By the mid-19th century, Europe had undergone major changes that affected their beliefs about themselves. In his book A Generation of Materialism, 1871-1900 (New York: Harper & Brothers, 1941), Carlton J. H. Hayes listed the following major developments in Europe:

• the French Revolution introduced the idea of the nation-state as an organizing concept for politics, and the Napoleonic Wars showed the strength of the nation-state
• the rise of Liberalism supported a belief in progress and change
• the Industrial Revolution changed how people worked and acquired goods, the number of goods in circulation, and economic relationship between industrialized and non-industrialized regions of the world
• art and religion adapted to the new emphasis on materialism
• new techniques for communication and organization gave rise to the concept of "the masses" as a political and economic force

Carrington went on to say that these changes led to the "resurgence of economic nationalism and national imperialism." They initiated a period of intense national competition that culminated in two world wars in the 20th century. That competition, coming at the end of the 19th century, provided a direct challenge to the balance-of-power system created in 1815 to keep the peace in Europe after the Napoleonic Wars.

Three centuries of the slave trade had taught Europeans that Africans were inferior, and that helped to justify imperialism in the minds of many Europeans. Even slave abolitionists contributed to this by arguing that Africans had to be "protected" from slavers; i.e. they couldn't take care of themselves. The limited information brought back to Europe by explorers like Mungo Park and Henry Morton Stanley made Africans appear warlike and/or childlike, and they wrote books and gave lectures that popularized the notion of Africa as "the dark continent." For example, this relatively favorable quotation from a first-time visitor to Africa illustrates the prevailing beliefs among Europeans:

Naturally, Africans had a somewhat different understanding of their culture and institutions in the 19th century. While it is impossible to generalize about the entire continent in a few sentences, it is accurate to say that the continent that produced the first humans, and which developed universities as early as the 11th century, was in a state of turmoil by the 19th century. Much of the cause can be traced to the resumption of regular contacts with Europeans beginning in the 15th century and the impact of European expansion on the Muslim world. Among the consequences were ...

• the development of the overseas slave trade which created African states whose power was based on guns
• the end of the overseas slave trade in the early 19th century, undermining those states -- mostly along the coast -- which had grown strongest due to the slave trade
• Muslim reform movements that developed in response to the adoption of some aspects of European modernization by the Ottoman Empire, the center of the Muslim political world
• the expansion of the trade in slaves and ivory along the East African coast following efforts to end the slave trade in West Africa
• the proliferation of guns obtained from European and (to a lesser extent) Muslim sources

In the late 19th century, the technological gap between Europeans and Africans, already present since the 16th century, began to widen at a faster pace. The first successful use of gunpowder was by Ottoman forces at Constantinople in 1453, and its use spread to Europe more so than to Africa. Europeans adapted the technology until firearms were small enough to mount in ships or be carried by foot soldiers. They also improved the speed and economy of firearms production, making them more plentiful.

In the 19th century, European society was also more highly militarized as a result of its recent experience during the Napoleonic and Crimean Wars. The Napoleonic Wars lasted nearly a quarter century, involved all parts of Europe as well as parts of Africa and the Americas, and popularized Egyptian culture, especially in France. The Crimean War, which was fought in the Black Sea from 1853 to 1856, provided a generation of officers who craved military action and a testing ground for technologies that proved their worth in colonizing Africa.

Other technological changes affected the timing and process of imperialism. The British learned in 1857 how railroads and the telegraph could enable a relatively small number of British personnel to survive a rebellion in India, Advances in medical science, particularly in the field of tropical disease, made it safer for Europeans to go to Africa, and consequently easier (and cheaper) for the government, churches, military and commercial firms to recruit European staff people. Advances in firearms, particularly developments with the repeating rifle, machine gun and lightweight artillery, enabled smaller military units to defeat larger numbers of opponents, further reducing the cost of conquest. Improved steam engines gave steamships larger capacities by requiring less space for fuel, while railroads extended the reach of European commerce beyond the coasts.