It's a Sin—Contraceptive Use, Religious Beliefs, and Long‐run Economic Development

• Author: Klaus Prettner,Holger Strulik
• Date: 01 August 2017
• DOI: http://doi.org/10.1111/rode.12280
• Published date: 01 August 2017

It’s a Sin—Contraceptive Use, Religious Beliefs,

and Long-run Economic Development

Klaus Prettner and Holger Strulik*

Abstract

This study presents a novel theory on the interaction of social norms, fertility, education, and their joint

impact on long-run economic development. The theory takes into account that sexual intercourse is

utility enhancing and that the use of modern contraceptives potentially conflicts with prevailing social

norms (religious beliefs). The theory motivates the existence of two steady states. At the traditional

steady state, the economy stagnates, fertility is high, education is minimal, and the population sustains a

norm according to which modern contraceptives are not used. At the modern steady state, the population

has abandoned traditional beliefs, modern contraceptives are used, fertility is low and education and

economic growth are high. Social dynamics explain why both equilibria are separated by a saddlepoint-

equilibrium (a separatrix), i.e. why it is so hard to transit from the traditional regime to the modern

regime.

1. Introduction

The literature on long-run economic development has established the onset of the

fertility transition as an important prerequisite for the take-off to modern growth

(Galor, 2005, 2011; Dalgaard and Strulik, 2013). Fertility, in turn, depends crucially on

the use of modern contraceptives. More precisely, the demographic literature

identifies contraceptive use as one of the leading proximate determinants of fertility

(Bongaarts and Potter, 1983), but what are the deep determinants of contraceptive

use? In particular, why are modern contraceptives not used when they are available at

little or no cost? One potential explanation, which is explored in this paper, is that the

use of contraceptives conflicts with religious beliefs and entrenched social norms.

When contraceptives are not used and fertility is high, education levels of

children are low. This is the well-known child quality–quantity trade-off at the

center of unified growth theory (see Galor, 2005, 2011, for surveys). In the present

context, the quantity–quality trade-off generates a further feedback at the aggregate

(community- or society-) level, which makes the prevalence of traditional beliefs

sustainable. Specifically, it will be assumed that the value of traditional religious

beliefs is individual-specific and increasing in the aggregate number of believers, as

argued in the economics of religion (e.g. Iannaccone, 1998) and declining in

education (or income), capturing the impact of increasing knowledge and

modernization (Inglehart and Baker, 2000).

We show that this setup motivates the existence of two locally stable steady

states. At one steady state, individuals share a belief in traditional religion and do

*Strulik: University of Goettingen, Department of Economics, Platz der Goettinger Sieben 3, 37073,

Goettingen, Germany, E-mail: holger.strulik@wiwi.uni-goettingen.de. Prettner: University of Hohenheim,

Institute of Economics, Schloss, Museumsfl€

ugel, 70599, Stuttgart, Germany. We would like to thank Gani

Aldashev, Casper Worm Hansen, Ingrid Henriksen, Sophia Kan, Lars Loenstrup, Omer Moav, Manuel

Oechslin, Sjak Smulders, two anonymous referees, and the editor, Andy McKay, for helpful comments.

Review of Development Economics, 21(3), 543–566, 2017

DOI:10.1111/rode.12280

©2016 John Wiley & Sons Ltd

not use contraceptives. Fertility is high, education is low and the economy

stagnates. At the other steady state, traditional beliefs are abandoned and

contraceptives are used. Fertility is low, education is high and the economy grows

at a constant rate. The steady states are separated by a separatrix, i.e. a threshold

for which the dynamics on either side lead to one of the steady states.

1

This means that in order to leave the steady state of stagnation, society has to

solve a collective action problem according to which sufficiently many individuals

start using contraceptives. This observation explains the self-sustainability of the

steady states and why it is sometimes so hard to instigate widespread use of

contraceptives even when they are freely distributed. The size of the collective

action needed to leave stagnation depends on the location of the separatrix in the

religiosity–education space. If the value of traditional religion is sufficiently low or

if the productive value of education is sufficiently high, the traditional equilibrium

ceases to exist and society converges towards balanced growth. Along the transition

path, average fertility and the share of believers in traditional religion are gradually

declining, and average education, aggregate growth and the share of users of

modern contraceptives are gradually rising.

The paper contributes to unified growth theory by emphasizing the role of

education and the fertility transition for the take-off to long-run growth.

2

The

channel of traditional religion and contraceptive use, however, remained

unexplored by conventional unified growth theory. Conventional theory ignores the

human desire for sexual intercourse and thus, naturally, the use of contraceptives

can play no role for the fertility transition. Implicitly, conventional theory assumes

that sex is a functional and joyless activity executed to achieve a desired number of

children. This approach, however, makes it difficult to discuss the role of religion

and social norms for the use of contraceptives.

Here, we explicitly acknowledge that sex is a utility enhancing activity. The use

of modern contraceptives allows households to experience utility from sex without a

proportional increase in child births. Contraceptive use, however, may conflict with

the religious beliefs of households. For linguistic ease, we define traditional religion

as a belief-system, shared by members of a community, which prohibits the use of

modern contraceptives. The value of traditional religion is assumed to be

individual-specific and increasing in the number of households sharing these beliefs.

The value of the alternative (modern) belief-system is, for simplicity and without

loss of generality, normalized to zero. Households, as usual, decide on the number

of children and their education. In the present context, they additionally solve the

meta-decision problem of whether they share traditional beliefs and abstain from

contraception or whether they abandon traditional beliefs, enjoy more sex and limit

their fertility. Since child rearing is a time consuming activity, the limitation of

fertility generates extra time (potential income), which is used by households to

improve their children’s education.

3

The assumption that sex is a utility enhancing activity is perhaps self-evident but

there is also compelling evidence from the happiness literature (Blanchflower and

Oswald, 2004; Kahneman et al., 2004). The fact that humans like sex is readily

explained by evolutionary psychology. In pre-modern times, when contraceptives

were unavailable (and reproductive biology not yet understood), enjoying sex was a

Darwinian fitness-maximizing trait. The notion that during evolution humans had

no clear notion of how sexual intercourse was related to fertility, is helpful to

motivate the desire for sex without the desire for (more) children as well as the

demand for contraceptives (Wright, 1994; Potts, 1997). Acknowledging that sexual

544 Klaus Prettner and Holger Strulik

©2016 John Wiley & Sons Ltd