Previous Research Projects (Archive)

R. Zäske, J.M. Kaufmann & S.R. Schweinberger

Recognizing people from their voices is a routine performance in social interactions that critically depends on the degree of familiarity with a speaker (Yarmey et al., 2001). It has been suggested that the processing of unfamiliar and familiar voices involves partially distinct cortical areas (von Kriegstein & Giraud, 2004) and differs qualitatively (Kreiman & van Lancker Sidtis, 2011). However, the neural processes mediating the transition from unfamiliar to familiar voices and the conditions under which voices are learned, remain largely unexplored. While forensic research has begun to study voice learning and recognition in the 1930s to improve the reliability of earwitness testimony for once-heard “unfamiliar” voices, this branch of research continues to rely on, almost exclusively, behavioural measures. By contrast, more recent neuroscientific research is strongly inspired by cognitive models of face perception. With respect to learning, these studies tend to look at short-term implicit effects of priming and adaptation. Accordingly, current models of person perception are void of learning mechanisms that are associated with explicit speaker recognition (Belin et al., 2004; Campanella & Belin, 2007). Thus, the applicability of these models to everyday face and voice recognition is limited.

Based on the notion that voice learning may be affected by characteristics of (1) the stimulus material, (2) speaker and listener attributes as well as (3) specific task demands, we will study effects of dynamic information in faces, distinctiveness and accents, speaker and listener age as well as selective attention on voice learning. To this end, we will relate behavioural measures of learning and recognition to electrophysiological and functional magnetic resonance imaging data which provide high temporal and spatial resolution, respectively. Taken together, we expect that the present studies will significantly contribute to our understanding of how voice representations are formed in person memory.

Publications:

• Zäske, R., Volberg, G., Kovács, G., & Schweinberger, S. R. (2014). Electrophysiological correlates of voice learning and recognition. Journal of Neuroscience, 34(33), 10821-10831. doi: 10.1523/JNEUROSCI.0581-14.2014

M. C. Steffens, T. Rakíc, and A.P. Simpson

Research in this project tests social perception, categorization, and impression formation related to gender and ethnicity, using complex and ecologically valid stimuli that go beyond the presentation of labels or photographs only. The first aim is to follow up on key findings from the first funding period. Series of experiments will test with experimental paradigms, supplemented by ERPs, the conditions under which expectancy violations determine impressions of speakers with dialects or foreign accents. The second aim is based on the idea that changeable information may be diagnostic and thus used for social categorization when crossed with ethnicity and gender information (e.g., wearing headscarves or ethnically-associated hats; powerful/powerless speech). The third aim represents an extension of our current work to a new area. In a cooperation between psychology and phonetics, we will critically examine the finding that information about individuals’ sexual orientation is manifest in phonetic speech characteristics. The relevant speech markers in German speech will be extracted (which will be an extension of existing findings from Anglo-Saxon speakers); they will be related to variables pertaining to speakers’ gender role orientation and respective social-group identification; and to the perception of sexual orientation in voices and voice-face stimuli. The ultimate aim of this project in relation to the entire Research Unit is contributing to the elaboration of person perception models with regard to the early integration of social-category information from different modalities.

Stefan R. Schweinberger
Coworkers: Verena G. Skuk

The human voice carries a wealth of social information including emotion, gender, age or person identity, yet relatively little research has been devoted to processes mediating auditory perception of people via their voices. In the first funding period, we initially explored the role of attention for explicit and implicit voice memory for famous voices. We then conducted a substantial series of experiments on adaptation-induced aftereffects in voice perception. Building on this successful research, on further substantial and directly relevant work we conducted in the first funding period, and on ample methodological expertise acquired by the researchers in the project, we will pursue three main issues in voice perception:

1. First, exploiting the fact that new voice morphing software TANDEM-STRAIGHT permits independent morphing across each of five acoustic parameters (F0, formant frequencies, spectrum level information, aperiodicity, and time), we investigate the differential contribution of these acoustic parameters to the perception of speaker gender and age.
2. Second, in an attempt to delineate individual contributions of basic low-level information to adaptation, we use single parameter-modified adaptor voices to create aftereffects in the perception of speaker gender and age.
3. Systematic research using larger samples of personally familiar voices for recognition is almost non-existent. We will test twelfth grade secondary school pupils as a homogeneous group to create a unique database that will allow us to assess the relative contribution of acoustic parameters, speech type, perceived voice characteristics (such as rated distinctiveness of a voice), and personal contact to the accuracy in individual voice recognition. This sample will also allow us to probe gender differences (both on the speaker and listener level), and to assess own voice recognition.
4. Finally, we plan to continue earlier work on voice averaging using full sentences to test a prototype account of familiar voice representation, and we will perform an EEG study investigating induced oscillatory responses as potential correlates of voice familiarity. Overall, we expect that this project continues to substantially improve our understanding of basic acoustic, perceptual and neuronal processes involved in human voice perception.

