Static and Phasic Cross-Talk Effects in Discrete Bimanual Reversal Movements

The authors examined the hypothesis that the phasic and the static cross-talk effects found in bimanual movements with different target amplitudes originate at different functional levels of motor control, which implies that the effects can be dissociated experimentally. When the difference between the short and the long amplitudes assigned to the 2 hands of 12 participants was decreased, the static effect disappeared. In contrast, the phasic effect, which can be observed only at short preparation intervals, did not disappear; although it became smaller in absolute terms, in relative terms it did not. In addition, the authors compared the time course of amplitude assimilation with the time course of amplitude variability and examined the correlation between left hand and right hand amplitudes. The disappearance of the phasic amplitude assimilation at increasing preparation intervals turned out to be delayed relative to the decline of the correlation between amplitudes. That finding suggests that the assimilation of mean amplitudes and the correlation between left hand and right hand amplitudes are not fully equivalent indicators of intermanual interactions, but may indicate different kinds of inter-limb coupling.     

Response to Commentaries: Actions as Perceptual-Conceptual "Gestalts"

The author clarifies the objective and essence of the psychological, or perceptual-cognitive, approach to voluntary movement. According to that approach, voluntary movements are organized and performed as meaningful, perceptible events with bodily and environmental aspects. Body-oriented control is thus not neglected in the perceptual-cognitive approach but is actually an important issue. He further clarifies how material and psychological factors relate to each other in motor control and why they are not considered a coalition of constraints. The central importance of the sparse coding principle for the perceptual-cognitive approach is underlined. Finally, the author argues that the psychological information format is particularly suitable for motion control and stresses the power of the perceptual-cognitive approach to possibly provide a unifying framework for understanding human voluntary movements.     

Determinants of Offline Processing of Visual Information for the Control of Reaching Movements

The authors investigated the use of visual feedback as a form of knowledge of results (KR) for the control of rapid (200-250 ms) reaching movements in 40 participants. They compared endpoint accuracy and intraindividual variability of a full-vision group (FV) with those of no-vision groups provided with KR regarding (a) the endpoint in numerical form, (b) the endpoint in visual form, or (c) the endpoint and the trajectory in visual form (DEL). The FV group was more accurate and less variable than were the no-vision groups, and the analysis of limb trajectory variability indicated that their superior performance resulted primarily from better movement planning rather than from online visual processes. The FV group outperformed the DEL group even though both groups were obtaining the same amount of spatial visual information from every movement. That finding suggests that the effectiveness with which visual feedback is processed offline is not a simple function of the amount of visual information available, but depends on how that information is presented.     

Eye-Hand Coordination in Rhythmical Pointing

The authors investigated the relation between hand kinematics and eye movements in 2 variants of a rhythmical Fitts's task in which eye movements were necessary or not necessary. P. M. Fitts's (1954) law held in both conditions with similar slope and marginal differences in hand-kinematic patterns and movement continuity. Movement continuity and eye—hand synchronization were more directly related to movement time than to task index of difficulty. When movement time was decreased to fewer than 350 ms, eye—hand synchronization switched from continuous monitoring to intermittent control. The 1:1 frequency ratio with stable π/6 relative phase changed for 1:3 and 1:5 frequency ratios with less stable phase relations. The authors conclude that eye and hand movements in a rhythmical Fitts's task are dynamically synchronized to produce the best behavioral performance.     

Comment on “Retention Characteristics of Motor Short-Term Memory Cues”

Marteniuk (1973) used negative results, which may be attributed to a lack of power, to question the adequacy of variable error as a measure of forgetting. He also used these negative results, along with constant error results which were consistent with the Laabs (1971, 1973) model of motor memory, to reject parts of the model related to variable error. Caution is advised when interpreting negative results and interchanging dependent measures.     

