Memory decays at the same rate in macaques with and without brain lesions when expressed in d' or arcsine terms

Abstract

Data from the literature on the effect of lesions upon recognition memory in the monkey have been examined. On the basis of percentage scores the published data can be interpreted as showing that the ability to recognize a previously seen object decays faster in macaques with brain lesions than it does in normal animals. A reanalysis of the extensive data in terms of d' of Signal Detection Theory or by arcsine transform suggests, on the contrary, that the rate of decay from 0 to 600 s, is essentially the same in normal animals and in those with lesions (particularly temporal lobe lesions). Indeed, in d' or arcsine terms, the effect of the lesions is fully developed at the shortest times used, and shows no increase as a function of the delay between initial presentation and test. Thus, very different conclusions stem from the choice of scale.