sodium amytal test: anesthetize one hemisphere and check for language function dichotic listening test: report more digits heard by dominant half functional brain imaging: fMRI or PET used to see which half is active when performing a language test
The process of change by which new species develop from preexisting species over time? The process by which species change over time is evolution. The process by which new species develop from preexisting species over time is evolution.
Speciation is about how species form. It is a major part of evolutionary biology. Darwin thought most species arose directly from pre-existing species. This is called anagenesis: species by changing, or 'phyletic evolution'.