NetLogo User Community Models

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## WHAT IS IT?

This model replicates a very early (1963) simulation coded originally in IPL-V, an assembler-like list-processing language, which models elementary social behavior. In a team of employees with different degrees of competence sometimes an employee asks another employee for help. Help is granted in initial interactions and, later on, when earlier help granted to the same colleague was rewarded satisfactorily.

## HOW IT WORKS

Agents, depending on their competence, ask other agents with assumed higher competence to help them to perform their duties. The latter expect to be rewarded for their help and refuse help when the expected reward is too small.

## HOW TO USE IT

The agents are labelled with their number and their (constant) competence (a number between 0 and 1 (the label is between 0 and 999), the links show (with their width) how often help is requested (red) and granted (green) as well as the reward for help received (grey).

## THINGS TO NOTICE

Unlike in the original paper and model (see below), the replication shows an emerging sociogram depicting the frequencies of help requests, rewards and help given.

The history of help requested and granted and the rewards received are logged in a file named `logfile_YYYY-MM-DD-hh-mm-ss.sss.txt`. The final result can be found in a spreadsheet named `result_YYYY-MM-DD-hh-mm-ss.sss.csv`.

The agents are represented on the screen as person shapes in a colour representing their competence on a circle with an agent with competence 0 at three o'clock and an agent with competence 1 at twelve o'clock.

The plot shows the cumulative number of cases when help was requested, when help was granted and when help was granted only because it was the first interaction between the requesting and the granting agent.

## THINGS TO TRY

Change the reward probability and see what happens. And change the number of agents.
And repeat the model with different random initialisations and see which agents cooperate most often and whether there is a pattern.

## EXTENDING THE MODEL

The feature in the original according to which an agent estimates the expected reward from its experience with similar help requesting agents is not (yet) implemented as the original paper says next to nothing where such information might have been stored.

## NETLOGO FEATURES

No unusual features of NetLogo that the model uses.

## RELATED MODELS

None so far.

## CREDITS AND REFERENCES

The original paper is Gullahorn, J.T., and J.E. Gullahorn. 1963. “A Computer Model of Elementary Social Behavior.” Behavioral Science 8 (4) (January):354–62. doi:10.1002/bs.3830080410.

This replication was written by Klaus G. Troitzsch in the context of a book chapter "What Social Simulation Should Learn from Its History" to appear in a volume edited by Edmund Chattoe-Brown in 2025