Evaluating the effects of discriminability on behavioral persistence during and following time‐based reinforcement

With four children with autism we evaluated a refinement to time‐based reinforcement designed to reduce response persistence when we simultaneously introduced time‐based reinforcement and extinction. We further evaluated whether this refinement mitigated response recurrence when all reinforcer deliveries ceased during an extinction‐only disruptor phase. The refinement involved increasing the saliency of the contingency change from contingent reinforcement (during baseline) to time‐based reinforcement by delivering different colored reinforcers during time‐based reinforcement. Behavioral momentum theory predicts that increasing the discriminability of the change from variable‐interval to variable‐time reinforcement should lead to faster reductions in responding. We present data on four participants, three of whom displayed response patterns consistent with the predictions of behavioral momentum theory during time‐based reinforcement. However, the participants showed more varied patterns of recurrent behavior during extinction. We discuss these results within a translational research framework focusing on strategies used to mitigate treatment relapse for severe destructive behavior, as time‐based reinforcement is one of the most commonly prescribed interventions for destructive behavior displayed by individuals with intellectual and developmental disabilities.     

How providing more or less time to solve a cognitive task interferes with upright stance control; a posturographic analysis on healthy young adults

Contrasted postural effects have been reported in dual-task protocols associating balance control and cognitive task that could be explained by the nature and the relative difficulty of the cognitive task and the biomechanical significance of the force platform data. To better assess their respective role, eleven healthy young adults were required to stand upright quietly on a force platform while concomitantly solving mental-calculation or mental-navigation cognitive tasks. Various levels of difficulty were applied by adjusting the velocity rate at which the instructions were provided to the subject according to his/her maximal capacities measured beforehand. A condition without any concomitant cognitive task was added to constitute a baseline behavior. Two basic components, the horizontal center-of-gravity movements and the horizontal difference between center-of-gravity and center-of-pressures were computed from the complex center-of-pressure recorded movements. It was hypothesized that increasing the delay should infer less interaction between postural control and task solution. The results indicate that both mental-calculation and mental-navigation tasks induce reduced amplitudes for the center-of-pressure minus center-of-gravity movements, only along the mediolateral axis, whereas center-of-gravity movements were not affected, suggesting that different circuits are involved in the central nervous system to control these two movements. Moreover, increasing the delays task does not infer any effect for both movements. Since center-of-pressure minus center-of-gravity expresses the horizontal acceleration communicated to the center-of-gravity, one may assume that the control of the latter should be facilitated in dual-tasks conditions, inferring reduced center-of-gravity movements, which is not seen in our results. This lack of effect should be thus interpreted as a modification in the control of these center-of-gravity movements. Taken together, these results emphasized how undisturbed upright stance control can be impacted by mental tasks requiring attention, whatever their nature (calculation or navigation) and their relative difficulty. Depending on the provided instructions, i.e. focusing our attention on body movements or on the opposite diverting this attention toward other objectives, the evaluation of upright stance control capacities might be drastically altered.     

Effects of muscle fatigue on the usability of a myoelectric human-computer interface

Electromyography-based human-computer interface development is an active field of research. However, knowledge on the effects of muscle fatigue for specific devices is limited. We have developed a novel myoelectric human-computer interface in which subjects continuously navigate a cursor to targets by manipulating a single surface electromyography (sEMG) signal. Two-dimensional control is achieved through simultaneous adjustments of power in two frequency bands through a series of dynamic low-level muscle contractions. Here, we investigate the potential effects of muscle fatigue during the use of our interface. In the first session, eight subjects completed 300 cursor-to-target trials without breaks; four using a wrist muscle and four using a head muscle. The wrist subjects returned for a second session in which a static fatiguing exercise took place at regular intervals in-between cursor-to-target trials. In the first session we observed no declines in performance as a function of use, even after the long period of use. In the second session, we observed clear changes in cursor trajectories, paired with a target-specific decrease in hit rates.     

Investigating the effects of movement speed on the lumbopelvic coordination during trunk flexion

Movement speed during trunk flexion has long been reported to affect task performance and biomechanical responses. The current study investigated how movement speed changed lumbopelvic coordination, especially lumbopelvic continuous relative phase and phase variability during trunk flexion. Eighteen subjects executed a paced trunk flexion routine over time periods of 3, 7, 11 and 15 seconds. The results demonstrated that compared with the 3-s condition, lumbopelvic continuous relative phase was 98.8% greater in the 15-s condition, indicating a more anti-phase coordination pattern. This pattern is suggested to mitigate the increased spinal loading associated with the longer duration of muscle exertion. Additionally, phase variability was 18.8% greater in the 15-s trials than the 3-s trials, such an unstable coordination pattern is likely caused by the more active neuromuscular control. Findings of this study provide important information about the effects of movement speed on lumbopelvic coordination during trunk flexion.     

