Persistence and plasticity in the human memory system: An empirical investigation of the overwriting hypothesis

The human memory system must resolve a critical tension, ensuring that knowledge endures over time (persistence), whilst simultaneously retaining a capacity for updating when knowledge is outdated or erroneous (plasticity). In this thesis, I examine the provocative idea that memory traces can be overwritten with new information, especially during transient periods of retrieval-induced plasticity that occur when a trace undergoes reconsolidation. A systematic review of human reconsolidation studies finds that the evidentiary support for this claim is remarkably tenuous. Furthermore, the theory fails to survive several strong empirical tests. In Experiments 1-7, I do not replicate a previous finding that is widely cited as a convincing demonstration of human reconsolidation. In Experiments 8-10, I revisit the ‘destructive updating’ account of the classic ‘misinformation effect’ in the context of reconsolidation theory. These experiments show that the effect can be eliminated when an appropriate recognition test is used, demonstrating that event traces are not irrecoverably lost, and therefore cannot have been overwritten during reconsolidation. In Experiment 11, I examine whether prior retrieval will help or hinder the correction of naturally occurring semantic misconceptions. Contrary to reconsolidation theory, I find that knowledge updating is not contingent on memory retrieval, nor does it result in the overwriting of prior knowledge. Finally, in the context of media ‘breaking news’ reports (Experiment 12), I find that the provision of an explicit retraction message, coupled with an alternative account with high causal coverage, is insufficient to eliminate reliance on false information. Finally, I contend that the widespread proliferation of ad hoc hypotheses, and the absence of systematic direct replication, has caused the field of reconsolidation to descend into a theoretical quagmire. I make several recommendations based on the principles of open science that may help to restore mechanisms of self-correction and foster genuine theoretical progress

Postretrieval new learning does not reliably induce human memory updating via reconsolidation

Reconsolidation theory proposes that retrieval can destabilize an existing memory trace, opening a time-dependent window during which that trace is amenable to modification. Support for the theory is largely drawn from nonhuman animal studies that use invasive pharmacological or electroconvulsive interventions to disrupt a putative postretrieval restabilization ("reconsolidation") process. In human reconsolidation studies, however, it is often claimed that postretrieval new learning can be used as a means of "updating" or "rewriting" existing memory traces. This proposal warrants close scrutiny because the ability to modify information stored in the memory system has profound theoretical, clinical, and ethical implications. The present study aimed to replicate and extend a prominent 3-day motor-sequence learning study [Walker MP, Brakefield T, Hobson JA, Stickgold R (2003) Nature 425(6958):616-620] that is widely cited as a convincing demonstration of human reconsolidation. However, in four direct replication attempts (n = 64), we did not observe the critical impairment effect that has previously been taken to indicate disruption of an existing motor memory trace. In three additional conceptual replications (n = 48), we explored the broader validity of reconsolidation-updating theory by using a declarative recall task and sequences similar to phone numbers or computer passwords. Rather than inducing vulnerability to interference, memory retrieval appeared to aid the preservation of existing sequence knowledge relative to a no-retrieval control group. These findings suggest that memory retrieval followed by new learning does not reliably induce human memory updating via reconsolidation

Selection bias, vote counting, and money-priming effects: A comment on Rohrer, Pashler, and Harris (2015) and Vohs (2015)

When a series of studies fails to replicate a well-documented effect, researchers might be tempted to use a "vote counting" approach to decide whether the effect is reliable-that is, simply comparing the number of successful and unsuccessful replications. Vohs's (2015) response to the absence of money priming effects reported by Rohrer, Pashler, and Harris (2015) provides an example of this approach. Unfortunately, vote counting is a poor strategy to assess the reliability of psychological findings because it neglects the impact of selection bias and questionable research practices. In the present comment, we show that a range of meta-analytic tools indicate irregularities in the money priming literature discussed by Rohrer et al. and Vohs, which all point to the conclusion that these effects are distorted by selection bias, reporting biases, or p-hacking. This could help to explain why money-priming effects have proven unreliable in a number of direct replication attempts in which biases have been minimized through preregistration or transparent reporting. Our major conclusion is that the simple proportion of significant findings is a poor guide to the reliability of research and that preregistered replications are an essential means to assess the reliability of money-priming effects. (PsycINFO Database Recor

An overview of using small punch testing for mechanical characterization of MCrAlY bond coats

Considerable work has been carried out on overlay bond coats in the past several decades because of its excellent oxidation resistance and good adhesion between the top coat and superalloy substrate in the thermal barrier coating systems. Previous studies mainly focus on oxidation and diffusion behavior of these coatings. However, the mechanical behavior and the dominant fracture and deformation mechanisms of the overlay bond coats at different temperatures are still under investigation. Direct comparison between individual studies has not yet been achieved due to the fragmentary data on deposition processes, microstructure and, more apparently, the difficulty in accurately measuring the mechanical properties of thin coatings. One of the miniaturized specimen testing methods, small punch testing, appears to have the potential to provide such mechanical property measurements for thin coatings. The purpose of this paper is to give an overview of using small punch testing to evaluate material properties and to summarize the available mechanical properties that include the ductile-to-brittle transition and creep of MCrAlY bond coat alloys, in an attempt to understand the mechanical behavior of MCrAlY coatings over a broad temperature range

Cell-based screen for altered nuclear phenotypes reveals senescence progression in polyploid cells after Aurora kinase B inhibition.

Cellular senescence is a widespread stress response and is widely considered to be an alternative cancer therapeutic goal. Unlike apoptosis, senescence is composed of a diverse set of subphenotypes, depending on which of its associated effector programs are engaged. Here we establish a simple and sensitive cell-based prosenescence screen with detailed validation assays. We characterize the screen using a focused tool compound kinase inhibitor library. We identify a series of compounds that induce different types of senescence, including a unique phenotype associated with irregularly shaped nuclei and the progressive accumulation of G1 tetraploidy in human diploid fibroblasts. Downstream analyses show that all of the compounds that induce tetraploid senescence inhibit Aurora kinase B (AURKB). AURKB is the catalytic component of the chromosome passenger complex, which is involved in correct chromosome alignment and segregation, the spindle assembly checkpoint, and cytokinesis. Although aberrant mitosis and senescence have been linked, a specific characterization of AURKB in the context of senescence is still required. This proof-of-principle study suggests that our protocol is capable of amplifying tetraploid senescence, which can be observed in only a small population of oncogenic RAS-induced senescence, and provides additional justification for AURKB as a cancer therapeutic target.This work was supported by the University of Cambridge, Cancer Research UK, Hutchison Whampoa; Cancer Research UK grants A6691 and A9892 (M.N., N.K., C.J.T., D.C.B., C.J.C., L.S.G, and M.S.); a fellowship from the Uehara Memorial Foundation (M.S.).This is the author accepted manuscript. The final version is available from the American Society for Cell Biology via http://dx.doi.org/10.1091/mbc.E15-01-000

The effectiveness of refutation texts to correct misconceptions among educators

Teachers around the world hold a considerable number of misconceptions about education. Consequently, schools can become epicenters for dubious practices that might jeopardize the quality of teaching and negatively influence students’ wellbeing. The main objective of this study was to assess the efficacy of refutation texts in the correction of erroneous ideas among in-service teachers. The results of Experiment 1 indicate that refutation texts can be an effective means to correct false ideas among educators, even for strongly endorsed misconceptions. However, the results of Experiment 2 suggest that these effects may be short-lived. Furthermore, attempts to correct misconceptions seemed to have no beneficial effect on teachers’ intention to implement educational practices that are based on those erroneous beliefs. The implications of these results for the training of preservice and in-service teachers are discussed