Textures that we like to touch: An experimental study of aesthetic preferences for tactile stimuli

We report two experiments designed to investigate the nature of aesthetic preferences for tactile textures in humans. In Experiment 1, the participants rated their preference for a range of actively and passively explored textures presented on their hands and on their cheeks. The results revealed that those textures that were subjectively-rated as smoother were preferred over those that were rated as rougher. Moreover, certain textures were disliked more during active than during passive stimulation. In Experiment 2, the speed of tactile stimulation was controlled in order to elicit vigorous responses from C-tactile fibers (present only in hairy skin), which are thought to play a central role in pleasant aspects of touch. The results revealed that textures were preferred when presented on the hairy skin of the forearm than on the glabrous palm of the hand. These results provide preliminary evidence regarding people’s preferences for different attributes of tactile surface.     

The Interrater Reliability of Subjective Assessments of the Babinski Reflex

The Babinski reflex is a clinical diagnostic tool; however, the interrater reliability of this tool is currently greatly contested. A comparison between rater groups with objective measurements of the Babinski reflex was therefore conducted. Fifteen recorded Babinski reflexes were assessed by 12 neurologists and 12 medical students as being either pathological or nonpathological. Kinematic and electromyographic variables were collected and used to assess which aspects of the Babinski reflex predict classification. Substantial interrater agreement within the neurologist and student groups (κ = .72 and .67, respectively) was shown; however, there were some differing aspects between what neurologists and students used to assess the reflex as determined by objective kinematic measurements.     

Tailoring emotions in romantic relationships: A person-centered approach

Adapting the concept of emotional labor to romantic relationships, we examined how people tailor their emotions based on beliefs about partner expectations. Participants (N = 521) completed measures of faking one’s felt emotions (surface acting) and attempting to change felt emotions (deep acting) in response to four contexts. Using latent profile analysis, we identified five profiles (non-actors, deep-actors, moderates, actors, and extreme regulators), and evaluated how profile membership corresponded to relationship quality, self-esteem, and general emotional regulation tendencies. Relationship quality was higher among deep actors and non-actors compared with actors and extreme regulators. Although people may benefit from deep acting, the co-occurrence of surface acting appears to maximize the costs and minimize the benefits of deep acting in romantic relationships.     

Role of stiffness in weight perception

Abstract:  Here, we focused on a load-on task to clarify the judgment mechanism for weight perception. We measured hand trajectory and surface electromyography to estimate time-varying stiffness and torque patterns in joints. Our results showed that the goal of learning motor skills under load-on tasks is to maintain the hand position, and that humans produce force with cocontraction and increasing stiffness levels according to the weight of an object. Finally, we examined whether stiffness is an effective parameter as an efferent signal for weight perception and found that stiffness plays an important role in weight perception.     

A simple formula for the estimation of surface tension from two length measurements for a sessile or pendant drop

We present a very simple formula for the determination of surface tension from only two length measurements for pendant or sessile liquid drops (together with knowledge of their density). The formula is derived from an analytic theory of Morse and Witten for the shape of a drop under a small applied force. We also discuss its validity in the presence of measurement accuracy.     

Inner speech sustains predictable task switching: direct evidence in adults

It has been proposed that inner speech supports task selection in task-switching studies, especially when the need for endogenous control is increased. This has been established through the suppression of inner speech in cognitive-flexibility tasks that leads to poorer performance. The aim of this study is to quantify the role of inner speech in a flexibility task by using surface laryngeal electromyography, which, contrary to previous studies, enables participants to freely verbalise the tasks. We manipulated endogenous and exogenous flexibility in a mathematical switching task paradigm. Experiment 1 shows that inner speech acts as a support for switching and is recruited more often when the tasks are of an endogenous type. The main result of Experiment 2 that language is recruited more for the mixing cost than for the switch cost (regardless of the endogenous factor) extends past findings obtained through articulatory suppression.     

