LEXICON SIZE AND FOOT PREFERENCE IN THE AFRICAN GREY PARROT (PSITTACUS-ERITHACUS)

To study footedness and lexicon size in African Grey parrots, an inter national survey of parrot owners was conducted. Responses were obtaine d from 524 individuals, including 70 owners of African Grey parrots (a ll animals greater than or equal to 10 months old). Right-footed Afric an Grey's (N = 36) had significantly larger lexicons than left-footed African Grey's (N = 34; p =.01). This difference could not be accounte d for by group differences in training efforts or socialization/housin g with conspecifics. Other investigators have provided convincing evid ence of lateralization, in the avian brain, for the analysis and memor y of differing types of stimuli. In addition, there appears to be pref erential left hypserstriatal activation for long-term memory consolida tion. Our results suggest a relationship between lateral asymmetry for motor preference and asymmetric CNS mediation of a ''higher cognitive '' function (i.e., the categorization and long-term mnestic processing of human speech sounds).