Citations for Tests of the Inertia Hypothesis about the Timing of Cohabitation and Marital Outcomes

This post is to provide citations relevant for some of the work Galena Rhoades and I (and colleagues) have conducted on the subject of premarital cohabitation, specifically, the prediction of a timing effect related to when couples moved in together and marital outcomes. 

Before any of these studies were conducted, we predicted that couples who cohabited only after engagement (or marriage) would, on average, do better in marriage than those who began to cohabit prior to having such clear, mutual plans to marry. This is the inertia hypothesis. It specifies that part of the risk associated with living together before marriage is that it makes it harder to break up (it increases constraints)--for some couples, prematurely. Thus, among those who marry, couples who started living together before already having mutual plans to marry will be, on average, at greater risk for poor outcomes in marriage because these couples made it harder to break up before clearly deciding they agreed on a future together. Put another way, the inertia risk is that constraints to remain together develop ahead of a mutual and high commitment to a future together. There should be less risk when dedication is mutual and clear, prior the increase in constraints that comes with moving in together.

The theory behind this is explained in great depth in the citations under “theory” below.

This prediction has found support in every place where we know it possible to test, including findings in 8 studies using 7 different samples. It is a strong hypothesis based on decades of research and theory about aspects of commitment, and it has a lot of evidence of replication. 

For a non-technical summary of this line of reasoning, click here.

For an annotated summary of our research on cohabitation, including abstracts and thinking from study to study, click here.  [This is like a walking tour through our line of research on this issue and related subjects.]
 
My goal here is to give easy access to relevant citations. Where possible, I give links that provide access to the entire article.

Theoretical Papers

The first paper below is the core citation where we lay out the most detail about the risk of inertia and its implications. The second paper is the first major test of the theory and provides a great deal of background about it.  The third paper is a general overview of the construct of commitment, its role in securing romantic attachment, and then a detailed application of ideas related to dedication, constraint, and signaling in the way two people develop a commitment to a future together.  

Stanley, S. M., Rhoades, G. K., & Markman, H. J. (2006). Sliding vs. Deciding: Inertia and the premarital cohabitation effect. Family Relations, 55, 499-509.

 

Kline, G. H., Stanley, S. M., Markman, H. J., Olmos-Gallo, P. A., St. Peters, M., Whitton, S. W., & Prado, L. (2004). Timing is everything: Pre-engagement cohabitation and increased risk for poor marital outcomes. Journal of Family Psychology, 18, 311-318.  [Kline is now Rhoades.]

Stanley, S. M., Rhoades, G. K., & Whitton, S. W. (2010). Commitment: Functions, formation, and the securing of romantic attachment. Journal of Family Theory and Review, 2, 243-257.

Empirical Findings for the Engagement (marriage plans) Effect

Kline, G. H., Stanley, S. M., Markman, H. J., Olmos-Gallo, P. A., St. Peters, M., Whitton, S. W., & Prado, L. (2004). Timing is everything: Pre-engagement cohabitation and increased risk for poor marital outcomes. Journal of Family Psychology, 18, 311-318.

Rhoades, G. K., Stanley, S. M., & Markman, H. J. (2009). The pre-engagement cohabitation effect: A replication and extension of previous findings. Journal of Family Psychology, 23, 107-111.

Stanley, S. M., Rhoades, G. K., Amato, P. R., Markman, H. J., & Johnson, C. A. (2010). The timing of cohabitation and engagement: Impact on first and second marriages. Journal of Marriage and Family, 72, 906-918.

Goodwin, P. Y., Mosher, W. D., & Chandra, A. (2010). Marriage and cohabitation in the United States: A statistical portrait based on Cycle 6(2002) of the National Survey of Family Growth. Vital Health Stat 23 (28). Washington D.C.: National Center for Health Statistics.

Manning, W. D., & Cohen, J. A. (2012). Premarital cohabitation and marital dissolution: An examination of recent marriages. Journal of Marriage and Family, 74, 377 - 387.
[This study has a complicated variant of the marriage plans finding regarding premarital cohabitation.]

Rhoades, G. K., and Stanley, S. M. (2014). Before “I Do”: What do premarital experiences have to do with marital quality among today’s young adults? Charlottesville, VA: National Marriage Project.

