premise: The science of laterality the study of mental functions and the side of the brain from which they originate was advanced recently by research that found that around 30 per cent of dogs were either left- or right-pawed and the remainder were ambidex- trous. The research became of commercial interest when it was realized that the dogs that showed no preference for left or right were more likely to react badly to loud noises such as fireworks or thunderstorms. Such behaviour makes a dog unsuitable for a career sniffing out drugs or guiding the blind. As things stand, one in every two dogs fails the training programmes for these roles because of an intolerance of loud noise.
hypothesis: The case made in the passage would be strengthened if an intolerance to loud noise were manifest in dogs before they began training for careers as guides for the blind or to sniff out drugs.