Proceedings of the Annual Meeting of the Cognitive Science Society

Conceptual structure in humans, pigeons, and monkeys was investigatedusing a multidimensional scaling procedure. Pigeons and monkeys wereinitially trained to discriminate between stimultaneously presented treeand nontree pictorial stimuli. Preference data was collected by insertingprobe trials In which the animals were forced to choose between two treestimuli. Analogous data for human subjects was collected by havingsubjects rate their preferences for the same stimuli. Tree preferencerelationships in the different datasets were obtained using the DEDICO Mprocedure. These analyses revealed striking interspecies differences inconceptual structure. The analysis of human tree preferences revealed a'whole vs. part' pattern in which stimulus preference was a function ofstimulus completeness. Pigeon tree preferences were qualitatively differentfrom human tree preferences, and also appeared to be less elaborate. Ingeneral, 'branchy' stimuli were preferred over 'leafy' stimuli, and a 'wholevs. part' pattern did not emerge. The data for monkeys also illustrated apreference for 'branchy' structures over 'leafy' structures. Individualdifferences between monkey preferences were also revealed, and were foundto be related to performance on the initial discrimination task. Monkeysthat had a well-defined tree preference pattern learned this task fasterthan did monkeys with a less defined structure. The results of all of theanalyses demonstrated interspecies differences in tree concepts, and suggested the possibility that these may be related to different functional experiences or requirements.