Does articulatory suppression remove the irrelevant speech effect?

Salamé and Baddeley (1982) reported that the effect of irrelevant speech on the serial recall of visually presented sequences was abolished when subjects performed articulatory suppression during presentation and recall of the target items. They argued that this is because suppression isolates visually presented material from the phonological store, which they consider to be the locus of the irrelevant speech effect. In the present experiment, an alternative interpretation of Salamé and Baddeley's findings was investigated. Salamé and Baddeley used nine-item sequences, and observed very low levels of recall when articulation was suppressed. It is therefore possible that Salamé and Baddeley's failure to observe any additional effect of irrelevant speech reflects either a floor effect or else a strategic choice by subjects to abandon the use of a phonological memory code because of task difficulty. In the experiment reported here, this issue was investigated by using both six- and nine-item sequences. Results revealed no effect of irrelevant speech under articulatory suppression even at the shorter sequence length. The results therefore replicate and extend the findings of Salamé and Baddeley (1982), and provide support for their view that visually presented material must be articulated before it becomes susceptible to interference from irrelevant speech.