Context in Environmental Modelling – the room around the elephant

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An Invited talk at iEMSs, Leipzig 2012 (http://www.iemss.org/sites/iemss2012).

Abstract:

Behaviour in society and the responses from the environment are both highly context-dependent. There is a lot of evidence that hyman cognition and behaviour depends sharply on the percieved context. Human collective and social behaviour is even more so, indeed may be structured around co-determined contexts that are then entrenched within our training, infrastructure and habits. Similarly ecological niches, where species adapt to each other can be highly specific to a particular set of environmental affordences. The response to a pertabation (e.g. reduction of a resource or introduction of a new species) depends highly on the environmental context.

However, to a very large extent, our formal models of the environment and of our interaction with the environment are context-free. It is often simply assumed that the variations due to specific contexts can be dealt with as a kind of "noise" to a main trend or interaction. Whilst this maybe sometimes the case, this assumption is rarely justified by any evidence or indeed convincing argument . Often it seems that context is ignored simply because it seems too difficult to do otherwise, so work proceeds simply on the hope that context-dependency can be treated as a kind of noise. Other strategies to avoid the issue of context include keeping to within a single, very restricted context (which prevents any general conclusions) or remaining in the world of analogy and natural language discourse (where context-dependency is masked by the innate ability of humans to reapply analogies on the fly). I argue that this must often not be the case and that a collection of context dependent interactions if treated in this way, can result in very different outcomes, especially when one needs to scale any conclusions.

I then seek to show some possible ways forward, ways to include some of the context-dependency in our techniques and models. These include kinds of agent-based modelling that include context-awareness in the agents and actors, kinds of data-mining that could be used to search for patterns in a context-dependent manner, and new techniques from the field of visual analytics to visualise and interact with data via a visual interface in a context-friendly manner.

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  • AI, NL, Sociology, Philosophy, Mobile devices, Psychology, Cognitive ScienceFor detailed argument seem my previous papers on thisDustbin Like complexitywill talk about this problem later
  • Imagine a professor of physics in a wild place – does his intelligence help him to survive?
  • Reader 1980, Man on Earth
  • leakage  noisenot the case where un-modelled aspects are effectively randomdiscuss random gas example
  • Context in Environmental Modelling – the room around the elephant

