Peer influence on event reports among adolescents and young adults

When two or more people witness an event together, the event report from one person can influence others’ reports. In the current study we examined the role of age and motivational factors on peer influence regarding event reports in adolescents and young adults. Participants (N=249) watched a short video of a robbery then answered questions with no co-witness information or with information believed to be from a co-witness. Public and private response conditions were included to explore motivations for peer influence. Co-witness information influenced participants’ responses, although the effect was equally strong in the private and the public co-witness conditions. Peer influence on event reports was steady across a large age range (11- to 25-year-olds).     

Flashbulb memories: Conceptual and methodological issues

Abstract

Although flashbulb memory research is now well established, it is still not clear exactly what researchers are referring to as flashbulbs, and what is the best way to address the phenomenon. There are at least two ways in which the term “flashbulbs” is used, and at least two conceptual approaches that can be used to research them. The first usage corresponds to the bold theoretical conjectures put forward by Brown and Kulik (1977). The second results from empirical classification and intuitively lacks the essence conveyed by the first meaning. The two approaches concentrate on the cognitive and societal aspects, respectively. Although these are not incompatible, they make different assumptions and use different methodologies. We argue that research should be directed towards more unified theorising, and we describe methodologies appropriate for this approach.     

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.     

In Defence of Kripkenstein: On Lewis’ Proposed Solution to the Sceptical Argument

Abstract

In Wittgenstein: On Rules and Private Language, Saul Kripke argues for an extreme form of meaning scepticism. One influential reply to Kripke’s arguments was developed by David Lewis. The reply developed by Lewis makes use of the notion of mind-independent relations of similarity and difference. The aim of the paper is to argue that Lewis’ reply is not satisfactory: the challenge to find a refutation of Kripke’s sceptical arguments remains unmet.     

Interplay of Biomechanical Constraints and Kinematic Strategies in Selecting Arm Postures

In this study, the authors examined the interplay between biomechanics and control strategies in the resolution of excess degrees of freedom at the joint level. Seven participants made aimed arm movements from 30 starting points and several starting postures to targets. Final arm postures for movements to a target exhibited substantial joint angle variation. Through regression modeling and by comparing observed final arm postures with biomechanically plausible postures, the authors identified 3 kinematic strategies: (a) Maintain deviations from the average angle at the starting point to the joint's final posture; (b) make torso rotations that are a fixed proportion of shoulder rotations; and (c) adopt a characteristic combination of 4 wrist-positioning approaches. The results demonstrated that kinematic strategies can account for substantial variance in final arm postures, if one takes into account 2 types of individual differences—those that arise inevitably from biomechanical constraints and those that reflect choices in movement strategy.     

The Semantics of Secrecy: Young Children's Classification of Secret Content

The authors explored whether young children can distinguish potential secrets from nonsecrets by their content, as can older children, adolescents, and adults. Ninety children, 4, 5, and 6 years old, rated the secrecy of items from an adult-validated list of personal information about an age- and gender-appropriate puppet. Two factors of the children's data corresponded to the adult categories of nonsecrets and secrets, and a third factor corresponded to surprises. All ages rated surprises as significantly more secret than nonsecret items; however, the surprise items contained linguistic cues to secrecy. A tendency to rate nonsecrets as secret decreased with age, but only the 6-year-olds rated secrets other than surprises as significantly more secret than nonsecrets. Thus, children acquire the implicit rules defining secret content from a somewhat later age than that reported for the cognitive or behavioral capacities for secrecy.     

Physical and Observational Practice Afford Unique Learning Opportunities

In 2 experiments, the authors studied the effectiveness of physical and observational practice on learning and the effect on learning of combining physical practice and observation, as compared with providing physical practice alone. In Experiment 1, retention and transfer performance of 30 university students after physical, observational, or no practice were contrasted. Consistent with findings from other studies, the retention results indicated that observational practice is inferior to physical practice. The transfer data indicated no differences between observation and physical practice groups. In Experiment 2, retention and transfer performance of 30 participants in physical and combined (alternating physical and observational) practice groups were contrasted. The retention results showed no differences between the combined and physical practice groups, but the combined group performed significantly better than the physical practice group on the transfer test. Those findings suggest that a combination of observation and physical practice permits unique opportunities for learning beyond those available via either practice regimen alone.     

Offline Improvement during Motor Sequence Learning Is Not Restricted to Developing Motor Chunks

Robust offline performance gains, beyond those that would be anticipated by being exposed to additional physical practice, have been reported during procedural learning and have been attributed to enhancement consolidation, a process by which memory is transformed in such a way that it is not only more resistant to forgetting but may also involve a reorganization of information that supports superior task execution. The authors assessed the impact of increasing within-session practice extent on the emergence of offline performance gains. Practice-dependent improvements occurred across 12 and 24 30-s practice trials of a 5-element motor sequencing task. Offline improvements were observed following both 12 and 24 trials. The improvement following 12 trials was associated with the formation of motor chunks important for establishing movement sequence structure. In contrast, the offline improvement after 24 trials was not related to further changes in movement structure beyond those that had emerged during practice. These data suggest that additional memory operations, beyond those needed to amalgamate subsequences of the SRT task, are susceptible to enhancement consolidation.