Irrelevant speech, changing state, and order information

The changing state effect is the finding that a stream of irrelevant sounds that change more (e.g., different digits in random order) disrupts memory more than a stream of irrelevant sounds that change less (e.g., a single digit repeated over and over). According to the Object-Oriented Episodic Record (O-OER) model, the changing state effect will be observed only in memory tasks that have an order component or which induce serial rehearsal or serial processing. In contrast, other accounts-including the Feature Model, the Primacy Model, and various attentional theories-predict that the changing state effect should be observable when there is no order component. Experiment 1 first demonstrated that the irrelevant stimuli created for the current experiments produced a changing state effect in immediate serial recall in both on-campus and online samples. Then, three experiments assessed whether a changing state effect is observable in a surprise 2AFC recognition test. Experiment 2 replicated Stokes and Arnell (2012, Memory & Cognition, 40, 918-931), who found that although irrelevant sounds reduce performance on a surprise recognition test of words presented previously in a lexical decision task, they do not produce a changing state effect. Experiments 3 and 4 used two different encoding tasks (pleasantness and frequency judgment) and also found no changing state effect. The results support the prediction of the O-OER model and provide additional evidence against the other accounts.