Rhoades, G. K., Stanley, S. M., Markman, H. J., & Allen, E. S. (2015). Can marriage education mitigate the risks associated with premarital cohabitation? Journal of Family Psychology, 29(3), 500-506. 

 

Stanley, S. M., & Rhoades, G. K. (2023). What's the plan? Cohabitation, engagement, and divorce. Institute for Family Studies: Charlottesville, VA.

Related Findings (to inertia or cohabitation in general)

The study that kicked off a lot of interest in possibility that cohabitation led some men to marry women they might not have otherwise married, and thoughts about asymmetrical commitment.

- Stanley, S. M., Whitton, S. W., & Markman, H. J. (2004). Maybe I do: Interpersonal commitment and premarital or nonmarital cohabitation. Journal of Family Issues, 25, 496-519.

Constraints predict remaining together net of how dedicated people are to their relationship. 

- Rhoades, G. K., Stanley, S. M., & Markman, H. J. (2010).  Should I stay or should I go? Predicting dating relationship stability from four aspects of commitment. Journal of Family Psychology, 24(5), 543-550.  doi: 10.1037/a0021008

Constraints take a jump up in the transition to moving in together, and start to increase rapidly. 

- Rhoades, G. K., Stanley, S. M., & Markman, H. J. (2012). The impact of the transition to cohabitation on relationship functioning: Cross-sectional and longitudinal findings. Journal of Family Psychology, 26(3), 348 - 358.

Living together before marriage or engagement is associated with asymmetrical commitment between partners, and it does not abate once married. 

- Rhoades, G. K., Stanley, S. M., Markman, H. J. (2006). Pre-engagement cohabitation and gender asymmetry in marital commitment. Journal of Family Psychology, 20, 553-560.

And, a bit more on asymmetrical commitment which includes a few points about cohabitation (not broken down by timing of plans for marriage). 

- Stanley, S. M., Rhoades, G. K., Scott, S. B., Kelmer, G., Markman, H. J., & Fincham, F. D. (2017). Asymmetrically committed relationships. Journal of Social and Personal Relationships, 34, 1241–1259. 

On asymmetrical commitment studies, see also this post. 

This next study examines reasons people give for living together. One finding: Just about the worst, top answer someone can have for moving in together seems to be to test the relationship. That's associated with poor outcomes. Probably, people who report this as the main reason already know something concerning about their partner or the relationship, and they are moving in hoping to get a better answer.

- Rhoades, G. K., Stanley, S. M., & Markman, H. J. (2009). Couples' reasons for cohabitation: Associations with individual well-being and relationship quality. Journal of Family Issues, 30, 233 - 258.

On reasons for cohabiting, see also this post. 

We have more studies that include findings on cohabitation. Contact me if interested. 

Giving Up Options Before Making a Choice--a 24 Minute Audio on The Risks of Sliding

If you are interested in a 24 minute talk on how Sliding (vs Deciding) can lead to losing options before making a choice, I have a new audio for you. Click here. That will take you to a recording of a talk I gave yesterday at an event at the University of Denver. The talk might be just what someone you know needs to know to make wise choices in dating, romance, and marriage.

In the talk, I discuss:

• Puppy Love
• The ambiguity of relationships in this age
• Sliding vs. Deciding
• A brief review of findings on cohabitation before marriage (and why it is especially more risky for some people, at least before engagement)
• How people are often giving up options before making a choice
• The nature of commitment and the anchoring force of decisions

If you want to watch (and not just hear) the Relationship DUI video I use during the talk, it is here.

Inertia Created by Your Past Self Can Impact Options for Your Future Self

One of the ways in which our present self makes poor decisions that our future self has to live with is in the area of cohabitation.  And it’s often not really even “decisions” that we’re talking about. Our present self often slides into things that our future self will have to make hard, careful decisions about in order to make life work.

So, cohabitation is one of those areas where people sometimes get themselves stuck in a place that is not so great and that their future self will have to cope with; by that I mean either to work hard to unravel things or to make a difficult situation work out.  Does it turn out this way, difficult, all the time? Surely not. But some of the time, the nature and timing and “who” of cohabitation is one of the big ways that one’s current self does things that the future self may not be so happy about. Read on a bit more for a great link based on a key idea coming from our work on this subject.

