Breeding density affects the movements of gull chicks, the size of their home ranges and their association with neighbours.

Colonies of ground-nesting species often have heterogeneous nest densities and their offspring experience different social conditions depending on the size and location of the breeding territory. For example, unintentional territory crossing by mobile chicks can trigger strong aggression from neighbouring adults, as observed in semi-precocial gulls. This would be expected to shape chicks' movement tendencies, exploratory behaviour and propensity for social contact through aversive feedback learning or pre-natal maternal effects, as mothers may pre-adapt their offspring's behaviour to the expected early life conditions. Therefore, we hypothesize that lesser black-backed gull chicks reared in denser areas of the breeding colony will move less, have smaller home ranges and have fewer social contacts with chicks from neighbouring nests. To test this, we first cross-fostered full clutches between and within high- and low-density parts of the colony, and then used ultra-wideband tags to track free-ranging chicks. In line with our predictions, we found that chicks reared in denser areas had a lower movement activity and smaller home ranges. However, these chicks still had more social contacts, although not necessarily with a higher number of unique individuals. Pre-natal breeding density had no significant effect on any of the parameters. We conclude that parental nest choice strongly affects the early social environment of their chicks, which can shape the development of their (social) phenotype, with potentially long-lasting consequences.

Face the (trigger) failure: Trigger failures strongly drive the effect of reward on response inhibition.

Response inhibition is typically understood as the ability to stop inappropriate actions and is often investigated using the stop-signal task, in which a go response, triggered by a go signal, has to be inhibited upon the onset of a stop signal. In this task, response inhibition has been formalized as a race between a go and a stop process, which allows the latency of the stop process (stop-signal reaction time; SSRT) to be estimated. Yet, non-parametric SSRT estimations assume that the stop process is initiated without fail, which appears problematic as it is known that participants fail to do so on a subset of trials ("trigger failures"). Importantly, non-parametric methods systematically overestimate SSRT when trigger failures are present, and a growing literature is demonstrating that reported SSRT differences between groups and individuals are also (or rather) driven by differential trigger-failure rates. In the present study, we extend this line of research to a within-individual manipulation, namely the influence of reward on stop performance. We first reanalyzed four data sets of studies that had reported a facilitating effect of stimulus-based reward on SSRTs. Reanalyzing this data, we found that reward decreased the rates of trigger failures. When accounting for these differential trigger-failure rates, the effect of reward on SSRTs (i.e., stop latency) appeared to be virtually abolished. We then conducted a preregistered online follow-up study, implementing a typical block-based reward manipulation. The results of this study indicated simultaneous reward effects on trigger-failure rates and on SSRT. In sum, the present results indicate that trigger failures are an important source of variance in response inhibition, dovetailing with an evolving multicomponential view of response inhibition.

From cookies to carrots; the effect of inhibitory control training on children's snack selections.

Children consume too much sugar and not enough fruit and vegetables, increasing their risk of adverse health outcomes. Inhibitory control training (ICT) reduces children's and adults' intake of energy-dense foods in both laboratory and real-life settings. However, no studies have yet examined whether ICT can increase healthy food choice when energy-dense options are also available. We investigated whether a food-specific Go/No-Go task could influence the food choices of children aged 4-11, as measured by a hypothetical food choice task using healthy and unhealthy food images printed on cards. Participants played either an active game (healthy foods = 100% go, unhealthy foods = 100% no-go; Studies 1 & 2), a food control game (both healthy and unhealthy foods = 50% go, 50% no-go; Studies 1 & 2) or a non-food control game (sports equipment = 100% go, technology = 100% no-go; Study 2 only) followed by the choice task. In Study 2, food card choices were also measured before training to examine change in choices. A post-training real food choice task was added to check that choices made in the card-based task were representative of choices made when faced with real healthy and unhealthy foods. Overall, the active group chose the greatest number of healthy food cards. Study 2 confirmed that this was due to increases in healthy food card choice in this group only. Active group participants chose a greater number of healthy foods in the real food choice task compared to children in the non-food control group only. The results are discussed with reference to methodological issues and the development of future healthy eating interventions.

How to withhold or replace a prepotent response: An analysis of the underlying control processes and their temporal dynamics.

