Thinking Sparks!: Emergent Attention Heads in Reasoning Models During Post Training
Researchers demonstrate that post-training in reasoning models creates specialized attention heads that enable complex problem-solving, but this capability introduces trade-offs where sophisticated reasoning can degrade performance on simpler tasks. Different training methodsβSFT, distillation, and GRPOβproduce fundamentally different architectural mechanisms, revealing tensions between reasoning capability and computational reliability.