Probabilistic Opinion Pooling with Imprecise Probabilities

The question of how the probabilistic opinions of different individuals should be aggregated to form a group opinion is controversial. But one assumption seems to be pretty much common ground: for a group of Bayesians, the representation of group opinion should itself be a unique probability distribution (Madansky [44]; Lehrer and Wagner [34]; McConway Journal of the American Statistical Association, 76(374), 410–414, [45]; Bordley Management Science, 28(10), 1137–1148, [5]; Genest et al. The Annals of Statistics, 487–501, [21]; Genest and Zidek Statistical Science, 114–135, [23]; Mongin Journal of Economic Theory, 66(2), 313–351, [46]; Clemen and Winkler Risk Analysis, 19(2), 187–203, [7]; Dietrich and List [14]; Herzberg Theory and Decision, 1–19, [28]). We argue that this assumption is not always in order. We show how to extend the canonical mathematical framework for pooling to cover pooling with imprecise probabilities (IP) by employing set-valued pooling functions and generalizing common pooling axioms accordingly. As a proof of concept, we then show that one IP construction satisfies a number of central pooling axioms that are not jointly satisfied by any of the standard pooling recipes on pain of triviality. Following Levi (Synthese, 62(1), 3–11, [39]), we also argue that IP models admit of a much better philosophical motivation as a model of rational consensus.     

The effect of spatial-frequency filtering on the visual processing of global structure

In three experiments we measured reaction times (RTs) and error rates in identifying the global structure of spatially filtered stimuli whose spatial-frequency content was selected by means of three types of 2-D isotropic filters (Butterworth of order 2, Butterworth of order 10, and a filters with total or partial Gaussian spectral profile). In each experiment, low-pass (LP), bandpass (BP), and high-pass (HP) filtered stimuli, with nine centre or cut-off spatial frequencies, were used. Irrespective of the type of filter, the experimental results showed that: (a) RTs to stimuli with low spatial frequencies were shorter than those to stimuli with medium or high spatial frequencies, (b) RTs to LP filtered stimuli were nearly constant, but they increased in a nonmonotonic way with the filter centre spatial frequency in BP filtered stimuli and with the filter cut-off frequency in HP filtered stimuli, and (c) the identification of the global pattern occurred with all visible stimuli used, including BP and HP images without low spatial frequencies. To remove the possible influence of the energy, a fourth experiment was conducted with Gaussian filtered stimuli of equal contrast power (c(rms) = 0.065). Similar results to those described above were found for stimuli with spatial-frequency content higher than 2 cycles deg(-1). A model of isotropic first-order visual channels collecting the stimulus spectral energy in all orientations explains the RT data. A subsequent second-order nonlinear amplitude demodulation process, applied to the output of the most energetic first-order channel, could explain the perception of global structure of each spatially filtered stimulus, including images lacking low spatial frequencies.     

Effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle

Effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle. The risetime is a parametric characteristic of the eliciting stimulus frequently used to differentiate among psychophysiological reflexes. The aim of the present study was to examine the effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle. 100 participants underwent a psychophysiological reactivity test to five presentations of an intense acoustic stimulus (105 dB white noise) under one of five risetime conditions: 0, 24, 48, 96, and 240 ms. Total energy of the stimulus was controlled by increasing the base duration of the stimulus (1000 ms) by one third of the risetime. Results showed that risetime significantly affected motor startle but not cardiac defense. Startle amplitude decreased linearly with increasing risetime after 24 ms. On the other hand, repetition of the stimulus significantly affected cardiac defense but not motor startle. These results question the traditional differentiation between startle and defense based on risetime.     

Conditioned and unconditioned fear organized in the periaqueductal gray are differentially sensitive to injections of muscimol into amygdaloid nuclei

The lateral and basolateral nuclei of the amygdala (LaA and BLA, respectively) serve as a filter for unconditioned and conditioned aversive information that ascends to higher structures from the brainstem, whereas the central nucleus of the amygdala (CeA) is considered to be the main output for the defense reaction. It has been shown that the dorsal periaqueductal gray (dPAG) is activated by threatening stimuli and has important functional links with the amygdala through two-way anatomical connections. In this work, we examined the influence of chemical inactivation of these nuclei of amygdala on the freezing and escape responses induced by electrical stimulation through electrodes implanted in the dPAG of Wistar rats. Each rat also bore a cannula implanted in the LaA, BLA or CeA for injections of muscimol (0.5 microg/0.5 microL) or its vehicle. The duration of freezing behavior that outlasts electrical stimulation of the dPAG was also measured. On the following day, these animals were submitted to a contextual fear-conditioning using foot shocks as unconditioned stimulus. Conditioned freezing to contextual cues previously associated with foot shocks was also inhibited by injections of muscimol into these amygdaloid nuclei. The contextual conditioned freezing behavior is generated in the neural circuits of conditioned fear in the amygdala. The data obtained also show that injections of muscimol into the three amygdaloid nuclei did not change the aversive threshold of freezing, but disrupted the dPAG post-stimulation freezing. Previous findings that the latter freezing results directly from dPAG stimulation and that it is not sensitive to a context shift suggest that it is unconditioned in nature. Thus, the amygdala can affect some, but not all, aspects of unconditioned freezing. Post-stimulation freezing may reflect the process of transferring aversive information from dPAG to higher brain structures.     

