A field of study in which many modern scientists have developed an interest is social networking, especially with the coming of phenomena such as Facebook, Twitter and so on. Are these purely modern and human inventions, or are they products of our natural animal evolution? A key question is:
Do other animals, besides humans, form
‘social’ networks?
Take some time to think about and/or discuss the question above. You do not need any specialist knowledge to do this: it is an open discussion, an exploration of ideas.
However, you should try to bring some examples or evidence into the discussion.
You can use your own observations and experiences as evidence – for example, documentaries you have seen of animals in the wild, and the way they behave. Think, too, about what is meant by ‘social’ in this context.
Activity
typically live with only three or four others, groom for 5 per cent of their day at most.
Baboons, meanwhile, live in groups of 50 or more and can spend as much as 20 per cent of their time grooming. However, as group size and time spent grooming increases, this social effort is concentrated on fewer and fewer partners.
Although we use grooming in intimate relationships, the very intimacy of the activity makes it ineffective as a tool for bonding our large social groups. Instead, we have evolved alternative ways to create the same endorphin surge on a bigger scale. One of these is laughter, another is communal music-making.
Language, too, plays an important role – not only can we speak to many people at the same time, we can also exchange information about the state of our networks in a way that other primates cannot. Gossip, I have argued, is a very human form of grooming.
* ‘Grooming’ means tidying, removing dirt or nits from fur, etc.
DOC C
Primates with a large social network have bigger brains*
** Neocortex ratio = neocortex volume divided by volume of the rest of brain
* In Doc C ‘bigger brains’ means more than just brain volume. It is the proportion of the whole brain that is associated with higher functions like perception and communication. This is called the ‘neocortex’. In humans the neocortex is the part of the brain which enables language, reasoning and conscious thought.
Humans
Neocortex ratio**3 4 5
Mean group size
Now that you have had a chance to discuss and think about the issues and terms involved, we can turn to a text which deals with the subject on a more scientific level.
A scientific study
A scientist who has undertaken extensive research in this area is Robin Dunbar, Professor of Evolutionary Anthropology at the
University of Oxford. His research focuses on the evolution of sociality in the primates: the order that includes apes, monkeys and humans. He is particularly interested in the structure and dynamics of human social networks. The following extracts are from an article published in New Scientist. Although they all come from the same article, they are presented here as four separate documents to make them easier to refer to in the activity which follows.
DOC A
We tend to think of social networks as being distinctly human. In fact, they occur wherever animals live in ‘bonded’ groups – where individuals gather together because of their personal relationships rather than being forced to by environmental factors such as a food source or safe sleeping site. Bonded groups are found among all primates and a few other mammals . . . Such networks have benefits, but they are also costly to maintain and are only an option for the smartest of species.
DOC B
Monkeys and apes create and nurture social relationships by grooming* each other. The physical action of being groomed is rather like massage and triggers the release of
chemicals called endorphins. This creates a light euphoria that seems to make it possible for animals that groom each other to build a relationship based on friendship and trust.
The average time spent grooming by members of a species correlates with the size of their social group. Those, such as gibbons, which
DOC D
The larger a primate’s group size, the longer they spend grooming to cement bonds
20
15
10
5
01 30 60 90 120 150
Group size
Time spent grooming (percentage)
The four documents above – two textual and two graphical – are typical of those used for critical thinking questions in many
examinations. Once you are familiar with the content, have a go at answering the questions below, each of which is followed by a short commentary, discussing the question and suggesting a suitable answer (or answers).
1 In the paragraph marked Doc A, what viewpoint is the author challenging, and on what basic grounds does he make the challenge?
Activity
Commentary
This is a very straightforward question. In Doc A the author sets out his target for what follows: the view that social networks are distinctly human. He challenges this view by claiming that social networks occur wherever there are ‘bonded’ groups, defining bonding as gathering together for more than just physical reasons such as food and security.
This is the key difference between a social
gathering and a mere herd or pack. According to Professor Dunbar, these bonded groups occur among many animals, including all the primates – apes, monkeys, humans, etc. – and some other mammals too.
