The role of left inferior frontal cortex during audiovisual speech perception in infants.

In the first year of life, infants' speech perception attunes to their native language. While the behavioral changes associated with native language attunement are fairly well mapped, the underlying mechanisms and neural processes are still only poorly understood. Using fNIRS and eye tracking, the current study investigated 6-month-old infants' processing of audiovisual speech that contained matching or mismatching auditory and visual speech cues. Our results revealed that infants' speech-sensitive brain responses in inferior frontal brain regions were lateralized to the left hemisphere. Critically, our results further revealed that speech-sensitive left inferior frontal regions showed enhanced responses to matching when compared to mismatching audiovisual speech, and that infants with a preference to look at the speaker's mouth showed an enhanced left inferior frontal response to speech compared to infants with a preference to look at the speaker's eyes. These results suggest that left inferior frontal regions play a crucial role in associating information from different modalities during native language attunement, fostering the formation of multimodal phonological categories.

Eyes, More Than Other Facial Features, Enhance Real-World Donation Behavior.

Humans often behave more prosocially when being observed in person and even in response to subtle eye cues, purportedly to manage their reputation. Previous research on this phenomenon has employed the "watching eyes paradigm," in which adults displayed greater prosocial behavior in the presence of images of eyes versus inanimate objects. However, the robustness of the effect of eyes on prosocial behavior has recently been called into question. Therefore, the first goal of the present study was to attempt to replicate this effect. Additionally, it remains unclear whether the watching-eyes effect is driven specifically by reputation management (owing to the monitoring function of the eyes) or whether any cues indexing human presence more generally also have a similar effect. To address these questions, the current study compared prosocial behavior in the presence of eyes versus inanimate objects as well as other human features. The study was conducted as a field experiment at a children's museum. Each week, the donation signs were changed to show eyes, noses, mouths, or chairs. Total donation amount and number of patrons per week were recorded. Participants donated more when they were exposed to eyes than to inanimate objects (chairs). We thus replicated the previously reported watching-eyes effect. Moreover, more money was donated when individuals were exposed to eyes than to more general cues of human presence (nose and mouth). The current findings suggest that eyes play a special role in promoting cooperation in humans, likely by serving as cues of monitoring and thus eliciting reputation management behavior.

Early Reputation Management: Three-Year-Old Children Are More Generous Following Exposure to Eyes.

To enhance their reputations, adults and even 5-year-old children behave more prosocially when being observed by others. However, it remains unknown whether children younger than five also manage their reputations. One established paradigm for assessing reputation management is the 'watching eyes paradigm,' in which adults have been found to be more prosocial in the presence of eyes versus control images. However, the robustness of this effect in adults has recently been called into question, and it has never been demonstrated in children. In Study 1, we used a method similar to that used in prior work: 3- and 5-year-old children took part in a prosocial task while in the presence of an image of eyes or flowers but without explicit mention or reference to the image. With this method, children did not show the watching eyes effect. In Study 2, 3-year-old children were tested with a modified watching eyes paradigm, wherein they first explicitly interacted either with images of eyes or with cloth flowers, and they then engaged in a prosocial task. With this modified watching eyes paradigm, 3-year-olds showed the predicted effect: They were more prosocial following exposure to eyes than flowers. These results offer potential insight into the mixed findings across the adult literature, such that the manner of exposure, and specifically how explicit the exposure is, may influence the watching eyes effect. Finally, no study to date has examined whether cues of human presence other than the eyes also influence prosociality. We found that children in the Mouth condition were prosocial at an intermediate level between the Eyes and Flowers conditions. Overall, the findings point to the remarkably early emergence of reputation management in human ontogeny.

Random-cavity lasing from electrospun polymer fiber networks.

Lasing emission from random cavities formed in networks of electrospun Rhodamine-doped polymer fibers is presented. Spatially resolved spectroscopy and spectral analysis prove that the observed laser emission stems from individual ring resonators randomly distributed throughout the network. These electrospun fiber lasers represent a facile and straightforward configuration for developing novel photonic devices that may advantageously utilize the network morphology.

On-chip microlasers for biomolecular detection via highly localized deposition of a multifunctional phospholipid ink.

We report on a novel approach to realize on-chip microlasers, by applying highly localized and material-saving surface functionalization of passive photonic whispering gallery mode microresonators. We apply dip-pen nanolithography on a true three-dimensional structure. We coat solely the light-guiding circumference of pre-fabricated poly(methyl methacrylate) resonators with a multifunctional molecular ink. The functionalization is performed in one single fabrication step and simultaneously provides optical gain as well as molecular binding selectivity. This allows for a direct and flexible realization of on-chip microlasers, which can be utilized as biosensors in optofluidic lab-on-a-chip applications. In a proof-of-concept we show how this highly localized molecule deposition suffices for low-threshold lasing in air and water, and demonstrate the capability of the ink-lasers as biosensors in a biotin-streptavidin binding experiment.