Role of muscarinic M1 receptors in inhibitory avoidance and contextual fear conditioning

The objective of the present study was to observe the effects of pre-training or post-training administration of dicyclomine, a M1 muscarinic antagonist, on inhibitory avoidance (IA) and contextual fear conditioning (CFC) and to investigate if the effects observed with the pre-training administration of dicyclomine are state-dependent. For each behavioral procedure (IA and CFC) groups of Wistar male rats were treated with saline or dicyclomine either 30 min before training (pre-training), immediately after training or 30 min before training/30 min before test (pre-training/pre-test). The animals were tested 24 h after training. The acquisition of IA and CFC was impaired by pre-training administration of dicyclomine. The consolidation of both tasks was not affected by dicyclomine given immediately after training. Pre-training/pre-test administration of dicyclomine impaired both tasks, an effect similar to that observed in the group which only received pre-training administration. Pre-test treatment induced dissociation between both tasks, impairing CFC retrieval, without interfering with the animals avoidance response. These results show that the dicyclomine did not affect IA and CFC consolidation, suggesting specific involvement of M1 muscarinic receptor only in acquisition these tasks, and these effects was not state-dependent. However, it is possible that the retrieval of these tasks may be mediated, at least in part, by different neurochemical mechanisms and may be dissociated by dicyclomine.     

Time of day-dependent latent inhibition of conditioned taste aversions in rats

We have determined that the temporal context of drinking can modulate latent inhibition of learned saline aversions in Wistar rats by changing the time of day of drinking of the preexposure and conditioning phases. Latent inhibition was absent in the group preexposed and conditioned to saline at different times of the day, but not in the group that was preexposed and conditioned at the same time of day. The results confirm a previous report that the time of day can modulate taste aversion learning independently of other environmental cues. It is proposed that the features and duration of the habituation training to the temporal contexts used may be critical for time-dependent latent inhibition to appear.     

Anxiety and counter-conditioning: the role of the behavioral inhibition system in the ability to associate aversive stimuli with future rewards

A total of 130 female undergraduates performed a counter-conditioning choice-task. This task presented two response alternatives and subjects were instructed to earn the maximum number of points. Responses to button 1 were normally followed by an immediate reward (an average gain of 7.5 points). Responses to button 2 were always followed by a punishment (an average loss of 20 points), but caused the next-but-one press on button 1 to give an average gain of 115 points. Thus, subjects were required to learn and maintain this counter-conditioning association. Four groups of subjects were formed according to the scores on the Sensitivity to Punishment and Sensitivity to Reward scales (which are measures of individual differences of Gray's anxiety and impulsivity personality dimensions, respectively). A 69.2% of subjects learned and maintained the counter-conditioning association. As predicted, personality results confirmed that subjects with lower scores on the Sensitivity to Punishment scale learned the counter-conditioning association better and faster when compared with high scorers. Results are consistent with Gray's Behavioral Inhibition System (BIS) model of anxiety which holds that individual differences in anxiety may relate to the ability to associate aversive stimuli with a future reward. Assuming that anxiety depends on BIS functioning, our results show that high trait anxious subjects, if compared with low anxious ones, would have a lower ability for associating an aversive event with a later appetitive one. This learning process would serve non-anxious subjects to reduce the aversiveness of cues of punishment and to cope better with stressful situations.     

Latinx Mental Health Scholars' Experiences with Cultural Adaptation and Implementation of Systemic Family Interventions

An increasing number of culturally adapted family-level interventions address mental health disparities with marginalized populations in the United States. However, with these developments many barriers have arisen, such as challenges with degree of cultural fit, engagement, and sustainability. We conducted 12 elite phenomenological interviews with mental health scholars involved in prevention and intervention family research with various Latinx communities within and outside of the United States. These scholars discussed their experiences of overcoming barriers in their research. We used thematic analysis to code and analyze participant responses, and our findings support the gaps in previous literature and highlight potential pathways to overcoming barriers in cultural adaptation research. Themes included the need for: (a) better understanding of the intersection between culture and context; (b) community-centered approaches to addressing implementation challenges; and (c) structural changes within institutional, governmental, and political levels. We discuss implications for researchers and practitioners working with Latinx families.     

Links Between Reactive Attachment Disorder,Caregiving and Temperament: A Differential Susceptibility Perspective

Abstract

The links between Reactive Attachment Disorder (RAD) and temperament received relatively little research attention, in spite of their clinical and social relevance. Children with RAD sustain disproportionate burdens of early adversity related to their caregiving environment. However, there seem to be important individual differences in susceptibility to adversity, since only a small number of children show signs of RAD. Based on the work of Zeanah and Fox, this review aims to bring new insights to this relevant clinical issue in light of recent research. A differential susceptibility hypothesis will be considered as a promising and innovative approach toward a further understanding of the links between temperament and RAD.     

Tactile spatial acuity differs between fingers: a study comparing two testing paradigms

Tactile spatial acuity (TSA) is a reliable and reproducible measure of somatosensory system function that has been used to study abroad range of subject populations. Although TSA is most often assessed at the fingertip, published studies employing identical stimuli disagree on whether TSA differs between the fingers of neurologically normal subjects. Using a validated grating orientation discrimination task, we determined TSA bilaterally at the index and ring fingers of 16 healthy young adults. Motivated by earlier work, we utilized two stimulus presentation paradigms, the method of constant stimuli (MCS) and a staircase (SC) method. We found that TSA was significantly higher (the discrimination threshold was lower) at the index than at the ring finger, which was consistent with a prior study. Although mean thresholds at both fingers were higher when measured with the SC than with the MCS paradigm, this difference did not reach statistical significance (p = .14). These findings should facilitate both design and interpretation of future studies investigating TSA.