Understanding public speakers’ performance: first contributions to support a computational approach

Communication is part of our everyday life and our ability to communicate can have a significant role in a variety of contexts in our personal, academic, and professional lives. For long, the characterization of what is a good communicator has been subject to research and debate by several areas, particularly in Education, with a focus on improving the performance of teachers. In this context, the literature suggests that the ability to communicate is not only defined by the verbal component, but also by a plethora of non-verbal contributions providing redundant or complementary information, and, sometimes, being the message itself. However, even though we can recognize a good or bad communicator, objectively, little is known about what aspects – and to what extent—define the quality of a presentation. The goal of this work is to create the grounds to support the study of the defining characteristics of a good communicator in a more systematic and objective form. To this end, we conceptualize and provide a first prototype for a computational approach to characterize the different elements that are involved in communication, from audiovisual data, illustrating the outcomes and applicability of the proposed methods on a video database of public speakers.publishe

Effect of attention on cortical processing of sound motion: An EEG study

The onset of motion in an otherwise continuous sound elicits a prominent auditory evoked potential, the so-called motion onset response (MOR). The MOR has recently been shown to be modulated by stimulus-dependent factors, such as velocity, while the possible role of task-dependent factors has remained unclear. Here, the effect of spatial attention on the MOR was investigated in 19 listeners. In each trial, the subject initially heard a free-field sound, consisting of a stationary period and a subsequent period of motion. Then, two successive stationary test tones were presented that differed in location and pitch. Subjects either judged whether or not the starting and final positions of the preceded motion matched the positions of the two test tones (‘motion-focused condition’), or whether or not the test tones were identical in pitch, irrespective of the preceded motion stimulus (‘baseline condition’). These two tasks were presented in separate experimental blocks. The performance level in both tasks was similar. However, especially later portions of the MOR were significantly increased in amplitude when auditory motion was task-relevant. Cortical source localization indicated that this extra activation originated in dorsofrontal areas that have been proposed to be part of the dorsal auditory processing stream. These results support the assumption that auditory motion processing is based on a complex interaction of both stimulus-specific and attentional processes

Familiarity and task context shape the use of acoustic information in voice identity perception

Familiar and unfamiliar voice perception are often understood as being distinct from each other. For identity perception, theoretical work has proposed that listeners use acoustic information in different ways to perceive identity from familiar and unfamiliar voices: Unfamiliar voices are thought to be processed based on close comparisons of acoustic properties, while familiar voices are processed based on diagnostic acoustic features that activate a stored person-specific representation of that voice. To date no empirical study has directly examined whether and how familiar and unfamiliar listeners differ in their use of acoustic information for identity perception. Here, we tested this theoretical claim by linking listeners' judgements in voice identity tasks to complex acoustic representation — spectral similarity of the heard voice recordings. Participants (N = 177) who were either familiar or unfamiliar with a set of voices completed an identity discrimination task (Experiment 1) or an identity sorting task (Experiment 2). In both experiments, identity judgements for familiar and unfamiliar voices were guided by spectral similarity: Pairs of recordings with greater acoustic similarity were more likely to be perceived as belonging to the same voice identity. However, while there were no differences in how familiar and unfamiliar listeners used acoustic information for identity discrimination, differences were apparent for identity sorting. Our study therefore challenges proposals that view familiar and unfamiliar voice perception as being at all times distinct. Instead, our data suggest a critical role of the listening situation in which familiar and unfamiliar voices are evaluated, thus characterising voice identity perception as a highly dynamic process in which listeners opportunistically make use of any kind of information they can access