The role of surface-based representations of shape in visual object recognition

This study contrasted the role of surfaces and volumetric shape primitives in three-dimensional object recognition. Observers (N?=?50) matched subsets of closed contour fragments, surfaces, or volumetric parts to whole novel objects during a whole–part matching task. Three factors were further manipulated: part viewpoint (either same or different between component parts and whole objects), surface occlusion (comparison parts contained either visible surfaces only, or a surface that was fully or partially occluded in the whole object), and target–distractor similarity. Similarity was varied in terms of systematic variation in nonaccidental (NAP) or metric (MP) properties of individual parts. Analysis of sensitivity (d′) showed a whole–part matching advantage for surface-based parts and volumes over closed contour fragments—but no benefit for volumetric parts over surfaces. We also found a performance cost in matching volumetric parts to wholes when the volumes showed surfaces that were occluded in the whole object. The same pattern was found for both same and different viewpoints, and regardless of target–distractor similarity. These findings challenge models in which recognition is mediated by volumetric part-based shape representations. Instead, we argue that the results are consistent with a surface-based model of high-level shape representation for recognition.     

The contribution of shape and surface information in the other-race face effect

Faces from another race are generally more difficult to recognize than faces from one's own race. However, faces provide multiple cues for recognition and it remains unknown what are the relative contribution of these cues to this “other-race effect”. In the current study, we used three-dimensional laser-scanned head models which allowed us to independently manipulate two prominent cues for face recognition: the facial shape morphology and the facial surface properties (texture and colour). In Experiment 1, Asian and Caucasian participants implicitly learned a set of Asian and Caucasian faces that had both shape and surface cues to facial identity. Their recognition of these encoded faces was then tested in an old/new recognition task. For these face stimuli, we found a robust other-race effect: Both groups were more accurate at recognizing own-race than other-race faces. Having established the other-race effect, in Experiment 2 we provided only shape cues for recognition and in Experiment 3 we provided only surface cues for recognition. Caucasian participants continued to show the other-race effect when only shape information was available, whereas Asian participants showed no effect. When only surface information was available, there was a weak pattern for the other-race effect in Asians. Performance was poor in this latter experiment, so this pattern needs to be interpreted with caution. Overall, these findings suggest that Asian and Caucasian participants rely differently on shape and surface cues to recognize own-race faces, and that they continue to use the same cues for other-race faces, which may be suboptimal for these faces.     

Facial reactions to different emotionally relevant stimuli

Facial EMG activity was measured from the Corrugator supercilii and the Zygomatic major muscle regions while 48 subjects were exposed to pictures of angry and happy facial expressions, snakes and flowers as well as low and high preference nature scenes. The valency perspective predicted that facial reactions should be related to the intensity of the positive and the negative valency of stimuli. The mimicking behavior approach predicted that facial reactions should only be reflected as a mimicking response to the facial stimuli, whereas the evolutionary:biological perspective predicted that the most clearcut positive and negative facial reactions should be evoked by facial stimuli and by snakes. In support of the latter perspective, the present results showed that angry faces and snakes evoked the most distinct Corrugator supercilii muscle response, whereas happy faces evoked the largest Zygomatic major muscle response.     

Muscle Strength Training Alters Muscle Activation of the Lower Extremity during Side-Step Cutting in Females

Abstract

The objective of this study was to examine the effects of muscle strength training on knee kinematics/kinetics and muscle activation patterns during anticipated side-step cutting. Three-dimensional knee kinematics/kinetics data and muscle activation of selected lower extremity muscles were measured while performing cutting before and after completing 10-week circuit strength training mixed typical resistance training and power training (intervention) or no training (control) from 25 female subjects. The muscle strength of quadriceps and hamstrings were measured before and after training using isokinetic dynamometer. No statistically significant differences were observed in quadriceps and hamstrings muscle strength, all kinematic/kinetic variables, and muscle activation for the control group. Both quadriceps (p?=?0.005) and hamstrings (p?=?0.030) muscle strength were increased after training. An increased biceps femoris (p?=?0.003) and H:Q ratio of activation (p?=?0.016), as well as decreased gastrocnemius muscle activation (p?=?0.012) during pre-activation phase in intervention group were found. No significant differences were found in knee kinematics and kinetics both at the time frame of the initial contact and the peak tibial anterior shear force after training. In conclusion, muscle strength training altered some muscle activations of lower extremity muscles, which might affect the risk of ACL injury, but it did not change the kinematic/kinetic parameters.