What is uniquely human? A report from The Social Brain Conference
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| Photo credit: Anders Gade |
By James Burkett
James Burkett is a 2014 recipient of the Emory Center for Ethics Neuroethics Travel Award. He is a graduate student in Emory's Neuroscience program, conducting research on social attachment and empathy in Dr. Larry Young's lab.
This October 5th thru the 8th I had
the pleasure of attending the Federation of
European Neuroscience Societies’ (FENS) bi-annual Brain
Conference, held in Copenhagen, Denmark. FENS represents the neuroscience
societies of 42 different societies in 32 countries, and is the primary
organization for neuroscience in Europe. The conference, titled “The Social
Brain,” focused on how the brain produces and is affected by social behaviors
in humans and in animals. Chaired by eminent scientists Sarah-Jayne Blakemore
(Director of the University College London’s Institute of Cognitive
Neuroscience), Frans
de Waal (world-famous primatologist at Emory University), and Giacomo
Rizzolatti (discoverer of mirror neurons at University of Parma, Italy),
the conference brought together a wide array of human and animal researchers at
the top of their fields. Throughout the conference, this bipolar grouping was
frequently brought to the same question: what is it that makes humans different
from animals? What is uniquely human? As with a sculpture, this conference
seemed to answer this question by chipping away at the monolith of things
commonly thought of as unique to the human species.
For a long time, humans were thought to be unique for their
tool use [1,2]. However, many surprising examples of tool use have now been
seen in animals. Chimpanzees are now known to fashion weapons for use in
hunting, as well as using tools for nut cracking and termite retrieval; and will
sometimes be seen carrying favorite tools for great distances [1]. Even this
behavior is not unique to apes, however: Caledonian crows also craft and use
tools for grub
retrieval, and even have local tool-making traditions
they pass on to the next generation [2]. There are now many internet videos
showing crows solving
extremely complex tasks with available tools.
Several speakers showed that the human species is not unique
in its ability to cooperate and to understand cooperative relationships [1,3,4].
Chimpanzees, for instance, are perfectly capable of learning cooperative tasks
without training, and even spontaneously develop individual styles, preferred
partners, reputations, and feedback between partners on their choices [1]. They
may do this through the use of specialized “mirror neurons,” which are present
in motor planning and emotional areas of the brain and fire both when an action
or emotion is being experienced, and when it is being observed in others [3,4].
These mirror neurons were first discovered in Rhesus macaques, but have since
been found in humans and chimpanzees. Elephants readily learn cooperative
tasks as well, even waiting for their partner to arrive when a task is
presented that cannot successfully be performed alone [1]. Even more distant
from humans was a striking example of inter-species cooperative hunting between
groupers and moray eels,
where groupers show signs of shared intentionality and referential gesturing in
order to get moray eels to help them catch fish [5]. Tiny 5 gram cleaner wrasses, which
have more than 2,000 inter-species social interactions a day while cleaning
parasites off of other fish, show signs of cooperative strategies, individual
recognition, social prestige, audience effects, tactical deception and
reconciliation.
If an animal naturally cooperates, it should also be
sensitive to the results of cooperation, and there is now ample evidence that
this is the case. In a now-famous experiment, capuchins were shown to be
sensitive to unfairness:
when rewarded for a task with cucumber, they eagerly accept; but when they see
another capuchin being rewarded for the same effort with a grape, they bitterly
refuse the cucumber [1]. This sensitivity to inequality has since been seen in
many other species, including dogs and birds, and may be a general and
necessary behavior in cooperative species. Chimpanzees take this one step
further by showing a sense of fairness as well, choosing to reward others when
there is no benefit to themselves, and sometimes refusing a reward unless a
partner is also rewarded.
