How Could Language Have Evolved?
A crude plot of average hominid brain sizes over time.
Although after an initial flatlining this plot appears to show consistent enlargement of hominid brains over the last 2 million years, it is essential to note that these brain volumes are averaged across a number of independent lineages within the genus Homo and likely represent the preferential success of larger-brained species. From . Image credit: Gisselle Garcia, artist (brain images).