At the most basic level, dog behaviour is a set of movements that occur in response to something happening around him, either inside or outside of the body. This does not mean that dogs are unfeeling and unthinking machines performing purely automatic actions with no ability to control them (reflex). If this were true, it would also be the case for humans as well – after all, have you ever managed to NOT lick your lips after eating a doughnut?
Dogs, like humans are very complex animals and this is being seen in the results of a multitude of research conducted over the last few decades. It is true that there are built-in “patterns” of behaviour which have been used for survival throughout the history of the species, passed down through the genetic code to become automatic (and almost automatic) responses (think fight or flight, or a Border Collie with such a strong herding instinct she ends up herding the kids, or the Labrador who constantly carries things around in his mouth). This is often referred to as “Nature”, but how a dog sees and interacts with the world (“Nurture”) also affects how he might respond in a given situation. This includes how he is feeling at that specific moment in time (is he in pain? hungry? scared? happy? excited? relaxed?), what are his past experiences, and past memories, did something happen earlier in the day, the week, years before that was so strong it became stored as a memory (ready to “pop” out when you least expect it).
Going back to a basic level, dog (and human) behaviour can be affected by many different factors (either added together, or acting alone). This goes for both (what we class as) “normal” behaviour as well as “unwanted” (or disruptive) behaviour and is often represented in imagery as a “behaviour iceberg” – what you see is only a small fraction of what is really going on below the surface.

If we only deal with the behaviour we see, we risk missing something at a deeper level and instead of changing the behaviour, we only suppress it. Suppressed behaviour is very likely to occur again or can come out in a different form of behaviour (and sometimes more extreme).
Take a dog who growls at a child – we “see” the behaviour and tell the dog off, so the dog becomes quiet. After a few times of doing this, the dog no longer growls at the child and appears to ignore him. We think the dog is “fixed”. However one time the child gets a little too close to the dog and instead of growling, he snaps at him. His growling behaviour (which was a warning to stay away) has become suppressed, and as a result his warning behaviour has also become more extreme.

While we will probably never know what “else” is going on (does he not like children, did the child accidentally stand on his tail one time, did a different child pull his ears, is he feeling sick because he ate his food too quickly, did he stand on a sharp stick on his walk and is in pain …), the list is endless. BUT, by acknowledging the bigger picture, we can work on changing the dog’s emotional state so he no longer sees the child as a threat, and therefore does not feel the need to growl when the child is around. THIS is changing behaviour.
In order to make lasting behaviour changes at the base level, we have to dive below the surface and see what is really going on.