Noisy speech impairs retention of previously heard information only at short time scales.

When speech is presented in noise, listeners must recruit cognitive resources to resolve the mismatch between the noisy input and representations in memory. A consequence of this effortful listening is impaired memory for content presented earlier. In the first study on effortful listening, Rabbitt, The Quarterly Journal of Experimental Psychology, 20, 241-248 (1968; Experiment 2) found that recall for a list of digits was poorer when subsequent digits were presented with masking noise than without. Experiment 3 of that study extended this effect to more naturalistic, passage-length materials. Although the findings of Rabbitt's Experiment 2 have been replicated multiple times, no work has assessed the robustness of Experiment 3. We conducted a replication attempt of Rabbitt's Experiment 3 at three signal-to-noise ratios (SNRs). Results at one of the SNRs (Experiment 1a of the current study) were in the opposite direction from what Rabbitt, The Quarterly Journal of Experimental Psychology, 20, 241-248, (1968) reported - that is, speech was recalled more accurately when it was followed by speech presented in noise rather than in the clear - and results at the other two SNRs showed no effect of noise (Experiments 1b and 1c). In addition, reanalysis of a replication of Rabbitt's seminal finding in his second experiment showed that the effect of effortful listening on previously presented information is transient. Thus, effortful listening caused by noise appears to only impair memory for information presented immediately before the noise, which may account for our finding that noise in the second-half of a long passage did not impair recall of information presented in the first half of the passage.

The effects of temporal cues, point-light displays, and faces on speech identification and listening effort.

Among the most robust findings in speech research is that the presence of a talking face improves the intelligibility of spoken language. Talking faces supplement the auditory signal by providing fine phonetic cues based on the placement of the articulators, as well as temporal cues to when speech is occurring. In this study, we varied the amount of information contained in the visual signal, ranging from temporal information alone to a natural talking face. Participants were presented with spoken sentences in energetic or informational masking in four different visual conditions: audio-only, a modulating circle providing temporal cues to salient features of the speech, a digitally rendered point-light display showing lip movement, and a natural talking face. We assessed both sentence identification accuracy and self-reported listening effort. Audiovisual benefit for intelligibility was observed for the natural face in both informational and energetic masking, but the digitally rendered point-light display only provided benefit in energetic masking. Intelligibility for speech accompanied by the modulating circle did not differ from the audio-only conditions in either masker type. Thus, the temporal cues used here were insufficient to improve speech intelligibility in noise, but some types of digital point-light displays may contain enough phonetic detail to produce modest improvements in speech identification in noise.