The Descent of Man | Study Guide

Charles Darwin

Download a PDF to print or study offline.

Study Guide
Cite This Study Guide

How to Cite This Study Guide

quotation mark graphic


Course Hero. "The Descent of Man Study Guide." Course Hero. 4 Jan. 2019. Web. 23 June 2021. <>.

In text

(Course Hero)



Course Hero. (2019, January 4). The Descent of Man Study Guide. In Course Hero. Retrieved June 23, 2021, from

In text

(Course Hero, 2019)



Course Hero. "The Descent of Man Study Guide." January 4, 2019. Accessed June 23, 2021.


Course Hero, "The Descent of Man Study Guide," January 4, 2019, accessed June 23, 2021,

The Descent of Man | Chapter 3 : Comparison of the Mental Powers of Man and the Lower Animals | Summary



Darwin's objective in this chapter (and continued in the following chapter) is to show that there is no fundamental difference in the mental faculties between humans and higher mammals. Humans possess the same senses as lower animals, and while there are gradations of differences between these senses, apes see and horses hear and monkeys smell with similar structures and functions as humans because they are all ultimately related. Darwin notes a distinction between intelligence and intuition: all mammals possess both, but variations are notable between the variety of animals. For example, man has to learn, through intelligence and imitation and trial and error, how to make a tool or build a canoe; birds can build a nest and beavers can dam a river on their first try, suggesting something closer to instinct.

Darwin also explores the moral and emotional similarities between humans and mammals, asserting that these shared characteristics confirm the same progenitor animal form because it would be unlikely emotions and expressions could be so similar by sheer chance. Humans and mammals express feelings such as pain, fear, curiosity, shame, joy, anger, and boredom as well as complex emotions such as love for family and close kin. He describes a vengeful baboon who was angry at an officer: the baboon took dirt and mixed it with water to make mud, which he then threw at the offending officer the next time he saw the man. The complexity and planning needed to exact revenge is on par with human intelligence. Darwin did an experiment with monkeys at a zoo that involved a stuffed and a live snake—monkeys exhibit a fear of snakes—to show the mental similarities between man and mammals. First Darwin brought a stuffed snake into the cage, and all of the monkeys got very tense, some running around and shouting out warning noises. He then removed the stuffed snake and brought a live snake into the cage and put it into a bag. Monkeys—like humans—are exceptionally curious, and one after another, many of the monkeys couldn't resist: they cautiously approached the bag, looked into it, and then dashed away in fear.

Imitation plays a role in all mammals' development, and it's especially strong in man. No animals voluntarily imitate man except for monkeys, who sometimes enjoying ridiculing and mocking them. Paying close attention is another element in many mammals' mental development, especially man's. A cat diligently stalking its prey or a child watching their father repair a door are examples of attention's importance in increasing intellectual development.

Reason, according to Darwin, is man's summit. All animals posses some ability for reasoning. Association—making mental connections between things and ideas based on experience—is the initial step in reasoning, but man goes beyond simple association by virtue of his imagination and intellectual abilities and growing knowledge. Darwin cites an experiment where pike (fish have limited mental capacity) kept in a large tank repeatedly banged against a glass divider until they learned they would experience pain if they continued to do it. When the glass divider was removed and additional fish were added to the tank, the pike would not go beyond where the divider had been to attack the new fish because they so associated the area with pain. Because of their reasoning abilities, neither man nor monkeys would persist in banging against the glass divider and would understand that when the divider was removed, they could pass by it easily.

The idea that humankind alone is capable of progressive improvement through reason was a popular idea of the time, but Darwin refutes the notion. He examines how dogs and "savages" will go to low points of hollows because they have reasoned that that is where water will gather. This is a perfectly reasonable approach and will usually result in them finding water. Civilized man, Darwin points out, would figure out where the water is coming from and try to go directly to the source. Both situations are examples of reasoning.

Language is the chief distinction between humans and animals. Darwin acknowledges the clear examples of communication between animals—dogs bark, birds sing, wolves howl, and most animals have sounds they use when in danger or as a warning to others. He suggests humans probably began speaking through simple sounds and even songlike noises. Darwin believes the mental abilities involved in language and speech must have existed in man's progenitor before speaking even began (and not so in close relatives such as apes and monkeys). He also points out that lower animals, though they cannot "speak" like humans, have a keen understanding of human speech, as when a dog owner gives a specific command and the dog understands what to do.

Darwin ends the chapter with thoughts on belief in God and religion. He asserts that humankind did not have this kind of belief throughout the vast majority of his development from a lower form. (He notes that many races and "savages" do not even have words for religion or God in their vocabulary.) As humankind's faculties such as imagination and reasoning developed, they would attempt to understand what happens around them. He likens humans' belief in such ideas to that of a dog's devotion to its master: submissive and fearful. Darwin ascribes different ideas about religion or spirits to less civilized races or savages, and says that such poor reasoning has possibly led to superstitions, fetishism, and strange customs.


In Chapter 3 (continued in Chapter 4 as well) Darwin examines the mental and social aspects of humankind and the similarities and differences with animals. His argument is that there are no fundamental differences between humans and higher mammals' mental faculties. Previous chapters have established that they possess very similar physical and brain structures. But there are gradations of mental ability, and in certain key aspects—language and reasoning especially—humans have far outpaced their mammalian relatives. Darwin frequently provides examples of animals doing similar things or learning in similar ways to humans, which is one way for him to reinforce the overarching theory that humans and animals descended from the same lower form.

Darwin attempts to explain the unique features of human intellectual development in contrast to other mammals. This is partly because he believes that humans are the highest animal based on what humans have accomplished over the millennia that animals have not and partly because, as a naturalist, he cannot ignore the copious studies and scientific evidence that point to the clear relation between humans and animals (especially man's closest kin, monkeys and apes). His examination of instinct and intellect reflect this: both humans and animals possess both, but the evidence points to man relying less on instinct and more on reason, and vice versa for animals. The analysis of association as a primal way of learning supports this idea, as humans go beyond simple association to gain a more complex understanding of things. Darwin doesn't discount that higher animals such as apes may have a similar ability—it's simply not as developed as the human ability.

Language is the evolutionary development that Darwin feels is the most prominent difference between humans and mammals. Again showing that mammals also have systems and "languages" of communication, he does not hesitate to assert that humans' language abilities—combined with their mental abilities—have placed humans at the summit. His examination of language, a sense of beauty, and religion (or a belief in a god) point to the more community-based and social aspects of humans that he will explore further in the following chapter. Darwin again directs some of his observations at the theory of evolution's detractors and the "creationists" (those who believe that God created all beings), suggesting that religion and belief in a god or gods are universal among the less civilized savages.

It is important to note, however, that this argument has been refuted in modern times. While early human societies may not have conceptualized God as a singular deity, which would have been the case in Darwin's time, it is clear that most if not all human societies across time have held belief in the existence of a powerful being or beings. While the form this takes is highly variable, with some societies holding animistic beliefs where spirits embody aspects of the natural world and others believing their ruler represents the physical embodiment of a deity, it is a consistent idea that helped to structure human society across time.

Cite This Study Guide

information icon Have study documents to share about The Descent of Man? Upload them to earn free Course Hero access!