A two-point visual control model of steering

When steering down a winding road, drivers have been shown to use both near and far regions of the road for guidance during steering. We propose a model of steering that explicitly embodies this idea, using both a 'near point' to maintain a central lane position and a 'far point' to account for the upcoming roadway. Unlike control models that integrate near and far information to compute curvature or more complex features, our model relies solely on one perceptually plausible feature of the near and far points, namely the visual direction to each point. The resulting parsimonious model can be run in simulation within a realistic highway environment to facilitate direct comparison between model and human behavior. Using such simulations, we demonstrate that the proposed two-point model is able to account for four interesting aspects of steering behavior: curve negotiation with occluded visual regions, corrective steering after a lateral drift, lane changing, and individual differences.     

5-HT1a receptor antagonists block perforant path-dentate LTP induced in novel, but not familiar, environments

Numerous studies suggest roles for monoamines in modulating long-term potentiation (LTP). Previously, we reported that both induction and maintenance of perforant path-dentate gyrus LTP is enhanced when induced while animals explore novel environments. Here we investigate the contribution of serotonin and 5-HT1a receptors to the novelty-mediated enhancement of LTP. In freely moving animals, systemic administration of the selective 5-HT1a antagonist WAY-100635 (WAY) attenuated LTP in a dose-dependent manner when LTP was induced while animals explored novel cages. In contrast, LTP was completely unaffected by WAY when induced in familiar environments. LTP was also blocked in anesthetized animals by direct application of WAY to the dentate gyrus, but not to the median raphe nucleus (MRN), suggesting the effect of systemic WAY is mediated by a block of dentate 5-HT1a receptors. Paradoxically, systemic administration of the 5-HT1a agonist 8-OH-DPAT also attenuated LTP. This attenuation was mimicked in anesthetized animals following application of 8-OH-DPAT to the MRN, but not the dentate gyrus. In addition, application of a 5-HT1a agonist to the dentate gyrus reduced somatic GABAergic inhibition. Because serotonergic projections from the MRN terminate on dentate inhibitory interneurons, these data suggest 5-HT1a receptors contribute to LTP induction via inhibition of GABAergic interneurons. Moreover, activation of raphe 5-HT1a autoreceptors, which inhibits serotonin release, attenuated LTP induction even in familiar environments. This suggests that serotonin normally contributes to dentate LTP induction in a variety of behavioral states. Together, these data suggest that serotonin and dentate 5-HT1a receptors play a permissive role in dentate LTP induction, particularly in novel conditions, and presumably, during the encoding of novel, hippocampus-relevant information.     

Do not put the blame on me: Asymmetric responses to service outcome with autonomous vehicles versus human agents

The present study aims to examine customer responses to negative (vs. positive) service outcome with an autonomous vehicle (AV) vis-à-vis human agent. In the first study we manipulate the outcome of the service (negative vs. positive) and the type of service agent (AV vs. human) to evaluate customers' satisfaction with the service. Based on the results of the first study, in the second study we focus only on the negative outcome scenario and we examine how the perceived blame of the AV (vs. human agent) affects customers' satisfaction. Finally, in the third study we introduce another mediator, namely perceived competence, which explains why people attribute less blame to the AV (vs. human agent). Customers' satisfaction is higher for the AV only in the case of a negative service outcome, while no differences emerge when the service had a positive outcome. Additionally, AVs (vs. human agent) are perceived as less competent and blameworthy, leading to a higher customer satisfaction with the service in case of a negative outcome. These results show a customer under-reaction to negative service outcome with AVs. This has relevance for the design and policy implications related to AVs. Our results also provide insights into the psychological underpinnings of acceptance of AVs replacing human agents. This study extends previous literature by showing circumstances in which customers are more (or less) satisfied with an AVs (vs. human agents) and the psychological drivers of these asymmetrical responses.     

'Pure' constructional apraxia - a cognitive analysis of a single case

We report on a patient affected by selective drawing disabilities. The patient could correctly reproduce and draw simple geometric figures on request, but when he tried to reproduce more complex drawings or to draw common objects he performed very poorly. To identify the cognitive impairment in this patient, we adopted two test batteries based on recent information-processing models of drawing. Results showed that the patient's drawing disabilities were independent of visuo-perceptual and executive impairments. These findings support recent cognitive models of drawing abilities: some intermediate stages of drawing exist at which information is processed to prepare and guide motor output, and which may be selectively disrupted after discrete cerebral lesions.     

Risk Factors for Infant Abuse and Neglect in Group-Living Rhesus Monkeys

This study investigated maternal abuse and neglect of offspring in a large population of rhesus monkeys over a period of 29 years. Abuse and neglect did not occur together and were associated with different risk factors. Infant abuse was concentrated in 8 of 57 families and among closely related females. Abuse was also repeated with successive offspring. In contrast, infant neglect was not affected by genealogical factors, was not repeated with successive offspring, and was displayed mostly by primiparous mothers. These results suggest that abuse and neglect may be different phenomena and that infant abuse in group-living monkeys could represent a good animal model for investigating the mechanisms underlying the intergenerational transmission of child maltreatment.     

