Fitts’ Theorem in Oculomotor Control: Dissociable Movement Times for Amplitude and Width Manipulations

The authors examined whether movement times (MT) for discrete saccades are constant given equivalent index of difficulty (ID) values (i.e., unitary nature of Fitts’ theorem). To that end, we contrasted ID/MT relations for saccades equated for ID but differing with respect to their target amplitudes and widths. Results showed that MT increased with increasing ID within amplitude and width conditions; however, the ID/MT slope was markedly steeper in the former condition. Thus, the amplitude condition imposed greater information processing demands than the width condition—a result indicating that the constituent elements of Fitts’ theorem are dissociable (i.e., nonunitary). Further, examination of saccade kinematics demonstrated that the optimal MT for a given target amplitude was largely independent of target width.     

The Force/Force-Variability Relationship Under Controlled Temporal Conditions

Previously, an inverted U relationship between force and force variability was demonstrated in both static and dynamic responses. Recent research suggests that the inverted U function may be due to a lack of control of the temporal aspects of the response. To investigate this hypothesis, we examined the relationship between force and force variability in rapid movements under controlled temporal conditions. Subjects (N = 4) made rapid reversal responses with a horizontal lever (using elbow flexion and extension) such that the time to reversal (160 ms) and the distance to reversal (45°) were held constant in each of six load conditions (either 0, .260, .520, .780,1.040, or 1.560 kg added to the lever). When time to reversal and time to peak acceleration were held constant, a curvilinear relationship between force and force variability resulted, suggesting that the inverted U function is related to control of the temporal aspects of the response.     

Reaction Time of Healthy Older Adults Is Reduced While Walking Fast

Attentional requirements of walking at various speeds in older adults were examined. Twenty healthy older adults (69.9?±?2.77?years; 8 males) were asked to walk a distance of 10?m at a self-selected speed as well as 30% quicker and 30% slower. Concurrently, reaction time (RT) was evaluated by having participants respond as fast as possible to randomly presented auditory stimuli. Results reveal that an accelerated walking speed generated faster RT than slow and self-selected speeds, while no difference was found between the latter. Faster RTs during an accelerated walking speed may have been precipitated by the reduced equilibrium demands of the task.     

Kinesthetic Aftereffect and Augmenting/Reducing: A Two-Session Procedure,and Hence Identification of Stimulus-Governed Subjects,is Contraindicated

A few of the recent researchers of kinesthetic aftereffect (KAE) as an index of augmenting/reducing have continued to employ a two-session procedure. Findings that have accrued in the past decade indicate (a) The first administration of KAE is a reliable (internally consistent) and valid index of augmenting-reducing; (b) there are carry-over effects from the first to the second administration that bias the second session's preinduction scores; (c) KAE scores from sessions after the first do not relate to first-session scores (low retest reliability) and do not measure augmenting/reducing; and (d) unless special procedures are undertaken to avoid using the biased second- (or later-) session preinduction scores, a KAE procedure involving more than one session is contraindicated. When we reached a similar conclusion earlier (Baker et al., 1974), Petrie (1974) disagreed, arguing that a two-session procedure was needed to identify and eliminate an atypical subgroup, the “stimulus governed.” The case for determining which subjects are stimulus-governed is assessed and found wanting. Except in special circumstances, a one-session KAE procedure, in which all preinduction trials precede the first exposure to aftereffect induction, is indicated.     

Convergent Evidence for Basic Motivational Dimensions

Subjects (N = 217) rated the attractiveness of 56 general goals and then completed 3 theory-based tests of personality or motivation. Two goal factors—labeled Social-Economic Status and Competitive Achievement—seemed to reflect two broad domains of status-seeking motivation, and two other factors—labeled Growth Orientation and Interpersonal Security—pointed to separate domains of cooperative motivation. Thus, there was confirmation for the widespread assumption of two primary types of interpersonal motivation (solidarity and status) in our culture but also for important distinctions within each type. Canonical and direct correlations with the theoretically-grounded measures strongly supported that interpretation of the factors. Meaningful relationships between factors obtained from the questionnaire and the more rationally-based test scores indicated convergence in mappings of motivational space.     