Starting in the late 1990s, I started speaking in various public talks about a potential, large downside to cohabiting prior to marriage for at least some significant number of folks.  The key idea was that cohabitation has more inertia than dating without cohabiting and cohabitation essentially—maybe for way too many couples—makes it harder to break up before you’ve really decided you are sure of a future together. 

Galena Rhoades and I have been published a stream of studies on inertia and other aspects of the ways that commitment develops (or fails to) in relationships that can last a long time, regardless.  
There is a great column today capturing this idea of inertia, and since I’ve been too busy recently to write another entry here, I thought I’d direct your attention to it.  It’s very smart and well stated stuff. (Thanks for the heads up, Bill C.!)

Washington Post Column by Carolyn Hax

If you want to recap my favorite blog entry ever on the subject of inertia, it’s this one about the inertia of tech platforms and how similar that is to relationships.  I enjoyed this one a lot.

My blog on inertia and technology--applied to romantic relationships

And lastly, for those of you who want to read a summary of our studies in this area and on the general theme of commitment dynamics in developing romantic relationships short of marriage, see the paper at this link if you like.


Be kind to your future self, now!

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From Playlist to Paylist: iPods, iPhones, and the iNertia of Cohabitation

I’ve always been into music. You didn’t ask but my tastes are very eclectic if you’d like to know. My father, who passed on last year, was a geek before the word was popular. He was an electrical engineer with a pocket protector, but on top of that, he was into music—playing it (piano, organ) and listening to it with top-of-the-line audio equipment. That means I grew up around great speakers, tape players, and high quality turntables. (You could call the latter “record players” but seriously, we called them turntables. They sort of looked like things you’ll see some Hip Hop bands using now-a-days, in case you’ve never seen one.)

What would have been unimaginable when I was growing up was the mp3 player. When I was little, the closest things we had to something small you could carry around and listen to were transistor radios. A 9 transistor radio was a sign of impressive technology, back then. “Wow, bummer Tim, but it looks like you only have 6 transistors.”

The revolution in music listening, for me, came when mp3 players were out for a while and I realized you could pack a lot of music onto the little things and stick it in your pocket and have it with you wherever you went.

It was obvious to me, from even early on, that there was inertia built into whatever pathway one chose into digital music. Early decisions could take on a lot of weight in terms of how you’d be listening to music (and how much you’d pay) years and years later, or how often you’d have to re-rip your CDs or rebuy your mp3 songs. I resisted iPods for a long time for three reasons. First, I just didn’t want to be assimilated into the Borg. You had to commit to the Apple eco-system to get the most out of iPods. I was a PC guy then and really still am (though, geek that I am, I also have a MacBook, and I like it. For a little PC Mac humor, see my past entry here.)

Second, being into PCs more than Macs, I went with Microsoft’s commitment to the WMA format. Apple and iPods used the AAC format, and you could not play the files from one system in the other (for the most part). Third, I had always thought, and still do, that there are some non-iPod players that just sound better than any iPod device o iPhone ever made—like just about any model Sony mp3 player, for example. I will spare you the technical reasons why this is true.

I finally succumbed to iPod and now iPhone; not because of sound quality but because of ease of use.

ABRUPT SHIFT TO RELATIONSHIPS HERE

I and my colleagues have been working with a theory of what’s risky about cohabitation prior to marriage. It goes like this: all other things being equal, compared to dating without cohabiting, if two people are sharing one address, they will have a harder time breaking up, even if the relationship has serious weaknesses or problems. The reason is that cohabitation has more inertia than dating but not cohabiting. Whether or not one believes it is right to live together outside of, or before, marriage is determined by values and religious beliefs. That’s not my topic in this post. I’m focusing here on inertia, here.

Inertia is a great concept from physics speaking to the amount of energy it would take to move something a different direction than it’s already going (or to get an object at rest moving at all). I and my colleagues (especially Galena Rhoades) have been testing just about every prediction we can related to the theory of inertia and cohabitation. We have consistent, extensive evidence for it. What about cohabitation creates inertia? I’m not going to take space to give you a list, but just pause for a moment and think about it. Really. Just take a minute. You’ll think of a lot of things that can make it harder to break up after a couple moves in together and lives together for a while.

