Force and Directional Force Modulation Effects on Accuracy and Variability in Low-Level Pinch Force Tracking

The authors investigated how varying the required low-level forces and the direction of force change affect accuracy and variability of force production in a cyclic isometric pinch force tracking task. Eighteen healthy right-handed adult volunteers performed the tracking task over 3 different force ranges. Root mean square error and coefficient of variation were higher at lower force levels and during minimum reversals compared with maximum reversals. Overall, the thumb showed greater root mean square error and coefficient of variation scores than did the index finger during maximum reversals, but not during minimum reversals. The observed impaired performance during minimum reversals might originate from history-dependent mechanisms of force production and highly coupled 2-digit performance.     

Observer judgmental accuracy of personality: Benefits related to being a good (normative) judge

The current study tested the hypothesis that accuracy of personality judgment would be positively related to beneficial life outcomes. 189 participants observed targets across 5 dyadic interactions and made judgments of the 10 targets on the Big Five traits. Self and acquaintance ratings were used as the accuracy criteria. Normative accuracy for all traits was related to agreeableness, and normative accuracy for some traits was positively related to interpersonal control, interpersonal support, positive affect, and life satisfaction. Distinctive accuracy was not related to beneficial outcomes. These results imply that normative accuracy based on observation is associated with beneficial outcomes, whereas distinctive accuracy is not.     

Likable co-witnesses increase eyewitness accuracy and decrease suggestibility

This study examines the impact of likability on memory accuracy and memory conformity between two previously unacquainted individuals. After viewing a crime, eyewitnesses often talk to one another and may find each other likable or dislikable. One hundred twenty-seven undergraduate students arrived at the laboratory with an unknown confederate and were assigned to a likability condition (i.e., control, likable or dislikable). Together, the pair viewed pictures and was then tested on their memory for those pictures in such a way that the participant knew the confederate's response. Thus, the participant's response could be influenced both by his or her own memory and by the answers of the confederate. Participants in the likable condition were more accurate and less influenced by the confederate, compared with the other conditions. Results are discussed in relation to research that shows people are more influenced by friends than strangers and in relation to establishing positive rapport in forensic interviewing.     

Force Control Is Greater in the Upper Compared With the Lower Extremity

The authors investigated whether force control is similar between the upper and lower limbs and between contractions that involve 1 or 2 joints. Six volunteers (27.5 ± 11.2 years of age) attempted to produce consistent discrete rapid force responses of 30, 60, and 90 N by using 6 different body postures, 3 with the upper and 3 with the lower limb. One of the postures for each limb involved 2 joints. The standard deviation of peak force and impulse (aggregate of the force-time curve) was significantly greater (?25%) for the lower limb than for the upper limb (p < .01). Contractions that involved 1 or 2 joints within a limb had similar variability. Therefore, the upper limb might have better control of force than the lower limb because of its extensive use in fine motor tasks in daily activities.     

Eye-Hand Coordination in Rhythmical Pointing

The authors investigated the relation between hand kinematics and eye movements in 2 variants of a rhythmical Fitts's task in which eye movements were necessary or not necessary. P. M. Fitts's (1954) law held in both conditions with similar slope and marginal differences in hand-kinematic patterns and movement continuity. Movement continuity and eye—hand synchronization were more directly related to movement time than to task index of difficulty. When movement time was decreased to fewer than 350 ms, eye—hand synchronization switched from continuous monitoring to intermittent control. The 1:1 frequency ratio with stable π/6 relative phase changed for 1:3 and 1:5 frequency ratios with less stable phase relations. The authors conclude that eye and hand movements in a rhythmical Fitts's task are dynamically synchronized to produce the best behavioral performance.     

Decision Strategies and the Confidence–Accuracy Relationship in Face Recognition

The decision strategy used to select a choice set from an array of alternative options is known to affect the composition of the final choice set. Specifically, individuals incorporate more answers into their choice set when it is created by eliminating implausible items than when the set is created through the inclusion of plausible options. This difference is accounted for in a decision framework that posits a general reluctance to change the status quo (i.e., actively include or exclude an item). We extended this work to investigate, not only the decisions themselves, but also metacognitive judgments (i.e., confidence in the accuracy of the choice set). In two face recognition experiments, we tested the impact of decision strategy (Experiment 1) and confidence judgment strategy (Experiment 2) on the confidence–accuracy relationship. In Experiment 1, participants completed two blocks of recognition trials, one under inclusion (marking previously seen faces) and one under elimination (marking previously unseen faces) instructions. We observed superior resolution (i.e., discrimination between correct and incorrect) for inclusion trials, but only when they were completed prior to use of the elimination strategy. In Experiment 2, all participants completed face recognition trials under inclusion instructions, but we manipulated the strategy used to assess confidence. Again, we observed a significant impact of strategy on confidence–accuracy resolution. Thus, we observed that both the strategy employed to reach a decision and that employed to assess confidence affected the confidence–accuracy relationship. We discuss theoretical and applied (particularly for eyewitness identification and multiple‐choice testing) implications. Copyright © 2012 John Wiley & Sons, Ltd.     

Verbal Memory Deficits in Children with Less than 750 g Birth Weight

Numerous studies have documented memory deficits in very low birthweight (VLBW, &lt; 1500 g) children, yet we know little about the nature of these memory problems. To clarify memory sequelae and examine memory deficits in relation to the degree of low birth weight, we administered the California Verbal Learning Test–Children’s Version (CVLT-C) to a regional sample of 57 &lt; 750 g birthweight children and to groups of 53 750–1499 g birthweight children and 49 term-born controls. Group comparisons revealed significant differences between the &lt; 750 g birthweight group and term-born children on measures of list learning, delayed recall, and inaccurate recall. In addition, the percentage improvement in correct recognitions relative to long-term delayed recall was greater in the &lt; 750 g group than in the term-born controls. Similar differences were observed between VLBW children with and without abnormal neonatal cerebral ultrasounds (high- and low-risk groups). Differences in learning rate between the VLBW and term-born groups, and between high- and low-risk VLBW children, were evident even when vocabulary skill was covaried or when children with neurosensory deficits or IQ &lt; 80 were excluded from analysis. The findings document deficits in verbal memory in the subset of VLBW children at greatest biological risk, and suggest that acquisition processes are selectively impaired.     

对信息源的正向跟随倾向对决策效果的影响*

采用实验研究的方法,检验了二元选择情形下高准确率信息源(准确率x >50%)和低准确率信息源(准确率为1?x)对决策者预测效果的影响。尽管从逻辑上二者从准确率层面具有完全相等的信息价值,然而研究结果显示,决策者更倾向于采用正向跟随而非逆向跟随的方式处理来自信息源的信息。这导致低准确信息源的价值未能得以充分利用。学习和信息源的规范性对该信息处理倾向起到调节作用。     

Monitoring and meta-metacognition in the own-race bias

Although there is a great deal of research focused on identification issues related to own-versus other-race faces very few experiments have explored whether metacognitive monitoring contributes to the own-race bias. In the current experiment the typical own-race bias paradigm was modified so that type-2 signal detection measures (e.g.  and ) could be used to directly measure metacognitive monitoring at retrieval. A second goal of the experiment was to explore whether self-reported confidence ratings differed depending on whether they were directed at answer accuracy (e.g., judging a face as “studied”) versus at decisions about that answer (e.g., volunteering vs. withholding that answer). Overall the results demonstrated that monitoring does contribute to the own-race bias, in that participants were better at monitoring their memory for own-race faces. Further, there was a significant difference between the two confidence measures, and the pattern of this difference depended on whether responses had been volunteered or withheld.