The relationship between line bisection performance and emotion processing: where do you draw the line?

A recent study demonstrated that higher accuracy on a line bisection task related to greater ratings of evocative impact from paintings. The authors suggested that line bisection accuracy may act as a “barometer” for both visuospatial and emotion processing, likely as a function of overlapping neural correlates in the right temporoparietal region. We suggest and test an alternative explanation: that visuospatial bias interacted with asymmetries in the paintings and the rating scales to produce the apparent relationship between emotion and visuospatial functions. In the present study, using both visual-analogue and numeric rating scales, the relationship between line bisection performance and ratings of paintings (evocative impact, aesthetics, novelty, technique, and closure) was examined in a young adult sample. We demonstrate that left-hand line bisection bias direction, not line bisection accuracy, is related to most ratings, and that line bisection bias interacts with stimulus orientation (non-mirrored/mirrored) and rating scale direction (ascending/descending) in such a way that can explain the results of the previous study. We conclude that the line bisection task appears to be a sensitive measure of visuospatial attentional biases, which can influence ratings of asymmetrical paintings, and may affect how individuals perceive stimuli in their environment.