This paper will consider the practical and theoretical issues involved in comparing cognitive function across species, in particular monkeys and man. Examples will be taken from studies investigating the precise nature of frontal dysfunction in the neurodegenerative disorders of Parkinson's disease, Huntington's diseases and fronto-temporal dementia and the neuropsychiatric disorder of Schizophrenia. Using standard clinical tests of frontal lobe function it has proven difficult to distinguish the impaired performance of patients suffering from these conditions from neurosurgical patients with localised excisions of the frontal lobes. In some cases the frontal type deficits observed in these neurodegenerative and neuropsychiatric conditions may be the result of a dysregulation in the neurochemical modulation of frontal lobe activity e.g. Parkinson's disease & Schizophrenia. Alternatively they may be due to a disruption of fronto-striatal circuitry, e.g. Parkinson's disease, Huntington's disease & Schizophrenia, or a disruption of fronto-temporal cicuitry, e.g. Schizophrenia & Fronto-temporal dementia. In order to characterize fully both the psychological and neural basis of these deficits in patients, it is necessary to perform selective neurochemical and neuroanatomical lesions in monkeys, in parallel with clinical studies. To this end, we have developed a computerised battery of tests presented on a touch-sensitive screen designed to enable not only the presentation of the same tests to both humans and monkeys, but also to allow a decomposition of the possible factors contributing to task performance. The psychological issues which are relevant to the design of such tests suitable for use in both humans and experimental lesioned primates will be discussed taking examples from studies using a computerised analogue of the Wisconsin card sorting test and a test of self-ordered sequencing.

© 2000 Noldus Information Technology b.v.