Modification of muscle activation patterns during fast goal-directed arm movements

The motor programming of fast goal-directed arm movements was studied in a tracking task. A target jumped once or twice randomly to the left or right direction with an interstimulus interval (ISI) in a range between 50 and 125 msec. Double step stimuli were either two steps in the same direction (C-trial) or in opposite direction (R-trial). Tracking results show that at the beginning average EMG-activity is the same for responses to single step trials, R-trials and C-trials. Differences set in after some time equal to or somewhat shorter than ISI. It was concluded that muscle activation patterns of fast goal-directed movements are not preprogrammed but that they can be modified during the movement. The time interval between second target step and the moment when EMG activity of the double step response deviates from the EMG activity of a single step (RT2) could be smaller than the time interval between first target displacement and EMG onset. (RT1). If modification of the muscle activation pattern required a longer or larger activation of the active muscle, RT2 tended to be smaller than RT1, whereas RT2 was about equal to RT1 if the new muscle activation required a termination of the ongoing muscle activation pattern and the activation of another muscle.     

Stiffness as a control variable in motor performance

In the experiments described in this article we investigated the control of stiffness of the effector system in relation to parameters of the movement. If the velocity of a movement is chosen, it appears that at the same time the stiffness of the effector system is set to a preferred value. By changing the instruction given to the subject it is possible to change the relationship between velocity and stiffness without changing the kinematic parameters of the movement.Finally, the changes of stiffness and velocity in a learning process are studied. In conformity with what might be expected on intuitive grounds, it is found that velocity increases spontaneously during learning while stiffness decreases. The results are discussed in connection with the generation of motor programmes.     

Punishment of an alternative behavior generates resurgence of a previously extinguished target behavior

Resurgence is often defined as the recurrence of an extinguished behavior when a more recently reinforced alternative behavior is also extinguished. Resurgence has also been observed when the alternative behavior is devalued by other means (e.g., reinforcement rate or magnitude reductions). The present study investigated whether punishment of an alternative behavior would generate resurgence. A target response was reinforced during Phase 1 and then extinguished in Phase 2 while an alternative response was reinforced. During Phase 3, response‐dependent foot shocks were superimposed on the schedule of reinforcement for the alternative response and shock intensity was escalated gradually across sessions. Resurgence of the target response was reliably observed, mostly at higher intensities. The effect was replicated in two subsequent exposures to the sequence of conditions, with resurgence tending to occur at the lowest foot shock intensity. These results suggest that devaluation of an alternative behavior via punishment can generate resurgence. Although it is difficult to reconcile the overall pattern of results with Bouton's context account, these findings are consistent with the suggestion that resurgence results from a “worsening of conditions” for the alternative behavior and with the formalization of that suggestion in terms of a choice‐based matching‐law account (i.e., Resurgence as Choice).     

Investigation into Complementary and Integrative Health Approaches for Turkish Patients with Gastrointestinal Cancer

Journal of Religion and Health - The study was conducted to determine the levels of usage of complementary and integrative health (CIH) approaches and the symptoms experienced by Turkish patients...     

Response–reinforcer dependency and resistance to change

The effects of the response–reinforcer dependency on resistance to change were studied in three experiments with rats. In Experiment 1, lever pressing produced reinforcers at similar rates after variable interreinforcer intervals in each component of a two‐component multiple schedule. Across conditions, in the fixed component, all reinforcers were response‐dependent; in the alternative component, the percentage of response‐dependent reinforcers was 100, 50 (i.e., 50% response‐dependent and 50% response‐independent) or 10% (i.e., 10% response‐dependent and 90% response‐independent). Resistance to extinction was greater in the alternative than in the fixed component when the dependency in the former was 10%, but was similar between components when this dependency was 100 or 50%. In Experiment 2, a three‐component multiple schedule was used. The dependency was 100% in one component and 10% in the other two. The 10% components differed on how reinforcers were programmed. In one component, as in Experiment 1, a reinforcer had to be collected before the scheduling of other response‐dependent or independent reinforcers. In the other component, response‐dependent and ‐independent reinforcers were programmed by superimposing a variable‐time schedule on an independent variable‐interval schedule. Regardless of the procedure used to program the dependency, resistance to extinction was greater in the 10% components than in the 100% component. These results were replicated in Experiment 3 in which, instead of extinction, VT schedules replaced the baseline schedules in each multiple‐schedule component during the test. We argue that the relative change in dependency from Baseline to Test, which is greater when baseline dependencies are high rather than low, could account for the differential resistance to change in the present experiments. The inconsistencies in results across the present and previous experiments suggest that the effects of dependency on resistance to change are not well understood. Additional systematic analyses are important to further understand the effects of the response–reinforcer relation on resistance to change and to the development of a more comprehensive theory of behavioral persistence.     

