Theology and Evolutionary Psychology, Chapter 3: His Needs, Her Needs

Okay, back to our series on evolutionary psychology and its implications for theology.

Perhaps the biggest successes in evolutionary psychology have been in the area of sexuality. This should come as no surprise as we have already noted that both natural and sexual selection are sexy. For a good primer on this research read The Evolution of Desire by David Buss, a pioneer in this area.

But let's back up. When my wife and I were newlyweds, we signed up for a class at church for young married couples. Our study was using the widely used book His Needs, Her Needs where author Willard F. Harley describes the different relational and sexual "needs" of husbands and wives. The subtitle of the book is "Building an Affair-Proof Marriage." One of the premises of the book is that if she can get educated about HIS needs (he's more sexualized) while he gets educated about HER needs (she's more interested in emotional intimacy), then couples can better identify and satisfy their mutual needs. Many of you probably know this book because it has become a staple in many churches and many marital seminars borrow parts of its main thesis.

Now, His Needs, Her Needs does get a lot right. Sexually speaking, men and women ARE different. And I don't simply mean anatomically. I mean psychologically.

To illustrate this we can note that:

1. More sexualized (i.e., more likely to engage in masturbation and casual sex).
2. Stimulated, to a significant degree, through visual cues.
3. Less interested in a mate's ability to acquire resources.

1. Less sexualized (i.e., less likely to engage in casual sex).
2. Stimulated, to a significant degree, by emotional/relational cues.
3. More interested in a mate's ability to acquire resources.

As they say, men are from Mars and women are from Venus. His Needs, Her Needs begins with these differences and reasons from there. Evolutionary psychology backs up and wants to answer the question: Why are there these differences?

The best way to illustrate the evolutionary answer to this question is to use the concept of minimal parental investment (MPI). That is, what is the MINIMUM investment a male can make relative to a female to produce a viable offspring? We focus on the minimal investment because natural selection is very conservative and minimal investments provide the adaptive starting point.

With MPI in hand we can now succinctly state the root answer to the His Needs, Her Needs differences. The reason why men and women have different sexual psychologies is this:

Female MPI > Male MPI

That is to say, there is an asymmetry between the genders concerning their minimal parental investment. To illustrate this, let's make a few contrasts:

What is the MINIMUM time investment between the genders to produce a viable offspring?
Males: 3-5 minutes:-)
Females: 9 months.

Female MPI > Male MPI

What is the relative VALUE of the reproductive cells when we compare men and women?
Males: Sperm are produced in the billions, daily and across the lifespan (a vast and renewable resource).
Women: Eggs are limited, about 480 released across the lifespan, one each month (a finite and precious resource).

Female MPI > Male MPI

What RISK does the male and female face if impregnation occurs?
Male: Zero.
Females: Her very life.

Female MPI > Male MPI

You get the point. To summarize, when a woman has sex with a man, she risks everything. She is spending her one egg for the month on him, investing nine months of her life if impregnation occurs, and risks her very life at childbirth. Adaptively speaking, sex is downright scary for a woman. A literal matter of life and death.

What about for the man? Well, his time investment is minimal, his sperm can be wasted (he has, literally, millions to spare), and he doesn't give birth to the child. For him, sex is a romp. It's about risk-free pleasure.

What we see here is that the asymmetry in MPI places different adaptive burdens upon males and females. And this adaptive burden uniquely shaped the sexual psychologies of the genders.

Succinctly, females evolved a choosey sexual psychology. This choosey psychology manifests itself in two ways. First, she is less open to casual sexual encounters. Second, given her adaptive burden, females will be attracted to high investment mates (e.g., love and ability to support).

Males, conversely, don't have an adaptive penalty for causal sex. Thus, they are more sexualized. From an evolutionary perspective, there is no reason not to be sexualized. Sexually, males face little adaptive pressure from natural selection. However, males do face significant pressure from sexual selection.

Recall, sexual selection is driven by female mate choice. Thus, given that females are choosey (due to their own adaptive challenges) they have exerted an adaptive pressure on male sexual psychology.

