Four-alternative Forced Choice Research Articles

Audience participation fighting game: Exploring social facilitation for an enhanced APG experience

This paper discusses the popularity of live streaming video games and its potential to address psychological challenges, especially during the COVID-19 pandemic. An audience participation game (APG) that involve massive audiences in gameplay, blurring the lines between viewers and players, is introduced. The game highlights the dynamic adjustment of AI character strengths based on audience inputs, specifically cheering and jeering. The study examines factors that influence user experience (UX) and activeness in APG. System evaluation includes comprehensive AI testing, consisting of 500,000 one-minute game rounds, and a user experiment involving 82 participants. UX assessment is conducted using a pairwise preference, four-alternative forced choice (4-AFC), version of the Game User Experience Satisfaction Scale (GUESS). Finally, the paper concludes by offering guidelines and hypotheses for future research in the field of APGs.

Universality and superiority in preference for chromatic composition of art paintings

Color composition in paintings is a critical factor affecting observers’ aesthetic judgments. We examined observers’ preferences for the color composition of Japanese and Occidental paintings when their color gamut was rotated. In the experiment, observers were asked to select their preferred image from original and three hue-rotated images in a four-alternative forced choice paradigm. Despite observers’ being unfamiliar with the presented artwork, the original paintings (0 degrees) were preferred more frequently than the hue-rotated ones. Furthermore, the original paintings’ superiority was observed when the images were divided into small square pieces and their positions randomized (Scrambled condition), and when the images were composed of square pieces collected from different art paintings and composed as patchwork images (Patchwork condition). Therefore, the original paintings’ superiority regarding preference was quite robust, and the specific objects in the paintings associated with a particular color played only a limited role. Rather, the original paintings’ general trend in color statistics influenced hue-angle preference. Art paintings likely share common statistical regulations in color distributions, which may be the basis for the universality and superiority of the preference for original paintings.

Effect of glandularity on the detection of simulated cancers in planar, tomosynthesis, and synthetic 2D imaging of the breast using a hybrid virtual clinical trial.

The purpose of this study was to measure the threshold diameter of calcifications and masses for 2D imaging, digital breast tomosynthesis (DBT), and synthetic 2D images, for a range of breast glandularities. This study shows the limits of detection for each of the technologies and the strengths and weaknesses of each in terms of visualizing the radiological features of small cancers. Mathematical voxel breast phantoms with glandularities by volume of 9%, 18%, and 30% with a thickness of 53mm were created. Simulated ill-defined masses and calcification clusters with a range of diameters were inserted into some of these breast models. The imaging characteristics of a Siemens Inspiration X-ray system were measured for a 29kV, tungsten/rhodium anode/filter combination. Ray tracing through the breast models was undertaken to create simulated 2D and DBT projection images. These were then modified to adjust the image sharpness, and to add scatter and noise. The mean glandular doses for the images were 1.43, 1.47, and 1.47 mGy for 2D and 1.92, 1.97, and 1.98 mGy for DBT for the three glandularities. The resultant images were processed to create 2D, DBT planes and synthetic 2D images. Patches of the images with or without a simulated lesion were extracted, and used in a four-alternative forced choice study to measure the threshold diameters for each imaging mode, lesion type, and glandularity. The study was undertaken by six physicists. The threshold diameters of the lesions were 6.2, 4.9, and 6.7mm (masses) and 225, 370, and 399μm, (calcifications) for 2D, DBT, and synthetic 2D, respectively, for a breast glandularity of 18%. The threshold diameter of ill-defined masses is significantly smaller for DBT than for both 2D (p≤0.006) and synthetic 2D (p≤0.012) for all glandularities. Glandularity has a significant effect on the threshold diameter of masses, even for DBT where there is reduced background structure in the images. The calcification threshold diameters for 2D images were significantly smaller than for DBT and synthetic 2D for all glandularities. There were few significant differences for the threshold diameter of calcifications between glandularities, indicating that the background structure has little effect on the detection of calcifications. We measured larger but nonsignificant differences in the threshold diameters for synthetic 2D imaging than for 2D imaging for masses in the 9% (p=0.059) and 18% (p=0.19) glandularities. The threshold diameters for synthetic 2D imaging were larger than for 2D imaging for calcifications (p<0.001) for all glandularities. We have shown that glandularity has only a small effect on the detection of calcifications, but the threshold diameter of masses was significantly larger for higher glandularity for all of the modalities tested. We measured nonsignificantly larger threshold diameters for synthetic 2D imaging than for 2D imaging for masses at the 9% (p=0.059) and 18% (p=0.19) glandularities and significantly larger diameters for calcifications (p<0.001) for all glandularities. The lesions simulated were very subtle and further work is required to examine the clinical effect of not seeing the smallest calcifications in clusters.

