Anders Sandberg - The morons are marching rather slowly - http://www.aleph.se/andart/archives/2013/10/the_morons_are_marching_rather_slowly.html

iqevolve.m

Ng=100; % Number of genes
w=randn(1,Ng); % IQ effect of each allele

Np=1000; % Population size
g=rand(Ng,Np)<.5; % Initial population, 50% mixture of all alleles

ff=[]; % Store mean IQ

change=1e6; % Generation to modify fitness.

for generation=1:100

    iq = 100+w*g*3; % Calculate individual IQ

    ff=[ff mean(iq)];

    if (generation<change)
        % "Standard" fitness
        fitness = interp1([0 50 80 110 150 400],[0 0.1 1 1 0.5 0],iq);
    else
        % Fitness breeding for intelligence
        fitness = interp1([0 50 80 110 150 400],[0 0.1 1 2 2 2],iq);
    end
    % For Preston-Campbell fitness, run prestoncampbell.m and use
    %fitness = interp1(Cclass,Pchild,iq);

    %Breed new generation
    g2=g*0;
    for k=1:Np
        k1=selectrand(fitness); % Parent 1
        k2=selectrand(fitness); % Parent 2

        split=ceil(rand*Ng); % Crossover location
        g2(:,k)=g(:,k1);
        g2(split:Ng,k)=g(split:Ng,k2);
    end
    g=g2;

end
plot(ff)

prestoncampbell.m

% Number of children with parents in different IQ classes
f=[54 40	19    29  19   5  5
7  19	22    44  27   10 2
11 12	48    107 78   39 11
16 40	94    186 166  100	17
1  22	60    167 143  77	17
10 0	20    62  58   28	11
0  5	2     26  15   16	19];

class=[0 74; 75 84; 85 94; 95 105; 106 115; 116 125; 126 200];

% How many people are statistically in each class?
C=cdf('norm',class(:,2),100,15)
pop=[C(1); diff(C)]

% Fertility rate for mothers (I got the names flipped for the variables)
Pchildmale = sum(f)/sum(f(:));
Pchildmale = Pchildmale./pop'

% fertility ratefor fathers
Pchildfemale = sum(f')/sum(f(:));
Pchildfemale = Pchildfemale./pop'

clf
plot(Pchildmale)
hold on
plot(Pchildfemale,'r')
axis([1 7 0 2.2])
ylabel('Normalized probability of children')
set(gca,'XTickLabel',{'-74', '75-84', '85-94', '95-105', '106-115', '116-125', '126+'});
legend('Mother IQ','Father IQ')
xlabel('IQ')

% Estimated fitness function
Pchild=[0 0 Pchildmale+Pchildfemale 0];
Cclass=[0; 60; 74; (75+84)/2; (85+94)/2; (95+105)/2; (106+115)/2; (116+125)/2; 126; 200]';

selectrand.m

function index=selectrand(p)
% select with probability = p

index=1;
cs=0;
r=rand;
p=p/sum(p);
while(cs+p(index)<r)
    cs=cs+p(index);
    index=index+1;
end