The cognitive and neural architecture of sequence representation

The authors theorize that 2 neurocognitive sequence-learning systems can be distinguished in serial reaction time experiments, one dorsal (parietal and supplementary motor cortex) and the other ventral (temporal and lateral prefrontal cortex). Dorsal system learning is implicit and associates noncategorized stimuli within dimensional modules. Ventral system learning can be implicit or explicit It also allows associating events across dimensions and therefore is the basis of cross-task integration or interference, depending on degree of cross-task correlation of signals. Accordingly, lack of correlation rather than limited capacity is responsible for dual-task effects on learning. The theory is relevant to issues of attentional effects on learning; the representational basis of complex, sequential skills; hippocampal-versus basal ganglia-based learning; procedural versus declarative memory; and implicit versus explicit memory.     

Cerebral blood flow and anxiety in older men: an analysis of resting anterior asymmetry and prefrontal regions

Asymmetric resting blood flow in prefrontal and hemispheric regions, assessed by single photon emission computed tomography (SPECT), was examined as a potential biological marker for enhanced trait and state anxiety in 30 older men (ages 55-81). Average and asymmetric perfusion in dorsolateral, medial, and orbital regions of the prefrontal lobes was also assessed. Results indicated a significant association between lower levels of resting dorsolateral blood flow and greater state anxiety responses to a series of stressful provocations (measured on a separate occasion). A significant curvilinear (U-shaped) relation between asymmetric dorsolateral perfusion and state anxiety was also identified; increased asymmetric blood flow favoring either the right or the left dorsolateral region related to higher levels of state anxiety. However, this association was attenuated by age and systolic blood pressure. Resting perfusion in the dorsolateral region may represent a more reliable biological marker for state anxiety than trait anxiety in older men.     

A composite Gestalt completion test.

Most existing Gestalt completion tests contain items which have content recognizable 50 years ago but now are difficult for subjects to recognize. Four well-known Gestalt completion tests were examined and a composite test of the more familiar items among the tests was compiled and then administered to university students. The Cronbach alpha for the 21 selected items was .82. Exploratory factor analyses yielded a general factor and more specific factors, supporting the contention that alternative processes or structural characteristics described in the Gestalt completion literature may account for the common and unique variances found among Gestalt completion items.     

Discrete emotions elucidate the effects of crossed-categorization on prejudice

Three studies integrated crossed-categorization and discrete emotion approaches to prejudice and prejudice reduction. Study 1 made salient crossed-categorization using naturally occurring groups and examined the ability of emotions to account for prejudiced evaluations. Study 2 constructed novel crossed-categorizations in the laboratory to examine the role of appraisal-based emotions in evaluations of crossed-categories. Study 3 crossed gender and sexual orientation, for which elicited discrete emotions predict different evaluative responses than do shared and unshared group memberships alone. In all three studies, discrete emotions were able to account for the effects of crossed-categorization on evaluative measures of prejudice and revealed emotional paths to prejudice reduction which would be obscured by the evaluative measures alone. In Study 3, a discrete emotions approach better predicted evaluations than did shared and unshared group membership alone. These results converge to highlight the importance of discrete emotions in understanding the evaluative implications of crossed-categorization, especially for prejudice reduction.     

Integrating advice and experience: learning and decision making with social and nonsocial cues

When making decisions, people typically gather information from both social and nonsocial sources, such as advice from others and direct experience. This research adapted a cognitive learning paradigm to examine the process by which people learn what sources of information are credible. When participants relied on advice alone to make decisions, their learning of source reliability proceeded in a manner analogous to traditional cue learning processes and replicated the established learning phenomena. However, when advice and nonsocial cues were encountered together as an established phenomenon, blocking (ignoring redundant information) did not occur. Our results suggest that extant cognitive learning models can accommodate either advice or nonsocial cues in isolation. However, the combination of advice and nonsocial cues (a context more typically encountered in daily life) leads to different patterns of learning, in which mutually supportive information from different types of sources is not regarded as redundant and may be particularly compelling. For these situations, cognitive learning models still constitute a promising explanatory tool but one that must be expanded. As such, these findings have important implications for social psychological theory and for cognitive models of learning.     

Stimulus generalization and the response-reinforcement contingency

Generalization gradients along a line-tilt continuum were obtained from groups of pigeons that had been trained to peck a key on different schedules of reinforcement. In Exp. I, gradients following training on a differential-reinforcement-of-low-rate (DRL) schedule proved to be much flatter than gradients following the usual 1-min variable interval (VI) training. In Exp. II, the value of the VI schedule itself was parametrically studied; Ss trained on long VI schedules (e.g., 4-min) produced much flatter gradients than Ss trained on short VI schedules (30-sec; 1-min). The results were interpreted mainly in terms of the relative control exerted by internal, proprioceptive cues on the different reinforcement schedules. Several implications of the results for other problems in the field of stimulus generalization are discussed.     

Nodule Detection with Eye Movements

Radiologists often miss nodules that may represent lung cancer on chest radiographs. We investigated whether eye movements collected during the search for lung nodules by large samples of laypeople may provide information that could assist radiologists in their detection. For that purpose, we developed a partially invisible Markov model with partially unobserved states and analyzed eye tracking data of over 100 laypeople who reviewed 14 chest X‐ray images, of which seven contained a potentially cancerous nodule. We used the luminance value of the pixels in the X‐ray images as prior information on the possible location of a nodule and identified six regions of interest on each image that may contain a nodule. Our study demonstrated that the eye movements recorded from laypersons contained information that may assist radiologists in the detection of nodules in chest X‐rays, which has important implications for crowdsourcing of search for pulmonary nodules, which are discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

Searching working memory for the source of dual-task costs

Dual-task costs depend on the specific pairings of stimulus and response modalities. Such findings are analogous to domain-specific effects in the working memory (WM) literature, in which items compete for limited capacity when they involve related types of information. The present study explicitly examines the relationship between modality-pairing effects on dual-task costs and domain-specificity effects on WM capacity. Participants maintained a sequence of either locations or tones in WM, and then performed a choice reaction time task in which they responded either vocally or manually. The stimuli for the choice reaction time task were held constant, but its response modality affected the interference observed in WM: vocal responses interfered with WM for tones and manual responses interfered with WM for locations. These findings indicate that response selection engages domain-specific WM processes and that interference within these processes may account for modality-pairing effects.     

Hempel’s Provisos and <Emphasis Type="Italic">Ceteris Paribus</Emphasis> Clauses

The problem of ceteris paribus clauses and Hempel’s problem of provisos are closely-related difficulties. Both challenge advocates of accounts of scientific theories involving laws understood as universal generalizations, and they have been treated as identical problems. Earman and Roberts argue that the problems are distinct. Towards arguing against them, I characterize the relationship between Hempel’s provisos and one way of expressing ceteris paribus clauses. I then describe the relationship between the problems attributed to the clauses, suggesting that they form a single problem-cluster. However, Hempel’s way of formulating provisos and discussing what they involve entangles provisos with the problem of skepticism. This creates a departure in Hempel’s discussion of provisos from the distinctive problem of vacuity which characterizes the problem of ceteris paribus clauses, though for different reasons than Earman and Roberts suggest.