WHAT IS IT?
This model has been developed together with the publication ‘Modelling Value Change - An Exploratory Approach’
Value change and moral change have increasingly become topics of interest in the philosophical literature. Several theoretical accounts have been proposed. Such accounts are usually based on certain theoretical and conceptual assumptions and their strengths and weaknesses are often hard to determine and compare, also because they are based on limited empirical evidence.
We propose that a step forward can be made with the help of agent-based modelling (ABM). ABM can be used to investigate whether a simulation model based on a specific account of value change can reproduce relevant phenomena. To illustrate this approach, we built a model based on the pragmatist account of value change proposed in van de Poel and Kudina (2022). We show that this model can reproduce four relevant phenomena, namely 1) the inevitability and stability of values, 2) how different societies may react differently to external shocks, 3) moral revolutions, and 4) lock-in.

HOW IT WORKS
The model represents a society where humans address societal needs by using technologies. The usage of these technologies can cause moral problems. After having used technologies, humans will ensure that (new) moral problems are addressed. To do so, they have three options.
A first option is to adjust the values of society (value adaptation). As a result, the technology that has resulted in moral problems becomes less desirable.
A second option is to adjust the values of society, but only temporarily (value dynamism). The consequences are the same as for value adaptation, but the values that have been adjusted will return to their initial settings over time.
A third option is to create a new technology (innovation). If possible, the newly created technology will be in line with current values of the society (assuming agents aim for responsible innovation).

HOW TO USE IT
The model can be used to evaluate how different types of societies respond to moral problems caused by technologies.
In the section ‘Initial characteristics of the society’, characteristics of the society can be set. Societies are characterized by different preferable choices when confronted with new moral problems: value adaptation, value dynamism, and innovation. Some societies are also more open to change than others (‘openness to change’).
The section ‘Monitoring problem-solving capacity of the society’ shows how well the society is able to cope with moral issues. This is measured by the number of moral problems currently observed in society and their severity.
The section ‘Monitoring phenomena of value change’ can be used to observe a range of phenomena of value change discussed in the paper: ‘The inevitability and stability of values’, ‘Societies differ in openness – and resistance- to change’, ‘Moral revolutions’ and ‘Lock-in’. Whether phenomena of value change occur depends on the initial characteristics of the society.

THINGS TO NOTICE
Based on our analysis, we have observed that the phenomena of value change are essentially explained by the following input parameters.

The inevitability and stability of values
Essentially the variable ‘Value_memory_of_society’, which determines how long values are remembered by society, affects how well a society is able to address moral problems. This is particularly apparent when the value memory is between 0 and 20, in which case new values have already disappeared when new moral problems are found. This observation seems to suggest that without stable values, societies cannot adequately address moral problems in the model.

Societies differ in openness – and resistance- to change
The variable ‘Openness_to_change’ affects how well societies are able to cope with external shocks. This can be seen by observing that the severity of moral problems tends to be higher when openness to change is set to a lower value.
A second observation is that societies with a high openness to change can solve more moral problems but also create more new moral problems. The number of perceived moral problems that a society has to deal with is lower if the openness to change of a society is high. However, a high openness to change also leads to a higher number of unperceived moral problems as well as a higher number of new moral problems.

Moral revolutions
We find that moral revolutions are more likely if a society is confronted with a large number of moral problems and/or severe moral problems. Additionally, moral revolutions are more likely to occur in cases of an external shock. This can be seen by switching the variable ‘External_shocks_affecting_need_change’ to true and varying the size of need change. We also find that moral revolutions are more likely when the number of values in the model is low.

Lock-in
Lock-in can be perceived in the model, but which type of lock-ins are observed depends on the preferences of the society with regard to innovation, value adaptation and value dynamism. Lock-ins are successive and short when innovation and value adaptation are low, and value dynamism is high. Lock-ins are large but infrequent when value dynamism is high, and innovation and value adaptation are low. Lock-ins are infrequent and short when innovation and value dynamism are high, and value adaptation is low.