# A New Technical Ear Training Game and Its Effect on Critical Listening Skills
## 1 Introduction
### General Gain of Critical Listening Training  
A recent study by [PERSON] et al. [20] reported that \"_closed-loop_\" audiomotor training is an effective training method, especially to improve listeners' speech understanding in the presence of noise. A closed-loop training enables trainees to interact with the given environment and learn to recover from its own mistakes. It is a training approach that involves continuously monitoring a trainee's performance, such as accuracy or error rate, and adjusting the training process in response to that performance in real-time. Their study is distinct from other relevant ones [21; 22] because the research was focused on how much the training efficacy can be expandable to non-trained general auditory function(s). This \"plasticity\" or \"transferability\" of perceptual training to general tasks has been a debatable issue among researchers. In particular, opponents who are skeptical of the benefit of specific perceptual training argue that a training-related benefit would not \"transfer far beyond the training stimuli [23]\". Musical training, in contrast to those opponents' claim, is known to be effective to improve multiple auditory functions. What is the reason for this unique merit of musical training? [PERSON] and his colleagues suggested that musical training features a multimodal, interactive activity between listening and self-adjustment, the so-called \"closed-loop\" audiomotor training. For example, a violinist carefully and repeatedly controls his or her fingers to articulate tuned pitch amid other competing instrumental sounds. This move-and-match strategy in a critical listening activity seems to activate neural plasticity [24], which in return results in enhanced multiple auditory functions (as argued in [25,26]). Based on this merit of musical training that diversifies training efficacy in multiple auditory functions, the authors designed and tested a new training paradigm similar to a musical practice/training that features the \"closed-loop audiomotor\" training. The study result showed that when trainees utilized auditory and motor sensors simultaneously with real-time feedback, the training appeared to improve a non-trained task as well such as music training. Readers should note that music training and performance is not the only way to improve critical listening skills. Recently, [PERSON] et al. [27] comprehensively investigated the relationship between \"musical sophistication\" (as a general concept of engagement with music) and working memory for frequency, showing a significant correlation between the two. Nonetheless, there is evidence that music training can be specifically effective for improving selective auditory attention, which enables people to separate a target speech signal from non-target maskers (noises) [28].  
Therefore, if any critical listening training program could incorporate this \"closed-loop audiomotor\" feature, the training efficacy does not only increase for the trained tasks, but also stimulates and transfers to non-trained tasks. This motivated us to redesign our previously-developed technical ear training programs [19, 29, 30, 31, 32, 33] to incorporate two aforementioned features: (1) gamification to increase a trainee's motivation through interactivity and adaptive sequencing, and (2) closed-loop audiomotor training to broaden the efficacy of training to general, non-trained skills.  
In the following sections, the authors will describe the design strategy of the new gamified auditory training program, detailed functions of each of the four training modules, a training-induced influence on speech identification in a noisy environment, and discussion.