HiddenSinger: High-quality singing voice synthesis via neural audio codec and latent diffusion models.

Recently, denoising diffusion models have demonstrated remarkable performance among generative models in various domains. However, in the speech domain, there are limitations in complexity and controllability to apply diffusion models for time-varying audio synthesis. Particularly, a singing voice synthesis (SVS) task, which has begun to emerge as a practical application in the game and entertainment industries, requires high-dimensional samples with long-term acoustic features. To alleviate the challenges posed by model complexity in the SVS task, we propose HiddenSinger, a high-quality SVS system using a neural audio codec and latent diffusion models. To ensure high-fidelity audio, we introduce an audio autoencoder that can encode audio into an audio codec as a compressed representation and reconstruct the high-fidelity audio from the low-dimensional compressed latent vector. Subsequently, we use the latent diffusion models to sample a latent representation from a musical score. In addition, our proposed model is extended to an unsupervised singing voice learning framework, HiddenSinger-U, to train the model using an unlabeled singing voice dataset. Experimental results demonstrate that our model outperforms previous models regarding audio quality. Furthermore, the HiddenSinger-U can synthesize high-quality singing voices of speakers trained solely on unlabeled data.

Singing Voice Handicap Index-10 Minimal Clinically Important Difference: A Prospective Determination.

BACKGROUND/OBJECTIVES: The Singing Voice Handicap Index-10 (SVHI-10) is a validated patient-reported outcome measure (PROM) that assesses patients' perception of handicap related to singing voice. A normative value has been established with a score ≥20 being abnormal. However, there is no defined minimal clinically important difference (MCID). This study prospectively determines the MCID of SVHI-10 among a diverse group of singers. METHODS: 103 adult singers with and without voice complaints completed SVHI-10 twice, 30 days apart. MCID for the SVHI-10 was determined using distribution-based receiver-operating characteristic (ROC) curve analysis. RESULTS: Twenty-two men (1 transgender), 75 women (1 transgender), and 6 nonbinary individuals participated. The most frequently reported singing genres were classical (44.7%), musical theater (17.5%), and pop (10.7%). Mean initial SVHI-10 score was 13.05 (standard deviation 7.397), and mean follow-up SVHI-10 was 13.13 (7.994). There was a significant positive correlation between initial and follow-up SVHI-10 scores (r = 0.879, p < 0.001). SVHI-10 scores were significantly higher among participants who reported voice changes in the past year (p < 0.001) or sought voice treatment (p = 0.001) compared with participants who did not. SVHI-10 scores varied significantly based on singing type. The area under the ROC curve for SVHI-10 was 0.700 (p = 0.003). The SVHI-10 MCID was determined to be 9.5. CONCLUSIONS: An SVHI-10 score change ≥10 should be considered clinically meaningful. This definition has been missing from the literature and will improve understanding of patients' responses to treatment, which will help advance clinical care and track research outcomes. LEVEL OF EVIDENCE: 4 Laryngoscope, 2024.

Long-term self-reported attendance in exercise training or lung choir and status of quality of life following initial pulmonary rehabilitation for COPD.

