openHSU – Research Showcase

In auditory speech processing, implicit linguistic knowledge is activated and applied on phonetic and segment-related phonological processing level even if the perceived sound sequence is outside the focus of attention. In this study, the effects of language-specific phonotactic restrictions on pre-attentive auditory speech processing were investigated, using the Mismatch Negativity component of the human event-related brain potential. In German grammar, the distribution of the velar and the palatal dorsal fricative is limited by an obligatory phonotactic constraint, Dorsal Fricative Assimilation, which demands that a vowel and a following dorsal fricative must have the same specifications for articulatory backness. For passive oddball stimulation, we used three phonotactically correct VC syllables and one incorrect VC syllable, composed of the vowels [ε] and [ɔ] and the fricatives [ç] and [ʃ]. Stimuli were contrasted pairwise in experimental oddball blocks in a way that they differed in regard to their respective vowel but shared the fricative. Additionally to the usual Mismatch Negativity which is attributable to the change of the initial vowel and which was elicited by all deviants, we observed a second negative deflection in the deviant ERP elicited by the phonotactically ill-formed syllable only. This negativity cannot be attributed to any acoustical or phonemic difference between standard and deviant, it rather reflects the effect of a phonotactic evaluation process after both sounds of the syllable were identified. Our finding suggests that implicit phonotactic knowledge is activated and applied even outside the focus of the participants' attention.

Anecdotal reports and also empirical observations suggest a preferential processing of personally significant sounds. The utterance of one's own name, the ringing of one's own telephone, or the like appear to be especially effective for capturing attention. However, there is a lack of knowledge about the time course and functional neuroanatomy of the voluntary and the involuntary detection of personally significant sounds. To address this issue, we applied an active and a passive listening paradigm, in which male and female human participants were presented with the SMS ringtone of their own mobile and other's ringtones, respectively. Enhanced evoked oscillatory activity in the 35–75 Hz band for one's own ringtone shows that the brain distinguishes complex personally significant and nonsignificant sounds, starting as early as 40 ms after sound onset. While in animals it has been reported that the primary auditory cortex accounts for acoustic experience-based memory matching processes, results from the present study suggest that in humans these processes are not confined to sensory processing areas. In particular, we found a coactivation of left auditory areas and left frontal gyri during passive listening. Active listening evoked additional involvement of sensory processing areas in the right hemisphere. This supports the idea that top-down mechanisms affect stimulus representations even at the level of sensory cortices. Furthermore, active detection of sounds additionally activated the superior parietal lobe supporting the existence of a frontoparietal network of selective attention.

We investigated whether music experts and laypersons differ with regard to aesthetic evaluation of musical sequences. 16 music experts and 16 music laypersons judged the aesthetic value (beauty judgment task) as well as the harmonic correctness (correctness judgment task) of chord sequences. The sequences consisted of five chords with the final chord sounding congruous, ambiguous or incongruous relative to the harmonic context established by the preceding four chords. On behavioural measures, few differences were observed between experts and laypersons. However, several differences in event-related potential (ERP) parameters were observed in auditory, cognitive and aesthetic processing of chord cadences between experts and laypersons. First, established ERP effects known to reflect the processing of harmonic rule violation were investigated. Here, differences between the groups were observed in the processing of the mild violation — experts and laypersons differed in their early brain responses to the beginning of the chord sequence. Furthermore, ERP data indicated distinctions between experts and laypersons in aesthetic evaluation at three different stages. Firstly, during the interval of task-cue presentation, a stronger contingent negative variation (CNV) to the beauty judgment task was observed for experts, indicating that experts invest more effort into preparation for aesthetic processes than into correctness judgments. Secondly, during the first four chords, preparation for the correctness judgment required more exertion on the laypersons' side. Thirdly, during the last chord, laypersons showed a larger late and widespread positivity for the beauty compared to the correctness judgment, indicating a stronger reliance on internal affective states while forming a judgment.

Human aesthetic processing entails the sensation-based evaluation of an entity with respect to concepts like beauty, harmony or well-formedness. Aesthetic appreciation has many determinants ranging from evolutionary, anatomical or physiological constraints to influences of culture, history and individual differences. There are a vast number of dynamically configured neural networks underlying these multifaceted processes of aesthetic appreciation. In the current challenge of successfully bridging art and science, aesthetics and neuroanatomy, the neuro-cognitive psychology of aesthetics can approach this complex topic using a framework that postulates several perspectives, which are not mutually exclusive. In this empirical approach, objective physiological data from event-related brain potentials and functional magnetic resonance imaging are combined with subjective, individual self-reports.