The brain’s neural activity is irregular, changing from one moment to the next. To date, this apparent “noise” has been thought to be due to random natural variations or measurement error. However, researchers at the Max Planck Institute for Human Development have shown that this neural variability may provide a unique window into brain function. In a new Perspective article out now in the journal Neuron, the authors argue that researchers need to focus more on neural variability to fully understand how behavior emerges from the brain.