The Difficult Integration between Human and Animal Studies on Emotional Lateralization: A Perspective Article

Abstract

Even if for many years hemispheric asymmetries have been considered as a uniquely human feature, an increasing number of studies have described hemispheric asymmetries for various behavioral functions in several nonhuman species. An aspect of animal lateralization that has attracted particular attention has concerned the hemispheric asymmetries for emotions, but human and animal studies on this subject have been developed as independent lines of investigation, without attempts for their integration. In this perspective article, after an illustration of factors that have hampered the integration between human and animal studies on emotional lateralization, I will pass to analyze components and stages of the processing of emotions to distinguish those which point to a continuum between humans and many animal species, from those which suggest a similarity only between humans and great apes. The right lateralization of sympathetic functions (involved in brain and bodily activities necessary in emergency situations) seems consistent across many animal species, whereas asymmetries in emotional communication and in structures involved in emotional experience, similar to those observed in humans, have been documented only in primates.

Emotions and the Right Hemisphere: Editorial

“…Finally, Gainotti [ 16 ] takes into account the problem of the difficult integration between human and animal studies on emotional lateralization. Data from his review suggest that, in these studies, there are both elements of continuity and factors of discontinuity between the emotional asymmetries observed in animals and humans.…”

Is There a Causal Link between the Left Lateralization of Language and Other Brain Asymmetries? A Review of Data Gathered in Patients with Focal Brain Lesions

“…Furthermore, since language is considered a hallmark of our species, for more than one century hemispheric asymmetries were considered as a uniquely human feature. In more recent times, however, this idea has been challenged by an increasing number of studies describing hemispheric asymmetries for various behavioural functions in many non-human species (see reviews in [ 4 , 5 , 6 , 7 ]). Several theories have therefore been advanced to explain the general advantages and disadvantages of hemispheric specialization, mainly suggesting that this division of work could reduce the need for processing information in both hemispheres and the need for interhemispheric communication via the corpus callosum.…”