WEBVTT - BrainStuff Classics: Is There a Gene for Infidelity?

0:00:01.920 --> 0:00:06.400
<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey

0:00:06.480 --> 0:00:09.399
<v Speaker 1>brain Stuff, Lauren Vogelbaum here with a classic episode from

0:00:09.440 --> 0:00:12.640
<v Speaker 1>our archives. There are lots of ways for humans to

0:00:12.680 --> 0:00:17.440
<v Speaker 1>conduct romantic or sexual relationships, be they monogamous or non monogamous,

0:00:18.000 --> 0:00:21.480
<v Speaker 1>and we are not the only animals that vary these practices.

0:00:22.360 --> 0:00:26.400
<v Speaker 1>Today's question is could part of this behavior be genetic?

0:00:28.520 --> 0:00:32.760
<v Speaker 1>Hey brain Stuff, Lauren Vogelbaum. Here, consider the humble prairie vowle.

0:00:33.240 --> 0:00:38.479
<v Speaker 1>Unlike of species, prairie voles are faithfully monogamous. Their lives

0:00:38.479 --> 0:00:41.440
<v Speaker 1>may be short, they're an easy snack for hawks and snakes,

0:00:41.440 --> 0:00:44.440
<v Speaker 1>but once two prairie voles mate, they are bonded until

0:00:44.479 --> 0:00:48.160
<v Speaker 1>the end. Not so with the prairie voles close genetic cousin,

0:00:48.320 --> 0:00:52.720
<v Speaker 1>the philandering montane vole. Montane voles form weak social bonds

0:00:52.800 --> 0:00:55.920
<v Speaker 1>and prefer the mating strategy of use them and lose them.

0:00:55.960 --> 0:00:58.880
<v Speaker 1>The stark differences in mating behavior between these two voles

0:00:58.920 --> 0:01:02.440
<v Speaker 1>species have made excellent subjects for decoding the genetic roots

0:01:02.480 --> 0:01:06.520
<v Speaker 1>of sexual monogamy and infidelity. According to a number of studies,

0:01:06.560 --> 0:01:09.240
<v Speaker 1>prairie voles have more receptors in their brains for a

0:01:09.280 --> 0:01:12.640
<v Speaker 1>hormone called vasopressin, which is believed to play a key

0:01:12.760 --> 0:01:15.920
<v Speaker 1>role in pair bonding. Not only do the faithful prairie

0:01:16.000 --> 0:01:18.679
<v Speaker 1>voles have more of these receptors than their cheating cousins,

0:01:18.920 --> 0:01:20.959
<v Speaker 1>but the receptors are located in a part of the

0:01:20.959 --> 0:01:24.600
<v Speaker 1>brain that's closer to their reward center. So when prairie

0:01:24.680 --> 0:01:28.360
<v Speaker 1>voles mate, their bodies produced vasopressin, which causes their brains

0:01:28.400 --> 0:01:31.919
<v Speaker 1>to reward the vole couple with a flood of pleasurable emotions,

0:01:31.959 --> 0:01:35.200
<v Speaker 1>sealing the social bond. The brains of montane voles, on

0:01:35.240 --> 0:01:38.680
<v Speaker 1>the other hand, have far fewer vasopressin receptors and therefore

0:01:38.800 --> 0:01:42.479
<v Speaker 1>make much weaker connections between pair bonding and pleasure. So

0:01:42.520 --> 0:01:46.240
<v Speaker 1>it's on to the next conquest. The location and sensitivity

0:01:46.280 --> 0:01:49.680
<v Speaker 1>of hormone receptors is dictated by our genes, which naturally

0:01:49.760 --> 0:01:52.320
<v Speaker 1>leads to the question could the urge to cheat on

0:01:52.320 --> 0:01:55.200
<v Speaker 1>our romantic partners be partly a product of our genes?

0:01:55.640 --> 0:01:58.240
<v Speaker 1>Are some of us walking around with prairie vole brains

0:01:58.240 --> 0:02:00.480
<v Speaker 1>while others are stuck with the wandering eye of a

0:02:00.520 --> 0:02:04.120
<v Speaker 1>montane vole. The real stories about the roots of infidelity

0:02:04.160 --> 0:02:07.160
<v Speaker 1>and monogamy are far more complicated than whether you have

0:02:07.360 --> 0:02:10.600
<v Speaker 1>a cheating gene. Human sexual behavior is the product of

0:02:10.720 --> 0:02:15.040
<v Speaker 1>countless influences and interactions, from our early relationships with our parents,

0:02:15.080 --> 0:02:19.720
<v Speaker 1>to social norms around sexuality, to yes our genetic predispositions.

0:02:20.400 --> 0:02:23.800
<v Speaker 1>We spoke with Justin Garcia, and evolutionary biologist and sex

0:02:23.800 --> 0:02:28.520
<v Speaker 1>researcher at the pioneering Kinsey Institute at Indiana University. He said,

0:02:28.880 --> 0:02:31.400
<v Speaker 1>we are never prisoners of our biology, but it does

0:02:31.480 --> 0:02:34.680
<v Speaker 1>explain why some people wake up with somewhat different motivations

0:02:34.680 --> 0:02:37.840
<v Speaker 1>in these areas than other people. The influence of these

0:02:37.840 --> 0:02:42.639
<v Speaker 1>different genetically based motivations is difficult to quantify, but study

0:02:42.680 --> 0:02:46.320
<v Speaker 1>by Australian researcher Brendan ze Each offers some intriguing clues.

