Leg Perception of Object Heaviness

ABSTRACT

Perceived heaviness is a function of both the muscle activity used to wield an object and the resulting movement. Wielding reveals invariant properties of the effector-object system, such as rotational inertia. Recent research has proposed a psychophysiological mechanism for perceiving the heaviness of a handheld object through dynamic touch that captures how arm muscle activity and angular movement combined reveal this invariance (Waddell, Fine, Likens, Amazeen & Amazeen, 2016 Waddell, M. L., Fine, J. M., Likens, A. D., Amazeen, E. L., & Amazeen, P. G. (2016). Perceived heaviness in the context of Newton's Second Law: Combined effects of muscle activity and lifting kinematics. Journal of Experimental Psychology: Human Perception and Performance, 42, 363–374.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). The current study extends this hypothesis by investigating the dynamics of heaviness perception with the leg. Participants lifted objects of varying mass with knee extension lifts while reporting perceived heaviness. During each lift, the electromyogram (EMG) was recorded from the quadriceps, and peak angular acceleration was recorded about the knee. The resulting psychophysiological function revealed the hypothesized ratio of muscle activity to movement, similar to that found in Waddell et al. (2016) Waddell, M. L., Fine, J. M., Likens, A. D., Amazeen, E. L., & Amazeen, P. G. (2016). Perceived heaviness in the context of Newton's Second Law: Combined effects of muscle activity and lifting kinematics. Journal of Experimental Psychology: Human Perception and Performance, 42, 363–374.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]. This suggests that the dynamics for heaviness perception in the leg is similar to that shown in the arm in previous work.     

The impact of politeness and relationship on perceived quality of advice about a problem

Advice is a common but potentially problematic way to respond to someone who is distressed. Politeness theory (Brown & Levinson, 1987) suggests advice threatens a hearer's face and predicts that the speaker‐hearer relationship and the use of politeness strategies can mitigate face threat and enhance the effectiveness of advice messages. Students (N=384) read 1 of 16 hypothetical situations that varied in speaker power and closeness of the speaker‐hearer relationship. Students then read 1 of 48 advice messages representing different politeness strategies and rated the message for regard shown for face and for effectiveness. However, neither speaker‐hearer relationship nor politeness strategies was consistently associated with perceived threat to face or perceived advice effectiveness. We suggest revisions to politeness theory and additional factors that may affect judgments of face sensitivity and advice effectiveness.     

Perceptual independence of size and weight by dynamic touch

Historically, the existence of a size-weight illusion has led to the conclusion that perceptions of size and weight are not independent. A dependence of perceived heaviness on physical volume (perceptual separability), however, is different from a dependence on perceived volume (perceptual independence). Three experiments were conducted to evaluate perceptual independence. The relations between perceived size and weight and physical size and mass were evaluated in Experiment 1. Perceived weight, length, and width were structured only by the corresponding physical variables, whereas variations in volume were not separable from variations in mass. F. G. Ashby and J. T. Townsend's (1986) test for perceptual independence was applied in Experiment 2. Perceived weight was independent of perceived length and volume. Experiment 3 used a magnitude estimation paradigm to investigate the extent to which information-perception relations could be related to the observed patterns of separability and independence.     

Coupling of breathing and movement during manual wheelchair propulsion

The hypothesis of this study was that stable coordination patterns may be found both within and between physiological subsystems. Many studies have been conducted on both monofrequency and multifrequency coordination, with a focus on both the frequency and phase relations among the limbs. In the present study, locomotor-respiratory coupling was observed in the maintenance of small-integer frequency ratios (2:1, 3:1, and 4:1) and in the consistent placement of the inspiratory phase just after the onset of the movement cycle during wheelchair propulsion. Level of experience and various motor and respiratory parameters were manipulated. Coupling was observed across levels of experience. Increases in movement frequency were accompanied by a shift to larger-integer ratios, suggesting that a single modeling strategy (e.g., the Farey tree; D. L. González & O. Piro, 1985) may be used for coordination both within the motor subsystem and between it and other physiological subsystems.     

交多少朋友合适?谈亚里士多德对"大量交友"的评论

引言 结交多少个朋友合适?提出这样的问题似乎是钻牛角尖,也不属于哲学家的兴趣.然而,古代的哲学家并未忽视这个问题的重要性,他们都直接或间接地关注过"友谊".实际上,提出交多少朋友合适的问题,就是提出友谊的限度问题,更确切地说,是提出了与他人特殊关系的延展问题.我们看到,这种关系并不要求排他性,但将其无限扩展则难免使其变质.     