Background: Both adherence rates to pulmonary rehabilitation (PR) programmes and long-term attendance in exercise training after PR remain a challenge. In our previous randomised controlled trial (RCT), effects were positively associated with a dose-response pattern, regardless of whether PR contained conventional physical exercise training (PExT) or Singing for Lung Health (SLH) as a training modality within a 10 weeks' PR programme for chronic obstructive pulmonary disease (COPD). However, long-term status of this RCT cohort remains unknown. In this study, we investigated whether current status (=attendance in supervised exercise training or a lung choir and scoring in quality of life (QoL)) was related to initial PR completion, randomisation, or adherence. Methods: We collected data via telephone, using a researcher-developed questionnaire on current self-reported attendance in supervised exercise training or a lung choir and on perceived benefits of the initial RCT intervention. Additionally, we used COPD-validated questionnaires (primarily: QoL (measure: St George's Respiratory Questionnaire; SGRQ). Results: In 2023 (i.e., mean/median 4.7 years after initial PR), surviving participants were contacted (n = 196; 73% of 270), and 160 (82% of 196) were included. Out of the included participants, 30 (19%) had not completed initial PR. Compared to the initial PR-completers, non-completers reported less current attendance in exercise training or lung choir (24% vs. 46%, p = 0.03) but SGRQ scores were comparable. Yet, those who attended exercise training or lung choir at present (n = 66/160; 41% out of 160) reported better QoL score than those with no current attendance (SGRQ; Attending: 39.9 ± 15.4; Not attending: 43.1 ± 16.7; p = 0.02). Neither having had SLH instead of PExT, nor adherence level during initial PR, was related to current attendance or to QoL scores. Conclusion: This study indicates that long-term self-reported attendance and current QoL scores are positively related to initial completion of a PR programme. Surprisingly, neither initial PR content (PExT or SLH) nor initial PR adherence was related to long-term outcomes. We suggest that future PR programmes include special attention to those who do not complete PR to support long-term attendance and QoL status.

Twin Data Support a Sensitive Period for Singing Ability.

As with many other musical traits, the social environment is a key influence on the development of singing ability. While the familial singing environment is likely to be formative, its role relative to other environmental influences such as training is unclear. We used structural equation modeling to test relationships among demographic characteristics, familial environmental variables (early and current singing with family), vocal training, and singing ability in a large, previously documented sample of Australian twins (N = 1163). Notably, early singing with family, and to a lesser extent vocal training, predicted singing ability, whereas current singing with family did not. Early familial singing also mediated the relationship between sex and singing ability, with men who sang less with family during childhood showing poorer ability. Bivariate twin models between early familial singing and singing ability showed the phenotypic correlation was largely explained by shared environmental influences. This raises the possibility of a sensitive period for singing ability, with sociocultural expectations around singing potentially differentiating the developmental trajectories of this skill for men and women.

A test of the mechanistic process behind the convergent agonistic character displacement hypothesis.

In this era of rapid global change, understanding the mechanisms that enable or prevent species from co-occurring has assumed new urgency. The convergent agonistic character displacement (CACD) hypothesis posits that signal similarity enables the co-occurrence of ecological competitors by promoting aggressive interactions that reduce interspecific territory overlap and hence, exploitative competition. In northwestern Switzerland, ca. 10% of Phylloscopus sibilatrix produce songs containing syllables that are typical of their co-occurring sister species, Phylloscopus bonelli ("mixed singers"). To examine whether the consequences of P. sibilatrix mixed singing are consistent with CACD, we combined a playback experiment and an analysis of interspecific territory overlap. Although P. bonelli reacted more aggressively to playback of mixed P. sibilatrix song than to playback of typical P. sibilatrix song, interspecific territory overlap was not reduced for mixed singers. Thus, the CACD hypothesis was not supported, which stresses the importance of distinguishing between interspecific aggressive interactions and their presumed spatial consequences.

Three-Dimensional Finite Element Modeling of the Singer's Formant Cluster Optimization by Epilaryngeal Narrowing With and Without Velopharyngeal Opening.

This study aimed to find the optimal geometrical configuration of the vocal tract (VT) to increase the total acoustic energy output of human voice in the frequency interval 2-3.5 kHz "singer's formant cluster," (SFC) for vowels [a:] and [i:] considering epilaryngeal changes and the velopharyngeal opening (VPO). The study applied 3D volume models of the vocal and nasal tract based on computer tomography images of a female speaker. The epilaryngeal narrowing (EN) increased the total sound pressure level (SPL) and SPL of the SFC by diminishing the frequency difference between acoustic resonances F3 and F4 for [a:] and between F2 and F3 for [i:]. The effect reached its maximum at the low pharynx/epilarynx cross-sectional area ratio 11.4:1 for [a:] and 25:1 for [i:]. The acoustic results obtained with the model optimization are in good agreement with the results of an internationally recognized operatic alto singer. With the EN and the VPO, the VT input reactance was positive over the entire fo singing range (ca 75-1500 Hz). The VPO increased the strength of the SFC and diminished the SPL of F1 for both vowels, but with EN, the SPL decrease was compensated. The effect of EN is not linear and depends on the vowel. Both the EN and the VPO alone and together can support (singing) voice production.

