Prospect Theory and the Defence in Clausewitz's on War Paper

Prospect theory and the defence in Clausewitz’s On War Paper presented to the annual meeting of the International Studies Association, 16 March 2016, Atlanta, Georgia. Kenneth Payne, KCL It is quite clear how greatly the objective nature of war makes it a matter of assessing probabilities.1 Carl von Clausewitz, somewhat cryptically, argued that defence in war was stronger than attack. This seems to jar with much military writing then and now which praises the dynamism of the offensive and advocates using surprise as a means of overcoming an adversary’s strengths. Seizing the initiative, particularly when done by bold, visionary generalship, is the way to win victory in battle. By contrast, the defence seems reactive and passive, not commonly traits praised in military commanders or strategists. Waiting, Clausewitz averred, is the ‘leading feature’ of the defence.2 Passivity in the face of enemy hostility is not commonly remarked upon as a feature of martial prowess. Even when an attack was underway, the defensive force would remain on the back foot, reacting to events, rather than shaping them decisively; passively enduring the blows of the assaulting armies. As Clausewitz saw it, ‘prudence is the true spirit of defence, courage and confidence the true spirit of the attack’.3 How then could defence be the stronger of the two forces in war? Nonetheless, I argue here that Clausewitz was essentially correct, and for reasons that modern psychology would recognize. Specifically, I claim that the defence is stronger because we have an innate aversion to losing possessions, and this causes us both to fight more tenaciously to hold on to what we have, and to risk more to secure it. This argument chimes well with Prospect Theory, a prominent concept in cognitive psychology elaborated first by Daniel Kahneman and Amos Tversky in the late 1970s. Clausewitz, I argue, was a proto- 1 Clausewitz, C. v., M. Howard, et al. (1993). On war. London, David Campbell., p. 96 2 ibid, p. 741 3 ibid, p. 658 psychologist; indeed his psychological insights are the key to his enduring reputation as a great thinker.4 Moreover, when it came to the relative strength of the defence, his theorizing anticipated important aspects of the landmark work of Kahneman and Tvserky. I illustrate the theoretical argument throughout with historic and recent examples. In their research, Kahneman and Tversky identify a striking relationship between the way in which a situation is ‘framed’, or expressed, and the amount of risk that individuals are willing to accept (Kahneman and Tversky 1979). Specifically, given the choice between accepting a guaranteed loss or gambling on the small possibility of avoiding a still larger loss, we are more inclined to gamble on the possibility – because we might thereby avoid any loss. More inclined, that is, relative to our behaviour with the same payoffs and odds when they are expressed to us as a gain – the choice between a sure gain and the small possibility of an even larger gain. Here, we are typically comparatively risk averse, settling for the sure thing. In the most telling financial experiment that the two researchers did, the payoffs and probabilities in either the ‘gain’ or ‘loss’ scenarios would be exactly the same, with the only change being language in which the options were described. This was done by having the participants imagine themselves, in the ‘loss’ scenario having being given a sum which they might then lose some of – thereby finding themselves in a ‘domain of losses’ – below their initial imaginary starting point. In the other scenario, the possible payoffs were expressed simply as a gain from their existing coffers. In a nutshell, Prospect Theory suggests we are loss averse, and so relatively risk acceptant when we are in that ‘domain of losses’. This domain is psychological – it is judged relative to some anchor-point that we use as a benchmark for calculating risk. The mental benchmark or anchor helps to frame the payoffs. In Kahneman and Tversky’s experiments, these were financial, but the theory has been applied more broadly, to use non-financial anchors and payoffs. As we will see, in strategic studies there is considerable scope for ambiguity and subjectivity about what the benchmark is in the real world, outside the psychology lab with its clear-cut financial choices. This propensity to gamble more enthusiastically when the frame suggests we are in a domain of losses seems non-rational. And it is, at least in the sense of strict theoretical ‘rationality’, where actors are assumed to have ‘perfect knowledge’ of payoffs and probabilities, and consistently ordered preferences that they seek to satisfy. Rational actors, in the abstractly rational sense of utility theory, appraise risk the same way regardless of the frame. 