Sarah Boysen - US grants

An understanding of the capacity for numerical competence in non- human species could contribute significantly toward clarifying theoretical evolutionary changes in cognitive processing across phyla. In the proposed studies, chimpanzees previously trained on a variety of number-related tasks, including productive and receptive use of Arabic number symbols, will be tested for sensitivity to ordinality. These tasks will require the utilization of transitive inference logical reasoning, and will provide important empirical evidence that the chimpanzee may be capable of true counting, as demonstrated with very young children. These findings, together with previously demonstrated capabilities in the animals for one-to-one correspondence, productive and receptive labelling of homogeneous and heterogeneous arrays, the functional use of numbers, and rudimentary arithmetic processes (addition, identity) would provide critical evidence for a counting explanation for the animals' number-related behaviors. Training will also continue with on-going studies of functional number use (0-5), to include the additional Arabic numbers 6 & 7, as well as studies of rudimentary arithmetic processing in the chimpanzee.

Chimpanzees are well known to be our closest non-human relatives, but the surprising extent to which they share cognitive abilities with human beings is still being discovered. Drs. Boysen and Berntson are investigating the numerical competence of chimpanzees. Their preliminary research with young animals has demonstrated numerical skills including rudimentary counting and addition. Further studies should contribute to our understanding of the similarities and differences in cognitive capabilities across species and toward clarifying those processes that may support numerical skills in non-human primates. Besides these contributions to basic scientific knowledge, these studies may yield sharper tests for and understanding of numerical competence in children and, more generally, provide a better understanding of non-verbal intelligence. Thus, the present project may provide insights into the cognitive abilities of language- impaired or otherwise developmentally-challenged children. Motor tagging (touching or pointing to items) during counting will be evaluated for its functional significance relative to similar behaviors of children in the early stages of learning to count. This study will clarify whether or not these behaviors, which appeared spontaneously in one animal, serve as an organizing strategy for keeping track of those items that have already been counted and those that remain to be counted. Another study will explore subtraction, by presenting the animals an array of 2 to 6 pieces of fruit, covering it, and then removing 1 to 4 items out of the animal's view. Early results suggest that the chimpanzees are able to indicate the remainder of the hidden fruit by selecting the correct Arabic numeral from among alternatives 0 to 5. An adult female chimpanzee with extensive prior training on a range of concepts, including a symbolic language system, will begin training with numbers, following the same procedures that were used with the young animals. At the same time, a computer- assisted testing apparatus will be developed to facilitate training and data-collection with adult chimpanzees.

IBN 9321090 Boysen Linguistic, numerical, and some other cognitive capacities have long been believed to be uniquely human, but recent studies of animal behavior have revealed some surprising parallels. In order to understand how and why our ancestors developed these capacities, it is important to find out how widespread such abilities are in the animal kingdom and to learn what roles these abilities play in the natural lives of the animals that have them. Procedures developed for studying these abilities in animals have been put to use in the training of people with brain injuries and developmental disabilities. Dr. Boysen has been successfully studying numerical capacities of chimpanzees. Now she will explore number-related skills of capuchin monkeys with procedures that parallel her previous work on counting by chimpanzees. Capuchins are known to use tools in their natural habitat, such as rocks to pound nuts until they open and sticks to extract sap and insects. Because of this demonstrated expertise, capuchins are excellent candidates for exploring complex conceptual abilities such as counting and other number-related skills. The monkeys' training and testing will be completed using a computer touch-frame system that will permit them to make responses directly to a computer screen, automatically recording all data. Each monkey will first be trained on matching one, two, or three marks to an array of the same number of candies. Once the monkey can do that, the marks will be replaced with Arabic numerals, and the monkey must select the numeral that corresponds to the number of candies presented. Number comprehension will also be tested by showing the monkey a numeral on the computer monitor and having it choose an array composed of the same number of items. These phases of training directly parallel Dr. Boysen's earlier studies with chimpanzees, and thus will permit a direct comparison of the abilities of monkeys and apes with the emergence of numerical competence and cou nting in young children.

performance; mathematical ability; judgment; ethology; neural information processing; visual stimulus; choice; stimulus /response; paired stimuli; food; symbolism; preference; reinforcer; motivation; psychomotor reaction time; behavioral /social science research tag; Pan; behavior test;