The present study isolated and compared ERP components associated with flexible behavior in two action-control tasks. The 'withhold' groups had to withhold all responses when a signal appeared. The 'change' groups had to replace a prepotent go response with a different response on signal trials. We proposed that the same chain of processes determined the effectiveness of action control in both tasks. Consistent with this idea, lateral (Experiment 1) and central (Experiment 2) signal presentation elicited the same perceptual and response-related components in both tasks with similar latencies. Thus, completely withholding a response and replacing a response required a similar chain of processes. Furthermore, latency analyses revealed intra-individual differences: When the signal occurred in the periphery, differences between fast and slow change trials arose at early perceptual stages; by contrast, differences arose at later processing stages when signal detection was easy but stimulus discrimination and response selection were harder.

Why decision making may not require awareness.

Newell & Shanks (N&S) argue against the idea that any significant role for unconscious influences on decision making has been established by research to date. Inasmuch as this conclusion applies to the idea of an "intelligent cognitive unconscious," we would agree. Our concern is that the article could lead the unwary to conclude that there are no unconscious influences on decision making - and never could be. We give reasons why this may not be the case.

Repetition priming in the stop signal task: the electrophysiology of sequential effects of stopping.

Inhibition of a response affects the processing of subsequent stimuli. When a response has to be made to a stimulus to which a response was previously inhibited, response time increases. In this study, we investigated the neurophysiological underpinnings of this repetition priming phenomenon. We aimed at distinguishing between two possible mechanisms. Firstly, it could be that slowing after a successful inhibition trial originates at the response execution level and is due to the reactivation of the system responsible for motor inhibition interfering with execution of the go response. The second possibility is that interference occurs at the more abstract level of conflicting action goals or plans (i.e. "stop" and "go") that are activated prior to response execution. We analyzed activity over primary motor cortices and the parietal cortex in a stop signal task. Stimulus repetition led to a decrease in activity over primary motor cortices but irrespective of history of stopping. Stopping on the previous trial did affect the stimulus-locked parietal P300 only on repetition of the stimulus, mimicking the behavioral pattern. Furthermore, the P300 was lateralized and affected by both stimulus onset and response time, suggesting that the interference caused by inhibition priming is situated between stimulus perception and response execution. Taken together, these findings show that the prolonged response times to a stimulus that was previously successfully inhibited to, do not originate from reactivated suppression of motor output, but are caused by interference between a stop and a go goal in parietal cortex that hampers translation from stimulus to response.

A randomized double-blind trial of levamisole in the therapy of recurrent aphthous stomatitis.

A Controlled, double-blind study was performed to compare the effects of levamisole and placebo in eighteen patients with recurrent aphthous stomatitis. Levamisole is a drug which enhances defective cellular immune responses. It was administered in a flexible dosage schedule: 50 mg. three times daily for three consecutive days at the start of an aphthous lesion but with an interval of at least 2 weeks between courses of therapy. Placebo consisted of pills that were identical in appearance, taken according to the same schedule. Statistical evaluation showed decreased frequency of lesions, shorter duration, and diminished pain of lesions in the group receiving levamisole. Subsequent follow-up in an open trial confirmed these results.

Restoration by levamisole of low E-rosette forming cells in patients suffering from various diseases.

One hundred and fifteen patients presenting with various clinical conditions (multiple sclerosis, recurrent infections, HBAg-positive chronic hepatitis, Crohn's disease, ataxia-telangiectasia, SSPE and atopic dermatitis) were evaluated for E-rosette formation. Forty-two patients were found to have a low number of E-rosettes. Eighteen patients with low E-rosettes were treated with levamisole, an anti-anergic chemotherapeutic agent, and were compared with an untreated control group of sixteen patients. Levamisole treatment significantly increased low E-rosettes in these patients and this was accompanied by a remarkable clinical improvement and a significant reduction of haemolytic complement activity. Therefore our results suggest the important role of T-cell function in these various clinical conditions, in which cell-mediated immunity is thought to play a major role.

Increase of serum complement levels in cancer patients with progressing tumors.

Complement levels (CH50, C3, C4 and C1q) were determined in sera of 90 healthy subjects and 200 cancer patients. Complement levels of cancer patients were significantly higher than those of the healthy subjects, but there was a stage-linked increase of complement levels. Patients in remission had nearly normal complement levels, but patients with local tumor had increased complement levels, and a further increase was observed in patients with distant metastases. Treatment of these patients with radiotherapy or cytostatic drugs lowered the complement levels. At the terminal phase of the disease we also noted a drop in complement levels.