Development of the spatial contrast sensitivity function (CSF) during childhood: Analysis of previous findings and new psychophysical data.

Although the contrast sensitivity function (CSF) changes markedly during infancy, there is no consensus regarding whether, how, and why it continues to develop in later childhood. Here, we analyzed previously published data (N = 1928 CSFs), and present new psychophysical findings from 98 children (4.7–14.8 years) and 50 adults (18.1–29.7 years), in order to answer the following questions: (1) Does the CSF change during childhood? (2) How large is the developmental effect size? (3) Are any changes uniform across the CSF, or frequency-specific? and (4) Can some or all of the changes be explained by “non-visual” (i.e. procedural/cognitive) factors, such as boredom or inattentiveness? The new data were collected using a four-alternative forced-choice (4AFC) Gabor-detection task, with two different psychophysical procedures (Weighted Staircase; QUEST+), and suprathreshold (false-negative) catch trials to quantify lapse rates. It is shown that from ages 4 to 18 years, the CSF improves (at an exponentially decaying rate) by approximately 0.3 log10 units (a doubling of contrast sensitivity [CS]), with 90% of this change complete by 12 years of age. The size of the effect was small relative to individual variability, with age alone explaining less than one sixth of variability (16%), and most children performing as well as some adults (i.e. falling within the 90% population limits for adults). Development was frequency-specific, with changes occurring primarily around or below the CSF peak (≤ 4 cpd). At least half — and potentially all — of the changes observed could be explained by non-visual factors (e.g. lapses in concentration), although possible biological mechanisms are discussed.

In the Blink of an Eye: Reading Mental States From Briefly Presented Eye Regions.

Faces provide not only cues to an individual’s identity, age, gender, and ethnicity but also insight into their mental states. The aim was to investigate the temporal aspects of processing of facial expressions of complex mental states for very short presentation times ranging from 12.5 to 100 ms in a four-alternative forced choice paradigm based on Reading the Mind in the Eyes test. Results show that participants are able to recognise very subtle differences between facial expressions; performance is better than chance, even for the shortest presentation time. Importantly, we show for the first time that observers can recognise these expressions based on information contained in the eye region only. These results support the hypothesis that the eye region plays a particularly important role in social interactions and that the expressions in the eyes are a rich source of information about other peoples’ mental states. When asked to what extent the observers guessed during the task, they significantly underestimated their ability to make correct decisions, yet perform better than chance, even for very brief presentation times. These results are particularly relevant in the light of the current COVID-19 pandemic and the associated wearing of face coverings.

Contribution of Stimulus Variability to Word Recognition in Noise Versus Two-Talker Speech for School-Age Children and Adults.