What does this pressure produce? Well, given female choosiness females are hesitant to consent to sex unless the male is high investment. The male, facing this pressure, finds the sexual marketplace highly restricted. Thus, to have offspring the male will need to, of necessity, focus his attentions, affections, and resources upon a single women (or relatively few women). So, if a male were to do this what makes the most adaptive sense in HIS mate selection? What females should he focus his attention on?

Recall that natural selection is all about offspring. The more the merrier, Darwinianly speaking. Thus, if a male is focusing on a single female he should focus on one that has high reproductive potential (i.e., physical ability to bear children). Reproductive potential is highly correlated with both youth and genetic fitness. And in the ancestral environment the only way to gauge youth and genetic quality was via the visual system. Thus, the male sexual psychology evolved in response to these particular visual cues.

I could say more about all this. Much, much more. But the sum of the matter is this: Male and female sexual psychologies are predictable adaptations to the asymmetry in minimal parental investment. Just posit the inequality between MPI and a vast sexual data set is parsimoniously explained. It really is a nifty intellectual accomplishment.

What are are the theological implications for all this? I'll point out two.

1. Unwitting Darwinism
The funny thing about His Needs, Her Needs is that it is an unwitting celebration of Darwinian thinking. Male and female sexual needs are products of evolutionary processes. And the differences between the genders is a powerful data point in support of Darwin's theory. (We'll encounter this unwitting Darwinisn later on when we get to Family Values.) This situation is ironic given that His Needs, Her Needs is so popular in Christian communities who are often passionately anti-Darwin.

2. Kenotic Sexuality
Due to the unwitting Darwinism of many churched-based marital programs, we often teach people to overplay the Darwinian elements of sex, unwittingly reducing sex to a biological imperative. For example, yes, my sexual psychology, being male, is highly visual. But just how far should I push or indulge that facet of my psychology in my marriage? Should I use an evolved Darwinian trait to make demands of my spouse? Am I not, by insisting on my NEED, simply reducing sex to biological imperatives? Where is the kenosis and ego-transcendence in the sexual act? Should I not, in the name of Jesus, marginalize my needs, even in the marital bed? Aiming for a truly other-oriented sexuality?

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11 thoughts on “Theology and Evolutionary Psychology, Chapter 3: His Needs, Her Needs”

  1. As my grandmama use to say: "Higgamus, hagamus, woman is monogamus! Hagamus, higamus, man is polygamus!"

    George C.

  2. A limerick penance for poor spelling.

    Poorly linking o's and u's is my crime,
    when I drink margueritas with lime.
    I often get blurry
    when I spell in a hurry,
    but I can still rhyme on a dime.


    George C.

  3. Perhaps you are celebrating the God-given, natural, organic, physiological roots when you and your wife maximise your needs and responses.

    This is a very, very interesting post.

  4. The "personal" ads seem to reflect much of this dynamic as well, generally looking for youth and attractiveness, women looking for well-off men. One of my students did a research project looking at preferred attributes of a marital partner and gathered data amongst the students at this Christian college. The top three differences between the genders? Physical attractiveness (males favoring much more than females), Financial resources (females favoring much more than males), and Fun and Exciting personality (males favoring much more than females).

    The question I wrestle with is, how far can we stretch the biological leash? Is it a matter of stretching or transcending our biological needs or aiming/ordering our biological needs in the right direction? Both? Sexual needs can be viewed in a selfish manner or they can be viewed as a need for relationship, a reminder that we are never solitary individuals even in our biological drives. Is this the importance of "good" theological memes?

    Perhaps we need a Trinitarian sex book...marriage as an icon of the Trinity? Or does Rob Bell cover that in "Sex God"? (I'm currently in Romania and out of the loop on this)

  5. So you would equate our "evil nature" as simply a byproduct of evolution? I guess if one is an extreme materialist, and a Christian at the same time, one would be tempted down these paths. I just wonder how some trait that evolved to ensure survival could really be evil. But then again, I guess that is the whole arument Girard makes with sacrifice.

