The effects of acute stress on Pavlovian-instrumental transfer in rats

Pavlovian stimuli invigorate ongoing instrumental action, a phenomenon termed the Pavlovian–instrumental transfer (PIT) effect. Acute stressors can markedly enhance the release of corticotropin-releasing factor (CRF), and CRF injection into the nucleus accumbens increases the PIT effect. However, it is unknown whether acute stressors by themselves would amplify the PIT effect. Here, we examined the effects of acute stressors on PIT. Rats first received Pavlovian and instrumental training, and then the impact of the Pavlovian stimuli on instrumental responding was analyzed in the subsequent PIT test. Acute stressors were applied prior to the PIT test. Because the effects of acute stressors critically depend on stressor type and time of day, we used two acute stressors that involved one or several distinct stressors (denoted here as “single” vs. “multiple” stressors) applied either in the light or the dark period of the light:dark cycle. The results revealed that single and multiple stressors applied in the light period did not alter the PIT effect—that is, the ability of an appetitive Pavlovian stimulus to enhance leverpressing—or the basal leverpress rate. When applied in the dark period, single and multiple stressors also did not alter the PIT effect, but they did markedly reduce the basal leverpress rate. Diazepam pretreatment did not counteract the declines in basal instrumental responding in the PIT test that were induced by either a single or multiple stressors. Our findings suggest that acute stressors were unable to amplify the incentive salience of reward-predictive Pavlovian stimuli to activate instrumental responding, but, depending on the time of day of stressor exposure, they did reduce basal instrumental responding.     

A Non-factualist defense of the Reflection principle

Are there plausible synchronic constraints on how a subject thinks of herself extended over time? At first glance, Bas van Fraassen’s principle of Reflection seems to prescribe the sort of epistemic authority one’s future self should be taken by one to have over one’s current epistemic states. (The gist of this principle is that I should now believe what I’m convinced I will believe tomorrow.) There has been a general consensus that, as a principle concerning epistemic authority, Reflection does not apply to epistemically non-ideal agents. I agree with this, but argue here that it misses the point of Reflection. Rather than an epistemic principle concerning reasons for belief, Reflection concerns the semantics of belief avowal. I present a non-factual interpretation of Reflection, argue that the principle provides a constraint on the ways in which one can reflectively endorse one’s future epistemic self, and say something about the logic governing such an interpretation.     

Paying attention to distress: What's wrong with rumination?

We explored the notion—derived from conceptualisations of mindfulness—that what makes attention to distress harmful is negative judgement about it. In Study 1 we examined factors of Nolen-Hoeksema's Ruminative Response Scale (RRS). A “Brooding” scale included items describing negative judgements of experience, and a “Reflection” scale, comprised items describing analysis of thoughts and feelings without obvious judgement. Correlations of Reflection with depression and thought suppression were lower than those for Brooding, but still significant, perhaps because all items implied some judgement. In Study 2, items were reworded to de-emphasise evaluative judgements (RRS-nonjudging) and compared to the original RRS. Although the factor structures of the original and RRS-nonjudging versions were essentially identical, the RRS-nonjudging Reflection scale was uncorrelated with depression and thought suppression, and was more highly correlated with emotional processing than was the original Reflection scale.     

Ideomotor perception modulates visuospatial cueing

The ideomotor theory of action posits that the cognitive representation of an action includes the learned perceptual effects of the action. Support for this theory has come from studies demonstrating how perceptual features that match the outcome of a response can facilitate selection of that response. We investigated another, complementary implication of ideomotor theory: would a bias toward selecting a response result in a perceptual bias toward the known effect of the response? In other words, would an action tendency direct attention to the anticipated perceptual features? Through an initial acquisition phase, participants learned that two possible responses (left/right keypress) consistently produced two distinct colors. Next, in a test phase, we manipulated response bias at the beginning of each trial, using an uninformative spatial prime presented at the left or right periphery. We then examined the extent to which color transients that either matched or mismatched the induced response bias can orient participants’ visual attention. Results revealed a perceptual bias toward the color effect of the primed response, manifested in a stronger visual orienting toward this color. Thus, biasing response selection can bias perception. These findings extend the scope of the ideomotor theory to visual perceptual processes.     

Executive function and theory of mind: stability and prediction from ages 2 to 3

Several studies have demonstrated a relation between executive functioning (EF) and theory of mind (ToM) in preschoolers, yet the developmental course of this relation remains unknown. Longitudinal stability and EF-ToM relations were examined in 81 children at 24 and 39 months. At Time 1, EF was unrelated to behavioral measures of ToM but was significantly related to parent report of children's internal-state language, independent of vocabulary size. At Time 2, behavioral batteries of EF and ToM were significantly related (r=.50, p<.01). Furthermore, EF (Time 1) significantly predicted ToM (Time 2), independent of several controls. A reciprocal relation (internal-state language --> EF at Time 2) was nonsignificant with the controls included. Individual differences in EF were relatively stable.     

Individual differences in executive functioning and theory of mind: An investigation of inhibitory control and planning ability

This research examined the relative contributions of two aspects of executive function-inhibitory control and planning ability-to theory of mind in 49 3- and 4-year-olds. Children were given two standard theory of mind measures (Appearance-Reality and False Belief), three inhibitory control tasks (Bear/Dragon, Whisper, and Gift Delay), three planning tasks (Tower of Hanoi, Truck Loading, and Kitten Delivery), and a receptive vocabulary test (Peabody Picture Vocabulary Test [PPVT-3]). Multiple regression analyses indicated that two inhibition tasks (Bear/Dragon and Whisper) were significantly related to theory of mind after accounting for age, receptive vocabulary, and planning. In contrast, the planning tasks did not share unique variance with theory of mind. These results increase our understanding of the specific nature of executive function-theory of mind relations during early childhood.     

Group interventions for patients with cancer and HIV disease: part IV. Clinical and policy recommendations

Group interventions have assumed a growing role in primary prevention and supportive care for cancer and HIV disease. Earlier sections of this Special Report examined empirical findings for these interventions and provided recommendations for future research. The current section offers brief recommendations for service providers, policymakers, and stakeholders. Group services now occupy an increasingly prominent place in primary prevention programs and medical settings. In previous sections of this Special Report (Sherman, Leszcz et al., 2004; Sherman, Mosier et al., 2004a, 2004b) we examined the efficacy of different group interventions at different phases of cancer or HIV disease, considered characteristics of the intervention and the participants that might influence outcomes, and discussed mechanisms of action. Methodological challenges and priorities for future research were highlighted. In this, the final section, we offer brief recommendations for service providers, policymakers, and other stakeholders. We consider some of the barriers that constrain use of empirically-based group interventions and note how these programs might be implemented more widely and effectively.     

The Impact of Physical Maltreatment History on the Adolescent Mother–Infant Relationship: Mediating and Moderating Effects During the Transition to Early Parenthood

Using attachment theory as a framework, this paper examines how pregnant adolescents' experiences of physical maltreatment during childhood influence the subsequent mother-infant relationship in 203 low-income adolescents followed from the 3rd trimester of pregnancy through the 1st year of parenthood. The relation between physical maltreatment history and early difficulty in the mother-infant relationship was mediated by adolescents' evaluations of the relationship with their primary caretaker and the feelings they associated with motherhood measured prior to childbirth. In addition, a supportive romantic relationship during pregnancy acted as a protective factor by moderating the impact of maltreatment history on the quality of the subsequent mother-infant relationship. Findings support the importance of assessments and interventions that consider the social context and relational history of pregnant and parenting adolescents.