marriage Marriage Decision Biological

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					                   Marriage Decision

                Biological reasons: Genes?

 Mating decision:
   Do genes play a role?

 An odor experiment shows that women prefer the odor
 of men who are genetically similar to them, in the sense
 whose genes match each woman’s paternal genes.

 Like genes or unlike genes?  Inbreed or outbreed?
Extremes of both inbreeding and out-breeding should be

     Extreme inbreeding causes high risk of having a
    child who inherits bad versions of the same gene. A
    good example may be some European royal families.
    Also Darwin, who developed the theory of evolution,
    experienced the suffering of inbreeding.

     Out-breeding is thought to result in healthy children,
    but extreme out-breeding is also disruptive.

   Problem: It seems genes only explains the marriage
    decision mildly and ambiguously. Wealth, education
    and income play more important roles.
    Why people get married: an Economic perspective

     Gary Becker, who was the Nobel prize winner in
    Economic Science in 1992, gives the skeleton of a theory
    on marriage, by making the following two assumptions:
    Each individual wants to maximize his or her utility and
    the ''marriage market" is in equilibrium.

 Everyone gets married ''voluntarily", either out of their
  own preferences, or out of their parents’. We know that
  in economics we represent the preference by utility

 We will assume that those who want to get married are
  expecting their utility to increase compare to their
  original marital status, or they will stay single.

 The gains from marriage:
  Assume all the commodities can be combined into a
  single aggregate “z,” the underlying utility maximization
  problem is equivalent to maximization of “z”.
  Each household has a production function for “z”
  depending on the different inputs: x (market goods and
  services) and t (time).
 We have the following problem:

          z  f ( x1 , x2 ,...xm ; t1 , t 2 ,...t k ; E )
           m                k

           p x  w l
          i 1
                   i i
                           j 1
                                  j j   v

          lj tj  T
  Where x is market goods and services, t is the time
  proportion spent on household, E are the environmental
  conditions,     p i is the price for market good, w j is wage
  rate, l j is the time spent on the labor market, v is non-
  labor income and T is the time endowment.

 If we compare the above household production function
  with the individual production function, we must have
  the following relation if the individuals are married:
                 mm f  z m 0
                 fmf  z f 0
                 mm f  f m f  z m f  z m 0  z f 0 ,

  where mm f and f m f are the optimal production after
  they get married, and z m 0 and z f 0 are the optimal
  production for each one before the marriage.
How marriage influences the individual's labor supply?

 Changes in labor supply:

   Before marriage:

      For each individual, if we assume the following
  production function, and individuals choose their time

                       Maxzi  xi  ti
                       xi  wi  li
                       ti  li  1

  by solving it we get the optimal production level and
  labor supply:
                           zi  i

                          li 

                          ti 

    After marriage:

      The maximization problem becomes:
               MaxZ  ( xa  xb )(ta  tb )
                  xa  xb  wala  wblb
                  t a  la  1
                  tb  lb  1

 by solving it, we can get the optimal level of “z” and “t”:

     if wa  wb  w , then household production z  w ,

  for each individual  z *  , and there is indifference for
  the time allocation.

    if wa  wb , then household production
  z*  max( wa , wb ) and if wa  wb , then t a  0, t b  1 ; if
  wa  wb , then ta  1, tb  0 .

 In the real world, usually females’ wages are lower than
  males’, such that we may observe that female’s labor
  supply decrease after marriage, some of them even drop
  out of the labor force. The opposite is true for males.
 Changes in wage rate:

  The most common case is that, after marriage, females’
  wages go down, while males’ go up.

   The reasons may be:

   For females:

    Their time allocation may be influenced by
    marriage, namely they become less attached to the
    labor force. Household responsibilities including
    child-care, etc. are another issue.

   For males:

     They become more concentrated on their work and
    less mobile (less likely to change job).

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