ABSTRACT Listeners use many sources of information to make sense of speech sounds and the words these sounds are communicating. Segmental cues, such as power fluctuations across frequency bands, allow to distinguish between speech sounds. Prosody – the rhythmic and intonational aspects of speech – provides high-level information for speech comprehension. The present study investigates how listeners combine segmental and prosodic information during spoken word recognition. In a modified two alternative forced-choice task, participants heard two words and provided judgments of what word they heard for each. Critical trials consisted of/b/-/p/minimal pairs (e.g., bin-pin) in which voice onset time and aspiration of the second word were manipulated along a 9-step continuum. Critically, the intonational contour of the second word was also manipulated so that it either had contrastive or neutral intonation. The acoustic details of the first segment of the second word were also manipulated. Results show that listeners balance segmental and prosodic information in complex ways, where the effect of contrastive intonation varies depending on the ambiguity of the/b/-/p/onsets based on the VOT and aspiration manipulation, as well as the identity of the word that the current word is being contrasted from. Results were compared to predictions from three computational models to test which cue integration process yielded more human-like responses. The model that yielded the best fit proposed that the effect of prosody was weighed continuously as a function of the ambiguity of the segmental cues, suggesting a highly interactive process of integration.

ABSTRACT An experiment was conducted to test the common assumption that amplification produced by the outer and middle ear for air-conducted (AC) signals renders the perceptual contributions from bone conduction (BC) through the skull negligible under typical, free-field listening conditions. To evaluate this possibility, simulated BC signals reflecting varying levels of attenuation were mixed with the original version of the signal (i.e., in place of the AC signal). To simulate the BC signals, a sawtooth wave (F 0 = 43.06 Hz; maximum frequency = 5,000 Hz) was filtered using existing measurements from individual skulls as a bank of third-octave bands. The resulting signals were mixed with the original sawtooth, such that the relative peak amplitude of BC signals was −8, −20, −32, or −44 dB to the original signal. Listeners completed a 4IAX discrimination task to determine if they could detect the presence of the simulated BC signals (X) relative to the original sawtooth in isolation (A). Discrimination sensitivity (d´) tended to remain high at −8 dB and −20 dB conditions, and, as hypothesized, decreased with greater attenuation. However, d´ remained reliable (>1) for more than a quarter of the skulls, even in the −44 dB attenuation condition. This was despite the fact that third-octave bands below 3,150 Hz exceeded the combination of the expected levels of gain that are observed from AC and the measured attenuation from BC. Furthermore, remaining bands at or above 3,150 Hz reflected similar intensities for BC signals regardless of whether or not they were discriminated in the −44 dB condition. Taken together, these findings raise the possibility that at least a subset of human skulls might make audible contributions under typical (free-field) listening conditions, and certainly when the AC signal is reduced (such as when the ears are covered).

ABSTRACT The speech-to-song illusion is a robust effect where repeated speech induces the perception of singing; this effect has been extended to repeated excerpts of environmental sounds (sound-to-music effect). Here, we asked whether repetition could elicit musical percepts in cochlear implant (CI) users, who experience challenges with perceiving music due to both physiological and device limitations. Thirty adult CI users and thirty age-matched controls with normal hearing (NH) completed two repetition experiments for speech and nonspeech sounds (water droplets). We hypothesized that CI users would experience the sound-to-music effect from temporal/rhythmic cues alone, but to a lesser magnitude compared to NH controls, given the limited access to spectral information CI users receive from their implants. We found that CI users did experience the sound-to-music effect but to a lesser degree compared to NH participants. Musicality ratings were not associated with musical training or frequency resolution, and among CI users, clinical variables like duration of hearing loss also did not influence ratings. Cochlear implants provide a strong clinical model for disentangling the effects of spectral and temporal information in an acoustic signal; our results suggest that temporal cues are sufficient to perceive the sound-to-music effect when spectral resolution is limited. Additionally, incorporating short repetitions into music specially designed for CI users may provide a promising way for them to experience music.

ABSTRACT In natural settings, a wide variety of events frequently occur in our vicinity. Previous research has revealed individuals can accurately identify events when relying solely on what is heard. Although previous research suggests sound intensity is a dominant factor affecting event perception, event identification is likely dependent on additional acoustic variables. The present study examined the ability of individuals to identify and discriminate between events that had intersecting and variable temporal and acoustic properties. Participants were exposed to 60 audio recordings of an object that either moved in a particular direction (approached or withdrew) or changed in speed (accelerated or decelerated). The task of the participant was to identify which of four actions occurred on a particular trial. The findings revealed that, with the exception of events involving acceleration, participants were quite poor at event identification. The results further revealed object speed and event duration were the dominant factors affecting perceptual accuracy. It is argued that the observed perceptual error and perceptual ambiguity resulted from the variability and similarity in temporal and acoustic properties of the events used in the present study. The findings of the present study are believed to provide valuable insight into the information supporting auditory event perception and the ability of individuals to identify events in real-world settings.

