The Impact Of Training Method On Odour Learning And Generalisation In Detection Animals

Odour detection animals are required to learn many individual odours during training. Most organisations and agencies use single-odour (sequential) training, where animals learn one odour followed by another. However, this method may not be optimal for learning or for detecting target odours when they are mixed with other substances, which is an inevitable occurrence when animals are actively deployed in the field. Here, we used a Go/No-Go procedure to investigate the impact of three different training methods upon rats? ability to identify target-odours alone and within mixtures. A sequential group were trained with odour A followed by odour B or vice versa; a compound group were trained with odours AB presented as a single stimulus; and an intermixed group were trained separately on both odours A and B within a session. Following training, all groups were tested for their responses to A, B, and AB, as well as these odours combined with a novel odour C: AC, BC, ABC. Responses to the test stimuli significantly differed between groups (p = 0.002). The intermixed group generalised significantly better than the sequential (p = 0.005) and compound (p = 0.014) groups; and the compound group generalised significantly better than the sequential group (p = 0.023). These findings have important implications for the training of animals used for odour detection. They provide strong evidence that an intermixed training method may be more effective than the generally employed method of sequential single-odour training.