Auditory imagery ability influences accuracy when singing with altered auditory feedback.

In this preliminary study, we explored the relationship between auditory imagery ability and the maintenance of tonal and temporal accuracy when singing and audiating with altered auditory feedback (AAF). Actively performing participants sang and audiated (sang mentally but not aloud) a self-selected piece in AAF conditions, including upward pitch-shifts and delayed auditory feedback (DAF), and with speech distraction. Participants with higher self-reported scores on the Bucknell Auditory Imagery Scale (BAIS) produced a tonal reference that was less disrupted by pitch shifts and speech distraction than musicians with lower scores. However, there was no observed effect of BAIS score on temporal deviation when singing with DAF. Auditory imagery ability was not related to the experience of having studied music theory formally, but was significantly related to the experience of performing. The significant effect of auditory imagery ability on tonal reference deviation remained even after partialling out the effect of experience of performing. The results indicate that auditory imagery ability plays a key role in maintaining an internal tonal center during singing but has at most a weak effect on temporal consistency. In this article, we outline future directions in understanding the multifaceted role of auditory imagery ability in singers' accuracy and expression.

The Physiology of Vocal Damping: Historical Overview and Descriptive Insights in Professional Singers.

OBJECTIVE: Vocal damping has been historically described as a distinctive phonatory glottic behavior where the posterior part of the vocal folds is strongly adducted and vibration occurs in the anterior part. The aim of the present descriptive study is to analyze anterior glottis phonation patterns in professional singers through a multidimensional approach, in order to better understand the physiological underpinnings of vocal damping and their relation to glottic vibratory mechanisms. METHODS: Ten professional singers (five males and five females) with no vocal complaints were recruited. Each subject was asked to produce ascending and descending glissandos in a spontaneous way; sustained vowels and little sung fragments in vocal fry, chest voice, falsetto, and whistle register. Each singer was asked to produce - where possible - damping sounds. A multidimensional investigation including acoustic analysis, electroglottography, and videolaryngostroboscopy was carried out. RESULTS: Among the enrolled singers, nine out of 10 successfully produced vocalizations with a typical anterior-vibrating glottic pattern indicative of damping. All nine singers achieved a damping glottic configuration when vocalizing in the falsetto register and five were consciously able to switch between a full-glottic falsetto and a damping falsetto upon request. Three male and two female singers were able to produce a damping glottic configuration while emitting whistle notes. Three male singers demonstrated damping glottic configurations when producing high pitched chest notes. CONCLUSIONS: In conclusion, it is possible to state that damping is an existing and documentable glottic behavior, with a wide range of manifestations across vocal registers. The present preliminary study describes damping in the domains of chest voice, falsetto, and whistle register. A proper damping phenomenon, defined as the modification of the glottic vibratory boundaries according to pitch variations, is described for M2 emissions, both in male and female larynx. The analysis of passaggio patterns allows to describe damping-M2 as a possible vibratory submechanism.

Music and reading activities in early childhood associated with improved language development in preterm infants at 2-3 years of age.