An easy way to think of why inertia matters comes from thinking about two different types of commitment: Dedication and Constraint. The inertia problem with cohabitation comes from the fact that too many couples increase their constraints for staying together before they fully have clarified their mutual dedication to be together. That gets to why, for example, we have predicted and found, over and over again, that couples who wait until marriage or at least engagement (or some other serious, mutual, public plans to marry) report, on average, more marital happiness, less conflict, more compatibility, and on and on. [For those who believe that one should not cohabit before marriage, engaged or not, realize that I’m focusing here on one of the major explanations for why cohabitation can be a risky, not making a recommendation for how to cohabit before marriage.]

PLAYLISTS AND PAYLISTS

Okay, to repeat. I’m a geek. I read the computer magazines regularly and I read a lot about the stuff on the web. I was delighted this week to come across a wonderful article where a real tech writer likened her experiences with her iPhone to all the points I made above about relationships. The author’s name is Marguerite Reardon, and you can read her whole article here. Please check it out after you finish reading tis post. I’m going to give you a few quotes from her write-up.

She writes:

But sadly now I’m feeling a bit stuck with Apple. I’d like to check out other smartphone platforms, but doing so is going to require some work on my part. Like many who have been sucked into Apple’s clutches, it was innocent in the beginning. . . . Initially, I didn’t realize the commitment I was making. I didn’t think about the fact that I was locking myself into a platform for the rest of my life. But with each new product I bought from Apple, the deeper I fell into the borg. And now I feel like it would be painful to break up with Apple. Not because I love the products or company so much, but because it would be a huge pain in the butt to transfer all my stuff to a new platform. (used by permission)

This is a great definition of what I now officially dub iNertia.

iNertia = That effort it would take to move all your stuff to a new platform.

You moved in with iPhone? How much effort would it take to move out and move in with Android? (I do suspect an Android might be better at doing the things around the home you hate to do.) Or to move to, or back to, Windows Mobile?

And now for my favorite lines in Marguerite Reardon’s piece:

It reminds me of my mother’s relationship advice: Never move in with a boyfriend before you’re married. Not only will you not have any place of your own to go when you have a fight, but when you start combining your lives before you’ve really made that life-long commitment to marriage, it’s much harder to break up if things don’t work out. It starts feeling more like a divorce than a run-of-the-mill break-up.

This is a smart woman with a smart mom. I bet her mom has a pocket protector. She has to, since she has such an excellent grasp on prevention. I can’t really sum up what inertia says any better than that. She gets how iNertia has built up around her use of iPhones, iPods, and the whole Mac ecosystem, and she gets how this is exactly how some people get on the wrong path with this or that partner in life.

Think about romantic relationships before marriage. Metaphorically, what in romantic life has the same type of implications as the path one is on in terms of music format choices, device options, and an ever expanding list of apps? Don’t just think about cohabitation. Cohabitation is just the easiest way to explain inertia as it affects developing romantic relationships. There are many other aspects of how relationships develop that have the same effects. Can you see them? Are you living them?

If you are looking for the love of your life, you don’t have to be assimilated by the Borg. You can at least keep it from happening by accident.


NOTE: If you’d like a more formal review of our research on cohabitation and inertia, see the link at the left of this page (under “Linkage”) for a document you can download that reviews our published studies. It’s the “summary of our research on cohabitation” link. We have a lot more coming in the pipeline.

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First Comes Love, Then Comes . . . What?

There has been a growing awareness among social scientists that marriage and childbearing have become increasingly disconnected in U. S. society. In fact, from all the things I read, the old nursery rhyme that implies a sequence from love to marriage to a baby carriage is increasingly true mostly for those with college degrees and less and less true for great numbers of women and couples in the U. S. This is a huge change. It could easily be the largest change in family demography over the past 40 years. Social scientists and policy analysts endlessly debate if this trend portends something ominous or if it is just some kind of normal societal evolution. Whatever you think on that matter, it’s certainly true that fewer children than ever before will be raised throughout their childhood by their own two parents. Further, many studies suggest that a child has some advantages (on average) in life when raised by his or her own two parents. There are many complex (and likely less complex) reasons why that would be so. (And, it’s always worth pointing out—seriously—that there are many couples raising their own children together where it’s not exactly a wonderful thing for those children to have their parents together and there are vast numbers of single parents doing an amazing job of raising their children.)

