When I was little I always wondered what animals are thinking and feeling but we were told that animals are not like humans and all they have is just instinct. That was 30 plus years ago and research has delivered new and interesting discoveries about dogs, their brains and how they work.
While a humans brain is larger in relative size, has more folds and a larger frontal cortex, a dogs brain is not that different to a human brain. They share the same brain structure that produce emotions and the same hormone production and chemical changes occur in both dogs and humans in emotional states. Just like in us humans, dogs have oxytocin release which is involved in feeling love and affection.
Sharing the same neurology and brain chemistry suggests that dogs basic emotions are similar to that of humans of around 2-5 year old; joy, fear, anger, disgust, love & affection.
The scientific consensus seems to agree on dogs not being able to feel guilt, pride and shame but there still needs to be more research done.
What may be different though is how emotions are processed since humans larger frontal cortex gives us the advance of higher level processing, thoughts, judgement, empathy etc. This is which gives us humans the ability not just to feel emotions but to analyze them and then judge whether to share them or inhibit showing them to avoid causing hurt or shame in another human or ourselfs for example.
In dogs however, brain sections associated with smell use larger size brain area to analyze scents. Their olfactory system is extremly sensitive and can have effects on emotions as well just like in us humans.
It is what is sometimes forgotten in the training world, that conditioning methods may train away a behaviour the dog is showing during and emotion / feeling but training has not changed the emotion itself. If a dog is fearful or depressed for example, we have to find the reason of why the dog feels that way. By obeservation and communication with the owner, vet and the dog we can detect whether your dogs emotional behaviours are down to physical or behavioural problems. Anxiety and depression can in many cases be due to the dog being in pain due to an undiagnosed physical issue.
It might be more likely that changes to the environment and/or lifestyle need to be made before any desensitation or counter conditioning processes start, if at all. And just like with human beings, any modification program can take a lot of effort and time.
That said, that fact we know that dogs are emotional and feeling beings should inspire us to ensure our furry friends are as happy and content with their individual life as we are everyday.