# Erratum to: A moderate role for cognitive models in agent-based modeling of cultural change

The Original Article was published on 13 September 2013

## Correction

After publication of (Abrams 2013), I discovered errors in two formulas in the settle-nets paragraphs of the POPCO main loop section in Methods (page 13 in the PDF file). I correct these errors here. In the definition of the weighted sum n i of input activations a j from nodes j to node i across links with weights w ij , the direction of the inequality was reversed. The definition of n i should read:

${n}_{i}=\underset{j}{âˆ‘}{w}_{\mathit{\text{ij}}}max\left(0,{a}_{j}\right)\phantom{\rule{2.77626pt}{0ex}}\phantom{\rule{2.77626pt}{0ex}}\phantom{\rule{2.77626pt}{0ex}}\text{for}\phantom{\rule{2.77626pt}{0ex}}{w}_{\mathit{\text{ij}}}<0\phantom{\rule{0.3em}{0ex}}.$

There were also errors in the definition of s i , the weighted sum of a nodeâ€™s current activation a i and its summed inputs p i and n i across positively and negatively weighted links, respectively. The definition of s i should read as follows:

${s}_{i}=\left(1âˆ’.1\right)\phantom{\rule{0.3em}{0ex}}{a}_{i}+\left(.99âˆ’{a}_{i}\right)\phantom{\rule{0.3em}{0ex}}{p}_{i}+\left({a}_{i}âˆ’\left(âˆ’.99\right)\right)\phantom{\rule{0.3em}{0ex}}{n}_{i}$

I regret these errors and hope that they do not cause confusion. Full source code for the version of POPCO used in Abrams (2013) can be found at https://github.com/mars0i/popco.

## References

1. Abrams M: A moderate role for cognitive models in agent-based modeling of cultural change. Complex Adaptive Syst Model 2013, 1(16):1â€“33.

## Author information

Authors

### Corresponding author

Correspondence to Marshall Abrams.

The online version of the original article can be found at 10.1186/2194-3206-1-16

## Rights and permissions

Reprints and permissions