The defensive symbolic aspects of slips is abundantly documented by clinical material. Slips may be employed by the ego to serve instinctual and symbolic processes from all psychosexual levels; slips may also be unconsciously utilized for 'the symbolic expression of … certain ego identifications and superego demands'. On other occasions the slip may produce anxiety and defensive reactions against the anxiety. They may be 'normal' phenomena of everyday life or assume symptomatic proportions in other instances. In analysis, slips may be used to 'bait' or interest the analyst.