4 A point I make extensively in Kenneth Payne, The Psychology of Strategy: Exploring Rationality in the Vietnam War (London: Hurst & Co. 2015) There is, though, a plausible logic to the bias - there may be sound evolutionary reasons for our instinctive fear of losing possessions or aversion to gambling on possible acquisitions. Gambling to acquire new resources, including territory, food, and sexual partners, comes with uncertain odds and the possibility of grave consequences. Losing resources in marginal environments may similarly prove decisive in the struggle for survival. Proverbially, of course, a bird in the hand truly seems worth two in the bush, and discretion is the better part of valour. There is likely to be an emotional dimension to this evolved loss aversion – even though this is unspecified in the original, cognitive psychological theory. Emotions can serve to shape decision-making that is evolutionarily advantageous, making such choices more instinctual and timely, while freeing up limited cognitive resources. And so we might find that losing relative to the reference point makes us angry and more resolute in our purpose – distorting our perception of the odds (Druckman & McDermott, 2008). Clausewitz and the defence About a century and a half before Kahneman and Tversky, Carl von Clausewitz set out an argument about the defence in war that goes a considerable way towards their take on loss aversion. Clausewitz’s writings on war contain throughout a remarkable psychological dimension: he was keenly aware that war was a struggle of wills between belligerents, and that it was intimately bound up with probability and chance. Indeed, he wrote that ‘in the whole range of human activities, war most closely resembles a game of cards’.5 Clausewitz offered some largely plausible practical explanations for the dominance of the defence, including shorter internal lines of communication for the defender, the capacity to wait and choose when and where to offer battle, the ability to shape one’s disposition ahead of any invasion. But there was also the moral and practical support offered by one’s own population coming under attack. It is this moral and emotional dimension that I suggest holds the key to Clausewitz’s assertion, along with the notion of possession. Clausewitz wrote that ‘the collective influence of the country’s inhabitants is far from negligible’, and added the sort of passions exhibited by the Spanish population in their popular war against the Napoleonic forces were a ‘genuine new source of power’.6 Elsewhere he had noted the passionate hatred of the people as an essential force in war, part of his ‘remarkable trinity’. And while he did not expand much on these ideas, preferring instead to concentrate on the more 5 On War., p. 97 6 Ibid, pp. 446-7 material aspects of defence, they seem to me to be key to understanding his contention that defence was the stronger of the two forces. Set against these moral advantages for the defence was the moral lift for the attacker of being the dynamic force, looking to seize the initiative, rather than waiting, passively as the other side decided on action. Militaries prize the initiative, and incline towards activity over passivity. Taken to the extreme, this gives us the cult of the offensive that dominated military thinking ahead of the Great War, and indeed during it, when wave after wave of offensives in Western Europe smashed fruitlessly against powerful static defences. In his own time, Napoleon amply demonstrated the battlefield advantages of the bold offensive, sending huge columns of motivated, patriotic Frenchmen against the lines of defenders. On a larger strategic canvass too, Napoleon’s lighting advances through Europe seemed to demonstrate the gains to be had from decisive and dynamic campaigning. And there are historic examples aplenty of bold operational art attaining success through attack – consider the lightning surprise attack of the Japanese at Pearl Harbour and in Malaya in 1941, or the dramatic breakthrough by German Panzer divisions at Sedan in 1940, before their charge across northern France to the channel ports. By the same token, however, we can plunder the historical record to find examples of the defence winning out, in battle or campaigns, and sometimes against the odds. Herodotus’s description of the 300 Spartans at Thermopylae and the epic British defence of Rorke’s Drift against Zuli impi provide compelling illustrations that heavily outnumbered defenders can thwart determined assault. Clausewitz, in common with other military thinkers then and now, stress the value of mass. Quantity has a quality of its own, as the saying, sometimes attributed to Stalin, has it. Yet terrain, technology, professionalism and moral cohesion all come into play to offset an attacker’s superiority in numbers. If that is true tactically in one battle, then so too at the larger operational level defence can dominate, just as it did in the trenches of the Western Front during the Great War.

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