Monday, March 8, 2010

Brief: Do trust levels predict sexual activity among the young?

I'm becoming more convinced that the decline in trust levels during the late 1980s may have a lot to do with the decline starting a few years later in all sorts of risky behavior. The logic is simple: the more (or less) trusting you are of others, the more (or less) risk you're willing to take in social life, and also exploiters will have a more (or less) easy time finding "suckers." We looked before at homicide rates. Now let's turn to sexual activity among young people.

For trust levels, I use the General Social Survey's question on whether you think others can be trusted, and restricted respondents to those from 18 to 25 years old. The GSS doesn't survey minors, so I used this age range for "young people." The time series for trust doesn't seem to vary wildly based on which age range you restrict it to, so it seems OK to use trust levels among young adults as a proxy for trust levels among adolescents. For risky sexual activity, I use the pregnancy rate among females ages 15 to 17 (here), which are yearly from 1972 to 2006; and the percent of high schoolers who have had sex before age 13 (here), which are bi-yearly from 1991 to 2007. The trust data are from 1972 to 2008, and coverage is usually bi-yearly or more frequent.

Here are the results. Trust levels are in blue and sexual activity measures in red.

Although the relationship is not perfect, there's a close match overall, and the timing looks like the trust level changes first, followed by a change in sexual activity. That fits with trust being the cause and risky behavior the effect. The correlation across years between trust and the pregnancy rate is +0.47, and between trust and the early sex rate it is +0.44. The Youth Risk Behavior Survey that I got the early sex rate data from has three other measures of teenage sexual activity, and the relationships are similar but not quite as strong.

The correlations with trust are: +0.15 for percent of high schoolers who'd had sex at least once in the past 3 months; +0.21 for the percent who've had 4+ partners in their life; and +0.23 for the percent who've ever had sex. * I also created an index of young sexual activity, which is just the sum of the fraction of students responding positively to each of the 4 questions. This is the expected number of "yes" answers that a high schooler would give while reading off the check-list of risky sex behaviors. The correlation between this index and trust is +0.25.

In general, I think these correlations are weaker just because there are fewer data -- 1991 to 2007, every other year -- than in the case of pregnancy rates. I suspect that the pre-1991 picture for the 4 behaviors surveyed in the YRBS would have looked highly similar to the teen pregnancy rate, so if we had those data, they would probably make the pattern even stronger. In any case, it seems clear that, while not the entire story, how trusting people are of one another plays a substantial role in how willing young people are to engage in risky sexual behavior. That's not too surprising if we think of trust as a form of insurance, but it's still something that's been completely overlooked as far as I know from the social science lit on these two topics that have previously been studied independently of each other.

If I can find good data on cross-national differences in number of lifetime sex partners, or other measure of promiscuity, I might use the national trust level data from the World Values Survey and turn this into a fuller post. It depends on how easy the former data are to get. Informally, though, my impression is that the low-trust countries are more sexually conservative, while the high-trust ones are more sexually liberal.

* The sexual activity correlations paired the sex activity variable and trust variable for the same year if possible (for 1991 and 1993), but since the data use different sets of alternate years after that, I paired the sex variable in a certain year with the trust variable in the following year.

GSS variables used: trust, age, year

Tuesday, March 2, 2010

Brief: Did third-wave feminism ruin Gen-X guys' sex lives?

There was a society-wide hysteria that reached a fever pitch in 1991, encompassing the rebirth of identity politics, feminism ("third-wave"), gay rights, and political correctness in general. The panic was still pretty high through 1994, although it died off afterward. Compared to second-wave feminism -- which focused more on equal pay, a lower housework burden, and so on -- third-wave feminism was much more focused on sexual harassment, rape, male libido, etc.

Was all that paranoia about all men being crypto-rapists just cheap talk, or did it have real consequences for the relation between the sexes? An easy way to test this is to look at how likely men were to remain virgins after graduating college through their 20s. I used the General Social Survey to focus on males aged 21 to 29 when they were surveyed. I grouped them into 3-year birth cohorts, except for the last one, where a tiny number of late-'80s males were lumped into the previous cohort just to make the sample sizes better.