Speech-in-speech recognition scores tend to be more variable than the speech-in-noise recognition scores, both within and across listeners. This variability could be due to listener factors, such as individual differences in audibility or susceptibility to informational masking. It could also be due to stimulus variability, with some speech-in-speech samples posing more of a challenge than others. The purpose of this experiment was to test two hypotheses: (1) that stimulus variability affects adults' word recognition in a two-talker speech masker and (2) that stimulus variability plays a smaller role in children's performance due to relatively greater contributions of listener factors. Listeners were children (5 to 10 years) and adults (18 to 41 years) with normal hearing. Target speech was a corpus of 30 disyllabic words, each associated with an unambiguous illustration. Maskers were 30 samples of either two-talker speech or speech-shaped noise. The task was a four-alternative forced choice. Speech reception thresholds were measured adaptively, and those results were used to determine the signal-to-noise ratio associated with ≈65% correct for each listener and masker. Two 30-word blocks of fixed-level testing were then completed in each of the two conditions: (1) with the target-masker pairs randomly assigned prior to each block and (2) with frozen target-masker pairs. Speech reception thresholds were lower for adults than for children, particularly for the two-talker speech masker. Listener responses in fixed-level testing were evaluated for consistency across listeners. Target sample was the best predictor of performance in the speech-shaped noise masker for both the random and frozen conditions. In contrast, both the target and masker samples affected performance in the two-talker masker. Results were qualitatively similar for children and adults, and the pattern of performance across stimulus samples was consistent, with differences in masked target audibility in both age groups. Although word recognition in speech-shaped noise differed consistently across target words, recognition in a two-talker speech masker depended on both the target and masker samples. These stimulus effects are broadly consistent with a simple model of masked target audibility. Although variability in speech-in-speech recognition is often thought to reflect differences in informational masking, the present results suggest that variability in energetic masking across stimuli can play an important role in performance.

Investigation of Human and Model Observer Performance of Mass Detection in a Prototype Digital Breast Tomosynthesis System

Task-based assessment of image quality using a theoretical observer model has recently gained attention in medical imaging fields. Observer models whose performance can suitably match that of a human observer under various imaging conditions have been considered a key concept for virtual clinical studies. This work focused on experimental study in which a prototype digital breast tomosynthesis (DBT) system, developed by the Korea Electrotechnology Research Institute, was used to compare the task-based Fourier metrics of a detectability index with the performance of human observers. Different angular ranges of ±7°, ±10.5°, ±14°, ±17.5°, ±21°, and ±24.5° were used to detect four different sizes of spheroidal masses with the same 15-projection samplings. A total of 16 human observers participated in the study. Human observer performance was measured using four-alternative forced choice (4AFC) tests for different detection tasks, including detecting spheroidal masses. To determine the task-based detectability index (d′), the non-prewhitening matched filter observer was calculated by analyzing the task function, local spatial resolution, and local noise of spheroidal masses. The percentage of signals correctly detected (Pc) with the 4AFC tests was then compared with the detectability index for tasks presented in 2D slices (dslice′2). The average Pc for 16 human observers was 0.87 (range = 0.56–1). Results showed that Pc decreased as the angular range increased from ±7° to ±24.5° with different mass sizes. Our result also showed that the performance of the task-based theoretical model observer could reasonably estimate d′ for all inserted lesions of different sizes and acquired under different conditions, while presenting a trend similar to those of the human observers. Consequently, our study is expected to contribute to quantitative imaging performance analysis under various DBT imaging acquisition parameters.

A four-alternative forced choice (4AFC) methodology for evaluating microcalcification detection in clinical full-field digital mammography (FFDM) and digital breast tomosynthesis (DBT) systems using an inkjet-printed anthropomorphic phantom.

The advent of three-dimensional breast imaging systems such as digital breast tomosynthesis (DBT) has great promise for improving the detection and diagnosis of breast cancer. With these new technologies comes an essential need for testing methods to assess the resultant image quality. Although randomized clinical trials are the gold standard for assessing image quality, phantom-based studies can provide a simpler and less burdensome approach. In this work, a complete framework is presented for task-based evaluation of microcalcification (MCs) detection performance for DBT imaging systems. The framework consists of three parts. The first part is a realistic anthropomorphic physical breast phantom created through inkjet printing, with parchment paper and iodine-doped ink. The second is a method for inserting realistic MCs fabricated from calcium hydroxyapatite. The reproducibility and stability of the phantom materials were investigated through multiple samples of parchment and ink over 6 months. The final part is an analysis using a four-alternative forced choice (4AFC) reader study. To demonstrate the framework, a task-based 4AFC study was conducted using a clinical system to compare performance from DBT, synthetic mammography (SM), and full-field digital mammography (FFDM). Nine human observers read images containing MC clusters imaged with all three modalities and tried to correctly locate the MCs. The proportion correct (PC) was measured as the number of correctly detected clusters out of all trials. Overall, readers scored the highest with FFDM, (PC=0.95±0.03) then DBT (0.85±0.04), and finally SM (0.44±0.06). For the parchment and ink samples, the linear attenuation properties were very stable over 6 months. In addition, little difference was found between the various parchment and ink samples, indicating good reproducibility. This framework presents a promising methodology for evaluating diagnostic task performance of clinical breast DBT systems.

