). An alternate explanation comes from research on eye-movement control in visual scenes; in scene viewing, a sudden change in the visual scene that leads to an increase in perceptual integration difficulty can increase the Tau parameter (Glaholt, Rayner, & Reingold, 2013;Walshe & Nuthmann, 2014). Thus, higher WM span may facilitate integration of perceptual information (words, objects) into the overall stimulus representation, thereby reducing Tau.…”

Not all fixations are created equal: The benefits of using ex-Gaussian modeling of fixation durations

“…Although this approach has been used as a way to estimate fixation duration distributions in reading studies (e.g., Sheridan & Reingold, 2012 ; Staub, 2011 ), it is less frequently used in studies of visual exploration of complex scenes, which still tend to rely on the mean as the main reported measure. Although a handful of studies on scene viewing has already adopted this method (e.g., Glaholt, Rayner, & Reingold, 2013 ; Luke et al, 2014 ), no study has provided a dedicated account of the justifications, the reliability of the ex-Gaussian parameters over time and the possible advantages of this method in revealing differential modulations of fixation duration by divergent experimental factors. In what follows, we discuss these issues and show that ex-Gaussian modeling has potential benefits for future studies and theories.…”

Effects of Scene Properties and Emotional Valence on Brain Activations: A Fixation-Related fMRI Study

“…This correlation was significantly stronger in the case of fixations executed on negative images as opposed to neutral ones. We hypothesized that any possible interaction between emotional category and noise level in brain correlates of fixations would be related to fixation duration, which decreases in an emotional condition (Bradley et al, 2011 ; Kaspar et al, 2013 ) and with a declining noise level (Glaholt et al, 2013 ; Henderson et al, 2014 ). Our results, however, do not support this prediction.…”

“…Indeed, in free viewing conditions spatial deployment of attention is reflected in the temporal and spatial characteristics of fixations (for a review see Henderson, 2003 ). Specifically, fixations are not randomly distributed; their location and duration strongly depend on the informative value linked to both high-level scene characteristics, such as object-background composition, and basic low-level physical properties, such as signal-to-noise ratio (Buswell, 1935 ; Mackworth and Morandi, 1967 ; Yarbus, 1967 ; Kayser et al, 2006 ; Henderson et al, 2009 ; Ossandón et al, 2012 ; Glaholt et al, 2013 ; Henderson et al, 2014 ; Onat et al, 2014 ). Interestingly, emotional content strongly attracts attention and influences eye movements, possibly due to its evolutionary and behavioral relevance (Calvo and Lang, 2004 ; Nummenmaa et al, 2006 ; Calvo et al, 2007 , 2008 ; Humphrey et al, 2012 ; Niu et al, 2012 ; Kaspar et al, 2013 ; Pilarczyk and Kuniecki, 2014 ).…”

“…Several eye-tracking studies have shown that both the noise level and emotional content of an image affect fixations, which become longer as the clarity of an image decreases due to either high or low spatial filtering (Glaholt et al, 2013 ; Henderson et al, 2014 ) or other distortion methods preventing scene comprehension (Luke and Henderson, 2016 ). Emotional content also affects fixation number and duration.…”