The Role of Trait Inferences in Evaluative Conditioning

Evaluative Conditioning (EC) effect is a change in evaluative responding to a neutral stimulus (CS) due to its pairing with a valenced stimulus (US). Traditionally, EC effects are viewed as fundamentally different from per-suasion effects. Inspired by a propositional perspective to EC, four studies (N = 1,284) tested if, like persuasion effects, EC effects can also be driven by trait inferences. Experiments 1-2 found that promoting trait inferences (by pairing people with trait words rather than nouns) increased EC effects. Experiments 3-4 found that under-mining trait inferences (by questioning the validity of those inferences) decreased EC effects. In all experiments, however, EC effects were still significant when trait inferences were invalid. Taken together, our findings (a) suggest that trait inferences can play an important role in EC effects, (b) constrain theoretical models of EC, and (c) have important implications for applied EC interventions.

Interoception modulates the self-prioritization effect

Self-relevant information is processed faster and more accurately than non-self-relevant information. Such a bias is developed even for newly associated information with the self, also known as the self-prioritization effect (SPE). Interoception, which refers to the overall processing of information from inside the body, is crucial for self-relevant processing; however, little is known about its role in SPE. In this study, we investigated the relationship between the magnitude of SPE and interoceptive accuracy (IAc), defined as an individual’s ability to accurately perceive one’s own interoceptive state. Additionally, to explore the causal relationship, we measured SPE by presenting self- or non-self-relevant stimuli based on the participant's cardiac cycle in the shape-label matching task. We demonstrated that IAc was negatively correlated with the magnitude of SPE in terms of discrimination of the relevance of the stimuli. In addition, a correlation was observed only when the stimuli were presented during cardiac systole. Furthermore, IAc was negatively correlated with the processing of self-relevant stimuli but not with non-self-relevant stimuli. Our findings suggest that individuals with high IAc were less able to discriminate whether an external neutral stimulus was self-relevant when the stimulus was presented at systole. Our results may reflect the tendency to recognize the self-relevance of stimuli based on interoception in individuals with high IAc. Since the present study used geometric shapes, which are not easily recognized as stimuli that can induce changes in the interoception, individuals with high IAc assigned less self-relevance to the stimuli, resulting in weaker SPE. From this perspective, we further discussed the conditions that lead to stronger SPE in individuals with high IAc, in contrast to the present study results.

The Influence of Negative Orthographic Neighborhood in the Lexical Decision Task: Valence and Arousal Contributions

This study investigated whether the visual recognition of neutral words might be influenced by the emotional dimensions (i.e., valence and arousal) of orthographically similar lexical representations, and whether this might also depend on emotional-related traits of participants (i.e., alexithymia). To this end, 108 participants performed a lexical decision task with 80 neutral words with a higher frequency orthographic neighbor that varied in valence (from neutral to negative) and arousal (from low to high). The main finding was the expected interaction effect between the valence and arousal of the neighbor on the lexical decision times of neutral stimulus words. Longer reaction times were found when the valence score of the neighbor decreased from neutral to negative for words with a low-arousal orthographic neighbor while this emotional neighbor effect was reversed for words with a high-arousal negative neighbor. This combined influence of the valence and arousal of the neighbor was interpreted in terms of increased lexical competition processes and direct influence of the affective system on the participant’s response. Moreover, this interaction effect was smaller when the level of alexithymia of the participants increased, suggesting that people with a higher level of alexithymia are less sensitive to the emotional content of the neighbor. The results are discussed within an interactive activation model of visual word recognition incorporating an affective system with valence and arousal dimensions, with regard to the role of the alexithymia level of participants.

The Opioid Receptor Antagonist Naloxone Enhances First-Order Fear Conditioning, Second-Order Fear Conditioning and Sensory Preconditioning in Rats

The opioid receptor antagonist naloxone enhances Pavlovian fear conditioning when rats are exposed to pairings of an initially neutral stimulus, such as a tone, and a painful foot shock unconditioned stimulus (US; so-called first-order fear conditioning; Pavlov, 1927). The present series of experiments examined whether naloxone has the same effect when conditioning occurs in the absence of US exposure. In Experiments 1a and 1b, rats were exposed to tone-shock pairings in stage 1 (one trial per day for 4 days) and then to pairings of an initially neutral light with the already conditioned tone in stage 2 (one trial per day for 4 days). Experiment 1a confirmed that this training results in second-order fear of the light; and Experiment 1b showed that naloxone enhances this conditioning: rats injected with naloxone in stage 2 froze more than vehicle-injected controls when tested with the light alone (drug-free). In Experiments 2a and 2b, rats were exposed to light-tone pairings in stage 1 (one trial per day for 4 days) and then to tone-shock pairings in stage 2 (one trial per day for 2 days). Experiment 2a confirmed that this training results in sensory preconditioned fear of the light; and Experiment 2b showed that naloxone enhances sensory preconditioning when injected prior to each of the light-tone pairings: rats injected with naloxone in stage 1 froze more than vehicle-injected controls when tested with the light alone (drug-free). These results were taken to mean that naloxone enhances fear conditioning independently of its effect on US processing; and more generally, that opioids regulate the error-correction mechanisms that underlie associative formation.

