Do Fathers Matter?: What Science Is Telling Us About the Parent We've Overlooked (11 page)

The researchers tried offering their program to fathers only, and also to mothers and fathers together, to see which might work better. The program, based on an earlier intervention developed by the Cowans, included exercises, discussions, and short presentations led by male and female pairs of mental-health professionals. The discussions covered parenting, the couples’ relationships, and stresses and support outside the family.

The program was most successful when it was given to mothers and fathers together. Their children were “much less likely to show signs of depression, anxiety, and hyperactivity,” the researchers said. The program also decreased parenting stress and improved the parents’ relationships. Some of the couples were so enthusiastic about the program that they continued meeting on their own after the project was completed.

Pregnancy is a key time for an expectant father to become involved with his partner and with the creature they can see on ultrasound and his partner can feel kicking and moving inside her. This might not ease the financial worries and other fears that can plague men during pregnancy, but it could put them on a path to becoming the fathers they want to be.

When we rid ourselves of the things we
think
we know about fathers, and replace them with what we’re now learning, we can do more to encourage fathers to become involved with their children. How many men understand that they are experiencing hormonal changes during their wives’ pregnancies? How many understand that being involved with the pregnancy is an important step on the way to being more involved with the child? The idea of the egalitarian family, which many couples say they accept, still outruns the reality. The more we learn about fathers, the more we can bring the idea and the reality together.

FOUR

Fathers in the Lab: Of Mice and Men

I’m standing in a laboratory at Randolph-Macon College in Ashland, Virginia, watching a caged mouse desperately trying to escape. Catherine Franssen, a postdoctoral researcher, has just slipped on a pair of rubber gloves, picked up a few mice, and dropped them into shoebox-size clear plastic cages lined with wood shavings. She’s putting the mouse fathers, with their pups, into unfamiliar cages—an exercise the mice don’t like. The idea is to see how the fathers will react to the stress in the presence of their pups.

Some of the mice are huddling nervously, but one of them is jumping frantically up and down, trying to launch himself over the side to what he thinks will be freedom. What’s remarkable about this mouse is that he doesn’t show any interest in including his pups in his escape plans. As he jumps up and down, he occasionally lands on top of them. They can’t walk yet, so they can’t get out of the way. This doesn’t concern their father in the least. He continues leaping for the top of the cage.

On the reasonable assumption that few human fathers would be interested in donating their brains to science during their partners’ pregnancy or when their children are born, researchers have resorted to animals to find out what makes fathers behave the way they do. Studying mice might seem like a stretch. Humans and rodents don’t have a great deal of mutual affection. When we meet, we’re more likely to turn and run in opposite directions. But think about this the next time you set a mousetrap: humans and mice share 90 percent of their genes. Mice are not as close to us, genetically, as chimpanzees, but they’re not far behind.

Franssen works with Kelly G. Lambert, a neuroscientist and the head of the psychology department at Randolph-Macon. I sat down with Lambert on a warm spring day, just after classes had ended, and asked her how reliable a proxy the mouse brain was for a human’s gray matter. She promptly opened a refrigerator in her lab, grabbed a pair of tweezers, pulled a mouse brain out of a little plastic vial, and set it down gently on a paper towel. It was pale yellow, furrowed, and about the size of a marble. And it was shaped just like a miniature human brain.

Lambert said that if she were to carefully dissect the brain and spread it out on the table, she would find all the structures found in the human brain. There
are
differences. Most of them can be found in the cortex, the site of many higher brain functions. “There is a huge difference between the rat and the human, and even chimps and humans, in the complexity of the cortex,” Lambert notes. And of course the mouse brain is much smaller. If she were to flatten and spread out the cortex of the mouse brain, it would be smaller than a postage stamp. If she did the same thing with a human cortex, it would cover most of a coffee table.