The delinking of marriage and child bearing/rearing is not as simple as it sounds. Marriage has become unlinked to childbearing but that does not exactly translate directly into unmarried parents not raising their own children. Increasingly, cohabiting couples are giving birth and remaining together as they raise their children, at least for some period of time. But, while we all know married couples have a hefty risk of divorce, this does not mean that the math looks identical for cohabiting couples. Most social scientists understand cohabitation as something that represents a much wider range of variability than marriage. By this I mean something quite simple. If a couple tells you they are cohabiting, you don’t know a lot about that couple from only that little bit of information. They could be more like a dating couple than anything else or they could be quite a bit like a married couple—and anything in between. Cohabitation as a form of relationship is far less informative about a relationship than marriage. If a couple tells you they are married, you’d have higher confidence in thinking you knew certain things about them as a couple. Broadly speaking, marriage often but not always reflects greater levels and clarity about commitment. That is why the average married couple who gives birth is far more likely to still be together when that child is two (or pick any other age) than the average cohabiting couple who gives birth. On average, cohabitation is a more tenuous context for children because there is greater vulnerability about commitment. So, the great increase in the number of children born out of wedlock, even when born to cohabiting couples, does translate into ever fewer children being raised by their own two parents.

My colleagues Galena Rhoades, Howard Markman have been studying what types of factors make it more likely a non-married couple will be together one year later. (We’re actually very interested in who is together many years later, but what we’ve analyzed so far is the one year point.) Obviously, the level of dedication one has to their partner is a factor in who will still be together in a year; those who want a future with their partner are more likely to stick to the path of having that future.

But there are other things that make it likely that a couple will remain together. In two separate studies in our lab that Galena Rhoades headed up, we find other interesting factors that predict who will remain together. For example, having a lease together, a joint gym membership, a pet, making payments on each other’s credit cards, making home improvements together—and many other such behaviors—are all associated with it being more likely a couple will be together in the future. That makes tons of sense, right? Those things reflect an increasingly intertwined life together. These types of things are part of a broader view that I and other has suggested: that there are a lot of reasons couples remain together, and some of those things are about how intertwined two partner’s lives become, and how that can make it harder to leave no matter what your level of interest is in staying. I call all such things that make it harder to leave—should you want to leave—constraints. Couples stay together because of both dedication to remain together and constraints that make it harder to part. Constraints are things that make it costly or more challenging to leave. In those two studies we have coming out, we show that all sorts of simple things—various other constraints we measure and simple behaviors like those listed above—make it more likely that non-married couples will remain together regardless of their level of dedication to remain together. (This is all true for married couples, too.)

Back to babies and couples. In one of these studies we have in the pipeline (accepted for publication) we found that all sorts of things make it more likely that a non-married couple will remain together. Things as serious as signing a lease together or sharing finance as well as less serious things like having vacation plans or a gym membership. But do you know what didn’t predict which couples would remain together? (Um, I just gave you a pretty huge clue, right?) Yes, having a baby together didn’t affect the odds of the relationships continuing. By the way, were talking about a very large national data set here of non-married people in serious romantic relationships who are generally in their 20s and early 30s. Yes, having a baby together is not one of the things that is associated with being together a year later (and we’ll be checking in the future out to two and three and four years later).

What’s that mean? It seems to me that it means things are tilting toward the place where not only is childbearing and rearing increasingly disconnected from marriage, they are becoming increasingly disconnected from remaining together as a couple who has any kind of future together, except maybe as co-parents. That makes it seems like (a whole lot like) some of these things we are measuring (like sharing finances or a pet) are decisions that reflect more about the future of the relationship than conceiving and bearing a child together. Think about that one a bit and I’ll pick up more about these issues next time.

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How Endowed?

I’m back now and ready to write a bit more about the endowment effect. To recap, this is a well-known, potent mechanism wherein people come to value things they already have more than they would value them if they did not have them. It applies to anything but I’m applying it to romantic relationships.

Let’s focus on the downside of this. As I noted in the prior post, the upside of this is that, in good marriages, this effect adds to the total forces of commitment that help you keep on doing what you promised to do—in ways that benefit you, your family, and your children. On the other hand, let’s think about all the relationships, like dating relationships, where some people get stuck with a not very good thing.

