Possums in the closed field test

Abstract

Summary Six brush-tail possums were run through six problems in the Hebb-Williams closed field test, three of which permitted direct visual solution and three of which did not. In comparison with the performance of rats and cats, possums made markedly more errors on both types of problem. Because of the large differences in total error, proportional measures were used to compare the three species on different segment of performance. A measure based on the proportion of total errors made on those problems permitting direct visual solution discriminated between the cats and the rats and possums, while a measure based on the proportion of total errors made on the first four of the eight runs given on each test problem discriminated between the possums and the rats and cats.