An experimental investigation of reassurance and responsibility

Repeated reassurance-seeking is a common phenomenon in obsessive-compulsive disorder (OCD). This behaviour may exacerbate compulsive urges (e.g., to check, to seek additional reassurance) by undermining confidence (Dar, 2004; Hout & Kindt, 2004), and preventing the disconfirmation of irrational threat-relevant thoughts and beliefs. The current investigation examined the effects of repeated reassurance and perceived responsibility/threat on anxiety, checking behaviour, memory and confidence. Volunteer undergraduate participants were randomly assigned to one of four conditions: high responsibility-high reassurance, high responsibility-low reassurance, low responsibility-high reassurance, or low responsibility-low reassurance, and were asked to perform several trials of a sorting task. On two separate occasions (i.e., before and after a critical trial, in which only members of the high reassurance groups received reassurance regarding their performance), participants were asked to rate their current anxiety, their urges to check their performance, their urges to be reassured that they had sorted correctly, and their confidence in the accuracy of their performance. They also completed a test to assess their memory accuracy (i.e., their ability to recall details of the experimental task). Results revealed that higher levels of perceived responsibility were associated with the maintenance of compulsive urges (to check and to seek reassurance) and performance-related doubt. Manipulations of reassurance did not significantly affect participants' ratings of the above-listed variables. The results of this study are discussed in terms of cognitive and behavioural models of OCD, and methodological issues are examined. Directions for future research are also suggeste

An investigation of excessive reassurance seeking in OCD

Excessive reassurance-seeking (ERS) is a common problem among individuals dealing with emotional and/or psychological difficulties. Prior research on ERS has focused almost exclusively on the potential consequences of this behaviour in the contexts of Depression and Hypochondriasis, and this research has shown that ERS contributes to interpersonal difficulties and emotional distress. Despite anecdotal evidence that ERS is a hallmark feature of Obsessive-Compulsive Disorder (OCD), comparatively few studies have examined OCD-related ERS. The goal of the present research was to examine various cognitive, behavioural and affective processes that may be involved in the perpetuation of ERS, specifically within the contexts of OCD and Depression. Given the purported functional equivalence between OCD-related reassurance seeking and compulsive checking (Rachman, 2002), the current investigations also aimed to compare ERS and repeated checking activity across a number of important domains (i.e., content, precipitating factors, function and termination criteria). Toward these goals, Study I employed a semi-structured interview with clinical (OCD and Depression) and non-clinical individuals to examine factors involved in the onset, maintenance and termination of ERS and repeated checking. Results revealed that individuals with OCD tend to seek reassurance about perceived general threats (e.g., fire, theft), whereas ERS tends to be focused on perceived social threats (e.g., abandonment, loss of support) among depressed individuals. Clinical participants reported greater anxiety, sadness and perceived threat in association with ERS and repeated checking than healthy control participants. Study 2 examined how manipulations of threat, responsibility, and ambiguity of feedback impacted upon non-clinical participants' anxiety and compulsive urges (to seek reassurance and to check) in a series of experimental vignettes. Consistent with hypotheses, higher levels of perceived threat, responsibility and ambiguity of feedback were associated with greater anxiety and compulsive urges. Results also suggested that perceived threat and responsibility partially mediated the effects of ambiguity of feedback on anxiety, urges to check, and (for threat) urges to seek reassurance. The collective results of these studies are discussed in terms of cognitive and behavioural models of OCD, and directions for future research are suggested

Planet Hunters. VI: An Independent Characterization of KOI-351 and Several Long Period Planet Candidates from the Kepler Archival Data

We report the discovery of 14 new transiting planet candidates in the Kepler field from the Planet Hunters citizen science program. None of these candidates overlapped with Kepler Objects of Interest (KOIs) at the time of submission. We report the discovery of one more addition to the six planet candidate system around KOI-351, making it the only seven planet candidate system from Kepler. Additionally, KOI-351 bears some resemblance to our own solar system, with the inner five planets ranging from Earth to mini-Neptune radii and the outer planets being gas giants; however, this system is very compact, with all seven planet candidates orbiting $\lesssim 1$ AU from their host star. A Hill stability test and an orbital integration of the system shows that the system is stable. Furthermore, we significantly add to the population of long period transiting planets; periods range from 124-904 days, eight of them more than one Earth year long. Seven of these 14 candidates reside in their host star's habitable zone.Comment: 27 pages, 6 figures, 5 tables, Accepted to AJ (in press) (updated title from original astro-ph submission

Galaxy Zoo: morphological classifications for 120 000 galaxies in HST legacy imaging

We present the data release paper for the Galaxy Zoo: Hubble (GZH) project. This is the third phase in a large effort to measure reliable, detailed morphologies of galaxies by using crowdsourced visual classifications of colour-composite images. Images in GZH were selected from various publicly released Hubble Space Telescope legacy programmes conducted with the Advanced Camera for Surveys, with filters that probe the rest-frame optical emission from galaxies out to z ∼ 1. The bulk of the sample is selected to have mI814W < 23.5, but goes as faint as mI814W < 26.8 for deep images combined over five epochs. The median redshift of the combined samples is 〈z〉 = 0.9 ± 0.6, with a tail extending out to z ≃ 4. The GZH morphological data include measurements of both bulge- and disc-dominated galaxies, details on spiral disc structure that relate to the Hubble type, bar identification, and numerous measurements of clump identification and geometry. This paper also describes a new method for calibrating morphologies for galaxies of different luminosities and at different redshifts by using artificially redshifted galaxy images as a baseline. The GZH catalogue contains both raw and calibrated morphological vote fractions for 119 849 galaxies, providing the largest data set to date suitable for large-scale studies of galaxy evolution out to z ∼ 1

Orbital precession modulates interannual rainfall variability, as recorded in an Early Pleistocene speleothem

Interannual variability of African rainfall impacts local and global communities, but its past behavior and response in future climate projections are poorly understood. This is primarily due to short instrumental records and a lack of long high-resolution palaeoclimate proxy records. Here we present an annually resolved 91,000 year Early Pleistocene record of hydroclimate from the early homininbearing Makapansgat Valley, South Africa. Changes in speleothem annual band thickness are dominated by precession over four consecutive orbital cycles with strong millennial-scale periodicity. The frequency of interannual variability (2.0–6.5 yr oscillations) does not change systematically, yet its amplitude is modulated by the orbital forcing. These long-term characteristics of interannual variability are reproduced with transient climate model simulations of water balance for South Africa from the Late Pleistocene to Recent. Based on these results, we suggest that the frequency of interannual variations in southern African rainfall is likely to be stable under anthropogenic warming, but that the size of year-to-year variations may increase. We see an orbitally forced increase in the amplitude of interannual climate variability between 1.8 Ma and 1.7 Ma coincident with the first evidence for the Acheulean stone tool technology