Timing the Selection of Information During Rhythmic Catching

Catching a ball requires that information be available close to the catch but early enough for prospective or corrective control. In the present experiment, 6 participants were asked to throw and catch a ball continuously for 1 min while wearing liquid-crystal goggles that restricted viewing to specific amounts of time at specific intervals. Participants were free to select the information by varying the frequency and phasing of throwing relative to the goggles. Video analysis revealed that they elected a frequency of throwing that matched the goggle frequency and chose to view the ball at or around its zenith. Earlier portions of the ball's trajectory were viewed as the goggle frequency increased. Despite variations in the viewing location, participants elected to view the ball on average 365 ms before the catch. Analysis of the hand's trajectory further revealed that the time interval (M = 82 ms) between the ball's zenith and the initiation of the final motion of the hand toward the catch did not vary as a function of the frequency of throwing. The authors conclude that the timing constraints imposed by the hand's movement are the basis for the selection of information for catching.     

Displays that facilitate performance of multifrequency ratios during motor-respiratory coordination

A large number of ratios between movement and breathing are possible, but only a small number have been performed during exercise. The purpose of this study was twofold: (1) to investigate displays that might facilitate the performance of other ratios; and (2) to test predictions from the sine circle map and continued fractions in a model motor-respiratory task in which participants coordinated arm movement and breathing. Displays consisted of either real-time feedback or a template (non-feedback). The accuracy of ratio performance was significantly greater with the template in which the number and relative positioning of movements and breaths was depicted, compared to with real-time feedback. Across displays, the stability of ratio performance conformed to principles of the sine circle map and was significantly greater for ratios with longer continued fractions. Therefore, the motor-respiratory repertoire can be expanded by increasing participants’ understanding of the pattern to be performed, but performance is constrained by general dynamical principles.     

Affordances Guide Choice Behavior between Equal Schedules of Reinforcement in Rats

Abstract

Operant choice theories pose that behavior distribution between options is ruled by the consequences related with these options. Evidence suggests that rats’ performance is attuned to the affordances that the operant setting provides, such as lever height. Our aim was to explore in rats whether lever press distribution was influenced by the affordances furnished by two levers. Lever pressing was reinforced in two concurrent equal variable-ratio schedules of reinforcement, and in successive conditions lever height was varied asymmetrically—that is, one lever was higher than the other. Results showed a quadratic relation between response rates and lever height, a linear trend between preference and lever height, and higher between- and within-bout response rates on the lower lever in four out of the six pairs of lever heights assessed. These findings suggest that intermediate lever heights favored lever pressing with faster bout initiation and faster within-bout responding, and support the idea that preorganized properties of behavior (i.e., the organism’s abilities) interact with the environment before the operant contingency takes place.     

Strength Recovery Patterns Following Isometric and Isotonic Exercise

In 3 experiments, the author tested the hypothesis that coordination dynamics is the content of a generalized motor program (GMP) for rhythmic interlimb coordination. In Experiment 1, learners (N = 14) practiced a ?90° movement with either identically timed or differently timed limbs. Both acquisition and transfer to novel (effector and pattern) timings were unaffected by the learning condition and were suggestive of the intrinsic dynamics for in-phase and antiphase. In Experiment 2, learners' (N = 13) acquisition of 2 different phase relations (?90° and ?45°) was qualitatively identical. Attractor reconstruction revealed an increase in the predictability of individual movement trajectories and a decrease in attractor dimensionality over learning. Transfer for both ?90° and ?45° was again suggestive of the intrinsic dynamics. In Experiment 3, learning altered participants' (N = 8) performance of in-phase and antiphase relations. Together, the results suggested a single continuum of phase relations, called an attractor landscape, that produces similar patterns of CE and VE for both previously stable and learned coordinations.     

Sensory and perceptual interactions in weight perception

In four experiments, a multidimensional signal detection analysis was used to determine the influence of length, diameter, and mass on haptically perceived heaviness with and without vision. This analysis allowed us to test for sensory and perceptual interactions between mass and size. As in previous research, sensory interactions were apparent in all four experiments. A novel result was the appearance of perceptual interactions that became more prominent when diameter varied and when vision was allowed. Discussion focuses on how vision and the modalities of touch (i.e., haptic and dynamic) might influence which interactions appear in the data.