Perceptual asymmetries and handedness: a neglected link?

Abstract

Healthy individuals tend to weigh in more the left than the right side of visual space in a variety of contexts, ranging from pseudoneglect to perceptual asymmetries for faces. Among the common explanations proposed for the attentional and perceptual advantages of the left visual field, a link with the prevalence of right-handedness in humans has never been suggested, although some evidence seems to converge in favor of a bias of spatial attention toward the region most likely coincident with another person’s right hand during a face-to-face interaction. Such a bias might imply an increased efficiency in monitoring both communicative and aggressive acts, the right limb being more used than the left in both types of behavior. Although attentional and perceptual asymmetries could be linked to right-handedness at the level of phylogeny because of the evolutionarily advantage of directing attention toward the region where others’ dominant hand usually operates, it is also legitimate to question whether, at the ontogenetic level, frequent exposure to right-handed individuals may foster leftward biases. These views are discussed in the light of extant literature, and a number of tests are proposed in order to assess our hypotheses.

Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs

“…Note that we have observed similar cross-sensory oscillatory coupling between the auditory and visual systems using direct intracranial electrocorticographic recordings in human epilepsy patients ( Mercier et al, 2013 ). However, another plausible explanation for this unilateral effect may relate to the well-established hemispheric asymmetries in spatial attentional processes, although these typically lead to a left visual field bias in right-handers (e.g., Foxe et al, 2003 ; Marzoli et al, 2014 ), whereas the current results would seem to point to a right field advantage for MSI.…”

Laterality effects in the spinning dancer illusion: The viewing‐from‐above bias is only part of the story

“…As proposed for unimanual actions in a previous study with static human silhouettes (Marzoli et al ., ), the larger proportion of figures perceived as right‐footed could be due to a perceptual frequency effect (Faurie & Raymond, ). Indeed, given that most social interactions occur with right‐handed and right‐footed individuals, a perceptual and attentional bias towards the right limbs of human bodies could be adaptive in social life (see Marzoli, Prete, & Tommasi, for a more detailed discussion). The other side of the coin would be a reduced monitoring of the left limbs, and thus a reduced ability in discriminating left‐limbed movements compared to right‐limbed movements, which could perfectly explain the ‘surprise effect’ at the basis of the hypothesized advantage of left‐handers in fighting (Faurie & Raymond, ).…”

Lateralization and cognitive systems

“…In addition to animal research, several studies examined how lateralization impacts the functioning of different cognitive systems in the human brain. For example, it was investigated how handedness is related to other brain functions such as language lateralization (Carey and Johnstone, 2014 ), approach/avoidance motivation (Hardie and Wright, 2014 ), perceptual asymmetries (Marzoli et al, 2014 ), semantic priming (Fagard et al, 2014 ), response speed in the orthogonal Simon task (Iani et al, 2014 ) and cognitive performance in general (Prichard et al, 2013 ; Scharoun and Bryden, 2014 ). These studies are complemented by a review article investigating how twin studies could be useful in the quest to understand the complex interrelations of lateralization and cognitive systems (Ooki, 2014 ) as well as by a large-scale anatomical work investigating the effect of handedness on the structure of the cerebral cortex (Guadalupe et al, 2014 ).…”