Time estimation could be impaired in male,but not female adults with attention deficits

The ability to judge the passage of time is critical to behavioral regulation and planning and can be impaired among individuals with attention deficit. Time estimation was tested in young adults screened for attention deficit, based on scores of a self-report questionnaire for attention problems (CAARS), using a prospective reproduction paradigm. Four time intervals (3, 6, 12, and 24 s) were tested in two conditions: (1) reproduction of the duration of a visual stimulus and (2) reproduction of an empty time interval. A significant interaction between gender and group was found suggesting that males, but not females, with attention deficits made larger errors than controls. Males with attention deficits and both groups of females made larger underestimations of time judgement than control males.     

Measurement by subjective estimation: Testing for separable representations

Studying how individuals compare two given quantitative stimuli, say d₁ and d₂, is a fundamental problem. One very common way to address it is through ratio estimation, that is to ask individuals not to give values to d₁ and d₂, but rather to give their estimates of the ratio p=d₁/d₂. Several psychophysical theories (the best known being Stevens’ power-law) claim that this ratio cannot be known directly and that there are cognitive distortions on the apprehension of the different quantities. These theories result in the so-called separable representations [Luce, R. D. (2002). A psychophysical theory of intensity proportions, joint presentations, and matches. Psychological Review, 109, 520–532; Narens, L. (1996). A theory of ratio magnitude estimation. Journal of Mathematical Psychology, 40, 109–788], which include Stevens’ model as a special case. In this paper we propose a general statistical framework that allows for testing in a rigorous way whether the separable representation theory is grounded or not. We conclude in favor of it, but reject Stevens’ model. As a byproduct, we provide estimates of the psychophysical functions of interest.     

A re-examination of the algebraic properties of the AHP as a ratio-scaling technique

The Analytic Hierarchy Process (AHP) ratio-scaling approach is re-examined in view of the recent developments in mathematical psychology based on the so-called separable representations. The study highlights the distortions in the estimates based on the maximum eigenvalue method used in the AHP distinguishing the contributions due to random noises from the effects due to the nonlinearity of the subjective weighting function of separable representations. The analysis is based on the second order expansion of the Perron eigenvector and Perron eigenvalue in reciprocally symmetric matrices with perturbations. The asymptotic distributions of the Perron eigenvector and Perron eigenvalue are derived and related to the eigenvalue-based index of cardinal consistency used in the AHP. The results show the limits of using the latter index as a rule to assess the quality of the estimates of a ratio scale. The AHP method to estimate the ratio scales is compared with the classical ratio magnitude approach used in psychophysics.     

Conditioned task-set competition: Neural mechanisms of emotional interference in depression

Depression has been associated with increased response times at the incongruent-, neutral-, and negative-word trials of the classical and emotional Stroop tasks (Epp et al., Clinical Psychology Review, 32, 316–328, 2012). Response-time slowdown effects at incongruent- and negative-word trials of the Stroop tasks were reported to correlate with depressive severity, indicating strong relevance of the effects to the symptomatology. This study proposes a novel integrative computational model of neural mechanisms of both the classical and emotional Stroop effects, drawing on the previous prominent theoretical explanations of performance at the classical Stroop task (Cohen, Dunbar, & McClelland, Psychological Review, 97, 332–361, 1990; Herd, Banich, & O’Reilly, Journal of Cognitive Neuroscience, 18, 22–32, 2006), and in addition suggesting that negative emotional words represent conditioned stimuli for future negative outcomes. The model is shown to explain the classical Stroop effect and the slow (between-trial) emotional Stroop effect with biologically plausible mechanisms, providing an advantage over the previous theoretical accounts (Matthews & Harley, Cognition & Emotion, 10, 561–600, 1996; Wyble, Sharma, & Bowman, Cognition & Emotion, 22, 1019–1051, 2008). Simulation results suggested a candidate mechanism responsible for the pattern of depressive performance at the classical and the emotional Stroop tasks. Hyperactivity of the amygdala, together with increased inhibitory influence of the amygdala over dopaminergic neurotransmission, could be at the origin of the performance deficits.     

Brain mechanisms of altered consciousness in generalised seizures

In spite of the inherent difficulties in achieving a biologically meaningful definition of consciousness, recent neurophysiological studies are starting to provide some insight in fundamental mechanisms associated with impaired consciousness in neurological disorders. Generalised seizures are associated with disruption of the default state network, a functional network of discrete brain areas, which include the fronto-parietal cortices. Subcortical contribution through activation of thalamocortical structures, as well as striate nuclei are also crucial to produce impaired consciousness in generalised seizures.