Introduction: Children born preterm are at increased risk for adverse neurodevelopmental outcomes. Music and reading activities in childhood could ameliorate these difficulties, as they have shown benefits on both neural and behavioral levels. However, only a few studies have assessed these potential benefits in preterm-born children. We investigated whether music and language activities in early childhood are associated with improved developmental outcomes of preterm-born children. Methods: The cognitive, language, and motor skills of 45 children, born between 24 and 34 gestational weeks, were tested at 23-38 months of corrected age with the Bayley Scales of Infant and Toddler Development, Third Edition. Background information, including parental education, and the weekly amount of music and language-related activities was collected using parental questionnaires. Results: The amount of singing, playing musical instruments and reading aloud was associated with better language skills. Moreover, children who had participated in a music playschool had better language skills when compared to those children who had not participated in a music playschool. Maternal education was associated with music playschool participation and better language and motor skills in children attending music playschool. Discussion: Interactive music and language activities in early childhood may improve language skills in preterm-born children. Informing and guiding parents at an early stage to integrate these activities into their daily lives could be a one way of supporting the development of preterm-born children.

Parents in Neonatal Pain Management-An International Survey of Parent-Delivered Interventions and Parental Pain Assessment.

BACKGROUND: While parent-delivered pain management has been demonstrated to effectively reduce neonatal procedural pain responses, little is known about to what extent it is utilized. Our aim was to explore the utilization of parents in neonatal pain management and investigate whether local guidelines promote parent-delivered interventions. METHODS: A web-based survey was distributed to neonatal units worldwide. RESULTS: The majority of the 303 responding neonatal intensive care units (NICUs) from 44 countries were situated in high-income countries from Europe and Central Asia. Of the responding units, 67% had local guidelines about neonatal pain management, and of these, 40% answered that parental involvement was recommended, 27% answered that the role of parents in pain management was mentioned as optional, and 32% responded that it was not mentioned in the guidelines. According to the free-text responses, parent-delivered interventions of skin-to-skin contact, breastfeeding, and parental live singing were the most frequently performed in the NICUs. Of the responding units, 65% answered that parents performed some form of pain management regularly or always. CONCLUSIONS: There appears to be some practice uptake of parent-delivered pain management to reduce neonatal pain in high-income countries. Additional incorporation of these interventions into NICU pain guidelines is needed, as well as a better understanding of the use of parent-delivered pain management in low- and middle-income countries.

Investigation of Interdisciplinary Differences in Perceptual Evaluation of Voice Disorders.

Ear, nose, and throat (ENT) physicians, speech and language pathologists (SLPs), and singing instructors play complementary roles in the assessment and remediation of voice disorders in performing artists. Given that there are differences among these groups in the training they receive, and that there may be further differences due to their occupational settings and goals, it is unknown whether and to what extent these different disciplines diverge in their perceptions and evaluations of voice quality. Against this background, the present study compared perceptual evaluation of pathological voice by these voice-related disciplines. Using the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) scale, five ENT physicians, five SLPs, and five singing instructors evaluated voice samples recorded from 10 people with pathological voice. The participant groups' scores for each CAPE-V parameter were compared. It was found that the ENT physicians and SLPs were similar in their evaluations, whereas the singing instructors gave higher scores than the ENT physicians and SLPs on several CAPE-V parameters, suggesting that the singing instructors tended to rate the patients' voice quality as more severe on average than ENT physicians and SLPs. These findings highlight the similarities between ENT physicians and SLPs in their perceptual evaluations of pathological voice and suggest that singing instructors may show a more sensitive and heightened perceptual response to pathological voice than the other professional groups, possibly due to differences in occupational experiences and expectations among these voice-related disciplines.

Immediate Impact of Vocal Demand, Likelihood of Dysphonia, and Performance Aspects in Amateur Protestant Singers.

