Express saccades in distinct populations: east, west, and in-between.

Express saccades are low latency (80-130 ms), visually guided saccades. While their occurrence is encouraged by the use of gap tasks (the fixation target is extinguished 200 ms prior to the saccade target appearing) and suppressed by the use of overlap tasks (the fixation target remains present when the saccade target appears), there are some healthy, adult participants, "express saccade makers" (ESMs), who persist in generating high proportions (> 30%) of express saccades in overlap conditions. These participants are encountered much more frequently in Chinese participant groups than amongst the Caucasian participants tested to date. What is not known is whether this high number of ESMs is only a feature of Chinese participant groups. More broadly, there are few comparative studies of saccade behaviour across large participant groups drawn from different populations. We, therefore, tested an independent group of 70 healthy adult Egyptian participants, using the same equipment and procedures as employed in the previous studies. Each participant was exposed to two blocks of 200 gap, and two blocks of 200 overlap trials, with block order counterbalanced. Results from the Schwartz Value Survey were used to confirm that this group of participants was culturally distinct from the Chinese and Caucasian (white British) groups tested previously. Fourteen percent (10/70) of this new group were ESMs, and the pattern of latency distribution in these ESMs was identical to that identified in the other participant groups, with a prominent peak in the express latency range in overlap conditions. Overall, we identified three modes in the distribution of saccade latency in overlap conditions, the timing of which (express peak at 110 ms, subsequent peaks at 160 and 210 ms) were strikingly consistent with our previous observations. That these behavioural patterns of saccade latency are observed consistently in large participant groups, drawn from geographically, ethnically, and culturally distinct populations, suggests that they relate to the underlying architecture of the saccade system.

A Complex Story: Universal Preference vs. Individual Differences Shaping Aesthetic Response to Fractals Patterns.

Fractal patterns offer one way to represent the rough complexity of the natural world. Whilst they dominate many of our visual experiences in nature, little large-scale perceptual research has been done to explore how we respond aesthetically to these patterns. Previous research (Taylor et al., 2011) suggests that the fractal patterns with mid-range fractal dimensions (FDs) have universal aesthetic appeal. Perceptual and aesthetic responses to visual complexity have been more varied with findings suggesting both linear (Forsythe et al., 2011) and curvilinear (Berlyne, 1970) relationships. Individual differences have been found to account for many of the differences we see in aesthetic responses but some, such as culture, have received little attention within the fractal and complexity research fields. This two-study article aims to test preference responses to FD and visual complexity, using a large cohort (N = 443) of participants from around the world to allow universality claims to be tested. It explores the extent to which age, culture and gender can predict our preferences for fractally complex patterns. Following exploratory analysis that found strong correlations between FD and visual complexity, a series of linear mixed-effect models were implemented to explore if each of the individual variables could predict preference. The first tested a linear complexity model (likelihood of selecting the more complex image from the pair of images) and the second a mid-range FD model (likelihood of selecting an image within mid-range). Results show that individual differences can reliably predict preferences for complexity across culture, gender and age. However, in fitting with current findings the mid-range models show greater consistency in preference not mediated by gender, age or culture. This article supports the established theory that the mid-range fractal patterns appear to be a universal construct underlying preference but also highlights the fragility of universal claims by demonstrating individual differences in preference for the interrelated concept of visual complexity. This highlights a current stalemate in the field of empirical aesthetics.