Bowlby states that it is not possible to form an attachment after the critical period, which is a similar view to Rutter. However, some psychologists argue that the critical period is window of when children are maximally receptive to form attachments, but attachments can still form outside of this window. Tizard & Hodges found that children who were institutionalised still formed attachments when they were adopted between 4 and 8. This suggests that there is a sensitive period, not a critical one.