OBJECTIVES: To analyze the immediate impact of vocal demand, probability of dysphonia, and performance aspects in amateur protestant singers. METHODS: Cross-sectional, analytical study, with 76 amateur singers from a protestant church, 60 women and 16 men. All participants responded to a sociodemographic and performance questionnaire, the Evaluation of the Ability to Sing Easily for Brazil (EASE-BR), and the Dysphonia Screening Tool (DST-Br). The data were analyzed descriptively and inferentially, considering a significance level of 5%. RESULTS: The singers reported good voice status after a performance, with the possibility of singing again if necessary. Most individuals had a low probability of dysphonia, showing a lower mean score compared to those with a moderate probability. There was an association between "trying to sing louder than others" and "vocal self-assessment" with the immediate impact of vocal demand and dysphonia screening. Implementing vocal rest was significantly associated with EASE-BR, and trying to sing louder than the instruments and being able to hear yourself well while singing and water intake were associated with the total DST-Br score. CONCLUSIONS: The immediate impact of vocal demand after performance on this population did not compromise their ability to sing easily. Most singers had a low probability of dysphonia. "Trying to sing louder than the instruments" and "ability to hear oneself well while singing and water intake" were associated with dysphonia screening.

Navigating Vocal Challenges: Singing Difficulties in a Carnatic Singer with Clinically Normal Voice.

This study aimed to describe the clinical presentation and therapeutic course of a trained Carnatic singer with perceptually clinically normal voice who presented with singing difficulties. The participant of the study was a 25-year-old male individual who reported to the speech and language diagnostics unit with complaints of reduced vocal range for singing and strained voice while singing. After the routine voice evaluations, the subject was allotted Resonant Voice Therapy. The baseline recordings were compared with the subsequent voice recordings of the subject, on different parameters, along the course of the training. The post-training recordings showed an increase in the singing range of the subject from 9 semitones to 19-20 semitones with modifications in adharashruthi. There were reductions in the perturbation and noise-to-harmonic ratio found in post-training samples. This case study highlights the innovative application of RVT to expand pitch range in a Carnatic singer with normative vocal parameters but encountering singing difficulties. The findings underscore the potential of RVT as a transformative intervention, offering promising avenues for enhancing vocal performance and addressing challenges specific to Carnatic singing techniques.

The effect of choir-singing on self-reported embodied cognition in persons with dementia. A pilot study.

With an understanding of dementia through the lens of embodied cognition and a musical sense of the dynamics of the body, a fundamental continuity of personhood is possible. With music and singing, body and mind are positively affected for persons with dementia, and with promising evidence on emotional wellbeing during choir-singing. Based on this, we carried out a pilot-study to explore the effect of choir-singing on self-reported embodied cognition in persons with dementia. As part of a Danish TV documentary on choir-singing, 17 participants with a mean age of 71 years took part in choir rehearsals and a concert. The majority of the participants had moderate/severe dementia, and 29% mild dementia. Altogether 164 self-report forms were analysed and showed a highly significant increase in embodied cognition from before to after choir-singing. The results provide initial evidence that choir-singing for persons with dementia positively influence the participants' self-reported embodied cognition. Further, the positive effect seemed to increase in line with increasing level of dementia. The 8-item Embodied Cognition in Dementia Assessment Scales (EmDAS) showed good internal reliability and promising properties for evaluating the effect of embodied cognition. For future research, controlled trials with larger samples are needed to provide evidence of choir-singing for persons in various stages of dementia.

Investigating the Effect of Singing Bowl Sound on the Level of State-trait Anxiety and Physiological Variables of Patients Awaiting Angiography.

PURPOSE: Many patients are anxious and fearful while waiting for angiography, which may negatively affect the performance of this test and their physiological variables. The aim of this study was to investigate the effect of singing bowl sounds on situational anxiety and physiological variables of patients awaiting angiography. DESIGN: A semiexperimental pretest and post-test study. METHODS: This semiexperimental pretest and post-test study with 2 groups was conducted from October 2022 to March 2023 in 60 patients (30 in the intervention group and 30 in the control group) awaiting angiography at the Angiography Department of Rouhani Hospital, affiliated with Babol University of Medical Sciences. One hour before angiography, the intervention group received the singing bowl intervention in addition to routine departmental interventions, whereas the control group received only routine departmental interventions. The State-Trait Anxiety Inventory Form Y-1 was used to measure anxiety. FINDINGS: State-trait anxiety after the intervention was significantly lower in the intervention group than in the control group (P = .00). Systolic and diastolic blood pressure, pulse rate, and respiration were the same in the intervention and control groups before and after the intervention and showed no statistically significant difference (P > .05). CONCLUSIONS: The results indicated that the singing bowl intervention led to an improvement in anxiety in patients waiting for angiography. Considering that this intervention was performed with a simple, cheap, and accessible instrument, it is therefore suggested that this method be used to reduce state-trait anxiety in clinical anxiety-provoking conditions. Since the physiological variables of the patients before and after the intervention showed no statistically significant difference in both groups, it is suggested that the physiological variables should be investigated in future studies and several clinical situations so that a scientific opinion on the effect of the singing bowl on these variables can be given with more certainty.

