![]() An alternative theoretical mechanism for producing both primacy and recency effects is interference ( Nairne, 1988 Melton, 1963). As a result, retrieval for stimuli presented first is better compared to stimuli in the subsequent positions. Hence, items presented at the beginning receive more attention and produce a stronger neural trace. During encoding the amount of attention devoted to each stimulus is reduced across successive serial positions, such that each successive stimulus receives less attention than the previous one ( Brown, Preece, & Hulme, 2000 Page & Norris, 1998). An alternative interpretation is that, because initial items have minimal interference from preceding items and final items have no interference from subsequent items, both primacy and recency effects reflect the operation of a single memory system ( Wixted & Ebbesen, 1991 Crowder, 1982).Īn influential model of serial position memory effects posits an attentional primacy gradient. Experimental manipulations of stimulus presentation speed that affect only primacy items and postlist interference tasks that affect only recency items strongly support this view ( Lewandowsky & Brown, 2005 Glanzer, 1966 Murdock, 1962). Recency effects occur because the just-presented list items are encoded in the short-term store and are immediately available for output when the end of the list signals that retrieval is required ( Shiffrin & Atkinson, 1969 Glanzer & Cunitz, 1966). Subsequent retrieval is enhanced compared to items in the middle of the list, as these items are not rehearsed as strongly as the initial items. The classic theoretical interpretation is that primacy memory effects occur for initial list items that are encoded and relatively well rehearsed, thereby promoting transfer from short-term storage to long-term memory. After a list of words is presented, recall performance is greater for items from the beginning (primacy effect) and end (recency effect) compared to items presented in the middle of a list ( Capitani, Della Sala, Logie, & Spinnler, 1992 Atkinson & Shiffrin, 1968). The U-shaped serial position curve is one of the most well-established recall memory findings ( Murdock, 1962 Robinson & Brown, 1926 Ebbinghaus, 1913 Nipher, 1876). Recency effects appear to index operations determined by the anticipation of the last stimulus presentation, which occurred for both recalled and unrecalled memory items. ![]() The close relationship between the enhanced amplitude and primacy retrieval supports the view that this positive component reflects one of a process series related to attentional gradient and encoding of events for storage in memory. The late positive component was larger for recalled compared to unrecalled primacy items, but it did not differ between memory performance outcomes for the recency items. Greater recall and larger late positive component amplitudes were obtained for the primacy and recency items, with less recall and smaller amplitudes for the middle words. Both performance and late ERP amplitudes reflected classic recall serial position effects. This procedure was repeated for 20 different word lists. Participants were instructed to remember lists of words consisting of 12 common nouns each presented once every 1.5 sec, with a recall signal following the last word to indicate that all remembered items should be written on paper. Behavioral and event-related brain potential (ERPs) measures were used to investigate the encoding substrates of the serial position curve and subsequent recall in young adults. The occurrence of primacy versus recency effects in free recall is suggested to reflect either two distinct memory systems, or the operation of a single system that is modulated by allocation of attention and less vulnerable to interference.
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