Assessing unit-price related remifentanil choice in rhesus monkeys

Given a commodity available at different prices, a unit-price account of choice predicts preference for the cheaper alternative. This experiment determined if rhesus monkeys preferred remifentanil (an ultra-short-acting micro-opioid agonist) delivered at a lower unit price over a higher-priced remifentanil alternative (Phases 1 and 3). Choice between equal-priced alternatives also was assessed (Phase 2). A discrete-trials procedure was arranged in which three monkeys chose between two remifentanil alternatives by responding on one of two levers. Different prices were arranged by manipulating drug dose (0.3 and 0.1 microg/kg/injection) and/or the ratio requirement. Monkeys usually chose the larger-dose alternative even when it was more expensive. Only when unit prices were relatively high (e.g., large response requirements) did monkeys choose the cheaper (or equally priced) smaller-dose alternative. Employing larger doses (0.9 and 0.3 microg/kg/injection) attenuated the larger-dose preference. The results demonstrate that choice was not determined simply by unit price. An alternative model that employs demand-function analysis to generate choice predictions is proposed.     

Differences in postural control and movement performance during goal directed reaching in children with developmental coordination disorder

Poor upper-limb coordination is a common difficulty for children with developmental coordination disorder (DCD). One hypothesis is that deviant muscle timing in proximal muscle groups results in poor postural and movement control. The relationship between muscle timing, arm motion and children's upper-limb coordination deficits has not previously been studied. The aim of this study was to investigate the relationship between functional difficulties with upper-limb motor skills and neuromuscular components of postural stability and coordination. Sixty-four children aged 8-10 years, 32 with DCD and 32 without DCD, participated in the study. The study investigated timing of muscle activity and resultant arm movement during a rapid, voluntary, goal-directed arm movement. Results showed that compared to children without DCD, children with DCD took significantly longer to respond to visual signals and longer to complete the goal-directed movement. Children with DCD also demonstrated altered activity in postural muscles. In particular, shoulder muscles, except for serratus anterior, and posterior trunk muscles demonstrated early activation. Further, anterior trunk muscles demonstrated delayed activation. In children with DCD, anticipatory function was not present in three of the four anterior trunk muscles. These differences support the hypothesis that in children with DCD, altered postural muscle activity may contribute to poor proximal stability and consequently poor arm movement control when performing goal-directed movement. These results have educational and functional implications for children at school and during activities of daily living and leisure activities and for clinicians assessing and treating children with DCD.     

Reinforcer identification and evaluation of choice within an educational setting

Current research on preference methodology and the effects of choice with children who are typically developing is limited. This study evaluated two preference methodologies for identifying reinforcers across two choice options within the classroom. These methods include a teacher-generated list of reinforcers, a student-generated list of reinforcers, student choice from both lists, and teacher choice from both lists. Four elementary aged-children with no diagnosed learning or developmental disabilities participated. Both preference methods were effective in identifying reinforcers for all participants. Moreover, both choice options resulted in increases in responding. Results are discussed with respect to reinforcement and the effects of “choice.”     

Framing, intentions, and trust–choice incompatibility

The present paper examines how framing of messages and the intentions inferred from different—positive vs. negative—framings, interact with the development of trust. Empirical evidence is presented showing that different, logically equivalent, frames are supposedly interpreted as implying different intentions. Next, the relationship between different frames (and the corresponding intentions reflected from these frames) and trust are explored. Finally, and most important, the relationship between the assessment of trust, inferred from different frames, and the corresponding choice behavior resulting from these frames, are investigated. Specifically, consider agents A and B offering to sell exactly the same commodity, except that one agent formulates it in a positive and the other in a negative frame. The different frames may lead to different assessments of the trustworthiness of the two agents. Following common wisdom, if agent A is trusted more than B, then one should prefer to conduct transactions with the former rather than with the latter agent. Several experiments are presented that are incompatible with this conjecture. For example, when faced with a choice between two butchers, whose ground beef is advertised as containing 25% fat (negative frame) or 75% lean (positive frame), respectively, most people have more trust in the former yet most indicate they would buy their meat from the latter butcher. This phenomenon, in which negative framing weighs more in trust assessments, and positive framing weighs more in choice, is labeled trust–choice incompatibility. The robustness of the phenomenon is further demonstrated in several experiments, and possible explanations for its occurrence are discussed.     

What kinds of alternative possibilities are required of the folk concept(s) of choice?

Our concept of choice is integral to the way we understand others and ourselves, especially when considering ourselves as free and responsible agents. Despite the importance of this concept, there has been little empirical work on it. In this paper we report four experiments that provide evidence for two concepts of choice—namely, a concept of choice that is operative in the phrase having a choice and another that is operative in the phrase making a choice. The experiments indicate that the two concepts of choice can be differentiated from each other on the basis of the kind of alternatives to which each is sensitive. The results indicate that the folk concept of choice is more nuanced than has been assumed. This new, empirically informed understanding of the folk concept of choice has important implications for debates concerning free will, responsibility, and other debates spanning psychology and philosophy.     

Impacts of autonomy-supportive versus controlling instructional language on motor learning

The authors examined the influence of autonomy-supportive (ASL), controlling (CL), and neutral instructional language (NL) on motor skill learning (cricket bowling action). Prior to and several times during the practice phase, participants watched the same video demonstration of the bowling action but with different voice-over instructions. The instructions were designed to provide the same technical information but to vary in terms of the degree of choice performers would perceive when executing the task. In addition to measurements of throwing accuracy (i.e., deviation from the target), perceived choice, self-efficacy, and positive and negative affect were assessed at the end of the practice phase and after a retention test without demonstrations and instructions on Day 2. ASL resulted in perceptions of greater choice, higher self-efficacy, and more positive affect during practice than CL, and enhanced learning as demonstrated by retention test performance. Thus, granting learners autonomy appeared to endow them with confidence in their ability, diminished needs for control of negative emotional responses, and created more positive affect, which may help consolidate motor memories.     

The Selective Laziness of Reasoning

Reasoning research suggests that people use more stringent criteria when they evaluate others' arguments than when they produce arguments themselves. To demonstrate this “selective laziness,” we used a choice blindness manipulation. In two experiments, participants had to produce a series of arguments in response to reasoning problems, and they were then asked to evaluate other people's arguments about the same problems. Unknown to the participants, in one of the trials, they were presented with their own argument as if it was someone else's. Among those participants who accepted the manipulation and thus thought they were evaluating someone else's argument, more than half (56% and 58%) rejected the arguments that were in fact their own. Moreover, participants were more likely to reject their own arguments for invalid than for valid answers. This demonstrates that people are more critical of other people's arguments than of their own, without being overly critical: They are better able to tell valid from invalid arguments when the arguments are someone else's rather than their own.     

多目标追踪中“线索”研究的贡献

多目标追踪范式是探讨动态情景下注意加工过程的成熟技术,其对不同阶段注意线索加工与利用的分析,对深入了解注意的动态信息加工过程具有重要意义。从注意线索的视角述评呈现阶段的内源性线索与外源性线索以及追踪阶段的目标数量动态变化和轨迹线索的研究成果及限制因素,提出多目标线索研究是客体档案理论与视觉索引理论之争的关键。虽然多目标追踪范式为内源性线索、外源性线索的提取与策略等研究提供很多便利,但目前该范式在线索的认知资源分配和加工策略上仍有研究留白,尚需进一步探索。