[The P300 component of the event-related brain potential in a short-term memory paradigm].

In numerous investigations the P300-component of the event-related-brain-potential (ERP) has proved a valid indicator of memory activities. The present study explores the amplitude of the P300 in an isolated short term memory task with variant difficulties. In two experiments the reproduction of senseless memory material was examined using the categories "syllables" and "consonants". One syllable was thereby synonymous with the so-called "chunk" which represents a subjective unit arising from grouping of memory material. The results show a significant increase in P300-amplitude in a line with memory load in both categories. On the contrary there is no significant difference in the amplitude of P300 between the two categories. These results suggest that the costs for storing one syllable are comparable with those for one consonant.