Female Classical Singers Apply Different Resonatory Strategies Than Male: Insights from an MRI-Based Analysis.

INTRODUCTION: The morphology of the vocal tract plays a crucial role in singing. Adjustments of the lower part of the vocal tract are essential for voice quality and timbre. Structured investigations of this region are challenging due to the small extent of the morphological modifications. MATERIAL AND METHODS: This study analyzed the morphology of the endolaryngeal tube and parts of the surrounding hypopharynx for the sustained vowels /a/, /e/, /i/, //, and // by 11 female singer subjects who were at the beginning of their academic singing studies. As in a previous study with male subjects, analysis was based on two phonatory conditions: a natural, speech-like phonation and a singing phonation, like in classical singing. By means of 3D image processing from magnetic resonance imaging, multiple measures were derived. The data were statistically analyzed using linear mixed effects models and ANOVA. RESULTS: The female singers enlarged the ratio of the endolaryngeal tube to the adjacent hypopharynx for singing. DISCUSSION: In contrast to the findings of the male singers in a previous study, the ratios of the laryngeal volumes to the neighboring hypopharynx increased while singing. The female singer subjects of the present study increased those ratios, mediated by an over-proportional enlargement of the endolaryngeal tube. Existing acoustic differences to male singers are thus given a morphological basis. CONCLUSION: The study gives insight into the characteristic adjustments of the vocal tract of female classical singers. The resonatory strategies for females in classical singing differ from those found in males.

The effects of singing interventions on quality of life, mood and levels of agitation in community-dwelling people living with dementia: A quantitative systematic review.

Background and Aims: Music-based interventions have been found to benefit people living with dementia and have positive impacts on cognition and well-being. Most people with dementia live in the community and compared to people with dementia in residential care often have less access to music-based interventions. There are many forms of music interventions and singing has shown particular promise; in the realm of music interventions. It is important to determine what aspects of music interventions yield the most benefits for people with dementia. This review aimed to synthesise evidence on the impacts of singing interventions on quality of life, mood and neuropsychiatric symptoms for community-dwelling people with dementia. Methods: We systematically searched three electronic databases (PsycINFO, MEDLINE and Web of Science) for studies reporting on singing interventions with community-dwelling people with dementia. Studies were eligible for inclusion if they reported on a singing intervention with people living with dementia that included an outcome measure of quality of life, mood or agitation. Fourteen publications were identified and included in this review, with a total of n = 361 people with dementia. Results: Despite some inconsistencies across the literature, evidence suggests that singing interventions led to an improvement in mood and a reduction in agitation levels in people living with dementia. There was no strong evidence to suggest that singing interventions led to significant improvements in quality of life. Conclusions: This review highlights the potential of singing interventions as an effective psychosocial intervention for community-dwelling people with dementia. For key developments in this area, we urge that future studies include a control group where possible which will allow for more robust examinations of singing interventions and allow intervention effects to be distinguished from general deterioration in dementia symptoms over time.

Effects of Singing on Vascular Health in Older Adults with Coronary Artery Disease: A Randomized Trial.