Nevertheless, Lambert’s work is based on the proposition that mice can teach us an enormous amount about human behavior. “I’m looking at stress and resilience and parental behavior, coping, how the brain responds to enriched environments. They’ve got so much genetic similarity. And I can control for diet and age, control we are never going to have with humans. They can give us clues we just can’t pick up with humans.”

Lambert has a lot riding on the answer. She’s spent twenty-five years designing experiments to let “rodents speak their mind,” as she puts it. She refers to her lab animals as her “rodent colleagues,” and observes that she is among the minority of humans who have had “valuable professional relationships with rodents.” When she’s thinking about human behavior, she often asks herself: “What Would Rodents Do?”

Their virtue is that they don’t have a cover story. “When I assess a rodent, I get the real deal—pure, unadulterated, raw behavior. When I’m working with rats, I ask a question and get the answer,” Lambert says. Humans, she says, are quite different. They have a remarkable ability to fabricate stories to justify their behavior. In one study, for example, women said their children were among the things in their lives that made them happiest. But the same women said that child care was one of their least favorite activities. Apparently, not everything about babies is so enchanting after all. Lambert says she doesn’t get that kind of double talk from her rodents. The father I saw stomping on his pups, for instance, wasn’t the least bit self-conscious about his lack of interest in his kids.

Rodents are also remarkably sophisticated, as Lambert likes to point out. Until a few years ago, researchers believed that only humans and other primates—gorillas and chimps, for example—were capable of metacognition, which means, roughly, that they know what they know and what they don’t. But in 2007, Jonathon Crystal and colleagues at the University of Georgia tested rats’ ability to discriminate between long and short sounds. Rats that could tell the difference got a reward. Those that failed the test got nothing.

Then the researchers gave the rats a third option: if, based on their training, they weren’t sure whether a sound was long or short, they could opt not to take the test—which would get them a small reward. Amazingly, researchers found that some rats declined to take the test, opting for the smaller reward rather than gambling on all or nothing. And when the test was made more difficult, more rats opted out. The rats were able to tell whether they would likely pass the test—they understood what they were capable of. This ranks them ahead of middle-aged fathers who think they might run a 10K, only to reconsider after huffing and puffing their way to the end of the block.

*   *   *

Lambert began her studies of rat parents with an effort to understand how females make the switch from ensuring their own survival to ensuring that of their offspring. She and Craig Howard Kinsley, a colleague at the University of Richmond in Virginia, reasoned that a variety of circuits must start to fire in a rat’s brain when she becomes a mother. A mother must take risks to protect her young, sometimes leaving the pups alone to find food, exposing them to predators. In the effort to find food, she might be exposing herself to predators, too. Lambert and Kinsley guessed that the rat’s foraging skills would improve when she becomes a mother, because she would need to squelch any fear and anxiety, get out there and grab some food for the kids, and hightail it back to the nest before a hawk could sink its deadly talons into one of her pups or a snake swallow one whole. The operation had to be as efficient as possible to reduce the risks for her young.

Lambert and Kinsley conducted a series of experiments that proved their hunch was correct. When female rats became mothers, they developed enhanced spatial learning and memory. As she and Kinsley wrote, young rats that had been mothers once or twice “were much better than age-matched virgin rats at remembering the location of a food reward in two different kinds of mazes.” Lambert and Kinsley didn’t stop there. Next, they put females who had never been pregnant together with pups, turning the females into rat foster mothers. The foster mothers showed the same improvement in the maze as the biological mothers! Simply being in the
presence
of offspring—their own or somebody else’s—turned female rats into better foragers.

Some of Kinsley’s students also found that motherhood turned rats into better hunters. The students put hungry females into a five-foot-square enclosure in which a cricket—a treat for rats—had been hidden in the wood chips. Females that had never been pregnant took an average of 270 seconds to find and eat the cricket; lactating females did it in just over 50 seconds. The researchers also found that the mothers were less likely to freeze up or otherwise demonstrate fear while exploring the unfamiliar enclosure during the experiment. And they found reduced activity in portions of the hippocampus and amygdala, parts of the brain the regulate stress and emotion.

