Listening to trees in the forest: Attentional set influences how semantic and acoustic factors interact in auditory perception.

Studies of auditory object perception claim that semantic properties dominate acoustic properties in determining identification accuracy. Yet the direction of the semantic effect is mixed, with some studies showing an advantage for detecting incongruent sounds and others reporting a congruent sound advantage. Here we examine the role of the participant's attentional set when identifying auditory objects in naturalistic soundscapes. We varied the acoustic and semantic properties of the sounds orthogonally in two experiments. In Experiment 1 participants tuned their attention broadly to detect any change between two successive soundscapes (e.g., two restaurant soundscapes, with and without a child coughing). In Experiment 2 they tuned attention more narrowly to a probe presented after a soundscape (e.g., a restaurant soundscape with a child coughing, followed by the coughing sound alone). In both experiments, semantic relations between the objects and backgrounds helped to disambiguate objects that blended acoustically with the background. When attending globally (Experiment 1), objects that were acoustically similar yet semantically incongruent tended to be missed (e.g., bouncing basketball on a construction site), as though camouflaged by the gist of the soundscape. When attending locally (Experiment 2), semantically congruent foil objects led to false positive reports under acoustically similar conditions (hammering sounds on a construction site), as though the gist of the soundscape contributed to their plausible inclusion. In summary, although attentional set had a strong influence on the specific kinds of errors made, both results pointed to participants using a semantically congruent high-level schema to report the sounds they heard.

Bystanders are less willing to resuscitate out-of-hospital cardiac arrest victims during the COVID-19 pandemic.

AIM: The COVID-19 pandemic may influence the willingness of bystanders to engage in resuscitation for out-of-hospital cardiac arrest. We sought to determine if and how the pandemic has changed willingness to intervene, and the impact of personal protective equipment (PPE). METHODS: We distributed a 12-item survey to the general public through social media channels from June 4 to 23, 2020. We used 100-point scales to inquire about participants' willingness to perform interventions on "strangers or unfamiliar persons" and "family members or familiar persons", and compared mean willingness during time periods prior to and during the COVID-19 pandemic using paired t-tests. RESULTS: Survey participants (n = 1360) were from 26 countries; the median age was 38 years (IQR 24-50) and 45% were female. Compared to prior to the pandemic, there were significant decreases in willingness to check for breathing or a pulse (mean difference -10.7% [95%CI -11.8, -9.6] for stranger/unfamiliar persons, -1.2% [95%CI -1.6, -0.8] for family/familiar persons), perform chest compressions (-14.3% [95%CI -15.6, -13.0], -1.6% [95%CI -2.1, -1.1]), provide rescue breaths (-19.5% [95%CI -20.9, -18.1], -5.5% [95%CI -6.4, -4.6]), and apply an automated external defibrillator (-4.8% [95%CI -5.7, -4.0], -0.9% [95%CI -1.3, -0.5]) during the COVID-19 pandemic. Willingness to intervene increased significantly if PPE was available (+8.3% [95%CI 7.2, 9.5] for stranger/unfamiliar, and +1.4% [95%CI 0.8, 1.9] for family/familiar persons). CONCLUSION: Willingness to perform bystander resuscitation during the pandemic decreased, however this was ameliorated if simple PPE were available.