That I like
that's something we all need to remind ourselves whenever a new study comes out on the benefits of xyz over abc
Well if causation is established, or even if Occam's Razor says the most likely culprit is that neutering/not neutering caused a certain thing, then sure, it's not unreasonable to make that leap.
But in many (if not most) cases, particularly in the realm of behavior and psychology, where things are not so concrete, it becomes very difficult to move beyond correlation.
So it is important to note that when a study says "neutered males may be more aggressive" - well, that's probably true, assuming we have a well-formed study. BUT...why
are they more aggressive? The jump most people will immediately make is that neutering causes aggression.
But, isn't it more likely that an evaluation of neutered dogs vs intact dogs will find neutered dogs more aggressive on the whole, because typically neutering is encouraged as part of a treatment for unwanted/unwarranted aggression? You're neutering them, you aren't performing brain surgery. It probably WILL affect the behavior but at the core, a dog just like any other creature is still a product of his genetics and environment.
Dogs without problem behaviors are more likely to be left intact, again, on the whole.
That would be my explanation as to why a study says neutered dogs are more aggressive. I find it very difficult to believe (excepting cases of pre-pubertal neutering, I can believe that messing with the hormones and the natural mental maturation process could
cause undesirable behaviors, including certain types of aggression - but that's just my unfounded opinion) that neutering a dog will CAUSE him to become aggressive.
I would definitely believe that neutering an already aggressive dog would still leave him with some level of aggression that is above that of a dog without aggression problems.
And, again, as a disclaimer, let me stress that I'm talking "in general." With over 75 million owned
dogs in this country, I'd find it to be sheer lunacy if there were no exceptions to that rule, particularly when we are talking about something as complex as behavior.
So any time one sees a study like this...it is important to be very careful not to leap to the conclusion that most closely matches your ideology. It's an impulsive instinct. Put on your skeptic hat and use your critical thinking skills to think what all the possible explanations might be for that correlation
to be found.