... Science has demonstrated that dogs can detect and then respond with action the exact moment an absent owner begins their return trip home. Such events - para normal is the usual name- would only be possible if there is a medium of communication between sentient beings that is beyond the five common senses. I.e. A Sixth Sense.
...
As a long time dog companion of many, many dogs, I can attest to dogs seeming to have some pretty remarkable senses, but I'm unaware of any scientific studies that have demonstrated this as being due to a "sixth sense" or paranormal abilities. If such a true scientific study DOES exist, I'd be very interested in reading it.
Dogs DO have a sense of smell that is truly FAR beyond our comprehension. They can smell such minute changes in our bodies that they can sense cancers, changes in insulin levels, impending panic accounts before WE'RE aware of them, epileptic seizures, our levels of stress...all via scent. Their noses are how they perceive the world, by a VERY large majority above all their other senses combined. Here's a fascinating scientific article about the canidae olfactory system...
Canine Noses
Of course, on top of that, their hearing is MUCH more acute than ours. I have a quiet car, but my dogs routinely pick up the sound of my car returning home when I'm still two miles or more from the house; they'll start barking, causing my wife to call and confirm that I'm getting close to home. They've picked me up as far as five miles away. Heck, it's possible some of THAT could be scent-related.
Another quite plausible explanation for dogs seeming to know when an owner is ABOUT to begin a journey home could be that they smell a family member who IS home change their mood simply because they know the person is about to head home.
I can't stress how important it is for dog trainers and owners to recognize the importance of a dog's nose...if you are uneasy, frustrated, worried, or stressed in any way while working with your dog, they will know IMMEDIATELY, and end up feeling just as stressed or worse. A trainer I work with is fond of telling some of her clients that "bad training is worse than no training," meaning if you don't feel good, serene, and confident, and can't make a training session fun for you and the dog, wait until you do and you can.