Are you talking to the future me? The moderator role of future self‐relevance on the effects of aging salience in retirement savings

Increasing the salience of aging has been shown to be a promising strategy to promote young adults' interest in saving for retirement. However, the processes responsible for this effect are still largely unknown. We hypothesize that increased savings choices will only occur when participants are also engaged in self‐relevant thoughts about their own future. Participants were exposed to a fictitious website advertising financial products. Study 1 (n = 78; M_age = 20.87) primed age salience and future self‐relevance orthogonally and showed that priming aging only caused increases in retirement investment decisions when self‐relevance was also high. Study 2 (n = 91; M_age = 23.40) tested whether the effects of age priming were due specifically to age or to a broader focus on the future. The study confirmed that investment decision effects are specific to exposure to the aging prime and not merely priming the future. The effects were also specific to investment in retirement funds and not just depositing money in a checking account. These findings have both theoretical and practical implications for the psychology of aging and retirement planning.     

Equivalences Among Polarity Algorithms

The concept of polarity is pervasive in natural language. It relates syntax, semantics and pragmatics narrowly (Giannakidou, in: Maienborn, von Heusinger, Portner (eds.), Semantics: an international handbook of natural language meaning, De Gruyter Mouton, Berlin, 2011; Israel in The grammar of polarity: pragmatics, sensitivity, and the logic of scales, Cambridge studies in linguistics, Cambridge University Press, Cambridge, 2014), it refers to items of many syntactic categories such as nouns, verbs and adverbs. Neutral polarity items appear in affirmative and negative sentences, negative polarity items cannot appear in affirmative sentences, and positive polarity items cannot appear in negative sentences. A way of reasoning in Natural Language is through Natural Logic (van Benthem in Essays in logical semantics, vol. 29 of Studies in linguistics and philosophy, Reidel, Dordrecht, 1986; Language in action: categories, lambdas, and dynamic logic, vol. 130 of Studies in logic, Elsevier, Amsterdam, 1991). This logic is based on the concept of polarity in order to make the meaning of a sentence weaker o stronger without changing its truth value. There exist many proposals to compute polarity in the Natural Logic context, the most widely known are the ones by: van Benthem (1986, 1991), Sánchez-Valencia (Studies on natural logic and categorial grammar, Ph.D. thesis, Universiteit van Amsterdam, 1991), Dowty (Proceedings of the 4th conference on semantics and theoretical linguistics, Cornel University, CLC Publications, Rochester, 1994), and van Eijck (in: ten Cate, Zeevat (eds.), 6th international Tbilisi symposium on logic, language, and computation, Batumi, Georgia, Springer, 2007). If Natural Logic is going to be used, as an inferential mechanism between text fragments, in Natural Language Processing applications such as text summarization, question answering, and information extraction, it is a priority to know what the existing relationship among the aforementioned algorithms is; for example, to implement the most general. We show in this paper the equivalence among the analyzed algorithms, filling a gap in Natural Logic research, particularly in computing polarity, and the soundness of their algorithms.     

Construct and concurrent validity of the Cambridge neuropsychological automated tests in Portuguese older adults without neuropsychiatric diagnoses and with Alzheimer’s disease dementia

We aimed to analyze the construct and concurrent validity of the Rapid Visual Information Processing (RVP), Paired Associates Learning (PAL), Reaction Time (RTI), and Spatial Working Memory (SWM) tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB®). Inclusion criteria were checked in a first session. The CANTAB and additional pencil-and-paper tests were administered within 1 week. The participants (aged 69–96 years) were 137 Portuguese adults without neuropsychiatric diagnoses and 37 adults with mild-to-moderate Alzheimer’s disease dementia. Comparisons were made between the CANTAB tests and between these tests and the Rey Complex Figure Test (RCFT), Verbal Fluency (VF) test, and some Wechsler Memory Scale-III and Wechsler Adult Intelligence Scale-III subtests. Most intra-test correlations were stronger than the CANTAB inter-test correlations. The RVP correlated more with VF animals (.44), the PAL with RCFT immediate recall (–.52), the RTI with RVP mean latency (.42), and the SWM with Spatial Span backward (–.39).