Recent changes to US research funding are having far-reaching consequences that imperil the integrity of science and the provision of care to vulnerable populations. Resisting these changes, the BJPsych Portfolio reaffirms its commitment to publishing mental science and advancing psychiatric knowledge that improves the mental health of one and all.

We present an experiment where subjects sequentially receive signals about the true state of the world and need to form beliefs about which one is true, with payoffs related to reported beliefs. We attempt to control for risk aversion using the Offerman et al. (Rev Econ Stud 76(4):1461–1489, 2009) technique. Against the baseline of Bayesian updating, we test for belief adjustment underreaction and overreaction and model the decision making process of the agent as a double hurdle model where agents with inferential expectations first decide whether to adjust their beliefs and then, if so, decide by how much. We also test the effects of increased inattention and complexity on belief updating. We find evidence for periods of belief inertia interspersed with belief adjustment. This is due to a combination of random belief adjustment; state-dependent belief adjustment, with many subjects requiring considerable evidence to change their beliefs; and quasi-Bayesian belief adjustment, with aggregate insufficient belief adjustment when a belief change does occur. Inattention, like complexity, makes subjects less likely to adjust their stated beliefs, while inattention additionally discourages full adjustment.

Experiments frequently use a random incentive system (RIS), where only tasks that are randomly selected at the end of the experiment are for real. The most common type pays every subject one out of her multiple tasks (within-subjects randomization). Recently, another type has become popular, where a subset of subjects is randomly selected, and only these subjects receive one real payment (between-subjects randomization). In earlier tests with simple, static tasks, RISs performed well. The present study investigates RISs in a more complex, dynamic choice experiment. We find that between-subjects randomization reduces risk aversion. While within-subjects randomization delivers unbiased measurements of risk aversion, it does not eliminate carry-over effects from previous tasks. Both types generate an increase in subjects’ error rates. These results suggest that caution is warranted when applying RISs to more complex and dynamic tasks.

A new observable consequence of the property of invariant item ordering is presented, which holds under Mokken’s double monotonicity model for dichotomous data. The observable consequence is an invariant ordering of the item-total regressions. Kendall’s measure of concordance W and a weighted version of this measure are proposed as measures for this property. Karabatsos and Sheu proposed a Bayesian procedure (Appl. Psychol. Meas. 28:110–125, 2004), which can be used to determine whether the property of an invariant ordering of the item-total regressions should be rejected for a set of items. An example is presented to illustrate the application of the procedures to empirical data.

Most dichotomous item response models share the assumption of latent monotonicity, which states that the probability of a positive response to an item is a nondecreasing function of a latent variable intended to be measured. Latent monotonicity cannot be evaluated directly, but it implies manifest monotonicity across a variety of observed scores, such as the restscore, a single item score, and in some cases the total score. In this study, we show that manifest monotonicity can be tested by means of the order-constrained statistical inference framework. We propose a procedure that uses this framework to determine whether manifest monotonicity should be rejected for specific items. This approach provides a likelihood ratio test for which the p-value can be approximated through simulation. A simulation study is presented that evaluates the Type I error rate and power of the test, and the procedure is applied to empirical data.

In van der Heijden and de Leeuw (1985) it was proposed to use loglinear analysis to detect interactions in a multiway contingency table, and to explore the form of these interactions with correspondence analysis. After performing the exploratory phase of the analysis, we will show here how the results found in this phase can be used for confirmation.

Randomized response is an interview technique for sensitive questions designed to eliminate evasive response bias. Since this elimination is only partially successful, two models have been proposed for modeling evasive response bias: the cheater detection model for a design with two sub-samples with different randomization probabilities and the self-protective no sayers model for a design with multiple sensitive questions. This paper shows the correspondence between these models, and introduces models for the new, hybrid “ever/last year” design that account for self-protective no saying and cheating. The model for one set of ever/last year questions has a degree of freedom that can be used for the inclusion of a response bias parameter. Models with multiple degrees of freedom are introduced for extensions of the design with a third randomized response question and a second set of ever/last year questions. The models are illustrated with two surveys on doping use. We conclude with a discussion of the pros and cons of the ever/last year design and its potential for future research.

