Memory enhances problem solving in the fawn-footed mosaic-tailed rat Melomys cervinipes

Problem solving is important for survival, allowing animals to access novel food resources or escape from predators. It was originally thought to rely on an animal's intelligence; however, studies examining the relationship between individual cognitive ability and problem solving performance show mixed results, and studies are often restricted to only one cognitive and one problem solving task. We investigated the relationship between general cognitive ability and problem solving across multiple tasks in the fawn-footed mosaic-tailed rat Melomys cervinipes. We measured general cognitive ability across different domains (memory in an odour learning association task, recognition in a novel object recognition task, size discrimination using different sized pieces of food, and learning across multiple presentations of a food-baited activity board). We also measured problem solving across different contexts (food-baited puzzle boxes in home cage, obstruction task, and food-baited activity board in a novel arena). Mosaic-tailed rats showed a general cognitive ability, with average problem solving latency, memory ability, and learning in the tile task being correlated. As such, individuals that were able to remember an association and learned to solve the tile task solved the problems faster than individuals that could not remember or learn. Our results suggest that problem solving in mosaic-tailed rats likely relies on some forms of simple cognition, particularly memory, but could also depend on other traits, such as an individual's persistence.