Anna S. Hasting

Speeding up syntax: On the relative timing and automaticity of local phrase structure and morphosyntactic processing as reflected in event-related brain potentials

Neurolinguistic research utilizing event-related brain potentials (ERPs) typically relates syntactic phrase structure processing to an early automatic processing stage around 150 to 200 msec, whereas morphosyntactic processing is associated with a later and somewhat more attention-dependent processing stage between 300 and 500 msec. However, recent studies have challenged this position by reporting highly automatic ERP effects for morphosyntax in the 100 to 200 msec time range. The present study aimed at determining the factors that could contribute to such shifts in latency and automaticity. In two experiments varying the degree of attention, German phrase structure and morphosyntactic violations were compared in conditions in which the locality of the violated syntactic relation, as well as the violation point and the acoustic properties of the speech stimuli, were strictly controlled for. A negativity between 100 and 300 msec after the violation point occurred in response to both types of syntactic violations and independently of the allocation of attentional resources. These findings suggest that the timing and automaticity of ERP effects reflecting specific syntactic subprocesses are influenced to a larger degree by methodological than by linguistic factors, and thus, need to be regarded as relative rather than fixed to temporally successive processing stages.

Setting the Stage for Automatic Syntax Processing: The Mismatch Negativity as an Indicator of Syntactic Priming

The present study investigated the automaticity of morphosyntactic processes and processes of syntactic structure building using event-related brain potentials. Two experiments were conducted, which contrasted the impact of local subject-verb agreement violations (Experiment 1) and word category violations (Experiment 2) on the mismatch negativity, an early event-related brain potential component reflecting automatic auditory change detection. The two violation types were realized in two-word utterances comparable with regard to acoustic parameters and structural complexity. The grammaticality of the utterances modulated the mismatch negativity response in both experiments, suggesting that both types of syntactic violations were detected automatically within 200 msec after the violation point. However, the topographical distribution of the grammaticality effect varied as a function of violation type, which indicates that the brain mechanisms underlying the processing of subject-verb agreement and word category information may be functionally distinct even at this earliest stage of syntactic analysis. The findings are discussed against the background of studies investigating syntax processing beyond the level of two-word utterances.

The Voice of Emotion across Species: How Do Human Listeners Recognize Animals' Affective States?

Voice-induced cross-taxa emotional recognition is the ability to understand the emotional state of another species based on its voice. In the past, induced affective states, experience-dependent higher cognitive processes or cross-taxa universal acoustic coding and processing mechanisms have been discussed to underlie this ability in humans. The present study sets out to distinguish the influence of familiarity and phylogeny on voice-induced cross-taxa emotional perception in humans. For the first time, two perspectives are taken into account: the self- (i.e. emotional valence induced in the listener) versus the others-perspective (i.e. correct recognition of the emotional valence of the recording context). Twenty-eight male participants listened to 192 vocalizations of four different species (human infant, dog, chimpanzee and tree shrew). Stimuli were recorded either in an agonistic (negative emotional valence) or affiliative (positive emotional valence) context. Participants rated the emotional valence of the stimuli adopting self- and others-perspective by using a 5-point version of the Self-Assessment Manikin (SAM). Familiarity was assessed based on subjective rating, objective labelling of the respective stimuli and interaction time with the respective species. Participants reliably recognized the emotional valence of human voices, whereas the results for animal voices were mixed. The correct classification of animal voices depended on the listeners familiarity with the species and the call type/recording context, whereas there was less influence of induced emotional states and phylogeny. Our results provide first evidence that explicit voice-induced cross-taxa emotional recognition in humans is shaped more by experience-dependent cognitive mechanisms than by induced affective states or cross-taxa universal acoustic coding and processing mechanisms.

Generating predictions: Lesion evidence on the role of left inferior frontal cortex in rapid syntactic analysis

A well-documented phenomenon in event-related electroencephalography (EEG) and magnetoencephalography (MEG) studies on language processing is that syntactic violations of different types elicit negativities as early as 100 msec after the violation point. Recently, these responses have been associated with activations in or very close to sensory cortices, suggesting the involvement of basic sensory mechanisms in the detection of syntactic violations. The present study investigated whether intact auditory cortices and adjacent temporal regions are sufficient to generate early syntactic negativities in the auditory event-related potential (ERP). We tested ten clinically non-aphasic patients with left inferior frontal lesions, but intact temporal cortices in a passive auditory ERP paradigm that had reliably elicited early negativities in response to violations of subject-verb agreement and word category in the past. Subject-verb agreement violations failed to elicit early grammaticality effects in these patients, whereas a group of ten age-matched controls showed a reliable early negativity. This finding supports the idea that sensory aspects of syntactic analysis as reflected in early syntactic negativities critically depend on top-down predictions generated by the left inferior frontal cortex. In contrast, word category violations elicited a small, marginally significant early negativity both in controls and patients, suggesting an additional involvement of temporal regions in early phrase structure processing. In an additional auditory oddball experiment patients showed a regular P300, but no N2b component in response to deviant tones, indicating that their deficit in generating sensory predictions extends beyond the language domain.

Early differential processing of verbs and nouns in the human brain as indexed by event-related brain potentials

A recent study on syntactic influences on the mismatch negativity (MMN) reported preliminary evidence that processing or representational differences between verbs and nouns could be reflected in modulations of this early component of the event‐related brain potential (ERP). However, this previous investigation was unable to separate the putative word category effects from possible influences of the direction of acoustic change on the MMN response. The present study disentangled these two effects by comparing the effects of the direction of acoustic change within and isolated from the lexical context that had previously been used to create the word‐category contrast. Although the direction of acoustic change exerted a significant influence on the MMN amplitude, some of the temporal and topographic characteristics of the MMN and the overall pattern of the deviance‐related ERP response proved to be specific to word‐category effects. These findings provide the first reliable evidence that the MMN can serve as an index of word‐category‐specific processing and support the notion of early processing and representational differences between verbs and nouns.

Human Novelty Response to Emotional Animal Vocalizations: Effects of Phylogeny and Familiarity

Darwin (1872) postulated that emotional expressions contain universals that are retained across species. We recently showed that human rating responses were strongly affected by a listeners familiarity with vocalization types, whereas evidence for universal cross-taxa emotion recognition was limited. To disentangle the impact of evolutionarily retained mechanisms (phylogeny) and experience-driven cognitive processes (familiarity), we compared the temporal unfolding of event-related potentials (ERPs) in response to agonistic and affiliative vocalizations expressed by humans and three animal species. Using an auditory oddball novelty paradigm, ERPs were recorded in response to task-irrelevant novel sounds, comprising vocalizations varying in their degree of phylogenetic relationship and familiarity to humans. Vocalizations were recorded in affiliative and agonistic contexts. Offline, participants rated the vocalizations for valence, arousal, and familiarity. Correlation analyses revealed a significant correlation between a posteriorly distributed early negativity and arousal ratings. More specifically, a contextual category effect of this negativity was observed for human infant and chimpanzee vocalizations but absent for other species vocalizations. Further, a significant correlation between the later and more posteriorly P3a and P3b responses and familiarity ratings indicates a link between familiarity and attentional processing. A contextual category effect of the P3b was observed for the less familiar chimpanzee and tree shrew vocalizations. Taken together, these findings suggest that early negative ERP responses to agonistic and affiliative vocalizations may be influenced by evolutionary retained mechanisms, whereas the later orienting of attention (positive ERPs) may mainly be modulated by the prior experience.