Working memory consolidation does not necessarily delay response selection: Disentangling the costs of task initiation and execution
26.329, Saturday, May 11, 2:45 - 6:45 pm, Royal Ballroom 6-8
Florian Sense1, Brad Wyble2, Mark Nieuwenstein3; 1Department of Psychometrics and Statistics, University of Groningen, 2Department of Psychology, The Pennsylvania State University, 3Department of Experimental Psychology, University of Groningen
Does working memory consolidation delay response selection? According to previous research, the answer is yes. The basis for this conclusion lies in findings that show a psychological refractory period effect (PRP) for response times (RT) for a second target that follows shortly after a first to-be-remembered target. The interpretation of this result is that memory consolidation and response selection both require access to a slow and capacity-limited processing mechanism. As a consequence, response selection would be postponed until the consolidation of the first target has been completed (e.g., Jolicoeur & DellAcqua, 1998). In the current study, we challenge this interpretation on the basis of the results of a study in which we compared the PRP effect between two conditions. In the standard condition, a single to-be-remembered letter was shown for 100 ms and followed at a stimulus onset asynchrony (SOA) of 100-600 ms by a digit that required a speeded parity judgment. In a second condition, the task was identical except that the blank interval separating the first and second targets was filled with an RSVP sequence of additional letters that each had to be reported at the end of the trial. As expected, the standard condition showed a decrease in RT with increasing SOA, reflecting a PRP effect. Strikingly, the RSVP condition revealed the same effect even though subjects were now consolidating additional letters into memory, and the number of letters encoded increased with SOA. These results show that the PRP effect is time-locked to the initiation of working memory consolidation upon detecting the first of a series of letters. This effect is explained in terms of an overhead cost associated with initiating the process of working memory consolidation.