Wilkins’s Finch Nesospiza wilkinsi is endemic to Nightingale Island (2.5 km2), Tristan da Cunha. It feeds on the woody fruits of the Island Tree Phylica arborea and in 2017 had a population of 120 breeding pairs. In 2021 it was uplisted from “Endangered” to “Critically Endangered” following damage to P. arborea woodland during severe storms in 2019. During a brief visit to Nightingale in February 2024, we confirmed that the finch population in the area of storm-damaged woodland has decreased by up to 75%, but the density in other areas was similar to that prior to 2019. Extrapolating from the 2017 survey, we estimated the current population to be 60–90 breeding pairs. Surveys of P. arborea structure in the storm-affected area indicated that some large trees had survived, despite being flattened, that recruitment of new trees is occurring, and that fruit loads on surviving trees are similar to those in 2017. Satellite imagery from 2005 showed similar woodland loss during another severe storm in 2001 to that experienced in 2019, indicating that the finch has survived similar events in the past. Coupled with the successful release of a biological control agent to limit the impact of the introduced brown soft scale Coccus hesperidum on Phylica fruit production, the future prospect for Wilkins’s Finch is less bleak than previously thought. However, the risk that global warming is increasing the frequency of severe storms remains a concern. Planting more woodland patches in sheltered areas would help to offset future storm damage.

Previous studies in rodents suggest that mismatch between fetal and postnatal nutrition predisposes individuals to metabolic diseases. We hypothesized that in nonhuman primates (NHP), fetal programming of maternal undernutrition (MUN) persists postnatally with a dietary mismatch altering metabolic molecular systems that precede standard clinical measures. We used unbiased molecular approaches to examine response to a high fat, high-carbohydrate diet plus sugar drink (HFCS) challenge in NHP juvenile offspring of MUN pregnancies compared with controls (CON). Pregnant baboons were fed ad libitum (CON) or 30% calorie reduction from 0.16 gestation through lactation; weaned offspring were fed chow ad libitum. MUN offspring were growth restricted at birth. Liver, omental fat, and skeletal muscle gene expression, and liver glycogen, muscle mitochondria, and fat cell size were quantified. Before challenge, MUN offspring had lower body mass index (BMI) and liver glycogen, and consumed more sugar drink than CON. After HFCS challenge, MUN and CON BMIs were similar. Molecular analyses showed HFCS response differences between CON and MUN for muscle and liver, including hepatic splicing and unfolded protein response. Altered liver signaling pathways and glycogen content between MUN and CON at baseline indicate in utero programming persists in MUN juveniles. MUN catchup growth during consumption of HFCS suggests increased risk of obesity, diabetes, and cardiovascular disease. Greater sugar drink consumption in MUN demonstrates altered appetitive drive due to programming. Differences in blood leptin, liver glycogen, and tissue-specific molecular response to HFCS suggest MUN significantly impacts juvenile offspring ability to manage an energy rich diet.

Heat stress from high temperatures has been recognised as a threat to several bird species and one that is likely to increase in severity and frequency as a result of global environmental change. Many seabirds are particularly vulnerable as their adaptations to forage in cold water can make it hard for them to resist heat gain while on land. The African Penguin Spheniscus demersus forages in cool water (10–20°C) but breeds and moults on land where temperatures can exceed 30°C. Little is known about its thermal physiology and when heat stress will occur. Here, we provide the first account of changes in body temperature and behaviour in African Penguins in response to an experimental increase in ambient temperature from 20°C to 35°C. Surprisingly, the highest body temperature observed (39.2°C) was recorded at the start of the study. Presumably, this response in body temperature was due to the stress of transport and handling. Penguins returned to normal body temperature (37.3°C) after 3.5 hours and maintained normothermia for roughly an hour. We then observed the onset of heat storage at an ambient temperature of 29°C, whereafter body temperature increased steadily at a rate of ca.0.2°C per 1°C increase in ambient temperature. Panting commenced at an ambient temperature of 31.4°C, when body temperature was 37.8°C. In addition to panting, penguins changed their posture to facilitate heat dissipation by standing, raising their heads, and extending their flippers. Our results corroborate field observations and support the argument that African Penguins are highly vulnerable to heat stress in the near future as extreme heat events become more severe and frequent due to climate change. Our results also confirm that penguins are sensitive to handling, which elicits a hyperthermic response. Given the general sensitivity of penguins to disturbance, from a conservation perspective, we advise that cautionary measures be implemented at colonies during critical life-history stages.

We report a case of hypoplastic left heart syndrome and with subsequent aortopathy and then found to have hereditary haemorrhagic telangiectasia/juvenile polyposis syndrome due to a germline SMAD4 pathologic variant. The patient’s staged palliation was complicated by the development of neoaortic aneurysms, arteriovenous malformations, and gastrointestinal bleeding thought to be secondary to Fontan circulation, but workup revealed a SMAD4 variant consistent with hereditary haemorrhagic telangiectasia/juvenile polyposis syndrome. This case underscores the importance of genetic modifiers in CHD, especially those with Fontan physiology.