Background: The impact of singing on cardiovascular health has not been extensively studied. The aim of this study is to investigate the effect of singing on cardiovascular biomarkers in an aging population with coronary artery disease. Methods: Participants had three study visits separated by 2-7 days, according to a randomized, single-blind, cross-over, controlled design: (1) a 30-minute period of coached singing from an in-person music therapist, (2) a 30-minute period of singing along to an instructional video and (3) a 30-minute rest (control). Primary outcomes included macrovascular endothelial function assessed by brachial artery flow-mediated dilation and microvascular function assessed by peripheral arterial tonometry (Framingham reactive hyperemia index; fRHI). Heart rate variability was a secondary outcome. Results: Sixty-five subjects (mean age 67.7± 0.8, 40% women) completed the study. Compared to control, there was an increase in fRHI for the singing video intervention (estimate 0.54, SE 0.25, p=0.005) but not for the coaching intervention (estimate 0.11, SE 0.18, p=0.570). There was no change in macrovascular function with either intervention. The low frequency/high frequency (LF/HF) ratio increased by 2.80 (SE 1.03, p=0.008), and the LnHF power decreased by -0.90 ms2 (SE 0.29, p=0.003) with the video (during to pre-change). When assessing post- to pre- change, the coaching intervention showed a significant change of -0.62 ms2 (SE 0.29, p=0.036) in LnHF power. Conclusions: Singing along to an instructional video for 30 minutes improved microvascular, but not macrovascular, endothelial function, in older patients with CAD. HRV changes with singing are similar to that of exercise. Clinical trial registration: ClinicalTrials.gov, identifier: NCT04121741.

Examining predictive meteorological variables in the singing behavior of northern white-cheeked gibbons (Nomascus leucogenys) in northern Lao PDR.

Considering the conservation attention needed to keep viable the few remaining wild populations of the Critically Endangered northern white-cheeked gibbon (Nomascus leucogenys), there has been a serious paucity of research undertaken for the species. To improve the effectiveness of surveys of this and other gibbon species, and ultimately their conservation, it is important to better understand the variables that affect their singing behavior-the feature that is currently used in most gibbon population surveys. We collected singing and meteorological data from 320 days, between October 2020 and March 2021, at 80 different locations, during an auditory presence/non-detection survey of N. leucogenys in northeastern Lao PDR. Songs were detected on 100 of the 320 days, a total of 154 song bouts. We analyzed the differences in song bout frequency, song bout timing (in relation to sunrise), and song bout length in relation to the meteorological variables of temperature, relative humidity, cloud cover, rain, fog, and wind. We found song bout frequency to be significantly greater on mornings with cloud cover (as a function of improved detection), on mornings without fog, on mornings without rain, and on warmer mornings. We found song bouts to start significantly earlier on mornings without fog and on warmer mornings when fog was present. Finally, we found song bouts lasted longer on mornings with fog and on warmer mornings. We did not find any significant relationships with relative humidity or wind. These patterns fit with prior research on behavioral responses of gibbons to weather and improve the understanding of gibbon vocal behavior to better prepare researchers for designing auditory surveys of Nomascus and other gibbon species.

Singing Does Not Necessarily Improve Memory More Than Reading Aloud.

The production effect refers to the finding that words read aloud are better remembered than words read silently. This finding is typically attributed to the presence of additional sensorimotor features appended to the memory trace by the act of reading aloud, which are not present for items read silently. Supporting this perspective, the production effect tends to be larger for singing (the singing superiority effect) than reading aloud, possibly due to the inclusion of further sensorimotor features (e.g., more pronounced tone). However, the singing superiority effect has not always replicated. Across four experiments, we demonstrate a production effect for items read aloud but observe a singing superiority effect only when items are tested in the same color in which they were studied (with foils randomized to color). A series of meta-analytic models revealed the singing superiority effect to be smaller than previously thought and to emerge only when test items are presented in the same color in which they were studied. This outcome is inconsistent with common distinctiveness-based theoretical accounts.