    1. 1. Context in Environmental Modelling – the room around the elephant Bruce Edmonds Centre for Policy Modelling, Manchester Metropolitan University Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 1
    2. 2. Acknowledgements Many thanks to all those with whom I have discussed these ideas, including: Emma Norling, Nick Shryane, Jason Dykes, Scott Moss, those at the Conference Series on “Modelling & UsingContext”, the regulars at the Manchester Complexity Seminar and those in the SCID Project. Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 2
    3. 3. Some Questions about Context• How important is the context when modelling process/aspect/system X/Y/Z?• How much can we ignore context…• …or, conversely, how much of the context do we have to include within our models?• If we include context-dependency does that stop us being scientific?• How can we square the context- dependency of the observed/involved world with our models of that world? Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 3
    4. 4. Talk Outline1. Context-dependency in the environment2. Context-dependency in human behaviour3. Some defensive responses to context- dependency4. Some possible ways forward Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 4
    5. 5. Note on Talking about Context• The word “context” is used in many different senses across different fields• Somewhat of a “dustbin” concept resorted to when more immediate explanations fail (like the other “c-word”, complexity)• Problematic to talk about, as it is not clear that “contexts” are usually identifiably distinct• Mentioning “context” is often a signal for a more “humanities oriented” or “participatory/involved” approach and hence resisted by “scientists” who are seeking general laws Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 5
    6. 6. Part 1:Ecological Context-Dependency Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 6
    7. 7. Ecological Context• A certain kind of environment might provide certain affordances/difficulties• Organisms adapt to exploit these but also create new affordances/difficulties• Migration between similar ecologies makes organisms ready to exploit each type available• The organisms are only fully understandable in their ecological context – the web of other organisms and their environment Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 7
    8. 8. A (colourful!) Picture of the World • Each square (patch) is a different, well- mixed location • There are 15 kinds of location with individuals in each (4 bit string) • Small stars are herbivores, circles those who have eaten another (the bigger the more it has eaten) • Different colours indicate different species (not all species are visually distinguishable) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 8
    9. 9. Brief (!) Model Outline• Basic energy economy (life tax, 90% transference, reproduction at 3, birth at 1 etc.)• Patches and organisms have a binary vector (lengths 4 and 100 respectively)• Fixed 100x100 random matrix made at start that broadly determines…• …who can eat who (or who extract energy from environment) determined by eater & eaten’s binary strings (sum of entries in matrix at rows and columns indicated by 1s)• Slow processes of mutation, migration etc. Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 9
    10. 10. Simulation at (up to) Reference Point First Successful Carnivores Simulation Herbivore Appear “Frozen” Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 10
    11. 11. From this point on…50 times for each of 16 different “aspects” (aswell as none, the base case)…• Reset world to this point• “Block” interaction on one of the dimensions (the entries in the matrix indicated by 1s in that column/row number are not summed)• Simulate the world for a further 100 ticks (with different random seed each time)• Measure the genetic diversity of the population overall and by each niche type (average hamming distance between all distinct agents) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 11
    12. 12. Affect of Blocking Different Aspects of Interaction(av. over 20 runs after 100 ticks, ±2SD) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 12
    13. 13. Effect of Blocking Aspects ofInteraction by Aspect Base Case (no blocking) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 13
    14. 14. Implications of EnvironmentalContext-Dependency• Whilst there are some underlying universals that affect the environment (water, genetics, energy…)• What characterises “the” environment is that it is not singular but a complex, overlapping patchwork of different ecological contexts• We can gain some understanding of what is happening within each context, but generic understandings across these can be weak Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 14
    15. 15. Part 2:Context-Dependency in Human Behaviour Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 15
    16. 16. A (simplistic) illustration of context from thepoint of view of an actor Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 16
    17. 17. Situational Context• The situation in which an event takes place• This is indefinitely extensive, it could include anything relevant or coincident• The time and place specify it, but relevant details might not be retrievable from this• It is almost universal to abstract to what is relevant about these to a recognised type when communicating about this• Thus the question “What was the context?” often effectively means “What about the situation do I need to know to understand? Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 17
    18. 18. Cognitive Context (CC)• Many aspects of human cognition are context- dependent, including: memory, visual perception, choice making, reasoning, emotion, and language• The brain somehow deals with situational context effectively, abstracting kinds of situations so relevant information can be easily and preferentially accessed• The relevant correlate of the situational context will be called the cognitive context• It is not known how the brain does this, and probably does this in a rich and complex way that might prevent easy labeling/reification of contexts Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 18
    19. 19. The Context Heuristic• The kind of situation is recognised in a rich, fuzzy, complex and unconscious manner• Knowledge, habits, norms etc. are learnt for that kind of situation and are retrieved for it• Reasoning, learning, interaction happens with respect to the recognised kind of situation• Context allows for the world to be dealt with by type of situation, and hence makes reasoning/learning etc. feasible• It is a fallible heuristic…• …so why do we have this kind of cognition? Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 19