Psychophysiological correlates of organizational change and threat of unemployment among police inspectors

The study examined psychosocial work-conditions and physiological reactions among thirty-six police inspectors (median age 45 years, 81% males) who participated in a reorganization. At this time, subjects were threatened by unemployment and had to reapply for their positions in a new police district. Data were collected during the reorganization and at three years follow-up, by means of questionnaires (Stress Profile) and blood samples. The blood samples were used to determine serum levels of gammaglutamyltransferase (GGT), glucose, lipids, prolactin, testosterone and cortisol. The results show a positive association betweenworry about employment and symptoms ofburnout during the reorganization. Mean scores for the Stress Profile sub-scalesworry about employment (p<.01) andwork-load (p<.05) decreased between measurements but an impairment inrelationships with management was noticed (p<.05). No significant changes were observed in terms of self-rated health complaints. Significant decreases in total cholesterol (p<.0001), LDL-cholesterol (p<.0001), LDL/HDL-ratio (p<.01), prolactin (p<.0001), as well as increases in testosterone (p<.01) and cortisol (p<.001) were observed for the whole sample. Glucose decreased with marginal significance (<.07). Controlling for age and gender, multivariate regression analyses showed that subjects who reported deteriorations insatisfaction with work manifested the most modest decreases in prolactin (p<.05). Also, the decrease in glucose was larger for subjects who experienced impairments in,satisfaction with work (p<.05), information (p<.05), task-oriented leadership, (p<.05), andrespect and dignity (p<.05). Subjects who perceived deteriorations in theethical and moral standards of the organization increased their cortisol level to a lower degree than their counterparts (p<.05). Favorable changes in employment status and psychosocial work environment seem to be related to improved physiological functioning.     

Effects of response cards on student participation and academic achievement: A systematic replication with inner-city students during whole-class science instruction

We evaluated the use of response cards during science instruction in a fifth-grade inner-city classroom. The experiment consisted of two methods of student participation-hand raising and write-on response cards-alternated in an ABAB design. During hand raising, the teacher called upon 1 student who had raised his or her hand in response to the teacher's question. During the response-card condition, each student was provided with a laminated board on which to write one- or two-word answers in response to each question asked by the teacher. Frequency of active student response was 14 times higher with response cards than with hand raising. All 22 students scored higher on next-day quizzes and on 2-week review tests that followed instruction with response cards than they did on quizzes and tests that covered facts and concepts taught with the hand-raising procedure.     

Planning maximally smooth hand movements constrained to nonplanar workspaces

The article characterizes hand paths and speed profiles for movements performed in a nonplanar, 2-dimensional workspace (a hemisphere of constant curvature). The authors assessed endpoint kinematics (i.e., paths and speeds) under the minimum-jerk model assumptions and calculated minimal amplitude paths (geodesics) and the corresponding speed profiles. The authors also calculated hand speeds using the 2/3 power law. They then compared modeled results with the empirical observations. In all, 10 participants moved their hands forward and backward from a common starting position toward 3 targets located within a hemispheric workspace of small or large curvature. Comparisons of modeled observed differences using 2-way RM-ANOVAs showed that movement direction had no clear influence on hand kinetics (p < .05). Workspace curvature affected the hand paths, which seldom followed geodesic lines. Constraining the paths to different curvatures did not affect the hand speed profiles. Minimum-jerk speed profiles closely matched the observations and were superior to those predicted by 2/3 power law (p < .001). The authors conclude that speed and path cannot be unambiguously linked under the minimum-jerk assumption when individuals move the hand in a nonplanar 2-dimensional workspace. In such a case, the hands do not follow geodesic paths, but they preserve the speed profile, regardless of the geometric features of the workspace.     

Threaded cognition: an integrated theory of concurrent multitasking

The authors propose the idea of threaded cognition, an integrated theory of concurrent multitasking--that is, performing 2 or more tasks at once. Threaded cognition posits that streams of thought can be represented as threads of processing coordinated by a serial procedural resource and executed across other available resources (e.g., perceptual and motor resources). The theory specifies a parsimonious mechanism that allows for concurrent execution, resource acquisition, and resolution of resource conflicts, without the need for specialized executive processes. By instantiating this mechanism as a computational model, threaded cognition provides explicit predictions of how multitasking behavior can result in interference, or lack thereof, for a given set of tasks. The authors illustrate the theory in model simulations of several representative domains ranging from simple laboratory tasks such as dual-choice tasks to complex real-world domains such as driving and driver distraction.     

On the nature of nonverbal working memory fractionation: a case of selective spatial short-term memory deficit in a child

Several lines of research on adult subjects demonstrate a visual/spatial fractionation of nonverbal working memory (WM), while behavioral studies on normal children support the idea of a static/dynamic distinction. In the present paper, we report a child (Z.M.) who failed on nonverbal WM tasks. To verify the nature of his defect, we carried out two experiments: in Experiment 1, Z.M. failed on spatial WM tasks but not on visual WM tasks and was not affected by the static/dynamic format of stimulus presentation; in Experiment 2, this visual/spatial dissociation was extended to the imagery domain. These results are best accounted for within the visual/spatial fractionation of WM and confirmed the role of WM in mental imagery. Clinical and rehabilitative implications of the present findings are also discussed.