|The Ant Problem|
|The Parity Problem|
|The Binomial-3 Problem|
Figure 5.5 shows that under lineage selection, the distance between successive best fit individuals in the population is also higher. Note that the weighted edit distance measure is not normalised by individual size. Because lineage selection produced smaller individuals, this measure was divided by the average individual size to produce a graph similar to the non-weighted measure, but where all the lineage selection experiments remained significantly higher.
The Ant problem was the only one to benefit in terms of fitness improvement from lineage selection. While the fitness for the Parity and Binomial-3 lineage selection experiments were statistically worse, a high level of fitness was achieved in very diverse populations. This behaviour is also reflected in the phenotypic entropy. The difference in entropy values between the control and lineage selection experiments appears to be somewhat correlated to fitness improvement. Only on the Ant problem did entropy stay at the much higher levels after similar initial behaviours. On the other two problems, entropy was much lower in the initial generations (see Figure 5.4). This indicates that the ability to achieve high entropy is hindered by lineage selection in the Parity and Binomial-3 problems, resulting in worse overall fitness. However, in the Ant problem, lineage selection helps to achieve higher levels of entropy and slightly better fitness.
For the Ant experiments, Figure 5.6 shows the last generation where fitness improved versus the best fitness of the run. Under lineage selection, the Ant problem finds better fitness on average 20 generations later than the control experiment. This is a good indicator that premature convergence is being avoided. The Parity lineage selection experiments had a similar change, where the best fitness was found between 10 and 15 generations later but with a slightly worse fitness. The Binomial-3 results were not significant with respect to fitness or the last generation of improvements.