Auditory-Perceptual Judgement of Speech-Language Pathologists in Fricative Distortion by EPG Task

Objectives: In a clinical setting, a ‘trained ear’ is the essentials for speech–language pathologists (SLPs) because most SLPs rely on the auditory - perceptual method during assessment and treatment for speech difficulties. However, transcribing distortion errors using only auditory-perceptual judgement is a difficult task. This study investigated the auditory– perceptual ability in terms of distortion errors for pre and present SLPs.Methods: Sixty pre and present SLPs completed a survey, then performed a perceptual judgement task which was manufactured by electropalatography (EPG). The task consisted of 30 questions, including distorted (dentalized, palatalized, lateralized) and normal speech samples of Korean fricative /s/ with different types of vowels (/ɑ/, /u/) and lengths (1-syllabled, 2- syllabled, sentence).Results: There was no significant difference in the distortion task among three groups. All participants had the highest score in “dentalization”, the lowest in “lateralization”, and all distortion types were perceived better in the /u/ context than /ɑ/. Also, SLPs tended to judge “lateralization” errors as “normal articulation” and many of the participants perceived “palatalization” as “lateralization”.Conclusion: The results of this study indicated that active auditory training for SLPs is necessary to improve auditory perceptual ability, and suggests that EPG could be a useful instrument for the auditory training program.

Divergent effects of absolute evidence magnitude on decision accuracy and confidence in perceptual judgements

Whether people change their mind after making a perceptual judgement may depend on how confident they are in their initial decision. Recently, it was shown that, when making perceptual judgements about stimuli containing high levels of 'absolute evidence' (i.e., the overall magnitude of sensory evidence across choice options), people make less accurate initial decisions and are also slower to change their mind and correct their mistakes. Here we report two studies that investigated whether high levels of absolute evidence also lead to increased decision confidence. We used a luminance judgment task in which participants decided which of two dynamic, flickering stimuli was brighter. After making a decision, participants rated their confidence. We manipulated relative evidence (i.e., the mean luminance difference between the two stimuli) and absolute evidence (i.e., the summed luminance of the two stimuli). In the first experiment, we found that higher absolute evidence was associated with decreased decision accuracy but increased decision confidence. In the second experiment, we additionally manipulated the degree of luminance variability to assess whether the observed effects were due to differences in perceived evidence variability. We replicated the results of the first experiment but did not find substantial effects of luminance variability on confidence ratings. Our findings support the view that decisions and confidence judgments are based on partly dissociable sources of information, and suggest that decisions initially made with higher confidence may be more resistant to subsequent changes of mind.

Perceptual Integration and Visual Illusions

In my first post I argued that inconsistencies in visual space reflect a conflict between visual experience and perceptual judgement. In this second post I argue that the same approach can be applied to (a) the integration of depth cues, and (b) illusions of visual space, to show that they too operate at the level of cognition rather than perception.

Flexible use of confidence to guide advice requests

A growing body of evidence indicates that subjective confidence plays an important role in guiding behaviour. Past studies have demonstrated a fixed relationship between confidence and behaviour, so that low confidence leads to one course of action, and high confidence to another. Here, we tested whether people display flexibility in their use of confidence, so that the mapping between confidence and behaviour is not necessarily fixed, but can instead vary depending on the specific context. This proposal was studied in three experiments, testing the hypothesis that the seemingly natural relationship between low confidence and advice requests varies according to whether people know, or do not know, the quality of the advice. Participants made an initial perceptual judgement, and then had to choose between re-sampling evidence or receiving advice from a virtual advisor, before making a final decision. The results from these experiments showed that, when no objective information about advisor reliability was available, people selected advice more often when their confidence was high rather than low, reflecting the use of confidence as a feedback proxy to learn about advisor quality. Importantly, participants were able to learn about the value of advice even in the absence of feedback and subsequently selected more advice from better advisors, indicating the value of using confidence in this way. In contrast, when participants had prior knowledge about the reliability of advisors, they requested advice more often when confidence was low, reflecting the use of confidence as a self-monitoring tool signalling that help should be solicited. These findings indicate that people use confidence in a way that is context-dependent and directed towards achieving their current goals.

Preventing action slows down performance in perceptual judgment

Action and vision are known to be tightly coupled with each other. In a previous study, we found that repeatedly grasping an object without any visual feedback might result in a perceptual aftereffect when the object was visually presented in the context of a perceptual judgement task. In this study, we explored whether and how such an effect could be modulated by presenting the object behind a transparent barrier. Our conjecture was that if perceptual judgment relies, in part at least, on the same processes and representations as those involved in action, then one should expect to find a slowdown in judgment performance when the target object looks to be out of reach. And this was what we actually found. This indicates that not only acting upon an object but also being prevented from acting upon it can affect how the object is perceptually judged.

Future Directions in Image Quality

With the advancements made in the field of image processing and computer vision, the last few decades have seen an increase in studies focused on image quality assessment. While this has resulted in the introduction of different new metrics which some show high correlation with the perceptual judgement of the human observers there still exists a huge room for improvement. In this short paper which is prepared as a complement to the workshop on Future Directions in Image Quality at CIC 27 in Paris, France we aim to introduce future directions in the field and challenges facing ahead.

Native and Non-Native Listeners Perceptual Judgement of English Accentedness, Intelligibility, and Acceptability of Indonesian Speakers

This research aimed at investigating the extent of accentedness and intelligibility as well as the acceptability of Indonesian foreign-accented speech perceived by native and non-native listeners, as well as finding their correlation to each other. It used qualitative research. The participant of the research was selected using purposive sampling. The participants were divided into speakers and listeners. There are six speakers and four listeners selected. The four listeners were native and nonnative listeners who rated and transcribed six recorded reading of Indonesian speakers by means of SPIN (Speech Perception in Noise) test. The results show that native listeners rate the speech almost the same way as non-native listeners do. The speeches with clear and accurate pronunciation are rated highly accepted and fully intelligible, regardless of having a very strong accent. In contrast, less clear and accurate pronunciations, as well as a very strong accent of the speeches, are rated unacceptable and still reasonably intelligible. The result of the correlation test between accentedness and intelligibility as well as accentedness and acceptability of the accent finds on no account of correlation to each other. Therefore, accentedness and intelligibility plus accentedness and acceptability of the accent are independent, so that strong foreign accent could stay acceptable and intelligible. The factors found to influence the judgment are the familiarity of the accent, clarity, and accuracy of pronunciation. Aforementioned findings have implication to challenge English teachers in Indonesia to develop meaningful activities to teach English pronunciation accurately to be regarded as fully intelligible and acceptable by listeners, especially native English listeners.

The Duality of phantasia in Plotinus: Two Faculties, or Two Representations?

This paper argues that the duality of phantasia consists not in its being divided between two faculties, but in its being the meeting point of two representations. First it is argued that Plotinus’ theory, according to which the representation is a judgement, rests on his reading of Theaetetus 184c–187a and its criticism in De Anima III, 2–3. Second, it is argued that the ‘image’ in which the Plotinian representation consists follows the perceptual judgement instead of preceding it. Third, it is argued that there is neither a sub-sensitive faculty of phantasia nor a sub-sensitive representation. Then, the exteriority of the objects of representation with respect to the soul is discussed. Finally, an interpretation is proposed concerning the necessity for Plotinus to posit two representations of the same object.