ABSTRACT
Research carried out over the past 15-20 years has shed considerable light on spatial memory in animals. Research with rats on the radial maze (Olton & Samuelson, 1976) indicates that these animals can retain memories of a large number of previously visited spatial locations (Olton, 1977, 1978, 1979; Roberts, 1984) and can retain this information well over retention intervals of several hours (Beatty & Shavalia, 1980b). Although spatial memory is generally resistant to retroactive interference (Beatty & Shavalia, 1980a; Maki, Brokofsky, & Berg, 1979), powerful effects of proactive interference have been found (Roberts & Dale, 1981) that may arise from time discrimination difficulties between recent and earlier visits to spatial locations (Roberts, 1984). Some disagreement exists about the format of rat spatial memory. Several lines of research suggest that rats form maplike representations of space, in which the relationships between visual objects are used to guide navigation (Gallistel, 1990; Mazmanian & Roberts, 1983; Morris, 1981; Suzuki, Augerinos, & Black, 1980). Other investigators argue that rats use a more restricted listlike memory on the radial maze (Brown, 1992; Olton, 1978; see also chapter 9 of this volume). Finally, research by A1 Riley and his students suggests that rats may code a sequence of arm visits in the radial maze in a flexible manner, using both retrospective and prospective codes (Cook, Brown, & Riley, 1985).
