The negativity bias theory suggests that humans have selective attention towards negativity, placing more weight to negative information rather than positive. Taking this theory into account – I don’t think it’s likely that the employee is going to ignore the constructive criticism. I think the sandwich method uses the positive comments to support the criticism, to remind the employee of their strengths and how they are going to improve their behaviour. Without the supportive positive comments, there is a chance the employee could become defensive.