title: Is it only humans that count from left to right?
abstract: We report that adult nutcrackers (Nucifraga columbiana) and newborn domestic chicks (Gallus gallus) show a leftward bias when required to locate an object in a series of identical ones on the basis of its ordinal position. Birds were trained to peck at either the fourth or sixth element in a series of 16 identical and aligned positions. These were placed in front of the bird, sagittally with respect to its starting position. When, at test, the series was rotated by 90 degrees lying frontoparallel to the bird's starting position, both species showed a bias for identifying selectively the correct position from the left but not from the right end. The similarity with the well-known phenomenon of the left-to-right spatially oriented number line in humans is considered.
authors.affiliation: Centre for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto, Italy. rosa.rugani@unitn.it
authors.forename: Rosa
authors.initials: R
authors.lastname: Rugani
authors.forename: Debbie M
authors.initials: DM
authors.lastname: Kelly
authors.forename: Izabela
authors.initials: I
authors.lastname: Szelest
authors.forename: Lucia
authors.initials: L
authors.lastname: Regolin
authors.forename: Giorgio
authors.initials: G
authors.lastname: Vallortigara
mesh_terms: D000818:Animals; D002645:Chickens; D003071:Cognition; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D046109:Passeriformes; D012691:Serial Learning; D013028:Space Perception; D013037:Spatial Behavior