Sznajd Model

"United we stand" — agreeing pairs convince their neighbors

Opinion A share over time
Opinion +1: 50% Opinion −1: 50% Step: 0 Consensus: —
0.010
10
40
The Sznajd model (2000) inverts the voter model: instead of an individual adopting a neighbor's opinion, two adjacent agreeing agents convince their four outer neighbors. This "outflow" rule captures social validation — a group is more persuasive than an individual. The system always reaches full consensus (+1 or −1) without noise; with noise, it maintains a disordered state below a critical noise level. The model explains herding behavior and market dynamics.