IC-201Activating neuroticism-positive neurons in Llama-3-8B-Instruct causes the largest decline in general capabilities, while activating conscientiousness-positive neurons improves all benchmarks
After identifying personality-related neurons via NPTI, the authors activate or deactivate them and measure the effect on four general benchmarks (GSM8K, IFEval loose/strict, CommonsenseQA). Most personality activations cause slight declines, but the effect is highly asymmetric: activating neuroticism+ neurons drops CommonsenseQA by 7.0 points (76.5 to 69.5) and IFEval strict by 4.7, while activating conscientiousness+ neurons actually improves every benchmark (e.g., GSM8K 77.9 to 78.2, CommonsenseQA 76.5 to 77.1). The authors attribute the neuroticism+ decline to the model exhibiting increased anxiety and lack of confidence in its explanations.
The intervention is artificial (neuron value manipulation via NPTI), not a natural operating condition; the effect is specific to the ~20,000 neurons identified by the authors' method and may not generalise to other identification procedures.