You are not asked to assess the evidence, nor to evaluate the argument. To do that you would need to have read more widely. But it is clear that if the author is right in saying that primates form groups that are bonded by relationships, rather than mere environmental factors, then there are grounds for the claim that social groups are not distinctly human.
2 Does the data in Doc C support the view that a species’ average group size tells us something about how ‘smart’ (i.e.
intelligent) it is?
Activity
Commentary
We will begin by saying something about the data itself. Doc C is a scatter graph. Scatter graphs are intended to show correlations. Here the correlation being investigated is between brain size (the horizontal axis) and average group size (the vertical axis) in primates. ‘Brain size’, as explained in the notes, is a shorthand for something rather more complicated, namely the amount of an animal’s brain that is associated with higher levels of intelligence. It is measured as a ratio, and obtained by dividing the volume of the whole brain by the volume of the neocortex. In humans the neocortex is over four times the volume of the rest of the brain, making the human brain the
‘biggest’ in the defined sense.
You may have noticed the somewhat unusual scale that has been used on the graph, especially on the vertical axis. The lowest band shows group sizes between 1 and 10, the second between 10 and 100. Mathematicians among you will recognise this as a logarithmic scale. It is a useful device when the range of
primates, which are already understood to be at the smarter end of the scale of animal intelligence. You may want to qualify your answer by saying that the graph tells us something about smartness and bonded groups.
Another point you might make is that the graph tells us only about the correlation between group size and brain size (or neocortex ratio to be precise.) Does this permit us to make the further claim that animals which form bigger groups are ‘smarter’? To put it another way, is there an assumption that brain size equals smartness? The problem is that we need a definition of smartness that connects it with brain size. Without that it would be jumping to a conclusion to say that group size – even bonded-group size – indicated intelligence.
Another point still that you could raise is that although there is a general match between group size and brain size, there are some exceptions. As we observed earlier, the three ape species apparently form smaller groups than many monkeys with similar-sized or even smaller brains. If apes are more intelligent because their brains are larger, why would they live in smaller groups? This at least requires some explanation if we want to make the connection between group size and smartness.
So a good answer to a question like this is more than simply yes or no. You may be satisfied that the graph does tell us something about the smartness of a species, but you must be able to say why you reached this judgement. You should also be prepared to qualify your answer by adding reservations, or acknowledging the assumptions that have to be made, or further questions that have to be answered. Likewise, if you decided that the graph does not tell us anything about smartness, you would need to give your reasons, and to acknowledge what it does tell us as well as what it does not.
values is large, as it is in this case. Group sizes start at about 3 and rise to around 150 (in humans). With an ordinary scale the graph would either have to be very tall, or the dots would be packed so tightly together that they would be difficult to tell apart.
Each dot or circle on the graph represents one species. The pattern of the dots suggests that the primates with bigger brains tend to form larger groups. Most of the monkeys with a brain size rated at less than 2 live in group sizes smaller than 10. Those with brain sizes between 2 and 3 form much larger groups:
anywhere between 10 and 100. With apes, too, there is a correlation between brain and group size, although their groups are slightly smaller in relation to their brain size. Only humans form groups of more than 100.
So, to get back to the main question, the graph does show a general correlation between brain size (as it is defined) and group size, both in monkeys and in apes. Humans top the table on both counts, and humans are very smart – or so we tell ourselves. Therefore it could be argued that group size is an indicator of smartness: the larger the group, the greater the intelligence. The author even offers an explanation for this in Doc A. Social networks, he says, are ‘costly’, and only the smartest species could manage them. (By ‘cost’ he probably means the time and effort that they take up, which could be spent eating or hunting instead.)
