![](bg8.png)
this detrimental behaviour. The need becomes even
more pressing when there are forces working against
the development of co-operative relations, here repre-
sented by the emotion of hope and the temptation to
defect to which it gives rise.
In many cases, however, simply correcting un-
wanted behaviour is not enough: action is also re-
quired to try to prevent recurrence of the unwanted
behaviour. Often, there are several ways in which the
emotional characteristics of agents can be changed to
achieve this; the strategy selected, however, may de-
pend on the aims and emotional characters concerned.
Here we have seen that the interventions that provide
the best value in terms of gains per intervention do
not necessarily lead to the best overall system score.
Moreover, the nature of the changes, or even whether
changes are worthwhile, will depend on the emotional
characteristics of the initial population. In homoge-
neous populations it will be possible to tailor the ed-
ucation to the population, but in a mixed population
this may not be possible.
Of course, what we have reported here applies to a
single simulation environment with single parameters
for aspects such as the likelihood of defection once
hope is activated; changing these parameters may sig-
nificantly affect the results. However, we believe that,
as with increasing the length of the simulations, the
effects are likely to be quantitative rather than qual-
itative. Thus we would expect that the greater the
chance of defection once hope is activated, the more
essential it will be to change the emotional character
of the most dysfunctional agents to keep the number
of interventions reasonable; if the probability of de-
fection is small, this becomes less important. Further
simulations will be run to confirm these conjectures.
Whilst simulating a society of agents is a good
way of investigating the emergence of co-operation,
in practice, societies do not allow agents to act as they
choose. Societies have a vision for what they deem to
be desirable behaviour and will actively intervene to
impose upon or persuade their members to adopt - or
at least conform to - this desirable behaviour. We be-
lieve that it is therefore important that such interven-
tions are themselves modelled, so that the interaction
of agents within a society can be better understood.
REFERENCES
Adam, C., Herzig, A., and Longin, D. (2009). A logi-
cal formalization of the OCC theory of emotions.
Synthese, 168(2):201–248.
Axelrod, R. (1984). The Evolution Of Cooperation.
Basic Books, Inc.
Bazzan, A. L. C. and Bordini, R. H. (2001). A frame-
work for the simulation of agents with emotions:
Report on experiments with the Iterated Pris-
oner’s Dilemma. In Proceedings of the 5th In-
ternational Conference on Autonomous Agents.
Burghouts, G. J., Heylen, D., Poel, M., Akker, R.
O. D., and Nijholt, A. (2003). An action se-
lection architecture for an emotional agent. In
Recent Advances in Artificial Intelligence, pages
293–297. Menlo Park: AAAI Press.
DeSteno, D., Bartlett, M. Y., Baumann, J., Williams,
L. A., and Dickens, L. (2010). Gratitude as
moral sentiment: Emotion-guided cooperation
in economic exchange. Emotion, 10(2):289–293.
Fehr, E. and G¨achter, S. (2002). Altruistic punishment
in humans. Nature, 415:137–140.
Hirshleifer, J. (1987). The Latest on the Best:
Essays in Evolution and Optimality, chapter
On the Emotions as Guarantors of Threats and
Promises, pages 307–326. MIT Press.
Lazarus, R. S. (1999). Hope: An emotion and a vi-
tal coping resource against despair. Social Re-
search, 66(2):653–678.
Lloyd-Kelly, M. (2014). Modelling Emotions and
Simulating their Effects on Social Interactions in
Agent Systems. PhD thesis, University of Liver-
pool.
Lloyd-Kelly, M., Atkinson, K., and Bench-Capon, T.
(2012a). Developing co-operation through simu-
lated emotional behaviour. In 13th International
Workshop on Multi-Agent Based Simulation.
Lloyd-Kelly, M., Atkinson, K., and Bench-Capon, T.
(2012b). Emotion as an enabler of co-operation.
In Proceedings of the 4th International Confer-
ence on Agents and Artificial Intelligence, pages
164–169.
Ortony, A., Clore, G. L., and Collins, A. (1988).
The Cognitive Structure of Emotions. Cambridge
University Press.
Simpson, B. (2003). Sex, fear, and greed: A social
dilemma analysis of gender and cooperation. So-
cial Forces, 82(1):35–52.
Snyder, C. R. (2002). Hope theory: Rainbows in the
mind. Psychological Inquiry, 13(4):249–275.
Steunebrink, B. R., Dastani, M., and Meyer, J.-J. C.
(2007). A logic of emotions for intelligent
agents. In 22nd Conference on Artificial Intel-
ligence, pages 142–147. AAAI Press.
Vohs, K. D., Mead, N. L., and Goode, M. R. (2006).
The psychological consequences of money. Sci-
ence, 314:1154–1156.
FosteringCo-operativeBehaviourThroughSocialIntervention
585