What kind of impact (permanent or temporary) can parental quarrels have over a child on the short-term and on the long-term?
I wish to know if some studies have been done on the matter. Answers with references will be appreciated.
I can't find a great deal of hard-data on this particular topic (impact of parental fights on children), but I do find a lot of resources on the short-term and long-term effects of parental divorce.
While it may be arguable that parental divorce is a "petty issue", I'm sure it can be agreed that there's a link somewhere between the quarrels and the more radical (and probably also more traumatizing) step that is the divorce or the separation of the parents.
Then I also find a ton of sites and blogs covering the matters of parental quarrels, fighting in front of kids, etc... But none that seem to back their hypotheses with any sufficient data, so I won't include them here. For instance, this link mentions "new research" but doesn't quote or source anything, and it tends to be often like these, so I'd dismiss most of that as without any valid claims.
For a more complete list of resources, see:
Image courtesy of Baby Blues.
I stress that this being personal and unsubstantiated and in no way qualifying as research or hard-data, it is to take with the same care as the blogs or sites I criticize above for lack of due process and research data. I Ain't A Psychologist, and I'm not a published scholar in this area either. Plus for all you know I may not have kids or know these people.
I have, probably like anybody, a number of acquaintances in my circle who are going through difficult family times. This won't count as hard data so it is to take with a grain of salt, but in some cases I've noticed very drastic changes in a child's behavior do to parents quarrel. I assume this may change from child to child based on their previous upbringing, and on their age as well, and that it will depend on various other factors (intensity of fights, recurrence, etc...). However, what I can say is that I've noticed these children to be more sensitive and more prone to overreact to tense situations, and have a stronger tendency to be also more extreme in their expressions.
I suppose one can surmise that as they see violence or exhuberance in adult communication, they integrate it as normal and will resort to this, and that they will want to attract attention in some cases and use these parental tensions to their advantage in others.
But I Ain't A Psychologist or Therapist.
In answering this, you are better considering a comparison between the quarrelling and the realistic alternative to it, not just the bickering in isolation. Here's how I'll define the situation:
The parents can't stop bickering, criticizing, squabbling, and putting each other down. The children are learning that this is how relationships work. They also feel criticized if they hear squabbling over something that involved them (you shouldn't have bought that toy, taken the child to that place, been late, etc). While there's no hitting, there is a constant stream of negativity.
Imagine three cases:
there isn't much good in the relationship, just bad, and the parents separate. The children no longer witness the fighting, which is good. However they see each parent less than they did before, and probably have less money than before. In most cases I've seen, the separation is an overall improvement for everyone, which is a measure of how unpleasant the squabbling was.
the parents get counselling and learn to speak to each other more respectfully, and to moderate the sniping and complaining in front of the children. The children learn that there is more than one way to handle a problem, and that it's possible to learn and grow. They probably also learn whatever techniques their parents have just learned. This is a great outcome but most likely cannot be done singlehandledly.
the parents continue to bumble along appearing to entirely dislike each other, but not separating. Perhaps one parent says something to the children about it from time to time, perhaps not. Over time, whatever was behind the squabbling (a shortage of money, not enough time to relax, worries over someone's health) goes away and the parents end up in a better place. The children may be completely messed up about relationships, or they may learn that patience and perseverance are good qualities. They will certainly learn that things can change over time.
The thing is, it's not "stop squabbling, you're wrecking your children." Because in some ways, we're all wrecking our children, by pushing them too hard or not pushing them or giving them too much on a silver platter or not giving them enough or being a doormat or being a perfectionist or whatever. The real question is, has this got so bad and so unfixable that I would be wrecking them less if we separated, or can we just muddle along? Or can I use worry about the children as a way to persuade my spouse to join me in making things better (for all of us) by getting counselling? Because if "just don't argue so much" was an option, doubtless the parents would have already chosen it.
There is some research on the impact for children of parental fighting. The short answer is that a lot depends on what the "fighting" is like --- conflict is a normal part of any healthy relationship, and having conflict with your spouse doesn't necessarily damage your kids. In fact, modeling for your kids how loving adults can healthily resolve a conflict can be an extremely valuable lesson.
But some kinds of parental fighting can make children feel stressed and insecure. Moreover, parental fighting can affect parents themselves, making them feel bad or unsafe, which in turn impacts their ability to parent effectively. When destructive fighting occurs over a long period of time, it can have a negative impact on children.
There is a large body of literature on parental discord and its effects on children. Try searching terms like "parental discord" or "family conflict" in google scholar (here are some results of such a search). A lot of the research on this topic may not apply to your family, though --- many researchers include abusive behavior (emotional and/or physical) when they measure discord, so lots of those studies won't necessarily apply to families with less intense conflict. To try to understand better where your situation (the nature of your arguments with your spouse, and the characteristics of your kids that may make them more or less resilient) fits into the kind of conflict that has been studied by scientists, start reading through articles like the ones listed and keep an eye out for how they defined conflict. Also notice the other articles that are cited while you read; if a cited article looks like it would be relevant, try to look up that article so you can read it in full.
Here is a blog post by a developmental psych researcher summarizing her views on the topic, including her review of the book Marital Conflict and Children: An Emotional Security Perspective by Cummings & Davies, which you might like to read for a more in-depth perspective on this issue. If you want something shorter than a book, here and here are scientific articles by the book's authors and some colleagues on the same topic.
There's also a study from some of my colleagues at the University of Oregon on how sleeping infants react to the sound of their parents arguing which you may have seen covered in the news a couple years ago. They focused specifically on less-extreme kinds of conflict (they looked just at angry voices during arguments).