Model and human observer reproducibility for detection of microcalcification clusters in digital breast tomosynthesis images of three-dimensionally structured test object.

We compare the reproducibility of the human observers and a channelized Hotelling observer (CHO), when reading digital breast tomosynthesis (DBT) images of a physical phantom containing a breast simulating structured background and calcification clusters at three dose levels. The phantom is scanned 217 times on a Siemens Inspiration DBT system. Volumes of interest, with and without the calcification targets, are extracted and the human observers' percentage of correct (PC) scores is evaluated using a four-alternative forced choice method. A two-layer CHO is developed using the human observer results. The first layer consists of a localizing CHO that identifies the most conspicuous calcifications using two Laguerre-Gauss channels. Then a CHO with eight Gabor channels estimates the PC score for the calcification cluster. Observer reproducibility is estimated by bootstrapping, and the standard deviation (SD) is used as a figure of merit. The CHO closely approximated the human observer results for all the three dose levels with a correlation of . For the larger calcification cluster sizes, both observers have similar reproducibility, whereas the CHO is more reproducible for the smaller calcifications, with a maximum of 5.5 SD against 13.1 SD for the human observers. The developed CHO is a good candidate for automated reading of the calcification clusters of the structured phantom, with better reproducibility than the human readers for small calcifications.

The Social Situation Affects How We Process Feedback About Our Actions.

Humans achieve their goals in joint action tasks either by cooperation or competition. In the present study, we investigated the neural processes underpinning error and monetary rewards processing in such cooperative and competitive situations. We used electroencephalography (EEG) and analyzed event-related potentials (ERPs) triggered by feedback in both social situations. 26 dyads performed a joint four-alternative forced choice (4AFC) visual task either cooperatively or competitively. At the end of each trial, participants received performance feedback about their individual and joint errors and accompanying monetary rewards. Furthermore, the outcome, i.e., resulting positive, negative, or neutral rewards, was dependent on the pay-off matrix, defining the social situation either as cooperative or competitive. We used linear mixed effects models to analyze the feedback-related-negativity (FRN) and used the Threshold-free cluster enhancement (TFCE) method to explore activations of all electrodes and times. We found main effects of the outcome and social situation, but no interaction at mid-line frontal electrodes. The FRN was more negative for losses than wins in both social situations. However, the FRN amplitudes differed between social situations. Moreover, we compared monetary with neutral outcomes in both social situations. Our exploratory TFCE analysis revealed that processing of feedback differs between cooperative and competitive situations at right temporo-parietal electrodes where the cooperative situation elicited more positive amplitudes. Further, the differences induced by the social situations were stronger in participants with higher scores on a perspective taking test. In sum, our results replicate previous studies about the FRN and extend them by comparing neurophysiological responses to positive and negative outcomes in a task that simultaneously engages two participants in competitive and cooperative situations.

Contextual modulation of prime response retrieval processes: Evidence from auditory negative priming

Contextual similarity between learning and test phase has been shown to be beneficial for memory retrieval. Negative priming is known to be caused by multiple processes; one of which is episodic retrieval. Therefore, the contextual similarity of prime and probe presentations should influence the size of the negative priming effect. This has been shown for the visual modality. In Experiment 1, an auditory four-alternative forced choice reaction time task was used to test the influence of prime-probe contextual similarity on negative priming and the processes underlying the modulation by context. The negative priming effect was larger when the auditory context was repeated than when it was changed from prime to probe. The modulation by context was exclusively caused by an increase in prime response retrieval errors in ignored repetition trials with context repetition, whereas repeating only the context but not the prime distractor did not lead to an increase in prime response retrieval. This exact pattern of results was replicated in Experiment 2. The findings suggest that contextual information is integrated with prime distractor and response information. Retrieval of the previous episode, including prime distractor, prime response, and context (event file), can be triggered when the former prime distractor is repeated, whereas a context cue alone does not retrieve the event file. This suggests an event file structure that is more complicated than its usually assumed binary structure.

