I believe the primary reason for European colonization of Africa was capitalism. European nations saw opportunity for new trade routes and potential wealth in some of Africa's natural resources. The geographical limitations of Europe also played a part in reasons why Europe colonized Africa.
To be more specific, by the later half of the 19th century, all of Europe was occupied. There was no room left for European nations to expand. Around the same time, an interest in the idea of exploring Africa began to take root. A few expeditions, however, produced a wealth of new found commodities. Word of the financial prospects in Africa began to spread throughout Europe, which created a race between European nations. Envoys were sent to secure peace agreements with native tribes, who were more willing to align with Europeans since slavery had been abolished throughout Europe by then. The rise of the railroad made it possible to transport goods and people throughout the continent, and advancements in medicine made it easier for Europeans to live there. Soon enough, European countries were vying to colonize Africa in order to grow their own empires and assert both financial and political power over other European nations.
Functional psychology which is also known as functionalism which tends to refers to general notion of the psychological philosophy under which one considers the behavior and mental life in regards with the active adaptation to an individual's environment. It also provides the general ground for developing theories about psychology which are not yet readily testable through experiments (controlled).