Approach motivation and cognitive resources combine to influence memory for positive emotional stimuli

Inspired by the elaborated intrusion theory of desire, the current research tested the hypothesis that persons higher in trait approach motivation process positive stimuli deeply, which enhances memory for them. Ninety-four undergraduates completed a measure of trait approach motivation, viewed positive or negative image slideshows in the presence or absence of a cognitive load, and one week later completed an image memory test. Higher trait approach motivation predicted better memory for the positive slideshow, but this memory boost disappeared under cognitive load. Approach motivation did not influence memory for the negative slideshow. The current findings support the idea that individuals higher in approach motivation spontaneously devote limited resources to processing positive stimuli.     

Asymmetric transfer effects between cognitive and affective task disturbances

Task-irrelevant features of a stimulus can disturb performance on a given task, and this can occur for cognitive reasons such as irrelevant stimulus position, and affective reasons such as high stimulus valence. The human brain adapts to such disturbances in order to ensure successful task performance. Adaptations can occur in a transient manner in response to recent events, and they can also be sustained to account for overall probabilities of disturbances. Here, we study the mutual interplay between affective and cognitive task disturbances under conditions of sustained conflict adaptation. More precisely, we examined the trajectory of finger movements in a speeded classification task and investigated whether adaptation to a high probability of spatial disturbances transfers to the impact of affective disturbances (Experiment 1) and whether adaptation to a high probability of affective disturbances transfers to the impact of spatial disturbances (Experiment 2). Our observations point towards an asymmetric transfer from adaptation to affective onto the processing of cognitive disturbances, but not the other way around.     

The divergent effects of fear and disgust on unconscious inhibitory control

Previous studies have shown that negative emotional distracters impair conscious inhibitory control. Recent research has shown that inhibitory control can be triggered unconsciously; therefore, in Experiment 1, we aimed to investigate whether negative emotional distracters affect unconscious inhibitory control. Furthermore, in Experiment 2, we examined whether fearful and disgusting distracters have differential effects on unconscious inhibitory control. Participants were instructed to perform a masked Go/No-Go task superimposed on a negative or neutral image cue (Experiment 1) or on a fearful, disgusting or neutral image cue (Experiment 2). Results showed that negative emotional distracters impaired unconscious inhibitory control; furthermore, disgusting distracters impeded unconscious inhibitory control when compared to fearful ones. This study is the first to provide evidence that fear and disgust may affect unconscious inhibitory control differently. These results expand the understanding of the relationship between emotions and inhibitory control.     

Perceiving emotions: Cueing social categorization processes and attentional control through facial expressions

Individuals spontaneously categorise other people on the basis of their gender, ethnicity and age. But what about the emotions they express? In two studies we tested the hypothesis that facial expressions are similar to other social categories in that they can function as contextual cues to control attention. In Experiment 1 we associated expressions of anger and happiness with specific proportions of congruent/incongruent flanker trials. We also created consistent and inconsistent category members within each of these two general contexts. The results demonstrated that participants exhibited a larger congruency effect when presented with faces in the emotional group associated with a high proportion of congruent trials. Notably, this effect transferred to inconsistent members of the group. In Experiment 2 we replicated the effects with faces depicting true and false smiles. Together these findings provide consistent evidence that individuals spontaneously utilise emotions to categorise others and that such categories determine the allocation of attentional control.     

Happiness increases verbal and spatial working memory capacity where sadness does not: Emotion,working memory and executive control

The effects of emotion on working memory and executive control are often studied in isolation. Positive mood enhances verbal and impairs spatial working memory, whereas negative mood enhances spatial and impairs verbal working memory. Moreover, positive mood enhances executive control, whereas negative mood has little influence. We examined how emotion influences verbal and spatial working memory capacity, which requires executive control to coordinate between holding information in working memory and completing a secondary task. We predicted that positive mood would improve both verbal and spatial working memory capacity because of its influence on executive control. Positive, negative and neutral moods were induced followed by completing a verbal (Experiment 1) or spatial (Experiment 2) working memory operation span task to assess working memory capacity. Positive mood enhanced working memory capacity irrespective of the working memory domain, whereas negative mood had no influence on performance. Thus, positive mood was more successful holding information in working memory while processing task-irrelevant information, suggesting that the influence mood has on executive control supersedes the independent effects mood has on domain-specific working memory.     

JPSSM since the beginning: intellectual cornerstones,knowledge structure,and thematic developments

Bibliometric analyses are applied to 35,975 citations from 721 articles published in the Journal of Personal Selling & Sales Management, spanning the journal’s first 35 years of existence (1980–2015). For each of three time periods (1980s, 1990s, and 2000s), the sales literature’s most influential article publications are objectively identified. Multidimensional scaling is then used to identify key intellectual themes across time. Based on the citation data, historical developments in the literature regarding (1) relationship marketing, (2) sales force technology, (3) sales force control systems, and (4) salesperson role stress are traced and briefly explored in some article-level depth. Co-citation trends and recently influential papers are used to identify opportunities for future research. Altogether, this paper presents a first-of-its-kind view of sales literature’s intellectual cornerstones, knowledge structure, and thematic developments over 35 years.