    20. 20. Social Intelligence Hypothesis• Kummer, H., Daston, L., Gigerenzer, G. and Silk, J. (1997)• The crucial evolutionary advantages that human intelligence gives are due to the social abilities it allows• Explains specific abilities such as imitation, language, social norm instinct, lying, alliances, gossip, politics etc.• Social intelligence is not a result of general intelligence, but at the core of human intelligence, “general” intelligence is a side- effect of social intelligence Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 20
    21. 21. An Evolutionary PerspectiveSocial intelligence implies that:• Groups of humans can develop their own (sub)cultures of technologies, etc. (Boyd and Richerson 1985)• These allow the group with their culture to inhabit a variety of ecological niches (e.g. the Kalahari, Polynesia) (Reader 1980)• Thus humans, as a species, are able to survive catastrophes that effect different niches in different ways (specialisation) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 21
    22. 22. Implications of SIH• That different complex “cultures” of knowledge are significant• An important part of those cultures is how to socially organise, behave, coordinate etc.• One should expect different sets of social knowledge for different groups of people• That these might not only be different in terms of content but imply different ways of coordinating, negotiating, cooperating etc.• That these will relate as a complete “package” to a significant extent Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 22
    23. 23. Social Embedding• Granovetter (1985)• Contrasts with the under- and over-socialised models of behaviour• That the particular patterns of social interactions between individuals matter• In other words, only looking at individual behaviour or aggregate behaviour misses crucial aspects• That the causes of behaviour might be spread throughout a society – “causal spread”• Shown clearly in some simulation models Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 23
    24. 24. Illustration of Causal Complexity Lines indicate causal link in behaviour, each box an agent (Edmonds 1999) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 24
    25. 25. Implications of Social Embedding• In many circumstances agents can learn to exploit the computation and knowledge in their society, rather than do it themselves (invest in what Warren Buffet invests in)• Knowledge is often not explicit but is something learned – this takes time• This is particularly true of social knowledge – studying guides as to living in a culture are not the same as living there for a time• Social embedding means that human behaviour can not be understood well separate from its cultural context Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 25
    26. 26. The Social Co-Development of SharedRecognised Context• Over time, due to their similarities, certain kinds of situation become recognised as similar by participants• This facilitates the development of a set of shared habits, norms, knowledge, language etc. that is specific to the context• The more this happens the more distinctive that kind of situation becomes and hence more recognisable by newcomers• Eventually these may become institutionalised in terms of infranstructure, training etc. (e.g. how to behave in a lecture theatre)• This co-development of context may be the reason for its social/evolutionary value Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 26
    27. 27. Implications of the Context-Dependency of Human Behaviour• Behaviour of observed actors might change sharply across different social contexts• The relevant behaviour, norms, kinds of interaction etc. might also change• Social contexts are co-developed and changing• They may be different for different groups• Some kinds of social behaviour seem to be inherently context-dependent (compliance)• It is unlikely that a lot of key social knowledge, norms, behaviour etc. will be generic• Models that assume a cross-context engine of human behaviour may be deeply misleading! Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 27
    28. 28. My Central Point• Given the sharp context-dependency of both human behaviour and the environment…• …how is it that a lot of our models use generic models of human behaviour and/or the environmental response? Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 28
    29. 29. Part 3: Defensive ResponsesContext in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 29
    30. 30. Some Possible Responses• Its too difficult, I’ll ignore it• I am looking at the wider/more general picture, what is common across contexts• I treat intra-context variation as random noise• I have included context, it is the variables a, b, c etc. which vary with the context• I am acting within context only• I am only modelling a single context• It is not scientific• I need an analytic expression for my model• Use natural language/analogical models only• I don’t have enough data Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 30
    31. 31. Ignoring Context• Much modelling happens with a single context in mind, in which case it can be ignored but only if – everyone is using the same idea of this context – there is no significant “leakage” of causation from outside the background, that is the scope is wide enough to include all significant influencing factors – The actors/organisms don’t deal with the same situation as different cognitive contexts Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 31
    32. 32. The “Simple is more General” Fallacy• If one has a general model one can make it more specific (less general) by adding more processes/aspects…• …in which case it can become more complex• However, the reverse is no true…• If one simplifies/abstracts then you don’t get a more general model (well almost never)! – there may be no simpler model that is good enough for your purpose – But, even if there is, you don’t know which aspects can be safely omitted – if you remove an essential aspect if will be wrong everywhere (no generality) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 32
    33. 33. Context-Dependency andRandomness Lots of information lost if randomness used to “model” contextual variation Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 33
