Working memory and changing-state hypothesis

Effects of secondary tasks on serial short-term memory were investigated to test conflicting predictions derived from the working-memory model (A. D. Baddeley, 1986, 1997) and the changing-state hypothesis (D. M. Jones, P. Farrand, G. Stuart, & N. Morris, 1995). In Experiments 1 and 2, disruptions due to the changing-state characteristic of secondary tasks occurred in the encoding phase of spatial and verbal serial memory tasks but not in a retention interval. Experiments 3 and 4 revealed changing-state effects on tasks relying on central-executive resources. In Experiments 5 and 6, interference between central-executive demanding secondary tasks and serial short-term memory was larger during the encoding phase than the retention interval. Crossover dissociations emerged between spatial and verbal serial short-term memory. The results extend the findings of D. M. Jones et al. (1995) and support the working-memory account for interference in short-term memory.