Social animals also employ very similar tactics to humans in
the maintenance of their relationships [1,6]. In social groups, conflicts are
inevitable, and for many years ecologists thought that conflict served to break
bonds of attachment and disperse social groups. However, more recent research
has demonstrated time and again in many species that social group members
actively reconcile after fights, which actually serves to bring group members
together and strengthen bonds. Risky pro-social interactions with new group
members may also serve to help form new social bonds [6]. In some species,
consolation happens after fights as well, typically initiated by individuals
with close relationships with the loser. These consoling behaviors have been
seen in many great apes, dogs, birds and elephants. In addition, recent
experiments in rats show that they are motivated to help their trapped
cagemates escape from an enclosure, and once they learn to do so, they will
release them very quickly even if they receive less of a food reward after
doing so [7]. Finally, the same brain neuropeptides that mediate social
behavior and social bond formation in animals seem to influence human
relationships as well, suggesting a common evolutionary origin for these
mechanisms in the brain [8].
In a talk presenting my own thesis work, I discussed
evidence of consolation in the prairie vole, a highly social monogamous rodent
[9]. Through a series of laboratory experiments, I demonstrated that male
prairie voles will show increased partner-directed grooming toward a male
sibling or female partner if that individual has been exposed to stress. I also
showed that observing their stressed cagemates induces stress and anxiety in
male prairie voles, suggesting that their behavior is based on empathy.
In order to console one another, animals must first be
capable to detect each other’s emotional states [1,7,9,10]. This is perhaps one
of the most broadly observed capacities of all, being present in virtually all
mammals and some other species as well. This is believed, at least in mammals,
to have its origins in motherhood. All mammals are raised by a mother, and
those mothers who are sensitive to the emotional signals and needs of their
offspring are more successful at rearing offspring. As an evolutionary result,
nearly all mammals have an implicit awareness of emotional cues, often
extending to other adults of their species. Sometimes this sensitivity even
extends across species, as has been observed in pet dogs that are responsive to
distress in their owners. Empathy shows similar patterns in humans as in other
animals: it is most often extended toward those closest to the subject, and the
more distressed a subject is by emotional displays in others, the less likely
the subject is to extend them help.
Related to empathy is observational/social learning, or the
ability to learn from watching another individual. This, too, is observed widely
among animal species, ranging from tool making/using techniques, to
child-rearing traditions, to food choices [11]. Some of the most striking
examples include the potato-washingJapanese macaques, which learned from one macaque to start washing the
dirty potatoes that the caretakers provided. Even when clean store-bought
potatoes were substituted, macaques for generations continued to wash their
potatoes in the sea. This also seems to suggest a form of culture in animals, which
pass along socially learned mannerisms to future generations that sometimes
have little or no functional relevance. Indeed, evidence of cultural practices
is quite strong in chimps, and some evidence exists even in rats.
Some believe that humans are unique in their capacity to
think about the mental states of others, an ability sometimes referred to as
“theory of mind.” However, this is also being challenged by clever beasts.
Studies have shown that human children develop theory of mind at exactly the
same age as they develop mirror self-recognition – a capacity which some of the
most advanced animals, including dolphins, elephants and great apes, also show in
adulthood [1]. However, even more convincing are recent experiments in Caledonian crows,
showing that they recognize the difference between a human-operated and a
randomly operated threatening device [2]. Human studies implicate specific
areas of the brain – the temporo-parietal junction, superior temporal sulcus,
and medial frontal cortex – as regions involved in thinking about the
minds of others [12,13]. In studies on Rhesus macaques, analogous brain regions
tend to expand with expanding group size, suggesting that they are involved in
thinking about group members in other species as well [13]. So, even the imaginative capacity of humans
seems not entirely unique.
The answer to the question of human uniqueness could be
something seemingly obvious: language [14]. “Language seems to invade almost
every aspect of cognition,” added Frans de Waal during a free discussion period.
Language itself is a symbolic representation of thought, and the subsequent
reliance on symbolic representations is reflected across a wide range of
cognitive processes, especially those involved in social communication and
learning. However, there is increasing evidence that some bird songs have
characteristics similar to language; that chimps and dogs can understand spoken
language, and may use gestural communication; and that some parrots may be able
to use spoken language in the same way that humans do [14].
