Dogs: forever wagging their tails with glee, running around chasing their own appendages and panting with seemingly endless happiness, their pared-down way of life is fulfilled by the simplest of pleasures.
Or is it? Not if they turn out to be pessimists, which the University of Sydney has revealed evendogs can be termed.
New research, which measures the positive and negative emotional states in dogs, shows that man's best friend can now be defined as a 'pessimist' or as an 'optimist', the findings of which have the potential to "completely remodel how animal welfare is assessed," Dr Melissa Starling, who conducted the research, suggests.
The dogs' level of optimism was tested by being taught to associate two different sounds, which were two octaves apart, with whether they would be served their preferred drink of milk, or whether they would get plain water.
The dogs were then played "ambiguous" tones, which if they responded to, showed they were optimistic in nature, because they expected good things to happen to them.
"Pessimistic dogs appeared to be much more stressed by failing a task than optimistic dogs. They would whine and pace and avoid repeating the task while the optimistic dogs would appear unfazed and continue," Dr Starling said.
It's not all doom and gloom however, as there are dogs in people's lives who are clearly full of joie de vivre, as seen in the participants of the Surf City Surf Dog competition.
Researchers in America have found that dogs can be plagued by other negative emotions however, as scientists at University of California, San Diego, have produced findings that show canines could be capable of experiencing jealousy.
In an experiment involving dogs, their owners, and a set of animated toy dogs, researchers found that the pets were more likely to show signs of aggression or demonstrate attention seeking behaviour when it became clear that their owners were more interested and affectionate towards the fake canines.
"We can't really speak to the dogs' subjective experiences, of course, but it looks as though they were motivated to protect an important social relationship," psychology professor Christine Harris, the author of the study, said.