Sequential Aiming with Two Limbs and the One-Target Advantage

Movement times to the first target in a 2-target sequence are typically slower than in 1-target aiming tasks. The 1-target movement time advantage has been shown to emerge regardless of hand preference, the hand used, the amount of practice, and the availability of visual feedback. The authors tested central and peripheral explanations of the 1-target advantage, as postulated by the movement integration hypothesis, by asking participants to perform single-target movements, 2-target movements with 1 limb, and 2-target movements in which they switched limbs at the first target. Reaction time and movement time data showed a 1-target advantage that was similar for both 1- and 2-limb sequential aiming movements. This outcome demonstrates that the processes underlying the increase in movement time to the 1st target in 2-target sequences are not specific to the limb, suggesting that the 1-target advantage originates at a central rather than a peripheral level.     

Handedness and Hemispheric Asymmetry in the Control Of Movements

This study investigated the influence of hemispheric specialization of function on the motor performance of the hands. Right-handed (n=17), ambidextral (n=21), and ambisinistral (n=12) subjects performed Fitts' (1954) reciprocal tapping task under two conditions with each hand. Conditions had the same index of difficulty but differed in movement precision. The left hand of righthanders was superior in the condition requiring the greatest amount of preprogramming. Conversely, the right hand was not superior in the condition having the greatest demand for feedback control. For ambidextrals, left-hand superiority in the relatively preprogrammed condition was also revealed. Ambisinistrals showed no significant difference between conditions with either hand. The results partially support the hypothesis that the motor performance of the hands mirrors the dominant processing mode of their contralateral hemisphere. Failure to find supportive evidence in ambisinistrals is consistent with the contention that they lack hemispheric specialization of function.     

Sequential remembering and lived remembering in the flow of experience: a videographic study / Recuerdo secuencial y recuerdo vivido en el curso de la experiencia: un estudio videográfico

Abstract

During the last 30 years the discussion on memory and remembering has advanced from a strictly cognitive perspective to a broader view, involving the body in these processes. Thus, the present article aims to recover Henri Bergson’s main ideas — published more than a century ago — emphasizing the tight relation between immediate experience, memory and bodily movements. First, contemporary perspectives on memory are reviewed. Afterwards, the results from a videographic study are presented, showing how deeply the body is engaged in the act of remembering. These results evidence the presence of two different ways of remembering: sequential and lively-experienced.     

All of The Myriad Worlds: Life in the Akashic Plenum

This article explores some experiential implications of Laszlo's Akashic Field hypothesis as well as similar information-rich field models such as those suggested by Bohm and Sheldrake. It examines the implications of such models for both ordinary and anomalous human experience, and proposes the idea that these models allow for the possibility of alternative experiential worlds as real as ordinary “material” reality. Such alternative realities are posited by many, if not all, major mythic and religious systems, and are said to be directly experienced in certain contemplative and shamanic traditions as well as during postmortem and near-death experiences. We note that information-rich holographic fields may be able to store concentrated non-overlapping quantities of information that can be selectively activated by distinct eliciting stimuli. Individual human consciousness itself might constitute just such a stimulus, thus accounting for the individual and cultural variations on commonly shared motifs in shamanic, near death, and other experiences of alternative realities.     

Mithraic iconography and ideology

L. Ron Hubbard created in Scientology an immense landscape of alternative worlds, realities, and possibilities. Scientology cosmology, mythology, and eschatology are inescapably linked to galactic events and Hubbard's retelling of human history is replete with science-fiction tropes – many of which found popularity in the early science-fiction tradition to which he belonged. In his therapeutic and religious teachings, Hubbard proposed a complex narrative that re-defined the essence of self and society in relation to the cosmos. For Scientologists, the fantastic becomes mundane as they position themselves within a vast and heavy quest to reshape themselves, the rest of humanity, and, for some, the entire universe. Understood within the science-fiction context from which Scientology emerged, one can better understand the grand nature of Hubbard's proposals as belonging to a specific tradition within the genre – namely, space opera. Consequently, this article analyses Hubbard's propositions using space-opera concepts, and argues that Hubbard re-defined a unique tradition in the course of creating a new reality.