How Do Romantic Relationship Satisfaction,Gender Stereotypes,and Gender Relate to Future Time Orientation in Romantic Relationships?

The present study is an investigation into how romantic relationship satisfaction and attitudes toward gender stereotypes about romantic relationship and gender are related to future time orientation in romantic relationships (FTORR). Four hundred and thirteen (208 men and 205 women) university students taking elective psychology courses at Middle East Technical University were given a scale including items about FTORR, romantic relationship satisfaction, and attitudes toward gender stereotypes about romantic relationships. All the participants were then involved in a heterosexual romantic relationship. Multiple regression results showed that for the women, attitudes toward men's assertiveness and men's dominance in relationships were more important predictors of FTORR than relationship satisfaction. For the men, attitudes toward men's assertiveness and romantic relationship satisfaction were important predictors of FTORR, but attitude toward men's dominance was not a predictor of FTORR. Women were more future oriented in their ongoing romantic relationships than were men. Finally, participants who were highly satisfied with their relationships scored higher on FTORR than those who were less satisfied.     

Increased forefoot loading is associated with an increased plantar flexion moment

The aim of this study was to identify the cascade of effects leading from alterations in force generation around the ankle joint to increased plantar pressures under the forefoot. Gait analysis including plantar pressure measurement was performed at an individually preferred and a standardized, imposed gait velocity in diabetic subjects with polyneuropathy (n = 94), without polyneuropathy (n = 39) and healthy elderly (n = 19). The plantar flexion moment at 40% of the stance phase was negatively correlated with the displacement rate of center of pressure (r = ?.749, p < .001 at the imposed, and r = ?.693, p < .001 at the preferred gait velocity). Displacement rate of center of pressure was strongly correlated with forefoot loading (r = ?.837, p < .001 at the imposed, and r = ?.731, p < .001 at the preferred gait velocity). People with a relatively high plantar flexion moment at 40% of the stance phase, have a faster forward transfer of center of pressure and consequently higher loading of the forefoot. This indicates that interventions aimed at increasing the control of the roll-off of the foot may contribute to a better plantar pressure distribution.     

Temporalities

The notion of time is traced both in Philosophy and in Physics (Newtonian Mechanics, Relativity, Cosmology, Quantum Theory). Distinct temporalities emerge and time appears as the essential condition for the realization of being, in accordance with ideas and theories developed by Peirce, Whitehead, and Heidegger.     

What Counts as Behavior? The Molar Multiscale View

Because the definition of behavior changes as our understanding of behavior changes, giving a final definition is impossible. One can, however, rule out some possibilities and propose some others based on what we currently know. Behavior is not simply movement, but must be defined by its function. Also, our understanding of behavior must agree with evolutionary theory. I suggest 4 basic principles: (a) only whole organisms behave; (b) behavior is purposive; (c) behavior takes time; and (d) behavior is choice. Saying that parts of an organism behave is nonsense, and, moreover, evolutionary theory explains the existence of organisms mainly through their adaptive behavior. Behavior is purposive in that behavior is shaped by its consequences, through an organism''s lifetime or through interactions with the environment across many generations of natural selection. Behavior takes time in that behavior is interaction with the environment that cannot take place at a moment. Moreover, at a moment in time, one cannot definitely identify the function of behavior. Identification of an activity requires a span of time. Behavior is choice in the sense that a suitable span of time always includes time spent in more than 1 activity. Activities include parts that are themselves activities on a smaller time scale and compete for time. Thus, behavior constitutes time allocation. An accounting problem arises whenever any behavior is attributed to multiple consequences. In the molar multiscale view, this raises the question of whether 2 activities can occur at the same time. The question remains open.