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Unconscious visual stimuli can be processed by human observers and modulate their behavior. This has been shown for masked prime stimuli that influence motor responses to subsequent target stimuli. Beyond this, masked stimuli can also affect participants' behavior when they are free to choose one of two response alternatives. This finding demonstrates that an apparently free-choice between alternative behaviors can be subject to influences that are outside of awareness. We report three experiments which exhibit that the temporal dynamic of free-choice priming effects corresponds to that of forced-choice priming effects. Forced-choice priming effects were relatively robust against variations of prime stimuli but sensitive to physical features of target stimuli. Free-choice priming effects, in contrast, depended largely on the stimulus-response compatibility of the prime. A simple accumulator model which accounts for forced-choice response priming can also explain free-choice priming effects by the assumption that unconscious stimuli can initiate motor responses when participants are engaged in a speeded choice-reaction time task. According to our analyses free-choice priming results from a response selection mechanism which integrates conscious and unconscious information from external, stimulus driven sources and also from internal sources. (Contains 5 figures and 1 supplementary data.)

Objective: Very brief exposure to masked images of spider stimuli can facilitate approach behaviour towards spiders in fearful subjects. We hypothesized that a similar effect might occur for fear of food in patients with anorexia nervosa (AN), possibly offering a new treatment approach, with advantages over other methods of food exposure. Methods: Patients with AN (n = 60) were randomly assigned to one of three experimental conditions and received a single session of exposure to either masked and very briefly presented food images, clearly visible food images, or masked non‐food images (i.e. household items). Effects of the three exposure conditions on fear of food and food avoidance were examined. Results: Contrary to our expectations, very brief food cue exposure was not superior to the control conditions regarding fear of food and approach behaviour towards food immediately after the intervention and body mass index four weeks later. Conclusion: This finding suggests important differences between fear of food in AN and specific phobias such as fear of spiders. The absence of an effect reveals limitations of the very brief exposure method, which might be better suited for evolutionarily relevant threat stimuli. Highlights: We hypothesized that very brief exposure to masked food images might reduce fear of food in patients with anorexia nervosa as a similar effect has been found for fear of spiders.We tested this hypothesis in an experimental design with two control groups (exposure to clearly visible food images or masked household items).We found no differences between the three groups, suggesting differences between fear of food and fear of spiders. [ABSTRACT FROM AUTHOR]

Background: Minimally invasive surgical (MIS) techniques are increasingly being used in foot and ankle surgery but it is important that they are adopted only once they have been shown to be equivalent or superior to open techniques. We believe that the main advantages of MIS are found in the early postoperative period, but in order to adopt it as a technique longer-term studies are required. The aim of this study was to compare the 2-year outcomes of a third-generation MIS distal chevron osteotomy with a comparable traditional open distal chevron osteotomy for mild-moderate hallux valgus. Our null hypothesis was that the 2 techniques would yield equivalent clinical and radiographic results at 2 years. Methods: This was a retrospective cohort study. Eighty-one consecutive feet (49 MIS and 32 open distal chevron osteotomies) were followed up for a minimum 24 months (range 24-58). All patients were clinically assessed using the Manchester-Oxford Foot Questionnaire. Radiographic measures included hallux valgus angle, the intermetatarsal angle, hallux interphalangeal angle, metatarsal phalangeal joint angle, distal metatarsal articular angle, tibial sesamoid position, shape of the first metatarsal head, and plantar offset. Statistical analysis was done using Student t test or Wilcoxon rank-sum test for continuous data and Pearson chi-square test for categorical data. Results: Clinical and radiologic postoperative scores in all domains were substantially improved in both groups (P < .001), but there was no statistically significant difference in improvement of any domain between open and MIS groups (P > .05). There were no significant differences in complications between the 2 groups ( > .5). Conclusion: The midterm results of this third-generation technique show that it was a safe procedure with good clinical outcomes and comparable to traditional open techniques for symptomatic mild-moderate hallux valgus. Level of Evidence: Level III, retrospective comparative study. [ABSTRACT FROM AUTHOR]