title: Left hemispheric advantage for numerical abilities in the bottlenose dolphin.
abstract: In a two-choice discrimination paradigm, a bottlenose dolphin discriminated relational dimensions between visual numerosity stimuli under monocular viewing conditions. After prior binocular acquisition of the task, two monocular test series with different number stimuli were conducted. In accordance with recent studies on visual lateralization in the bottlenose dolphin, our results revealed an overall advantage of the right visual field. Due to the complete decussation of the optic nerve fibers, this suggests a specialization of the left hemisphere for analysing relational features between stimuli as required in tests for numerical abilities. These processes are typically right hemisphere-based in other mammals (including humans) and birds. The present data provide further evidence for a general right visual field advantage in bottlenose dolphins for visual information processing. It is thus assumed that dolphins possess a unique functional architecture of their cerebral asymmetries.
authors.affiliation: Department Biopsychology, Inst. Cogn. Neurosci., Faculty of Psychology, Ruhr-University Bochum, 44780 Bochum, Germany. akilian@marine-mammal-cognition.de
authors.forename: Annette
authors.initials: A
authors.lastname: Kilian
authors.forename: Lorenzo
authors.initials: L
authors.lastname: von Fersen
authors.forename: Onur
authors.initials: O
authors.lastname: Güntürkün
mesh_terms: D000818:Animals; D003071:Cognition; D004193:Discrimination Learning; D004289:Dolphins / Q000523:psychology*; D007839:Functional Laterality; D008297:Male; D008433:Mathematics; D009900:Optic Nerve; D013647:Task Performance and Analysis; D014796:Visual Perception