Repetitive dynamic stereo test improved processing time in young athletes.

Current studies revealed the importance of perceptual training for the treatment of amblyopia. To improve stereo vision on a higher level, visual tasks have to be completed within a limited time window like in repetitive visual function tests. "Processing time" as the reaction time in which the absence or presence of depth was identified correctly, is of better predictive value for perceiving the depth than the stereo threshold only. To examine the long-term effects of repetitive dynamic testing of stereopsis on processing time. 15 male soccer athletes (13.3±3.2 years) underwent twelve sessions of a 15 minutes repetitive dynamic stereovision training over a period of six weeks, presented on a polarized 3D-TV in a four-alternative forced choice setup. We measured the response time of correct identified visual tasks of 11, 22, 44, 55, 66, 77 and 88arcsecs disparity before, after six sessions, after twelve sessions and after six month without testing. As response time is the sum of stereo processing time plus the motor reaction time, we defined the difference between the response times at 11 and 88arcsecs as "stereo processing time at 11arcsecs". A Wilcoxon Signed Rank Test was conducted between the testing sessions to evaluate significant changes in response time and stereo processing time. After six sessions the mean stereo processing time at 11arcsecs decreased significantly from 804.4 ms to 403.7 ms (Z = -2.499, p = 0.012). Six months after the last training the stereo processing time at 11arcsecs remained at the level of the last session. Our results suggest that repetitive testing of stereovision is effective in improving processing time of stereoscopic tasks in young male athletes significantly long-term.

Applying Rasch model analysis in the development of the cantonese tone identification test (CANTIT)

Objective: Applying Rasch analysis to evaluate the internal structure of a lexical tone perception test known as the Cantonese Tone Identification Test (CANTIT). Design: A 75-item pool (CANTIT-75) with pictures and sound tracks was developed. Respondents were required to make a four-alternative forced choice on each item. A short version of 30 items (CANTIT-30) was developed based on fit statistics, difficulty estimates, and content evaluation. Internal structure was evaluated by fit statistics and Rasch Factor Analysis (RFA). Study Sample: 200 children with normal hearing and 141 children with hearing impairment were recruited. Results: For CANTIT-75, all infit and 97% of outfit values were < 2.0. RFA revealed 40.1% of total variance was explained by the Rasch measure. The first residual component explained 2.5% of total variance in an eigenvalue of 3.1. For CANTIT-30, all infit and outfit values were < 2.0. The Rasch measure explained 38.8% of total variance, the first residual component explained 3.9% of total variance in an eigenvalue of 1.9. Conclusions: The Rasch model provides excellent guidance for the development of short forms. Both CANTIT-75 and CANTIT-30 possess satisfactory internal structure as a construct validity evidence in measuring the lexical tone identification ability of the Cantonese speakers.

Design and application of a structured phantom for detection performance comparison between breast tomosynthesis and digital mammography

