Perceived Tension, Movement, and Pleasantness in Harmonic Musical Intervals and Noises

Perceived valence, tension, and movement of harmonic musical intervals (from the unison to the octave presented in a low- and high-register) and standard noises (brown, pink, white, blue, purple) were assessed in two studies that differed in the crossmodal procedure by which tension and movement were rated: proprioceptive device or visual analog scale. Valence was evaluated in both studies with the visual analog scale. In a preliminary study, the proprioceptive device was calibrated with a psychophysical procedure. Roughness of the stimuli was included as covariate. Tension was perceived higher in dissonant intervals and in intervals presented in the high register. The higher the high-pitch energy content in the standard noise, the higher the perceived tension. The visual analog scale resulted in higher tension ratings than the proprioceptive device. Perception of movement was higher in dissonant intervals, in intervals in the high register, and in standard noises than in musical intervals. High-pitch spectrum noises were associated with more sense of movement than low-pitch spectrum noises. Consonant intervals and low-register intervals were evaluated as more pleasant than dissonant and high-register intervals. High-pitch spectrum purple and blue noises were evaluated as more unpleasant than low-pitch spectrum noises.

Event-related prosody reveals distinct acoustic manifestations of accuracy and confidence in speech

Speech prosody constitutes a fundamental way through which speakers communicate their levels of confidence. Yet, it remains unknown whether prosodic markers of uncertainty constitute mere indices, that are constitutively present when speakers feel doubtful, or rather, whether they reflect other underlying psychological variables. By combining a psychophysical procedure with an acoustic analysis of verbal reports, we tease apart the contributions of sensory evidence, accuracy, and subjective confidence to epistemic prosody. We find that loudness, duration and intonation reflect distinct underlying mental processes: while loudness is predominantly impacted by accuracy, duration and intonation truly reflect subjective confidence, over and beyond sensory evidence and accuracy. We also find that speakers’ accuracy can still be heard beyond their own metacognitive awareness, and that at the level of intonation, speakers who display better metacognitive sensitivity are also the best signalers. Our results highlight prosody as a fundamental interface through which confidence can be shared.

Inconsistencies in C. elegans behavioural annotation

High quality behavioural annotation is a key component to link genes to behaviour, yet relatively little attention has been paid to check the consistency of various automated methods and expert judgement. In this paper we investigate the consistency of annotation for the ‘Omega turn’ of C. elegans, which is a frequently used behavioural assay for this animal. First the output of four Omega detection algorithms are examined for the same data set, and shown to have relative low consistency, with F-scores around 0.5. Consistency of expert annotation is then analysed, based on an online survey combining two methods: participants judged a fixed set of predetermined clips; and an adaptive psychophysical procedure was used to estimate individual's threshold for Omega turn detection. This survey also revealed a substantial lack of consistency in decisions and thresholds. Such inconsistency makes cross-publication comparison difficult and raises issues of reproducibility.

Deceived by stripes: conspicuous patterning on vital anterior body parts can redirect predatory strikes to expendable posterior organs

Conspicuous coloration, which presumably makes prey more visible to predators, has intrigued researchers for long. Contrastingly coloured, conspicuous striped patterns are common among lizards and other animals, but their function is not well known. We propose and test a novel hypothesis, the ‘redirection hypothesis’, wherein longitudinal striped patterns, such as those found on the anterior body parts of most lacertilians, redirect attacks away from themselves during motion towards less vulnerable posterior parts, for example, the autotomous tail. In experiments employing human ‘predators’ attacking virtual prey on a touchscreen, we show that longitudinal striped patterns on the anterior half of prey decreased attacks to the anterior and increased attacks to the posterior. The position of stripes mattered—they worked best when they were at the anterior. By employing an adaptive psychophysical procedure, we show that prey with striped patterning are perceived to move slower, offering a mechanistic explanation for the redirective effect. In summary, our results suggest that the presence of stripes on the body (i.e. head and trunk) of lizards in combination with caudal autotomy can work as an effective anti-predator strategy during motion.