Lambert and her team also found some of the first evidence that having children could make mothers better multitaskers, a change that many human mothers would insist is true whatever the evidence might show. (And the evidence increasingly suggests that it
is
true.) The researchers set up a race to find a reward—a Froot Loop, as it happens—that involved “simultaneously monitoring sights, sounds, odors, and other animals.” The mothers who had been pregnant at least twice did far better than mothers who’d been pregnant once, and all of them did better than the hapless virgins. The more time the mothers spent with pups, the more skilled they became.

I did not go to see Lambert only to talk about mothers. When her work on females was published, I called to ask whether she planned to do similar research on male rodents. “We’re just beginning,” she told me. I waited until she had some results before driving down from New York to see her. For the research on fathers, rats wouldn’t work. Rat fathers don’t hang around. She calls them “drive-through dads.” So she switched to the California mouse, a species with devoted fathers, and the closely related deer mouse, for whom fatherhood is a far more casual affair. And then she began to do some of the same kinds of experiments she’d done with her rat mothers.

*   *   *

Male California mice, a species known scientifically as
Peromyscus californicus,
groom, retrieve, and huddle with their offspring—all the things that a good mouse father should do. And their care shapes the behavior of their pups. James P. Curley of Columbia University notes that paternal grooming is essential for young mice to be able to recognize new objects. Pups that are not properly groomed have difficulty with that task, and they show detrimental changes in stress hormones as well. Fathers’ behavior also appears to be related to the kind of paternal care their offspring will later provide when they become fathers themselves. Good fatherhood, of the type practiced by the California mouse, has numerous benefits for pups.

The situation is different, however, in one of the California mouse’s closest relatives—the common deer mouse, or
Peromyscus maniculatus
. The deer mouse is brown with a white underbelly, and not much longer than your index finger. And he is not a model father. Quite the opposite. This was the mouse that I watched trying to leap his way out of his cage while only occasionally paying his floppy pink-and-gray pups a brief bit of attention—stretching his head out to give them a sniff before scrambling away to resume his escape attempts. The deer mouse’s pathetic escape attempts and his lack of concern for his flesh and blood are typical of the behavior of mammal fathers, only a few of which have any interest in their offspring. The odd behavior of the deer mouse was a good reminder of how unusual human fathers are.

In a nearby cage, a California mouse father was demonstrating why Lambert had chosen this species to study. He is far from typical of mice and other mammals, and she wanted to find out what it was about him, his brain, and his hormones that made him so different. While we watched, he nervously explored his new environment, whiskers vigorously twitching, but he never left the pups alone for more than a few seconds. He inspected them, licked them, hovered over them, crouched near them while raising his head to look for threats, and regularly hunched his back and leaned over them again, like a bird perched on its eggs.

If I hadn’t known he was the father, I would have thought I was watching a mother protect her young long after the father has fled, as most mammal fathers do. Franssen confirmed my impression. She told me that his behavior was often indistinguishable from that of a California mouse mother. With the mother away in a different cage, the pups even nipped at their father’s underside, looking for a nipple to latch on to. It was fruitless. Male California mice have vestigial mammary glands, but they lack even the nonfunctional nipples that human fathers have. Lactation (and pregnancy) remain out of reach for these devoted fathers, but in other respects, the fathers among California mice do everything for their children that mothers do.

*   *   *

The differences in the paternal behavior of these two closely related species were discovered in the late 1980s and early 1990s by a psychologist named David Gubernick, first at Indiana University and then at the University of Wisconsin. Gubernick came to his research with an unusual background. He did his graduate work in psychology, but did postdoctoral study in zoology, which equipped him to look at two things in mouse family life: the immediate factors that could affect behavior (that’s psychology) and the evolutionary roots of that behavior (the perspective of zoologists).