History: Past Experiences or Lack Thereof  

Past experiences can play a big role in why dogs act aggressively. Obviously, this can mean a history of bad experiences but, less obviously, it can also mean a history that lacks good experiences or simply lacks experience in general. Let’s look at a few possible problems that can stem from a dog’s history: 


If something works, we tend to keep doing it and so do dogs. When dogs have a history of a behavior working out well for them, we call that a reinforcement history. After all, the term “reinforce” means to make stronger, right? When it comes to behavior, make stronger means to increase in frequency or intensity. So, it would only make sense that aggression which has been reinforced will not only continue, it will likely escalate in frequency and intensity. Below are just a few examples of how aggression might be reinforced: 

  • Makes Things Go Away: If a dog is annoyed, frightened or territorial and aggression makes the source of that fear, annoyance or threat go away, then the aggressive behavior was reinforced via the sense of relief given by the increase in distance.    
  • Releases Tension: If a dog is agitated in some way and aggressive behavior releases some of that tension, frustration and pent-up energy, the aggressive behavior is reinforced via the pathway of relief.  
  • Winning Battles: Being the victor feels good. It builds confidence, increases dominance status, allows access to resources, etc. Dogs with a history of victory tend to be more inclined to go to battle again. This can happen by winning a dog fight or by guarding the food bowl from a human or any number of other situations in which the dog “wins” by using an aggressive tactic. 

Dog Fights

A history of getting into fights or being attacked by other dogs can create a sense of fear or defensiveness around other dogs. For some dogs, even just one bad experience can cause them to develop a lifelong fight or flight response to other dogs. This is especially true if a fight or attack happens to a dog that does not have a long history of good dog interactions under their belt. This is why early socialization with other dogs (good dogs that won’t attack your puppy) is so important. 

Note: A reasonable correction from another dog does not qualify as an attack. Puppies actually need to learn about corrections. A correction history is super important and will help avoid trauma from a fight or an attack, should one occur. 

Dogs with a history of fighting often learn to anticipate fights or attacks. This puts them on edge when approached by other dogs, which can trigger a fight. They may react aggressively out of fear but some dogs will actually learn to enjoy fighting. Winning fights feels good, builds confidence, increases dominance status, allows access to resources, etc. Some dogs will learn that fighting gives them power or they may simply learn that the best defense is a good offense. You know, sort of a “get them before they get you” sort of thing. Losing fights, on the other hand, can lead to defensive or fear-based aggression. 

Dogs can have small fights (arguments) and be ok, especially if they already know the other dog well or have a long history of pleasurable dog-on-dog experiences, but full out fighting is something we really want to avoid as much as possible. What’s the difference? If it carries on for more than a matter of seconds, it is probably more than just an argument. (Note: 10 seconds of dogs fighting feels like an hour.) If you can’t break it up quickly and easily, it is probably more than just an argument. If there are serious injuries (something more than a scratch or a nicked ear), it was definitely more than just an argument. 


Staring in a dog’s face, making growling sounds or barking at a dog, waiving food or toys at a dog but not letting them have it…this is teasing and, make no mistake, it is not cute or funny. Teasing is bad, so just don’t do it. 

A history of being taunted and teased by humans (most often children or teenagers) can lead to dog aggression. Basically, the dog finally gets sick of it and lashes out. Some dogs will simply have no tolerance for this sort of agitation and will bite right away. Others tolerate it for a while but eventually get sick of it and lash out. 

Fortunately, most dogs will give a lot of warnings before they actually bite. Unfortunately, this causes some people to take it for granted that the dog won’t bite and continue teasing and taunting the dog until one day the dog finally bites them. Some dogs never actually bite but some do and some wind up biting very seriously, so this is no laughing matter.  

A dog with a history of being teased may come to mistrust humans. They are more likely to misinterpret innocuous behaviors or approaches from humans as threats and react aggressively towards an innocent person who was not even doing anything wrong. 


Whenever people see a dog that is aggressive, particularly if the dog is aggressive towards humans, their first reaction is to say that “the dog must have been abused.” Of course, abuse does happen but it’s not as common as people tend to think and, as we’ve covered throughout this series, there are many other causes of dog aggression. That being said, dog abuse is a real thing and we need to talk about it.

Let’s start with the obvious. It should be obvious that hitting, kicking or yelling at a dog might trigger a fight or flight response. To assume that the dog will accept such an assault without fighting back is foolish. Then, of course, even if the dog does simply cower from the initial assault, the next time they may be prepared to defend themselves more aggressively. 

