The effects of temporal synchrony on the perceived organization of elements in spatially symmetric and asymmetric grids

Three experiments were conducted to investigate the influence of fast temporally segmented presentations of alternate rows or columns on the perception of grids of either symmetrically or asymmetrically spaced dot-like stimuli. Experiments 1a and 1b demonstrated that observers were able to discriminate between temporally segmented presentations of rows/columns stimuli, but showed a reduced performance in discrimination between non-temporally segmented stimuli and temporally segmented stimuli that were spatially unstructured. Experiment 2 confirmed the influence of temporally segmented presentations of rows and columns using elements whose mean luminance summed to the same as the display background. Experiment 3 demonstrated that the influence of temporal cues reduced when display elements were asymmetrically spaced. The results are discussed in terms of the influence of external spatio-temporal factors on the neural mechanisms of visual grouping.     

Confirmatory factor analysis of the Behavior Rating Inventory of Executive Functioning (BRIEF) in children and adolescents with ADHD

The Behavior Rating Inventory of Executive Functioning (BRIEF) is a parent report measure designed to assess executive skills in everyday life. The present study employed a confirmatory factor analysis (CFA) to evaluate three alternative models of the factor structure of the BRIEF. Given the executive functioning difficulties that commonly co-occur with attention-deficit/hyperactivity disorder (ADHD), the participants included 181 children and adolescents with a diagnosis of ADHD. The results indicated that an oblique two-factor model, in which the Monitor subscale loaded on both factors (i.e., Behavioral Regulation, Metacognition) and measurement errors for the Monitor and Inhibit subscales were allowed to correlate, provided an acceptable goodness-of-fit to the data. This two-factor model is consistent with previous research indicating that the Monitor subscale reflects two dimensions (i.e., monitoring of task-related activities and monitoring of personal behavioral activities) and thus loads on multiple factors. These findings support the clinical relevance of the BRIEF in children with ADHD, as well as the multidimensional nature of executive functioning.     

Interaction of attention and temporal object priming

Within a 3 × 3 matrix of 90° corner junctions, detection of a Kanizsa-type square is facilitated when the target display is preceded by a 40-Hz flickering premask of 3 × 3 crosses, with four crosses synchronously oscillating at the subsequent target location. To examine whether this ‘synchrony-priming’ effect is influenced by, or dependent on, visuo-spatial attention, a spatial-cueing manipulation was introduced. Observers were presented with a visual or acoustic cue which indicated the likely target quadrant. The main finding was that synchrony priming was larger for invalidly, compared with validly, cued locations, and that the priming effect was figural, rather than spatial, in nature (i.e., confined to points associated with the completed boundary, rather than extending to the inner region, defined by the synchronous premask elements). This pattern of effects argues that target processing is expedited not by attracting spatial attention to the primed location, but by the prime expediting (figure-specific) target encoding, as a result of which the target position gains a processing and selection advantage relative to non-primed locations.     

Solving geometric analogy problems through two-stage analogical mapping

Evans' 1968 ANALOGY system was the first computer model of analogy. This paper demonstrates that the structure mapping model of analogy, when combined with high-level visual processing and qualitative representations, can solve the same kinds of geometric analogy problems as were solved by ANALOGY. Importantly, the bulk of the computations are not particular to the model of this task but are general purpose: We use our existing sketch understanding system, CogSketch, to compute visual structure that is used by our existing analogical matcher, Structure Mapping Engine (SME). We show how SME can be used to facilitate high-level visual matching, proposing a role for structural alignment in mental rotation. We show how second-order analogies over differences computed via analogies between pictures provide a more elegant model of the geometric analogy task. We compare our model against human data on a set of problems, showing that the model aligns well with both the answers chosen by people and the reaction times required to choose the answers.     

Individual differences in language lateralisation,schizotypy and the remote-associate task

We tested the hypothesis that the level of reduced laterality in language is correlated with the degrees of schizotypal personality in healthy individuals and with their performance in the remote-associate task (RAT). A total of 53 healthy participants completed a schizotypal personality measure of the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE; a questionnaire measuring the level of psychotic proneness), a consonant–vowel–consonant (CVC; requiring the identification of letter trigrams presented tachistoscopically in the left/right visual fields or both), measuring reduced language laterality and a remote-associate task (RAT; requiring to report a word, weakly associated with three cue words). Analysis revealed correlations between CVC and O-LIFE, as well as between CVC and RAT performance. The results suggest that reduced language lateralisation (reduced hemispheric integration) may play a role in schizophrenic language disorganization, as reflected in highly schizotypal individuals, and that hemispheric integration plays a role in the remote-associate task.     

A Neural Network Model for Attribute-Based Decision Processes

We propose a neural model of multiattribute-decision processes, based on an attractor neural network with dynamic thresholds. The model may be viewed as a generalization of the elimination by aspects model, whereby simultaneous selection of several aspects is allowed. Depending on the amount of synaptic inhibition, various kinds of scanning strategies may be performed, leading in some cases to vacillations among the alternatives. The model predicts that decisions of a longer time duration exhibit a lower violation of the simple scalability law, as opposed to shorter decisions. Furthermore, the model is suggested as a general attribute-based decision module. Accordingly, various decision strategies are manifested depending on the module's parameters.     

Preference reversal in multiattribute choice

A central puzzle for theories of choice is that people's preferences between options can be reversed by the presence of decoy options (that are not chosen) or by the presence of other irrelevant options added to the choice set. Three types of reversal effect reported in the decision-making literature, the attraction, compromise, and similarity effects, have been explained by a number of theoretical proposals. Yet a major theoretical challenge is capturing all 3 effects simultaneously. We review the range of mechanisms that have been proposed to account for decoy effects and analyze in detail 2 computational models, decision field theory (Roe, Busemeyer, & Townsend, 2001) and leaky competing accumulators (Usher & McClelland, 2004), that aim to combine several such mechanisms into an integrated account. By simulating the models, we examine differences in the ways the decoy effects are predicted. We argue that the LCA framework, which follows on Tversky's relational evaluation with loss aversion (Tversky & Kahneman, 1991), provides a more robust account, suggesting that common mechanisms are involved in both high-level decision making and perceptual choice, for which LCA was originally developed.     

The demise of short-term memory revisited: empirical and computational investigations of recency effects

In the single-store model of memory, the enhanced recall for the last items in a free-recall task (i.e., the recency effect) is understood to reflect a general property of memory rather than a separate short-term store. This interpretation is supported by the finding of a long-term recency effect under conditions that eliminate the contribution from the short-term store. In this article, evidence is reviewed showing that recency effects in the short and long terms have different properties, and it is suggested that 2 memory components are needed to account for the recency effects: an episodic contextual system with changing context and an activation-based short-term memory buffer that drives the encoding of item-context associations. A neurocomputational model based on these 2 components is shown to account for previously observed dissociations and to make novel predictions, which are confirmed in a set of experiments.