Too dog-tired to behave: Self-control in humans and dogs is sensitive to fatigue
Miller, Holly Pattison, Kristina Bourraseau, Camille Blampain, Justine Laude, Jennifer
Behaviour Meeting location:Newcastle, England date:4-8 August 2013
Self-control in humans and dogs appears to rely on a limited energy resource that can be depleted with prior exertion. There is evidence that glucose may be involved, as the consumption of glucose replenishes the depletion incurred by self-control. An alternative explanation is that the detection of glucose by carbohydrate taste receptors, and nutrient sensing neurons, activates the vagus nerve that in turn enhances the neurotransmission of norepinephrine and behavioural control. This hypothesis was investigated in two studies where dogs and humanswere given glucose, fructose or a placebo. Fructose was used because it does not affect blood glucose levels, has non-rewarding post ingestive consequences, but activates the vagus nerve. Dogs were required to exert self-control (or not) and were subsequently given a glucose, fructose, or calorie-free drink before their persistence on an unsolvable puzzle task was measured. Dogs persisted for the same duration after glucose and fructose, and less after placebo consumption. Humans similarly solved more word anagrams following the consumption of glucose and fructose than after the placebo. These observations suggest that vagal activation may be responsible for improving self-control and problem solving in dogs and humans.