Frontotemporal neural systems supporting semantic processing in Alzheimer’s disease

We hypothesized that semantic memory for object concepts involves both representations of visual feature knowledge in modality-specific association cortex and heteromodal regions that are important for integrating and organizing this semantic knowledge so that it can be used in a flexible, contextually appropriate manner. We examined this hypothesis in an fMRI study of mild Alzheimer’s disease (AD). Participants were presented with pairs of printed words and asked whether the words matched on a given visual–perceptual feature (e.g., guitar, violin: SHAPE). The stimuli probed natural kinds and manufactured objects, and the judgments involved shape or color. We found activation of bilateral ventral temporal cortex and left dorsolateral prefrontal cortex during semantic judgments, with AD patients showing less activation of these regions than healthy seniors. Moreover, AD patients showed less ventral temporal activation than did healthy seniors for manufactured objects, but not for natural kinds. We also used diffusion-weighted MRI of white matter to examine fractional anisotropy (FA). Patients with AD showed significantly reduced FA in the superior longitudinal fasciculus and inferior frontal-occipital fasciculus, which carry projections linking temporal and frontal regions of this semantic network. Our results are consistent with the hypothesis that semantic memory is supported in part by a large-scale neural network involving modality-specific association cortex, heteromodal association cortex, and projections between these regions. The semantic deficit in AD thus arises from gray matter disease that affects the representation of feature knowledge and processing its content, as well as white matter disease that interrupts the integrated functioning of this large-scale network.     

How undistorted spatial memories can produce distorted responses

Reproducing the location of an object from the contents of spatial working memory requires the translation of a noisy representation into an action at a single location—for instance, a mouse click or a mark with a writing utensil. In many studies, these kinds of actions result in biased responses that suggest distortions in spatial working memory. We sought to investigate the possibility of one mechanism by which distortions could arise, involving an interaction between undistorted memories and nonuniformities in attention. Specifically, the resolution of attention is finer below than above fixation, which led us to predict that bias could arise if participants tend to respond in locations below as opposed to above fixation. In Experiment 1 we found such a bias to respond below the true position of an object. Experiment 2 demonstrated with eye-tracking that fixations during response were unbiased and centered on the remembered object’s true position. Experiment 3 further evidenced a dependency on attention relative to fixation, by shifting the effect horizontally when participants were required to tilt their heads. Together, these results highlight the complex pathway involved in translating probabilistic memories into discrete actions, and they present a new attentional mechanism by which undistorted spatial memories can lead to distorted reproduction responses.     

Characterizing belief bias in syllogistic reasoning: A hierarchical Bayesian meta-analysis of ROC data

The belief-bias effect is one of the most-studied biases in reasoning. A recent study of the phenomenon using the signal detection theory (SDT) model called into question all theoretical accounts of belief bias by demonstrating that belief-based differences in the ability to discriminate between valid and invalid syllogisms may be an artifact stemming from the use of inappropriate linear measurement models such as analysis of variance (Dube et al., Psychological Review, 117(3), 831–863, 2010). The discrepancy between Dube et al.’s, Psychological Review, 117(3), 831–863 (2010) results and the previous three decades of work, together with former’s methodological criticisms suggests the need to revisit earlier results, this time collecting confidence-rating responses. Using a hierarchical Bayesian meta-analysis, we reanalyzed a corpus of 22 confidence-rating studies (N =?993). The results indicated that extensive replications using confidence-rating data are unnecessary as the observed receiver operating characteristic functions are not systematically asymmetric. These results were subsequently corroborated by a novel experimental design based on SDT’s generalized area theorem. Although the meta-analysis confirms that believability does not influence discriminability unconditionally, it also confirmed previous results that factors such as individual differences mediate the effect. The main point is that data from previous and future studies can be safely analyzed using appropriate hierarchical methods that do not require confidence ratings. More generally, our results set a new standard for analyzing data and evaluating theories in reasoning. Important methodological and theoretical considerations for future work on belief bias and related domains are discussed.     

On Biotechnology,Theology, and the Human Sciences

There may be very good Christian theological reasons to oppose human biotechnological enhancement. It is, however, difficult to discern what they are. Much of the specifically Christian response to transhumanist biotechnological enhancement has revolved around the metaphysics of human persons; this is hardly surprising, given that similar themes appear in other bioethical themes, such as over in vitro fertilization, abortion, and euthanasia. The main aim of this paper is to clarify the theological requirements for such responses, particularly those that are mistakenly delegated to scientists. In particular, the paper will focus on the need for a Christian theological account of human nature that does not unduly rely on biological accounts of the same.     

Experiences of Adults Who Identify as Primary Caregivers

The role of primary caregiver is unique. Understanding the role of the primary caregiver will better inform those in the counseling profession. The purpose of this qualitative research study was to gain a clearer perspective of the lived experiences of adults who identify as primary caregivers. The authors conducted semistructured interviews with 6 Caucasian female participants and analyzed the data using interpretative phenomenological analysis. The findings include personal perceptions and caregiver experiences pertaining to the caregiver role, caregiver mentality, professional identity, social and emotional responses, and self‐care among caregivers throughout the caregiving process. Implications for counselors and future research are presented.     

Looking for Renaissance People: Examining Domain Specificity-Generality of Creativity Using Item Response Theory Models

Creativity is increasingly identified as a key educational outcome at the local, regional, and national levels in several countries. Yet one key issue about the nature of creativity remains controversial: Whether creativity is domain specific or domain general. Resolving this issue would significantly impact the way creativity is identified, nurtured, and assessed in our schools. Three-hundred and fifty-nine undergraduate and graduate students completed measures that assessed their creative achievements in 6 distinct domains. Results based on item response theory models suggested that creativity was domain general, rather than domain specific, and part of the evidence provided by the classical test theory models seemed to favor the domain-specific view. These findings have great implications for researchers and practitioners who aim to assess and promote creativity in schools.