How do animals adopt a given behavioral strategy to solve a recurrent problem when several effective strategies are available to reach the goal? Here we provide evidence that striatal cholinergic interneurons (SCIN) modulate their activity when mice must select between different strategies with similar goal-reaching effectiveness. Using a cell-type specific transgenic murine system, we show that adult SCIN ablation impairs strategy selection in navigational tasks where a goal can be independently achieved by adopting an allocentric or egocentric strategy. SCIN-depleted mice learn to achieve the goal in these tasks, irrespective of their appetitive or aversive nature, similarly to controls. However, they cannot shift away from their initially adopted strategies as control mice do as training progresses. Our results indicate that SCIN are required for shaping the probability function used for strategy selection as experience accumulates throughout training. Thus, SCIN may be critical for resolution of cognit...