Much like what we saw with teasing, a dog with a history of mistreatment may misinterpret innocent human behavior as some sort of threat. This can lead to defensive or fear-based aggression that may seem unwarranted, unpredictable or “out of nowhere” to whomever winds up on the receiving end of it. 

What is less obvious to most folks is that even mild punishment can be abusive if it is delivered in a way that is unclear, unfair or unpredictable to the dog. In other words, if the dog has no idea why a punishment is happening, or how to avoid it, it is abusive. (see: Top 8 Punishment Mistakes

Important Note: Just to be crystal clear; I am not saying that all punishment is abuse. To the contrary, the fair and functional use of punishment (aka corrections), in combination with rewards, is far from abusive and does not make dogs aggressive. In fact, balanced dog training is commonly used to rehabilitate aggressive dogs. Many dogs we see here at Thriving Canine became aggressive in the first place due to spoiling and well-intended attempts to use “positive-only” training tactics. 


Most of us would agree that neglect is bad and that it should probably be included as a subcategory of abuse. At least that’s what we think when we see those videos of malnourished, flea ridden dogs, chained up and shivering in the cold while a Sarah McLaughlin song plays in the background, right? Clearly, that is neglect, and it’s easy to imagine how neglected dogs can be aggressive due to being fearful, untrusting and disconnected. However, much like we see with abuse, there are also more subtle forms of neglect that we often overlook and struggle to see how they can be causal factors in aggression cases. 

What if we block out the horrific images of hoarders with a bunch of starving dogs and simply interpret neglect to mean “failure to care for properly”? 

By that definition, I would postulate that there are much more innocent versions of neglect that go unrecognized by well meaning, loving and caring dog owners all the time. Many people who love their dogs dearly, “neglect” to provide them with enough exercise, socialization, training, fulfillment, leadership and so forth. As we’ve seen throughout this series, all of these things can be underlying factors in dog aggression cases. 

Yeah, yeah, Ok, I hear you, perhaps neglect is too strong a word but I wanted to drive home a point, which is this: Providing food, water, shelter and affection is simply not always enough to avoid dog aggression. I can’t tell you how many aggression cases I see where the owners are baffled and bewildered and just “can’t understand why” their dog that they “have never mistreated” behaves that way. Here’s the deal; just because you never hit the dog doesn’t mean you have “cared for the dog properly.” It takes a little more than that. That’s all I’m saying. 


This article covered but a few past experiences that could play a role in why your dog behaves aggressively at times. Hopefully the takeaway is that your dog is probably not just “being mean” for no reason. In many cases, unfortunately, we don’t even have a historical record other than that the dog was found roaming the streets, so that leaves a lot of room for guesswork. However, if we are fortunate enough to know something of the dog’s history, it can help us to understand and appreciate why he might behave aggressively, which can help us devise the best rehabilitation plan moving forward. Either way, we can’t go back in time, we can’t rewrite history but we do have the ability to write a better history moving forward. 

Everything a dog experiences today, tomorrow it will be their history. 

Chad Culp – Certified Dog Trainer, Canine Behavior Consultant, Owner of Thriving Canine. 

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Related Content:

Triggers and Underlying Causes of Dog Aggression: Part 1: Tight Leashes

Triggers and Underlying Causes of Dog Aggression: Part 2: Hyperactivity and Anxiety 

Triggers and Underlying Causes of Dog Aggression: Part 3: Overly Intense Play

Triggers and Underlying Causes of Dog Aggression: Part 4: Fear and Anxiety

Triggers and Underlying Causes of Dog Aggression: Part 5: Frustration and Agitation

Triggers and Underlying Causes of Dog Aggression: Part 6: Obnoxious Submission

Triggers and Underlying Causes of Dog Aggression: Part 7: Dominance

Triggers and Underlying Causes of Dog Aggression: Part 8: Misreading Social Cues

Triggers and Underlying Causes of Dog Aggression: Part 9: Pain or Stress

Triggers and Underlying Causes of Dog Aggression: Part 10: Guarding, Protecting and Spoiling 

Triggers and Underlying Factors of Dog Aggression: Part 11: Genetics 

Triggers and Underlying Factors of Dog Aggression: Part 12: History

Triggers and Underlying Factors of Dog Aggression: Part 13: Rude, Inappropriate or Non-Consensual Behavior