This paper introduces and applies a structured phantom with inserted target objects for the comparison of detection performance of digital breast tomosynthesis (DBT) against 2D full field digital mammography (FFDM). The phantom consists of a 48 mm thick breast-shaped polymethyl methacrylate (PMMA) container filled with water and PMMA spheres of different diameters. Three-dimensionally (3D) printed spiculated masses (diameter range: 3.8–9.7 mm) and non-spiculated masses (1.6–6.2 mm) along with microcalcifications (90–250 µm) were inserted as targets.Reproducibility of the phantom application was studied on a single system using 30 acquisitions. Next, the phantom was evaluated on five different combined FFDM & DBT systems and target detection was compared for FFDM and DBT modes. Ten phantom images in both FFDM and DBT modes were acquired on these 5 systems using automatic exposure control. Five readers evaluated target detectability. Images were read with the four-alternative forced-choice (4-AFC) paradigm, with always one segment including a target and 3 normal background segments. The percentage of correct responses (PC) was assessed based on 10 trials of each reader for each object type, size and imaging modality. Additionally, detection threshold diameters at 62.5 PC were assessed via non-linear regression fitting of the psychometric curve. The reproducibility study showed no significant differences in PC values. Evaluation of target detection in FFDM showed that microcalcification detection thresholds ranged between 110 and 118 µm and were similar compared to the detection in DBT (range of 106–158 µm). In DBT, detection of both mass types increased significantly (p = 0.0001 and p = 0.0002 for non-spiculated and spiculated masses respectively) compared to FFDM, achieving almost 100% detection for all spiculated mass diameters.In conclusion, a structured phantom with inserted targets was able to show evidence for detectability differences between FFDM and DBT modes for five commercial systems. This phantom has potential for application in task-based assessment at acceptance and commissioning testing of DBT systems.

Design of a model observer to evaluate calcification detectability in breast tomosynthesis and application to smoothing prior optimization.

In this work, the authors design and validate a model observer that can detect groups of microcalcifications in a four-alternative forced choice experiment and use it to optimize a smoothing prior for detectability of microcalcifications. A channelized Hotelling observer (CHO) with eight Laguerre-Gauss channels was designed to detect groups of five microcalcifications in a background of acrylic spheres by adding the CHO log-likelihood ratios calculated at the expected locations of the five calcifications. This model observer is then applied to optimize the detectability of the microcalcifications as a function of the smoothing prior. The authors examine the quadratic and total variation (TV) priors, and a combination of both. A selection of these reconstructions was then evaluated by human observers to validate the correct working of the model observer. The authors found a clear maximum for the detectability of microcalcification when using the total variation prior with weight βTV = 35. Detectability only varied over a small range for the quadratic and combined quadratic-TV priors when weight βQ of the quadratic prior was changed by two orders of magnitude. Spearman correlation with human observers was good except for the highest value of β for the quadratic and TV priors. Excluding those, the authors found ρ = 0.93 when comparing detection fractions, and ρ = 0.86 for the fitted detection threshold diameter. The authors successfully designed a model observer that was able to predict human performance over a large range of settings of the smoothing prior, except for the highest values of β which were outside the useful range for good image quality. Since detectability only depends weakly on the strength of the combined prior, it is not possible to pick an optimal smoothness based only on this criterion. On the other hand, such choice can now be made based on other criteria without worrying about calcification detectability.

Comparison of two psychometric functions in analyzing 4-AFC detection results using a task-based structured phantom for digital mammography

Introduction Detectability of spiculated and non-spiculated mass models and microcalcifications, in a structured background phantom of acrylic spheres and water, was studied for digital mammography via the four-alternative forced-choice (4-AFC) paradigm. Purpose To compare the threshold diameters for mass and microcalcification detection using two types of psychometric curves applied on the contrast-detail data. Material and methods Ten images of the structured phantom were acquired on 23 digital mammography systems under automatic exposure control. The 4-AFC study was performed with in-house developed software and 5 medical physicists as observers. Percentage correctly detected lesions (PC) was obtained for each target type. Two psychometric curves (Weibull and Logistic functions) were applied to determine the threshold diameters and number of detected targets (at PC = 62.5%). Results Both fitting procedures were successfully applied on all systems. After averaging over 23 systems, the threshold diameters for spiculated and non-spiculated masses and microcalcifications, with the Weibull psychometric curves, were 4.0 ± 0.3 mm (R2 = 0.61 ± 0.08), 4.6 ± 0.7 mm (R2 = 0.51 ± 0.11), and 0.114 ± 0.003 mm (R2 = 0.91 ± 0.03) respectively, and the values of 4.0 ± 0.4 mm (R2 = 0.61 ± 0.08), 4.7 ± 0.6 mm (R2 = 0.50 ± 0.11), and 0.114 ± 0.003 mm (R2 = 0.91 ± 0.03) were obtained with the Logistic function. The numbers of detected targets assessed from the two functions were not different (3–4 spiculated masses, 1–2 non-spiculated masses, and 4 groups of microcalcifications). If the PC values were not completely covering the lower and upper than 62.5%, there will be possibility different results occurred from these two functions. Conclusion Weibull and Logistic curve fits gave similar and reproducible threshold diameters for the structured phantom.

