RESUMEN
PURPOSE: This study investigated whether speakers adapt their breathing and speech (fundamental frequency [fo]) to a prerecorded confederate who is sitting or moving under different levels of physical effort and who is either speaking or not. Following Paccalin and Jeannerod (2000), we would expect breathing rate to change in the direction of the confederate's, even if the participant is physically inactive. This might in turn affect their speech acoustics. METHOD: We recorded the speech and respiration of 22 native German speakers. They produced solo and synchronous read speech in interaction with a confederate who appeared on a prerecorded video. There were three within-subject experimental conditions: the confederate (a) sitting, (b) biking with light effort, or (c) biking with heavier effort. RESULTS: During speech, the confederate's inhalation amplitude and fo increased with physical effort, as expected. Her breath cycle duration changed differently, probably because of read speech constraints. Overall, the only adaptation the participants showed was higher fo with increase in the confederate's physical effort during synchronous, but not solo, speech. Additionally, they produced shallower inhalations when observing the confederate biking in silence, as compared to the condition without movement. Crucially, the participants' acoustic and breathing data showed large interindividual variability. CONCLUSIONS: Our findings indicate that, in this paradigm, convergence only took place on fo during synchronous speech and that this phonetic adaptation happened independently from any speech breathing adaptation. It also suggests that participants may adapt their quiet breathing while watching a person performing physical exercise but that the mechanism is more complex than that explained previously.
RESUMEN
Gaze cues serve an important role in facilitating human conversations and are generally considered to be one of the most important non-verbal cues. Gaze cues are used to manage turn-taking, coordinate joint attention, regulate intimacy, and signal cognitive effort. In particular, it is well established that gaze aversion is used in conversations to avoid prolonged periods of mutual gaze. Given the numerous functions of gaze cues, there has been extensive work on modelling these cues in social robots. Researchers have also tried to identify the impact of robot gaze on human participants. However, the influence of robot gaze behavior on human gaze behavior has been less explored. We conducted a within-subjects user study (N = 33) to verify if a robot's gaze aversion influenced human gaze aversion behavior. Our results show that participants tend to avert their gaze more when the robot keeps staring at them as compared to when the robot exhibits well-timed gaze aversions. We interpret our findings in terms of intimacy regulation: humans try to compensate for the robot's lack of gaze aversion.
RESUMEN
Alcohol intoxication is known to affect many aspects of human behavior and cognition; one of such affected systems is articulation during speech production. Although much research has revealed that alcohol negatively impacts pronunciation in a first language (L1), there is only initial evidence suggesting a potential beneficial effect of inebriation on articulation in a non-native language (L2). The aim of this study was thus to compare the effect of alcohol consumption on pronunciation in an L1 and an L2. Participants who had ingested different amounts of alcohol provided speech samples in their L1 (Dutch) and L2 (English), and native speakers of each language subsequently rated the pronunciation of these samples on their intelligibility (for the L1) and accent nativelikeness (for the L2). These data were analyzed with generalized additive mixed modeling. Participants' blood alcohol concentration indeed negatively affected pronunciation in L1, but it produced no significant effect on the L2 accent ratings. The expected negative impact of alcohol on L1 articulation can be explained by reduction in fine motor control. We present two hypotheses to account for the absence of any effects of intoxication on L2 pronunciation: (1) there may be a reduction in L1 interference on L2 speech due to decreased motor control or (2) alcohol may produce a differential effect on each of the two linguistic subsystems.