    34. 34. Scaling by Size • Look at variance as system size increases… • Does variance as a proportion of size disappear? • In this case Law of large numbers does not apply • Simple examples: • Kaneko (1990): parallel globally coupled chaotic processes • Edmonds (199?): scaling Brian Arthur’s “El Farol Bar” Model Contextual variationVariance(scaled by size) Model with random noise Size Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 34
    35. 35. Context-Dependencyand “Being Scientific”• If the relevant context can be reliably indentified then…• …context-dependency is not the same as subjectivity (even if there are a some hard cases that escape definition)• Generality is nice if you can get it, but its no good pretending to have it if you can’t• Science should adapt to what it wishes to understand, not the other way around• It does mean (often) an acceptance that general/generic approaches are not useful Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 35
    36. 36. Analogical Thinking• Humans are good at using analogies, relating an idea or example from one context to another in a rich, relevant and flexible manner – it is a powerful method of thought• They build the mapping from the analogy to the a context “on the fly”, largely unconsciously• The mappings are different each time an analogy is applied, thus not a reliable source of transmittable knowledge – each person might build a different mapping unless they inhabit the same context• Many published models do not have an explicit mapping to a domain, but are used more as analogy• This is sometimes hidden, so when a simulation (or analytic model) does not directly map to observations but to an idea which then applies as an analogy to the domain and not directly, this gives a spurious impression of generality Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 36
    37. 37. Part 4: Some Ways ForwardContext in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 37
    38. 38. Some ways forward• Keeping the data and simply NOT summarising it (at least not prematurely)• Data mining local patterns to detect commonality of multiple models/measurements across similar contexts• More complex simulation models with context-dependent cognitive models• Context-sensitive microsimulation models• Context-oriented visualisation techniques• Use of “mundane”, context-specific models of human behavior rather than ambitious generic ones• Integrating personal/anecdotal accounts of behaviour – making use of qualitative evidence• Not leaving the context(s) – acting within the normal sphere of shared and relevant situations• Staging abstraction more gradually• Clusters of related models Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 38
    39. 39. Cleveland Heart Disease Data Set – theprocessed sub-set usedIn processed sub-set:• 281 entries• 14 numeric or numerically coded attributes• Attribute 14 is the outcome (0, 1, 2, 3, 4)• Some attributes: age, sex, resting blood pressure (trestpbs), cholesterol (chol), fasting blood sugar (fbs), maximum heart rate (thalach), number of major vessels (0- 3) colored by flourosopy (ca)• From the Machine Learning Repository Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 39
    40. 40. Fitting a Global Model (R=56%)Num = -0.01*age + 0.17*sex + 0.20*cp + 0.00*trestbps + 0.10*restecg + -0.01*thalach + 0.23*exang + 0.18*oldpeak + 0.16*slope + 0.43*ca + 0.14*thal + -0.60 (+/- 0.83) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 40
    41. 41. Looking for Clusters in HD Data Set(Start of Process) Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 41
    42. 42. Final Set of Clustered Solutions • Final solution set after some time. • Still complex but some structure is revealed • Note presence of “fbs” despite not being globally correlated and that “chol” helped define the context space Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 42
    43. 43. Clusters of Model Scopes suggest aContext M 1 M1 M2 suggests a contextA useful context is one that: – includes related models with different goals/predictions but similar scope Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 43
    44. 44. Basic Cognitive Model Reasoning/plan Context ning/belief Recognition revision/etc. Context-Structured Memory• Rich, automatic, imprecise, messy cognitive context recognition using many inputs (including maybe internal ones)• Crisp, costly, conscious, explicit cognitive processes using material indicated by cognitive context Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 44
    45. 45. Example – models in the cognition ofa trading agent 950 Volatility - past 5 periods 900 850 800 750 700 750 850 950 Volume - past 5 periods Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 45
    46. 46. The model contents in snapshot ofone trader model-256 priceLastWeek [stock-4] model-274 priceLastWeek [stock-5] model-271 doneByLast [normTrader-5] [stock-4] model-273 IDidLastTime [stock-2] model-276 IDidLastTime [stock-5] minus [divide [priceLastWeek [stock-2]] model-399 [priceLastWeek [stock-5]]] [times [priceLastWeek [stock-4]] [priceNow [stock-5]]] Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 46
    47. 47. Total Assets in a Typical Run 30000Total Value of Assets 25000 20000 15000 10000 5000 0 0 100 200 300 400 500 Time Black=context, White= non-context Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 47
    48. 48. Some Simulation Work addressingContext-Dependency in Cognition• (Schlosser & al 2005) argue that reputation is context dependent• (Edmonds & Norling 2007) looks at difference that context-dependent learning and reasoning makes in an artificial stock market• (Andrighetto & al 2008) show context- dependent learning of norms is different form a generic method• (Tykhonov & al 2008) argue that trust is context dependent Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 48
    49. 49. Conclusions• Ignoring it and simply hoping it won’t matter is not an option (if we are serious about our project)• There are ways forward to meaningfully make progress in dealing with context-dependency• And some of these involve the integration of qualitative/in situ approaches with quantitative/formal modelling• We will need a LOT more data both multi-dimensional and at a finer-granularity, but this is starting to come on stream• Context seems to be an important factor impeding the integration of both: action-oriented and model- based approaches, as well as quantitative and qualitative approaches• Please help Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 49
    50. 50. Ad for a workshop! The End Bruce Edmonds http://bruce.edmonds.nameCentre for Policy Modelling http://cfpm.org Context in Environmental Modelling - the room around the elephant, Bruce Edmonds, iEMSs, Leipzig, July 2012, slide 50

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