How the Minds of Long-Term Couples Connect

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Science (and probably your own experience, too) shows that cognitive decline is normative and to be expected as we age. One particular area that shows the most noticeable decline is memory, and, more specifically, episodic memory—the kind responsible for remembering what the capital of Brazil is (hint: it’s not Rio de Janeiro) or where you left your keys the other day (sorry, can’t help you there).

However, if you, like many others, are tempted to say, “It’s all downhill from here,” don’t despair. New studies have brought us some good news. At least for those of us who are aging in couples. Over time, long-term couples appear to develop a joint memory system that facilitates their individual access to shared knowledge. In other words, even as intra-personal episodic memory may decline, the inter-personal memory matrix appears to grow.

The Transactive Memory System (TMS)

Back in the ’80s, researchers (cf. Wegner et al., 1985, 1987) recognized that when we age in social systems, e.g., friends and families, we pull together from the joint cognitive resources of the group. This is referred to as a transactive memory system (TMS). In such a system, a person can pull from the knowledge and resources of the whole, which facilitates their individual functioning.

For instance, you may not be able to jump-start a car or say “I need a bathroom” in German, but know that you have a close friend or a relative who does. As long as you are aware of their knowledge and skills, you can utilize them. It is as if the people in our tribe are also resources to which we have immediate access.

Enter: Couples Research

In a recent study (Bernier, Harris, Morris, Savage, 2018), researchers found clear evidence that long-term couples develop interconnected memory systems, which facilitate each individual’s recall. The authors studied 39 couples who had been married between 13 and 65 years (mean of 49 years of marriage) by giving them three separate memory tasks: recalling a list of words, reciting all the countries in Europe, and listing the names of their mutual friends. The results demonstrated that couples did significantly better when recalling together, especially as the personal relevance of the tasks increased. These effects were even more pronounced when the individuals in the couple exhibited discrepant personal abilities or, in other words, they complemented each other.

One reason for this phenomenon may be that couples tend to develop specific conversational styles, which then facilitate recall. Our partners literally know how to give us prompts that will be personally meaningful and thus elicit sought-after memories (Hyden, 2011). Further, recent research has provided support for the theory that in long-term marriages, individuals literally impact each other’s brain synapses. Using functional magnetic imaging, Shi et al. (2019) demonstrated that the participants in their study—couples who had been living together for over 30 years—have significant special similarities in certain brain regions. What is more, the longer the duration of the marriage, the more “long-term marriage would shape brain network organization.”

Remember that “all downhill from here” thought? Turns out that episodic memory is exactly where the shared memory system in long-term couples shines the most.

Benefits and Gender Differences

So, who benefits the most from a shared memory system? Harris et al. (2022) discovered that couples’ so-called “collaborative facilitation” is dependent on effective communication strategies. This is consistent with prior research, in which the authors (Harris, Barnier, & Sutton, 2014) emphasized that the facilitative impact of joint remembering is the highest in couples who report better intimacy. In other words, couples who effectively utilize communication strategies, lean on each other, and know each other better tend to benefit the most. (Learn more about behaviors that undermine intimacy here.)

Long-term couplehood appears to have other cognitive benefits, too. Recently, it was discovered that married couples have a significantly lower risk of developing dementia (Sommerland et al., 2017). Interestingly, however, when it comes to leaning on each other, in heterosexual couples, it appears that men tend to rely much more heavily on their spouses than women do, and even more so with increasing age (Harris et al., 2022). Moreover, men appear to also turn to their wives more frequently when it comes to the use of external resources and networks maintained by their spouses (not only internal knowledge). This finding, in particular, is consistent with existing research about the inequality in day-to-day cognitive load and labor in heterosexual relationships (Ahn, Haines, & Mason, 2017).

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