What, if anything, sets humans apart from other species?

Question

As I grew up, I was taught that the difference between humans and animals was that human beings have free will and animals do not. The basis is that animals will act accordingly to the nature of their species. I never fully understood this statement and still wonder whether it is a valid claim.

From an evolutionary perspective, we would be regarded as a species at the top of the food chain. The main advantage in our development is our brains.

If we put aside the differences in what human beings are capable of, e.g. making clothes, machinery, etc., is there a real distinction between human beings and other animals? Do we really have free will, or an illusion of free will? Or are we behaving, as other animals, in accordance with the nature of our species?

I know this is a big question and could result in a range of debates over my definitions. So for the sake of clarity, let's keep this question limited to what defines a human brain as opposed to an animal brain and any evidence that supports any significant difference, allowing for the fact that the human brain is well-developed (as opposed to, e.g. to our canines).

Answer 1

Some articles with some information pertinent to your question, hope this helps:

According to "Human and animal cognition: Continuity and discontinuity" (Premack, 2007), that as several species have skills once thought to be unique to humans, that this suggests that there is a misleading (the article's word) disparity between 'brain' and 'mind'. So the article's focus is on:

What are the dissimilarities?

When examining 8 aspects, or competencies, including teaching, short-term memory, causal reasoning, planning, deception, transitive inference, theory of mind, and language, the authors found that the similarities to be minor, but the dissimilarities to be very large and that there is no disparity.

Each of these points are discussed in depth in the article (too big for this answer); however, the article's author concludes with a fundamental difference:

Animal competencies are mainly adaptations restricted to a single goal. Human competencies are domain-general and serve numerous goals. For instance “planning” may be tied to episodic memory, suggesting a broad competence.

Going further, according to "Evolution of the brain and intelligence", (Roth and Dicke, 2005), that a main difference is due to:

factors that correlate better with intelligence are the number of cortical neurons and conduction velocity, as the basis for information-processing capacity.

and critically (bolding mine):

The outstanding intelligence of humans appears to result from a combination and enhancement of properties found in non-human primates, such as theory of mind, imitation and language, rather than from ‘unique’ properties.

Answer 2

It is not that we are just generally smarter then animals, but we posses cognitive tools of a different kind that they don't. Two of them are language and the ability to simulate the future.

Regarding language, there is a wide consensus today that human language has some unique complexities that no animal form of communication has (see Pinker's "The Language Instinct"). It includes intricate syntactical structures and generative engines of vocabulary. Noam Chomsky was the first to argue that language is a universal capability, i.e. every healthy human being would be able to use it, and thus pre-wired into our brains from birth (and by that also debunking the Behavioral assumption that we are born tabula rasa).

The ability to simulate the future is the simply using our imagination to forecast the results of different actions or events. Again, you can every now and then find an animal that seems to know how certain actions will results, but it is always a product of learning from the past, while trying and erring. In contrast, people can imagine how the world would response to certain actions, without encountering a similar situation previously. (I'm sorry, but I can't recall right now a good reference for this. If you insist in the comments, I could run a quick search).

Of course these two features are not all that sets us apart from animals, qualitatively, and there a certainly more that hopefully would be brought in answers of others. However, as I personally see it, these two are special, since they equip us with unique cognitive abilities of a different kind and of dedicated brain machinery (but that's for a different question).

Answer 3

Actually, animals are able to imagine the future, at least to the extent that they use prospective control of their movements. And there are fantastic arguments for animals being self-aware, considering self-related processing as a feature of at least mammals if not many more animals (Northoff and Panksepp, The trans-species concept of self and the subcortical-cortical midline system, 2008).

A core self may be based on an integrating neuronal mechanism that accounts for self-related processing, integrating exteroception (perception of the external world via sight, sound, etc.) and interoception (perception of internal states of being) with emotional processing all in relation to a goal. It is coordinated action in the world, colored by emotional evaluation of anticipated and realized results. In fact, Solms and Panksepp (The "Id" Knows More than the "Ego" Admits: Neuropsychoanalytic and Primal Consciousness Perspectives on the Interface Between Affective and Cognitive Neuroscience, 2012) make a convincing case for affective consciousness, that attributing a positive or negative value to an experience and the arising movements/behaviors might be the whole point of consciousness.

Similar to other social animals, humans move in ways that reveal their attention, intentions, and feelings (Colwyn Trevarthen – pretty much everything he's written), but there are a few things that are different. Humans have an internal mechanism for time-keeping which Trevarthen describes as the Intrinsic Motive Pulse, or the natural flow of energy cycles in our brain that shape our movements and create a sense of time, allowing us to create memories and anticipate the future in unique ways. Rhythms between infants and adults are the same, so that we are able to communicate non-verbally, sharing pulse and quality to create narratives in a "communicative musicality" (Malloch, Mother and infants and communicative musicality, 1999).

Anyway, we begin to make cooperative meaning with one another from the moment we are born; that leads eventually to the transmission of culture, even across generations (Trevarthen, What is it like to be a person who knows nothing?). We make symbols and rituals that fill our world with meaning. Language is a product of the ways in which people are able to create consensual domains (Maturana, Biology of Language, 1978), the root of which is in sympathetic movement (Delafield-Butt and Trevarthen, Theories of the development of human communication, year?).

Answer 4

Our large cortex allows us to produce survival behaviour more sophisticated than any other species. Our basic traits are co-operation, competition and cheating. We excel at all three and can switch in a heartbeat according to the perceived situation. I suggest an evolutionary feedback loop between the traits and cortex size. Cheating, for example, only works if one or more others can be deceived. If their cortex is as large as yours you are less likely to succeed. The traits drive behaviour at every social grouping: family, tribe, nation, economic bloc. Language is only a tool for the traits. However in recent times the aforementioned feedback loop may have stopped working or even reversed. Increasing our species is reshaped by relative levels of fertility and promiscuity more than any other factor. We cannot countenance eugenics. Can we countenance the consequence of that distaste?