0:02:46.919 --> 0:02:49.680
<v Speaker 1>Z Each surveyed these sexual habits of nearly seven thousand,

0:02:49.760 --> 0:02:53.200
<v Speaker 1>four hundred twins and siblings in Finland and found that

0:02:53.320 --> 0:02:55.919
<v Speaker 1>nine point eight percent of men and six point four

0:02:55.960 --> 0:02:58.519
<v Speaker 1>percent of women had had more than one sexual partner

0:02:58.600 --> 0:03:01.480
<v Speaker 1>in the past year. But the fascinating finding was that

0:03:01.520 --> 0:03:04.960
<v Speaker 1>these sets of identical twins with identical genomes reported the

0:03:05.040 --> 0:03:08.880
<v Speaker 1>exact same levels of fidelity, while fraternal twins and regular

0:03:08.880 --> 0:03:12.440
<v Speaker 1>siblings did not. That indicates that the variations and genes

0:03:12.480 --> 0:03:16.840
<v Speaker 1>are powerful enough to influence sexual behavior beyond other environmental factors.

0:03:17.400 --> 0:03:20.360
<v Speaker 1>In fact, each put a number on it. Our genes

0:03:20.360 --> 0:03:23.440
<v Speaker 1>account for roughly sixty three percent of infidelity in males

0:03:23.480 --> 0:03:28.000
<v Speaker 1>and four percent in females. Vasopresident isn't the only hormone

0:03:28.000 --> 0:03:31.120
<v Speaker 1>that's been linked to varying levels of monogamy and infidelity.

0:03:31.560 --> 0:03:35.040
<v Speaker 1>Oxytocin is another hormone released during sex and also during

0:03:35.080 --> 0:03:38.840
<v Speaker 1>childbirth and nursing that strengthens social bonds and female roles

0:03:38.880 --> 0:03:41.960
<v Speaker 1>with more oxytocin receptors are also more likely to mate

0:03:41.960 --> 0:03:46.160
<v Speaker 1>for life. Garcia at the Kinsey Institute conducted a landmark

0:03:46.240 --> 0:03:49.760
<v Speaker 1>study of dopamine receptors and sexual straying. It's long been

0:03:49.880 --> 0:03:53.480
<v Speaker 1>established that people with fewer or weaker dopamine receptors engage

0:03:53.480 --> 0:03:57.160
<v Speaker 1>in riskier behavior, drug and alcohol abuse, and gambling to

0:03:57.280 --> 0:03:59.760
<v Speaker 1>get the same dopamine rush that the average person might

0:03:59.800 --> 0:04:03.160
<v Speaker 1>get from eating a snickers. Garcia tested a hundred and

0:04:03.200 --> 0:04:06.160
<v Speaker 1>eighty one participants, some of whom carried the weaker D

0:04:06.360 --> 0:04:09.440
<v Speaker 1>four variant of the dopamine receptor. He found the people

0:04:09.520 --> 0:04:12.840
<v Speaker 1>with the D four receptor were more likely to report

0:04:12.920 --> 0:04:16.240
<v Speaker 1>sexual infidelity, and when he looked at all participants who

0:04:16.320 --> 0:04:19.160
<v Speaker 1>cheated in the study, those with the D four receptor

0:04:19.240 --> 0:04:22.880
<v Speaker 1>were far more likely to do it multiple times. For Garcia,

0:04:22.960 --> 0:04:26.000
<v Speaker 1>the genetic evidence points to a more nuanced understanding of

0:04:26.040 --> 0:04:29.200
<v Speaker 1>what it means when somebody cheats in a relationship. He said.

0:04:29.520 --> 0:04:32.200
<v Speaker 1>The classic explanation is that they're not really in love,

0:04:32.600 --> 0:04:36.200
<v Speaker 1>but maybe they're more motivated by other feelings of sensation, risk,

0:04:36.360 --> 0:04:45.280
<v Speaker 1>and novelty. Today's episode is based on the article good

0:04:45.279 --> 0:04:48.280
<v Speaker 1>Excuse or is there actually a cheating gene on how

0:04:48.320 --> 0:04:51.400
<v Speaker 1>stuff works dot com written by Dave Rouse. Brain Stuff

0:04:51.480 --> 0:04:53.400
<v Speaker 1>is production of I Heart Radio in partnership with how

0:04:53.440 --> 0:04:55.799
<v Speaker 1>stuff works dot Com, and it is produced by Tyler Clay.

0:04:56.320 --> 0:04:58.640
<v Speaker 1>For more podcasts, my heart Radio is that the I

0:04:58.720 --> 0:05:01.520
<v Speaker 1>heart Radio app, Apple Podcasts, or wherever you listen to

0:05:01.560 --> 0:05:13.600
<v Speaker 1>your favorite shows. H