Paced and self-paced continuous reaction time

Studies of the effect of pacing in continuous RT tasks are inconclusive. They have failed to (1) compare paced and self-paced RT at matched error rates and (2) examine RT distributions as well as mean or median RT. In the present experiment RTs were corrected for error rate by relating them to the speed-accuracy tradeoff function, which was measured in each experimental session. In this way deciles of the RT distributions of paced and self-paced conditions were compared, for eight subjects and four successive sessions. The task was a four-choice continuous RT task, employing visual stimuli. The results show that RT distributions are wider in the paced conditions. RTs of the first deciles are faster for pacing whereas medians in paced and self-paced conditions are about equal. The results can be explained when it is assumed that the variable R-S intervals in paced conditions lead to a larger variability of RT.     

Stress Counseling Theory and Practice: A Cautionary Review

In this era of growing emphasis on professional and financial accountability, stress counseling remains vague and imprecise. This article grounds stress counseling in responsible clinical methodology through reexamining and organizing the durable empirical literature to help counselors develop credible and effective interventions. A flowchart schema incorporating primary stress coping modalities of environment, cognitions, emotions, and personal life philosophy is presented to systematize intervention efforts to maximize efficient stress counseling services.     

Coordination between arm and leg movements during locomotion

To evaluate the contrasting dynamical and biomechanical interpretations of the 2:1 frequency coordination between arm and leg movements that occurs at low walking velocities and the 1:1 frequency coordination that occurs at higher walking velocities, the authors conducted an experiment in which they quantified the effect of walking velocity on the stability of the frequency and phase coordination between the individual limb movements. Spectral analyses revealed the presence of 2:1 frequency coordination as a constant feature of the data in only 3 out of 8 participants at walking velocities ranging from 1.0 to 2.0 km/h, in spite of the fact that the eigenfrequencies of the arms were rather similar across participants. The degree of interlimb coupling, as indexed by weighted coherence and variability of relative phase, was lower for the arm movements and for ipsilateral and diagonal combinations of arm and leg movements than for the leg movements. Furthermore, the coupling between all pairs of limb movements was found to increase with walking velocity, whereas no clear signs were observed that the switches from 2:1 to 1:1 frequency coordination and vice versa were preceded by loss of stability. Therefore, neither a purely biomechanical nor a purely dynamical model is optimally suited to explain these results. Instead, an integrative model involving elements of both approaches seems to be required.