But there is a proviso. Yes, the data on group size and brain size does tell us something about the smartness or intelligence of a species, but only if the groups in question are
‘bonded’ or ‘social’ groups. We know from the earlier discussion that big herds, shoals and so on don’t count as social groups. If they did then there would be some animals (e.g. some fish) that have very small brains but gather together in groups of thousands. The graph on its own, therefore, is selective. It relates only to
large groups, spend much less time grooming than baboons, which form groups of 50 or more. Of course, two favourable examples do not prove the theory correct, or even give it much support. Doc D, on the other hand, provides many such examples. And, as in Doc B, the trend does support the hypothesis: time spent grooming does show a tendency to increase with group size. There are a few
‘outliers’, as they are called: one species which grooms more than most but has a group size of around 10; and the primate with the second-largest group size grooms less than many which live in smaller groups. (These are
‘outliers’ because the points on the graphs lie furthest from the centre of the bunch.) You can single out for yourself other examples which are not typical. The question you must ask is whether these anomalies are enough to discredit the theory, or whether they can be ignored, or explained (see Chapter 4.2, pages 140–1).
You might also have picked up on the fact which Professor Dunbar makes at the end of the first paragraph of Doc B: ‘As group size and time spent grooming increases, this social effort is concentrated on fewer and fewer partners.’ This may seem puzzling. It may even seem to contradict the main idea that group size goes with more grooming. For both reasons, it calls out for an explanation, which takes us on to our next and final question.
4 What explanation could be given for the fact that in large groups grooming is concentrated on fewer partners?
Activity
Commentary
There may be a number of plausible
explanations which you could give, so do not be concerned if your answer is different from the one here. It is a suggested answer, not the 3 In the first sentence of Doc B, the author
claims that monkeys and apes develop social relations by grooming each other.
How well does the rest of the document, and the information in the second graph (Doc D), support this claim?
Activity
Commentary
Firstly the author explains how grooming may account for the building of relationships within a group. It is known that naturally produced chemicals called endorphins can cause a pleasurable (euphoric) feeling in humans. We know that among the ‘triggers’
which release endorphins is massage, which is very similar to grooming. Laughter, music-making and so on have similar effects. If people share these pleasurable experiences it tends to bind them together as friends or partners. It is a plausible hypothesis that grooming has a similar effect among animals, and results in bonding between individuals within the group.
As we have seen several times in previous chapters, being plausible is not enough to make a hypothesis true. But it is enough to make it worth investigating further. This brings us to one of the key features of scientific reasoning: the need to test hypotheses by looking for further evidence which either corroborates or disproves it. The methodology is this: we suppose that the hypothesis is correct and ask ourselves what else would be true or probable as a consequence. In this case the question would be: If the grooming theory is right, what else would we expect to find?
One quite obvious expectation would be that animals with large social groups would do more grooming than those which form very small groups. In Doc B Professor Dunbar provides some data which suggests that this is indeed the case: gibbons, which don’t form
interacting with the wider group, as humans do. That would account for the concentration of grooming on small numbers of partners. If this is the right explanation, it would also support Dunbar’s claim that social groups are not a purely human phenomenon.
Summary
• Scientists make observations and use them both to construct and to test their theories.
• Critical thinking has much in common with scientific thinking.
only correct one. The clue is in human behaviour, and is discussed in the second paragraph of Doc B. Humans form large groups, compared with most if not all other primates – 150 on average (Doc C). Humans, as we know, use physical grooming only in very intimate relationships. With less intimate acquaintances, Dunbar argues, grooming takes more varied and more acceptable forms such as laughing, singing and gossiping. The explanation we are looking for may therefore be that other more advanced primates, with larger group sizes, and with brain sizes approaching those of humans, also reserve grooming for their most intimate partners.
Perhaps they too have other ways of
2 Find out more about the research of Robin Dunbar. Identify one of his theories and one or two items of evidence he gives in support of it.
1 Is there enough evidence in the extract you have read to conclude that some animals form social groups similar to those of humans? Write a short reasoned case to support your answer.
Questions in this form occur regularly in Cambridge Thinking Skills Paper 2.
End-of-chapter assignments
We return now to arguments, but to longer and more challenging texts than you have been working on so far.
Start by reading the passage below. It is followed by a number of questions that will