What the endowment effect means, in part, is that it’s easy to be biased in thinking that what you have is better than it is. Don’t get me wrong. If what you have is really good and maybe has a wonderful future, nothing I or anyone else is going to write or say will change your mind about it. In fact, don’t give it another thought. But think about a person who’s hanging around and dating someone who’s really not very good for them. It could be that the partner is just not the right type of person or even that they are dangerous in some way. Sometimes people overlook things that really do matter in terms of how their future could turn out as a couple. What might one overlook?

• Drug addiction or abuse
• A lack of a desire to have children when you know that you really want to have children sometime
• Differences in religious beliefs that you think don’t matter but you kind of know it might in the future
• Problems being responsible with money
• Completely different desires for how to spend free time

These are just a few of the types of things that relate to long-term happiness together that some people try very hard to believe just won’t matter. By the way, it’s possible that you are reading this and you realize that you are the one who brings more problems to your relationship and that maybe it’s your partner who should be thinking carefully about you. If that sounds like you, problems in your own life are things that you can work on. It’s possible to change. There are a lot of ways to get help, including religious organizations, community agencies, community mental health centers, jobs services, so forth.

Back to my main point: The endowment effect works on most everyone, and when you are in a relationship that has little chance of a solid future, it can be just one of the factors that makes it hard to get an accurate picture of what your future really would be if you married this person. Does the relationship have real value or is it just a mirage?

Safety note: It’s possible that someone who reads this is in a relationship that is dangerous. If you are in a relationship with someone who can be dangerous or who is highly controlling, you should know that the time one leaves such a relationship can be a particularly dangerous time. If that’s you and you are thinking through your options, find a way to make contact with local or national domestic violence workers who know how to help people increase their chances of staying safe. The national hotline number is: 1-800-799-SAFE(7233)

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Well Endowed: The Endowment Effect

Okay, that’s a bit of a misleading title for this post, but I am going to say some things today about the Endowment Effect.

First off, a definition: The Endowment Effect is psychological effect discovered by research psychologists and behavioral economists. It reflects the now well-proven fact that people place a greater value on a thing they already own than they would if they did not own that thing and had to buy it.

Kahneman, Knetsch and Thaler studied this effect in this way. What they did is give some participants in a study a mug—yes, like a coffee mug. They did not give other participants a mug. Then, they simply examined how much the people with the mugs would be willing to sell them for (around $7) and compared that to how much the people without mugs were willing to pay for one (around $3). The interesting thing here is that these participants only differed in whether or not they happened to be given a free coffee cup. But once owned, they want more to part with it then they’d have been willing to pay for it in the first place. Quite a bit more, in fact. There are now many studies that show this same phenomena in all sorts of ways.

Psychologist Daniel Kahneman would relate this to his brilliant work with Amos Tversky that showed, in many ways, that people are more motivated to avoid loss than to attain gain. (I say “brilliant” because, after all, they do reflect my own chosen discipline of psychology. Other than that, I’m sure I have no biases, endowment or otherwise.)

Economist Richard Thaler also named this effect the “status quo bias,” because it reflects the fact that it favors keeping what you already have. By the way, this goes a long, long way toward describing why some people do so poorly when they have a garage sale. They are just too attached to their junk. Those who come by are judging from a different standpoint, one that is closer to the real market value of the stuff. (I personally believe that the main purpose of a garage sale is not to make money but to get other nice people to come to your house and carry away all your junk.)

There are some tricky implications for romantic relationships here. For example, for the average pretty good to great marriage, the Endowment Effect helps you stick to their commitment when times are a bit tougher because you so highly value what you already have. And you should, because you’ve invested a lot and what you invested would result in a lot of loss if you don’t stick. If you are married, have built a life together, have children, and all sorts of other things, you are, so to speak, very well endowed.

On the other hand, what if you are dating and trying to find the right person to spend your life with? This Endowment Effect also means that you can easily get too settled with a current partner who’s not really a good long-term fit, and not move on when maybe you should.

I’ll go a bit deeper on some of the implications in my next post. I have a very busy week coming up, so it may be a bit more than a week before I get back to you. But I will be back!

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