  6. George,
    As always, I can't wait until you comments show up. They are either:
    A) Deeply thoughtful
    B) High Comedy

    or, I can add:

    C) Sometimes both

    Quite a mix, my friend.

    Yes, I think that is what I'm trying to explore here. The interface of biology and spirituality. I'm not sure what the answer is (I end the post with lot's of questions). I also think Ron's comment is pertinent.

    I also wonder about the notion of "God-given." Does that mean it's good? Or neutral? That is, many "God-given" attributes are only relatively good and many are downright moral burdens. For example, if the visual arousal system of males is "God-given" that "gift" is also the source of the pornography industry, strip clubs, and, indirectly, eating disorders in young women.

    Very interesting study! I poll students in my lectures and get the same results, but have never statistically quantified the trends at ACU.

    I struggle with the same issues you raise. I think humans are unique in that our self-reflective capacities allow us to "transcend" biological impulses. And theological memes can help with this. Clearly, the meme for celibacy can override the biological imperative to have sex and offspring. Memes may, in fact, be more powerful than genes. If so, God via His Revelation has given humanity a set of memes (i.e., the way of Jesus) that can allow us to find a peace and joy that is not, in a real sense, biologically possible.

    All this is one thing I think about when these issue come up.

    I go with Spinoza on this. Spinoza said that in a "state of nature" there is no sin. Sin only emerges as a social construct/contract. Succinctly, he says "sin is disobedience." I tend to agree. Thus, I don't think of any of these impulses as good or bad, "God-given" or a Condition of the Fall. I see the issues contextually, as they relate to people and how my actions aid or harm their humanity and ability to flourish.

    For example, I don't tend to see pornography as a sin of lust. I see it as one of harm. More deeply, I see the male sexual visual system as creating a "market" which creates economic incentives that can be leveraged against marginalized women (waving $$ in front of women with limited choices). Again, the sin here is less of lust, but how the biological situation is being allowed to dehumanize people.

  7. I cannot stand “His Needs, Her Needs”. It does get some things right but seems completely un-Christian in its approach. The “Love Bank” creates a comical economy of love as far from the selfless love of Jesus Christ as is imaginable. I have often wondered why this marriage enrichment course has become so prominent in the church.


  8. Hi Kelly,
    Well, this could cut both ways. The evolutionary characterization of men is "worse" here. However, in study after study, replicated across cultures, these trends do hold: High investment is something women prefer relative to men.

    But it should also be noted that the sexual revolution and the feminist movements have changed the sexual situation profoundly for women relative to conditions in the ancestral environment. Thus, it should not be surprising that these tendencies are easily ignored by modern women. A tendency is just that, a tendency. As a parallel example, just because a man inherits a visually oriented arousal system from his evolutionary past does not mean he has to go to strip clubs. He can and should refrain. And most men do. In the same way, many modern women may not care for a male mate at all, feeling perfectly able to support both her and her child by herself.

    (In the end, also note that I'm working through other people's work and conclusions for the sake of a theological analysis. I'm not an evolutionary psychologist. I'm just presenting its current paradigm. I'll defend it in these posts, but mainly for the sake of argument.)

    I agree. The whole "love bank" idea is theologically dubious.

  9. Richard, Kelly,

    Bram Dijkstra's Evil Sisters: The Threat of Female Sezuality and the Cult of Manhood speaks to some of the issue in the Post and responses. Dijkstra's critique of Freud and Jung is devastating. In his concluding commenting on Frued's "Dora" case, he says: "Freud's account of the Dora case is thus a fascinating delineation of the complex but ultimately circular logic that helped turn economic obsessions into evidence of of the "economics of sexual spending." Once the "vital" link between sexuality and "instinctual reversion" had been determined [by Freud], it became easy to demonstrate woman's "natural" desire to make the male "spend" the intellect with which he had been entrusted in the service of evolution."

    His blast at Jung states that not only had he cribbed from Plato [who doesn't?--GC] but that "the image of woman," the archtypical "anima," reflecting "images of nine-teenth century art" and "the ideal bourgeois wife with a touch of vampire thrown in to lend her an air of mystery."

    For what it's worth.


    George C.

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