Effect of response context and masker type on word recognition in school-age children and adults.

In adults, masked speech recognition improves with the provision of a closed set of response alternatives. The present study evaluated whether school-age children (5-13 years) benefit to the same extent as adults from a forced-choice context, and whether this effect depends on masker type. Experiment 1 compared masked speech reception thresholds for disyllabic words in either an open-set or a four-alternative forced-choice (4AFC) task. Maskers were speech-shaped noise or two-talker speech. Experiment 2 compared masked speech reception thresholds for monosyllabic words in two 4AFC tasks, one in which the target and foils were phonetically similar and one in which they were dissimilar. Maskers were speech-shaped noise, amplitude-modulated noise, or two-talker speech. For both experiments, it was predicted that children would not benefit from the information provided by the 4AFC context to the same degree as adults, particularly when the masker was complex (two-talker) or when audible speech cues were temporally sparse (modulated-noise). Results indicate that young children do benefit from a 4AFC context to the same extent as adults in speech-shaped noise and amplitude-modulated noise, but the benefit of context increases with listener age for the two-talker speech masker.

Exposure to an unfamiliar language bolsters talker learning

Listeners are better at identifying talkers who speak their native language than talkers who speak a foreign language, showing that phonological knowledge of a language facilitates talker identification. However, research with infants indicates that language comprehension is not necessary for improving talker identification. In this study, we asked whether language exposure alone could improve talker learning. Two groups of English-monolingual adults were recruited: one group from Montreal, Quebec, who receive regular French exposure, and the other from Storrs, Connecticut who receive no French exposure. In Experiment 1, we used a four-alternative forced choice task (4AFC) to train listeners about the voices of four English talkers and four French talkers. Results show that Montreal participants were faster at learning French voices than Storrs participants, showing that exposure to a foreign language is sufficient in boosting talker learning in that language. However, in Experiment 2, a 2AFC was used to ...

Effects of reading ability on native and nonnative talker recognition

Recent findings suggest that phonological knowledge influences talker identification. Specifically, talker identification is improved for native compared to nonnative talkers, and adults with reading disability show impaired talker identification even for native talkers [Perrachione et al., Science, 333, 595 (2011)]. Here, we examine whether effects of reading ability on talker identification emerge among unimpaired readers. Monolingual English adults were assigned to either the high or low reading group based on standardized assessments of reading and reading sub-skills. All readers learned to identify the voices of four English talkers and four French talkers. Training consisted of a two-alternative forced choice task with feedback provided on every trial. After training, retention of learning was tested using a four-alternative forced choice task without feedback. The results to date suggest that the high reading group learned both the native and nonnative voices faster compared to the low reading grou...

Masked speech recognition in a single-talker or a single-talker-plus-noise masker in school-age children and adults

Previous work has shown that masked speech perception is poorer in younger children than older children and adults, particularly when the masker is composed of speech. The present study tested the hypothesis that young children’s poor performance in speech maskers is due to reduced ability to benefit from transient improvements in the target-to-masker ratio (TMR). Listeners were normal-hearing school-age children (5–15 years) and adults. The target words and masker speech were produced by two different female talkers. Target stimuli were disyllabic words, and the masker was either: (1) speech-only or (2) speech-plus-noise. Both maskers included a continuous 60-dB-SPL stream of speech. The speech-plus-noise masker also included a continuous 50-dB-SPL speech-shaped noise. A four-alternative forced choice task was used, and target level was adapted to estimate threshold. Thresholds were higher for younger children than older children or adults for both masker conditions. While the inclusion of speech-shaped noise increased thresholds for all listeners, it had a smaller detrimental effect on younger children than on older children and adults. This result is consistent with the idea that greater susceptibility to speech-on-speech masking in younger children is related to a reduced ability to benefit from transient improvements in TMR.