Publications:

• Skuk, V. G., & Schweinberger, S. R. (2014). Influences of fundamental frequency, formant frequencies, aperiodicity and spectrum level on the perception of voice gender. Journal of Speech, Language, and Hearing Research, 57(1), 285-296, doi:10.1044/1092-4388(2013/12-0314)
• Skuk, V. G., & Schweinberger, S. R. (2013). Gender differences in familiar voice identification. Hearing Research, 296,  131-140, doi:10.1016/j.heares.2012.11.004
• Kawahara, H., Morise, M., Banno, H., & Skuk, V. G. (2013, October 29-November 1). Temporally variable multi-aspect N-way morphing based on interference-free speech representations. Paper presented at the Signal and Information Processing Association Annual Summit and Conference (APSIPA), 2013 Asia-Pacific, Kaohsiung. doi:10.1109/APSIPA.2013.6694355

Adrian P. Simpson
Coworkers: Melanie Weirich

Studies over the last 50 years have repeatedly shown there to be a number of acoustic and temporal differences between female and male voices that can’t merely be explained by anatomical differences such as vocal tract size or vocal fold length. While we know that many differences have a social component, i.e. they are learned behaviours, it is still unclear which aspects may have a biophysical origin. Non-uniform differences between male and female acoustic vowel spaces, as well as systematic differences in male and female sound durations are just two such areas. Using a series of articulatory and acoustic analyses together with listening experiments, this project is attempting to tease apart some of the socially acquired patterns from the biologically inevitable.

Publications:

• Weirich, M., & Simpson, A. P. (2013). Investigating the relationship between average speaker fundamental frequency and acoustic vowel space size. The Journal of the Acoustical Society of America, 134(4), 2965-2974.
• Weirich, M., & Simpson, A. P. (2014). Differences in acoustic vowel space and the perception of speech tempo.Journal of Phonetics, 43, 1-10.
• Weirich, M., & Simpson, A. P. (in press). Impact and interaction of accent realization and speaker’s sex on vowel length in German. In: A. Leemann, M.-J. Kolly, S. Schmid & V. Dellwo (Eds.), Trends in Phonetics and Phonology in German speaking Europe. Frankfurt, Deutschland: Peter Lang Verlagsgruppe.

Stefan R. Schweinberger
Coworkers: Romi Zäske, Verena G. Skuk

While the perception of faces from static portraits has been investigated in many studies, little research has been devoted to processes mediating auditory recognition of people via their voices. This is despite the fact that the voice is by far the most important auditory stimulus that supports person identification, and that it carries a wealth of further social information including emotion, gender, or age. This project is intended to fill a major gap in the research on auditory person perception, by addressing three key aspects of voice perception. First, using a design that incorporates both recognition memory and priming approaches, we explore the role of attention for explicit and implicit voice memory. Second, using novel voice morphing technology, we recently presented the first behavioural evidence that adaptation to non-linguistic information in voices elicits systematic auditory aftereffects in the perception of gender (Schweinberger et al., 2008). Here we will build on this new line of research, and will study behavioural and neurocognitive correlates of auditory adaptation to two other important social signals conveyed by voices: person identity and age. The studies on voice identity adaptation can be expected to have far-reaching theoretical implications with respect to the question of whether individual voices are represented in a prototype-referenced manner, similar to what has been suggested for the representation of facial identity. Finally, building on findings from the visual modality that different visual adaptation effects depend on attention and conscious perception to very different degrees, we will study the combined effects of attention and voice adaptation.

Publications

• Schweinberger, S. R., Kawahara, H., Simpson, A. P., Skuk, V. G., & Zäske, R. (2014). Speaker Perception. Wiley Interdisciplinary Reviews: Cognitive Science, 5(1), 15-25. doi: 10.1002/wcs.1261
• Zäske, R., Fritz, C., & Schweinberger, S. R. (2013). Spatial inattention abolishes voice adaptation. Attention, Perception & Psychophysics, 75(3), 603-613. doi: 10.3758/s13414-012-0420-y
• Zäske, R., Skuk, V.G., Kaufmann, J.M., & Schweinberger, S.R. (2013). Perceiving vocal age and gender: An adaptation approach. Acta Psychologica, 144(3), 583-593.