Here is the percent of 20-something respondents who said they'd had 0 female partners since turning 18 -- which in context I take to mean 0 partners ever -- shown by the middle year of the 3-year cohort (or by 1986 for the '84-'89 cohort):

The long-term trend looks like between 6% and 7% fall into the 20-something virgin group. The early-'60s cohort is much lower, which makes sense because that cohort was completely unaffected by feminist hysteria. They were born too late to come of age during the counter-culture and too soon to come of age during the early-'90s hysteria. As I've pointed out elsewhere on this blog, the late '70s and early '80s were a remarkably non-ideological and hysteria-free period. However, those who came of age during the early-'90s hysteria show much higher rates of virginity in their 20s -- about double the long-term trend, or 5 to 6 percentage points higher. The effect even lasts through those who came of age in the mid-'90s, although their departure from the trend isn't so extreme. It isn't until those who were born in the early '80s, who came of age in the late-'90s or later, that the rate returns to the trend.

People often poo-poo the framework of generations -- there's so much variation within generations, not as much across generations, no sharp changes, etc. Well here's a very clear demonstration of an abrupt and gigantic change in a key rite of passage for males, and the timing is not mysterious given what we know about larger cultural changes afoot in the early-'90s. This also supports my approach to see generations as a cohort of vulnerable individuals who are struck by a huge but passing hysteria (a shock to the social system). There's some age range in which people are vulnerable to bearing the scars of the hysteria -- not younger or older -- and those indelibe impressions cause a lot of them to look similar to each other and different from other groups. That's why you can still tell who was coming of age during the counter-culture even though that was 40 years ago.

GSS variables used: numwomen, cohort, sex, age

Monday, March 1, 2010

Brief: Trust and crime

I've been thinking more about trust and its effects on all areas of social interaction and culture. It's at the root, really: if you don't trust others, you will try to get by on your own. Sociability requires a certain level of trust, and in a social species like ours there are gains to be had by interacting with others -- especially in a modern market economy where you can outsource so many things to others in the market instead of doing them yourself. You don't make your own shoes, grow your own food, manufacture your own computer, or gather your own news about the President. Sounds great -- why would you possibly withdraw from that sociability?

If you trust others, you're making yourself vulnerable to exploitation. The more trusting people there are in a population, the easier it will be for exploiters to thrive, and that will drive up their numbers. The exploiters may become so numerous, and their effects so offensive, that people start to withhold their trust lest they become the next statistic. That state-of-mind could show up in behavior by simply not venturing out into the public sphere where they'd be vulnerable, hiding out in the safer personal sphere.

But then when there are far fewer trusting people, that dries up the resource that exploiters had been thriving on. Now there are lots of them competing to exploit a shrinking number of trusting people. So that will drive down the numbers of exploiters. Eventually people will realize how safe things have become and extend their trust once again, which will in turn drive up the numbers of exploiters as before, and the cycle repeats.

This variant on a model of how hosts and parasites, or predators and prey, interact in ecology suggests looking at data on how trusting people have been over time, and what the crime rate has been like. Before I showed that people rationally respond to changes in the homicide rate by becoming more afraid when it's going up and less afraid when it declines, with about a 2-year lag. So we know that perceptions are affected by crime levels -- but could crime levels be affected by perceptions, i.e. how trustworthy you think other people are?

The General Social Survey asks respondents whether other people can be trusted, cannot be trusted, or that it depends. Here is a plot over time of the percent of respondents who said that other people can be trusted (in black), together with the homicide rate (in red):

Clearly the relationship is less stark than it was for fear resonding to crime, where the correlation within a year was +0.74. Still, the correlation here is +0.53, meaning that indeed higher crime rates are associated with higher levels of trust. And as in the case of fear and crime, that understates the strength of the relationship since there is a time lag. In particular, trust levels started falling steadily before the homicide rate did so. So the predicted relationship is there: crime rates are high throughout the '70s and '80s, and at some point in the mid-late-'80s, people have had enough and start trusting others less and less. With far fewer trusting people to exploit, criminals start scaling back or dying off: the homicide rate peaks in 1991 and starts falling steadily afterward.

We will have to wait a few more decades to see if the rest of the story pans out -- whether with such low crime rates, people will assume it's safe to start trusting people again, and whether those higher levels of trust (if they did happen) would be followed by a rise in the crime rate.

Criminologists and others debate what causes crime to go up or down -- tougher or more lenient punishment by the government, technology that makes it easier or harder to report crimes, etc. I have only a passing familiarity with the range of causes they discuss, but as far as I know, how trusting the average person is does not get much attention, although there may be some minority contingent that does look at it. Perhaps it is as simple as a rise in crime following an increase in the number of people who criminals would consider "suckers," and a decline in crime following a contraction in the numbers of "suckers," just as we see between a host species and a parasite species. The logic is hard to argue against, and the graph above shows that it has some modest empirical support as well.

GSS variables used: trust, year