Despite all of the shared capacities between animals and
humans, there is still significant resistance, even among scientists, to using
traditionally “human” terms to describe the emotions, abilities and mental
states of animals [15]. Nonetheless, the uniqueness of humanity may be simply a
matter of combination and degree. Redouan Bshary, the
scientist behind the grouper and cleaner wrasse studies, said in his talk that
all animal brains represent a set of solutions to ecological problems [5]. When
an ecological problem can best be solved through a single mental capacity, you
are likely to find an animal that possesses that capacity. However, you might
find it in isolation – for instance, a grouper that can form shared plans and
make referential gestures toward a moray eel may not be able to think
abstractly, imagine the thoughts of others, or use tools. Each animal
independently evolves only those capabilities it needs for its own set of
ecological problems. Furthermore, while chimps and crows may build tools, and
dogs and birds may understand language, they are nowhere near to matching
humans in the degree to which these capabilities are developed. So, humans may
represent a unique evolutionary amalgam of capabilities that individually can
be seen elsewhere, but rarely all together, and never to the same degree.
Bibliography
[1] de Waal FB (2014 October). Mammalian origins of empathy and pro-sociality. Talk presented at
The Social Brain Conference, Copenhagen, Denmark.
[2] Gray R (2014 October). Can social and technical intelligence be decoupled? Cooperation, causal
cognition and inferences about agency in New Caledonian crows. Talk
presented at The Social Brain Conference, Copenhagen, Denmark.
[3] Ferrari PF (2014 October). Hard-wired, soft-wired and re-wired. Brain plasticity, sensorimotor experience
and early social development in primates. Talk presented at The Social
Brain Conference, Copenhagen, Denmark.
[4] Rizzolatti G (2014 October). Understanding others from inside: a neural mechanism. Talk
presented at The Social Brain Conference, Copenhagen, Denmark.
[5] Bshary R (2014 October). The social brain hypothesis applied to fishes. Talk presented at
The Social Brain Conference, Copenhagen, Denmark.
[6] Calcutt S (2014 October). Chimpanzees in newly formed social groups choose high-risk social
investments over low-risk ones. Talk presented at The Social Brain
Conference, Copenhagen, Denmark.
[7] Mason P (2014 October). Helping another in distress: Lessons from rats. Talk presented at
The Social Brain Conference, Copenhagen, Denmark.
[8] Young LJ (2014 October). The neurobiology of social relationships: implications for novel
therapies for Autism. Talk presented at The Social Brain Conference,
Copenhagen, Denmark.
[9] Burkett JP (2014 October). Consoling behavior in the prairie vole: neurobiology and basis in
empathy. Talk presented at The Social Brain Conference, Copenhagen,
Denmark.
[10] Keysers C (2014 October). The empathic brain and its plasticity. Talk presented at The Social
Brain Conference, Copenhagen, Denmark.
[11] Whiten A (2014 October). Imitation, culture, and the social brains of primates. Talk
presented at The Social Brain Conference, Copenhagen, Denmark.
[12] Mars R (2014 October). From monkey social cognition to human mentalizing. Talk presented
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[13] Rushworth M (2014 October). The medial frontal cortex and social cognition in humans and other
primates. Talk presented at The Social Brain Conference, Copenhagen,
Denmark.
[14] Mooney R (2014
October). Neural mechanisms of
communication. Talk presented at The Social Brain Conference, Copenhagen,
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[15] Panksepp J (2014 October). Three primary-process animal social brain
networks 9PANIC, SEEKING, PLAY) and development of three new antidepressants
for humans. Talk presented at The Social Brain Conference, Copenhagen,
Denmark.
Want to cite this post?
Burkett, J. (2014). What is uniquely human? A report from The Social Brain Conference. The Neuroethics Blog. Retrieved on , from http://www.theneuroethicsblog.com/2014/10/what-is-uniquely-human-report-from.html
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