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Honest Signals: How They Shape Our World (Bradford Books)

Pentland,(Sandy) Alex
The MIT Press: London, 2008
ISBN 9780262162562 (pb)

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Reviewed by Julie Dugdale
Equipe MAGMA, LIG (Laboratoire d'Informatique de Grenoble)

Cover of book Analysing what influences human decision-making has pre-occupied researchers for decades and has been the subject of countless books and articles. Pentland argues that much of human decision-making is largely determined, not by conscious rational logical decision-making, but rather by unconscious processes. This is our ability to pick-up and be influenced by what he calls honest signals. This 'social sense' thus forms another channel of communication that evolves around social relations rather than words. Pentland suggests that some honest signals are difficult to fake and hence provide "a window into our intentions, goals and values". The result is that the outcome of decision-making can be reliably predicted from signalling behaviours such as the amount of influence, activity, mimicry and consistency. For example, by looking at how active a person is within a conversation (in terms of the amplitude and frequency of speech and a person's gestures) it can reflect the level of interest. Likewise mimicry can be an honest signal for empathy, and the strength of influence in a conversation is an honest signal of attention. Moreover, people's behaviour is a function of their social network and so by attuning ourselves to the pattern of social signalling we can obtain tacit knowledge spread across this network and develop a form of 'network intelligence' that will lead to better decision-making. Therefore, by focusing on these honest signals we should be able to understand group behaviour more clearly.

Whilst some of the ideas in the book, such as the power of non-verbal communication, the existence of network intelligence and how it may be used to analyse group behaviour and organisation are not new, what is remarkable is that Pentland and his colleagues have developed a device to quantitatively measure these social signals. The small lightweight wearable device, which has been developed over the years at the Human Dynamics Laboratory at MIT, contains sensors which capture and analyse people's voice patterns and their movements. The sociometer records, not the content of speech but how people say it and how they act when talking. It records the time people spend talking, the physical activity of the speaker, gestures, turn-taking behaviour and the amount of variation in speech prosody, etc.

Through a series of studies, spanning both professional and social situations, the book shows how powerful this form of honest signalling is and how the sociometer may be used to predict behaviour. The message is that what is important in our decision-making is not the conscious content of what is said but how information is unconsciously presented. By recognising social signals that are associated with success we could, Pentland argues, change our personal style to become more effective. However, one interesting area that has not been touched upon is what would be the implications if our previously unconscious behaviour became conscious and intentional.

The convincing empirical evidence presented by Pentland shows that unconscious social signalling, rather than rational or logical reasoning plays a central role in both individual and group decision-making. This undoubtedly has implications for management and indeed the study of social networks. The work will also impact the development of communication technologies and network facilitating tools.

In terms of the audience, the book is very much in the genre of popular science and is largely aimed towards managers. For example, using the sociometer, new management tools with sensing capabilities could be developed that could for example produce real-time maps of an organisation's information flow and function. Whilst several examples are given as to how the technology could be used in future in the business domain the book could also be interesting to researchers interested in social interactions, social networks and group dynamics. The contents are supported by around 150 references, many giving more in-depth details of the experimental studies and describing the various stages in the development of the sociometer. The substantial annexes, which account for a third of the book, provide more detail on the experiments and how the sociometer actually measures activity, influence, consistency, and mimicry. However, it is a bit frustrating that we don't actually find out about the exact features and specification of the sociometer until two-thirds of the way through the book in one of the annexes. Overall though, the book is a short but captivating and absorbing read. It presents many interesting and substantiated ideas on the power of honest signals in determining decision-making together with a technology for quantitatively measuring and predicting social behaviours. It could be of interest to modellers in the JASSS community, in particular those working on modelling and understanding social networks, human communication and norms.


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