ABSTRACT To examine priming effects for tonal chord sequences using behavioral methods, experimenters typically employ a discrimination task that draws the participants’ attention to features of the stimulus other than those being assessed, but that may still be affected by the expectedness of the target event. And yet, despite an extensive body of evidence demonstrating tonal priming effects using several discrimination tasks, the relationships between task difficulty, musical expertise, and the expectedness of the target event are not well understood. Thus, this study predicts intonation discrimination performance for tonal chord sequences using measures related to the predictability of the terminal, target chord and the musical sophistication of the participant sample. One hundred participants (50 musicians) were presented with tonal chord sequences and asked to respond to a one-alternative forced choice (1AFC) intonation discrimination task, where out-of-tune targets were mistuned in a range from 1–100 cents sharp using a parametric adaptive staircasing procedure. Chord predictability was estimated using a probabilistic finite-context model, and musical sophistication was measured using the Goldsmith Musical Sophistication Index (Gold-MSI). As expected, discrimination thresholds varied substantially across the participant sample and were strongly negatively correlated with the Gold-MSI. What is more, moderation analyses revealed a significant interaction between intonation size and predictability, suggesting participants conflate chord intonation with unexpectedness when tuning differences are small.

ABSTRACT In three experiments, listeners heard standard and comparison auditory sequences on each trial and judged whether they were the same or different. In Experiments 1 and 2, the sequences comprised chords (i.e., simultaneous combinations of pure tones) that were familiar (major), less familiar but with no sensory dissonance (diminished), or unfamiliar and dissonant. Performance was better in the major condition than in the other two conditions, but only when the major chord was the standard sequence. When it was the comparison, performance was poor. In Experiment 3, the stimuli were metrical or nonmetrical rhythms comprised of snare-drum beats. A discrimination advantage for metrical sequences was evident when the metrical sequence was the standard pattern but not when it was the comparison. In short, order of presentation determined whether well-formed stimuli facilitated discrimination. Well-formed auditory sequences led to advantages in discrimination when they were the standard (presented first), but this advantage was eliminated when the well-formed sequence was the comparison (presented second).

ABSTRACT The presence of masking noise can impair speech intelligibility and increase the cognitive resources necessary to understand speech. The first study to demonstrate the negative cognitive consequences of noisy speech—published by Rabbitt in 1968—found that participants had poorer recall for aurally presented digits early in a list when later digits were presented in noise relative to quiet. However, despite being cited nearly 500 times and providing the foundation for a wealth of subsequent research on the topic, the original study has never been directly replicated. Here we report a replication attempt of that study with a large online sample and tested the robustness of the results to a variety of scoring and analytical techniques. We replicated the key finding that listening to speech in noise impairs recall for items that came earlier in the list. The results were consistent when we used the original analytical technique (an ANOVA) and a more powerful analytical technique (generalized linear mixed effects models) that was not available when the original paper was published. These findings support the claim that effortful listening can interfere with encoding or rehearsal of previously presented information.

ABSTRACTWe report a dissociation of two forms of auditory distraction within a single repeated-measures experiment using a novel Stroop serial recall task in which participants were oriented either to serially recall six color-words (low task-load condition) or the incongruent colors in which those words were presented (high task-load condition). The disruption of serial recall due to a single deviation in the voice delivering a sequence of task-irrelevant speech tokens (the deviation effect) was replicated in the low task-load condition but eliminated in the high task-load condition. In contrast, the disruption of serial recall by continuously changing compared to a repeating sound (the changing-state effect) did not differ according to task-load. The results provide further support for a duplex-mechanism account of auditory distraction: Disruption due to attentional diversion (cf. the deviation effect) is modulated by levels of focal task-engagement whereas interference-by-process (cf. changing-state effect) – in which the processing of the sound conflicts with seriation processes involved in task performance – is not.

ABSTRACTRecently, it was demonstrated that heard sentences containing semantically unexpected words disrupt visual-verbal serial recall more than sentences containing semantically expected words. This semantic mismatch effect did not become smaller over the course of the experiment, contrary to what has been observed with other semantic effects. This surprising finding was critically examined in the present study. In Experiment 1, unspecific habituation was investigated using a classical design and a larger number of trials compared to the original study. In Experiment 2, unspecific and specific habituation were investigated by presenting sixteen different distractor sentences in one condition and the same sentences sixteen times in the other condition. In both experiments, there was no evidence of habituation of the semantic mismatch effect. In Experiment 2, overall performance was significantly better with repeated distractor sentences as compared to different sentences, but the semantic mismatch effect remained unchanged. The disruptive effect of semantic mismatches on serial recall seems to be relatively resistant to habituation, suggesting a stable mechanism that allows to detect, and to react to, potentially meaningful information in the unattended channel.