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Objectives:  Nocebo   hyperalgesia  is an increase in pain through the expectation of such an increase as a consequence of a sham treatment.  Nocebo   hyperalgesia  can be induced by observation of a model demonstrating increased pain via verbal pain ratings. The aim of the present study was to investigate whether observing natural pain behavior, such as  facial pain expressions , can also induce  nocebo  responses. Materials and Methods:  Eighty female participants (age: 22.4 y±4.8) underwent a pressure-pain procedure (algometer) on both hands and rated their pain on a numerical rating scale. All participants received ointment on one of their hands, but no explanation was given for this. Before their own participation, the participants watched a video in which a woman underwent the same procedure and who either modeled increased pressure pain upon ointment application ( nocebo  condition) or showed a neutral facial expression throughout (control condition). Results:  A 2×2 analysis of variance with condition ( nocebo ; control) as a between-subjects factor and ointment application (with; without) as a within-subject factor revealed a main effect for ointment and a condition×ointment interaction. In the  nocebo  condition, pain ratings were higher with ointment than without. Discussion:  For the first time, it was shown that watching a model demonstrating pain through facial expressions induced  nocebo   hyperalgesia . As we mostly express pain through natural pain behavior rather than through pain ratings, this paradigm extends our knowledge of  observational learning  about pain and may have implications for contexts in which persons watch others undergo painful procedures.

Nocebo effects can be acquired by verbal suggestion, but it is unknown whether they can be induced through observational learning and whether they are influenced by factors known to influence pain perception, such as pain anxiety or pain catastrophizing. Eighty-five female students (aged 22.5 ± 4.4 years) were randomly assigned to one of three conditions. Participants in the control condition (CC) received information that an ointment had no effect on pain perception. Participants in the verbal suggestion condition (VSC) received information that it increased pain sensitivity. Participants in the social observational learning condition (OLC) watched a video in which a model displayed more pain when ointment was applied. Subsequently, all participants received three pressure pain stimuli (60 seconds) on each hand. On one hand, the ointment was applied prior to the stimulation. Numerical pain ratings were collected at 20-second intervals during pain stimulation. The participants filled in questionnaires regarding pain-related attitudes (Pain Anxiety Symptoms Scale, Pain Catastrophizing Scale, and Somatosensory Amplification Scale). Participants in the OLC showed higher pain ratings with than without ointment. Pain ratings within the CC and the VSC were at the same level with and without ointment. In the VSC, the pain ratings were higher than in the CC with and without ointment. The nocebo response correlated with pain catastrophizing but not with pain anxiety or somatosensory amplification. A nocebo response to pressure pain was induced by observational learning but not by verbal suggestion. This finding highlights the importance of investigating the influence of observational learning on nocebo hyperalgesia. (PsycINFO Database Record (c) 2016 APA, all rights reserved)

Individuals with bulimia nervosa (BN) or binge-eating disorder (BED) experience more frequent and intense food cravings than individuals without binge eating. However, it is currently unclear whether they also show larger food cue-induced increases in craving (i.e., food cue reactivity) than those without binge eating, as suggested by conditioning theories of binge eating. A group of individuals with BN or BED (binge-eating group,  n  = 27) and a group of individuals with low trait food craving scores and without binge eating (control group,  n  = 19) reported their current food craving before and after a food cue exposure. Although food craving intensity significantly increased in both groups, this increase was significantly stronger in the binge-eating group than in the control group. This result is in line with conditioning models of binge eating that propose that food cues are conditioned stimuli that elicit a conditioned response (e.g., food craving) and that this association is stronger in individuals with binge eating. As food craving increased in individuals with low trait food craving scores as well—although to a lesser extent—previous null results might be explained by methodological considerations such as not screening control participants for trait food craving.

Strong implicit responses to food have evolved to avoid energy depletion but contribute to overeating in today's affluent environments. The Approach–Avoidance Task (AAT) supposedly assesses implicit biases in response to food stimuli: Participants push pictures on a monitor “away” or pull them "near" with a joystick that controls a corresponding image zoom. One version of the task couples movement direction with image content-independent features, for example, pulling blue-framed images and pushing green-framed images regardless of content (‘irrelevant feature version’). However, participants might selectively attend to this feature and ignore image content and, thus, such a task setup might underestimate existing biases. The present study tested this attention account by comparing two irrelevant feature versions of the task with either a more peripheral (image frame color: green vs. blue) or central (small circle vs. cross overlaid over the image content) image feature as response instruction to a ‘relevant feature version’, in which participants responded to the image content, thus making it impossible to ignore that content. Images of chocolate-containing foods and of objects were used, and several trait and state measures were acquired to validate the obtained biases. Results revealed a robust approach bias towards food only in the relevant feature condition. Interestingly, a positive correlation with state chocolate craving during the task was found when all three conditions were combined, indicative of criterion validity of all three versions. However, no correlations were found with trait chocolate craving. Results provide a strong case for the relevant feature version of the AAT for bias measurement. They also point to several methodological avenues for future research around selective attention in the irrelevant versions and task validity regarding trait vs. state variables.