It seems that the defense mechanism (that prevents the execution of speech movements) can also activate (kick in) without prior strong emotional cues. This is shown in the 2-system model (in above image). This makes sense because we might also stutter without consciously noticing emotions. Here is the difference between stutterers and non-stutterers in how their brains process and prepare for speech movements: * **Non-stutterers**: Their mental simulations of future speech are generally positive and goal-oriented. They imagine successful communication and the achievement of their communicative goals. Their brains prepare for speech movements with readiness potentials present. The reward processing for speech movements is generally positive or neutral. * **Stutterers**: Their simulations often include the anticipation of stuttering and its negative consequences. They mentally experience these negative outcomes before they even start speaking. This affects their speech movements negatively. The readiness potential for speech movements is often absent. Their brains may inhibit speech movements unconsciously due to the anticipated negative outcomes, leading to stuttering. This inhibition occurs before they are even consciously aware of their speech movements. However, in stutterers there is a half-second delay between physical events and conscious experience, so by the time they are aware of a stutter, it has already happened. Their brains quickly assess the potential punishment (social rejection, embarrassment) associated with stuttering. ([source](https://understandingdysfluency.com/2018/11/14/anatomy-of-a-stuttering-block-time-movement-illusions-consciousness-part-ii/))