Effects of Crowd Size, Composition, and Noise Level On Pool Use in a Mixed-Species Penguin Colony

Studies on how visitors affect penguins in human care report a mixture of negative, neutral, and positive impacts on behavior and physiology. Swimming is a highly motivated behavior that may promote positive welfare in penguins. We investigated how visitor crowd size, composition, and noise levels impact pool use in a mixed-species colony housing king (Aptenodytes patagonicus; n = 20), gentoo (Pygoscelis papua; n = 14), and southern rockhopper (Eudyptes chrysocome; n = 24) penguins. We used video and sound loggers to record if penguins were on land or in water, the number of human adults and children present, and noise levels using 5-minute scan samples from 09:00-15:00 over 36 continuous days. Data were analyzed using linear mixed models with proportion of penguins in the water as the dependent variable and crowd size, composition, and noise levels in A-weighted (dBA) and C-weighted (dBC) scales as independent variables. Crowd size was positively associated with pool use in gentoo penguins. Crowd composition did not predict pool use in any species. Noise levels in dBA, which is adjusted to the higher frequencies of human hearing, positively predicted pool use in southern rockhopper penguins. Noise levels in dBC, which captures lower frequencies, did not predict pool use in any species. No evidence of negative visitor effects was observed. Instead, these results suggest visitors are a neutral stimulus to king penguins and may be enriching to gentoo and southern rockhopper penguins.

Leaving the Door Open: Trauma, Updating, and the Development of PTSD Symptoms

Humans try to make sense of the world using hypotheses that were formed by prior experiences. After trauma, these hypotheses can be exaggerated and resistant to change. This may result in difficulties to update expectations regarding the negative outcomes associated with traumatic stimuli. Critically, it has been proposed that such difficulties may drive the development of posttraumatic stress disorder (PTSD). However, direct evidence on the associations between trauma and impaired expectation updating is still absent. Moreover, it remains unclear whether such an impairment is correlated with PTSD symptoms. To address these gaps, we compared the ability to update traumatic and neutral stimulus-outcome expectations in 81 active-duty firefighters. Participants completed a performance-based reversal learning task and were assessed for PTSD symptoms. We predicted and found a selective impairment in updating trauma-related expectations. This impairment was evident for negative-to-positive but not for positive-to-negative updating. Moreover, impaired negative-to-positive updating was positively associated with PTSD symptoms. These findings support the predictive processing account of PTSD and suggest that strengthening updating processes could be an important goal for promoting resilience after trauma.

Enhanced processing of aversive stimuli on embodied artificial limbs by the human amygdala

Body perception has been extensively investigated, with one particular focus being the integration of vision and touch within a neuronal body representation. Previous studies have implicated a distributed network comprising the extrastriate body area (EBA), posterior parietal cortex (PPC) and ventral premotor cortex (PMv) during illusory self-attribution of a rubber hand. Here, we set up a fMRI paradigm in virtual reality (VR) to study whether and how threatening (artificial) body parts affects their self-attribution. Participants (N=30) saw a spider (aversive stimulus) or a toy-car (neutral stimulus) moving along a 3D-rendered virtual forearm positioned like their real forearm, while tactile stimulation was applied on the real arm in the same (congruent) or opposite (incongruent) direction. We found that the PPC was more activated during congruent stimulation; higher visual areas and the anterior insula (aIns) showed increased activation during aversive stimulus presentation; and the amygdala and pregenual anterior cingulate cortex (ACC) were more strongly activated for aversive stimuli when there was stronger multisensory integration of body-related information (interaction of aversiveness and congruency). Together, these findings suggest an enhanced processing of aversive stimuli within the amygdala when they represent a threat to body integrity.

Cortical Contributions to Higher-Order Conditioning: A Review of Retrosplenial Cortex Function

In higher-order conditioning paradigms, such as sensory preconditioning or second-order conditioning, discrete (e.g., phasic) or contextual (e.g., static) stimuli can gain the ability to elicit learned responses despite never being directly paired with reinforcement. The purpose of this mini-review is to examine the neuroanatomical basis of high-order conditioning, by selectively reviewing research that has examined the role of the retrosplenial cortex (RSC) in sensory preconditioning and second-order conditioning. For both forms of higher-order conditioning, we first discuss the types of associations that may occur and then review findings from RSC lesion/inactivation experiments. These experiments demonstrate a role for the RSC in sensory preconditioning, suggesting that this cortical region might contribute to higher-order conditioning via the encoding of neutral stimulus-stimulus associations. In addition, we address knowledge gaps, avenues for future research, and consider the contribution of the RSC to higher-order conditioning in relation to related brain structures.

The autonomic pain relief response is dependent of self or social influence on pain

Pain relief is defined as the ease of pain and is thus highly relevant for clinical applications and everyday life. Given that pain relief is based on the cessation of an aversive pain experience, it is reasonable to assume that pain relief learning would also be shaped by factors that alter subjective and physiological pain responses, such as social presence or a feeling of control. To date, it remains unclear whether and how factors that shape autonomic pain responses might affect pain relief learning. Here, we investigated how pain relief learning is shaped by two important factors known to modulate pain responses, i.e. social influence and controllability of pain. Skin conductance responses (SCRs) were recorded while participants learned to associate a formerly neutral stimulus with pain relief under three different pain conditions. In the social-influence condition (N = 34), the pain stimulation could be influenced by another person’s decisions. In the self-influence condition (N = 31), the participants themselves could influence the pain stimulation. Finally, in the no-influence condition (N = 32), pain stimulation was simply delivered without any influence. According to our results, the SCRs elicited by the stimulus that was associated with pain relief were significantly smaller compared to the SCRs elicited by a neutral control stimulus, indicating pain relief learning. However, there was no difference in the pain relief learning effect across the groups. These results suggest that physiological pain relief learning in humans is independent of social influence and pain controllability.

Development of a Semantically Related Emotional and Neutral Stimulus Set

When measuring memory performance for emotional and neutral stimuli many studies are confounded by not controlling for differential semantic relatedness between stimulus sets. This could lead to the misattribution of the cause of an emotional enhancement of memory effect (EEM), because differential semantic relatedness also contributes to the EEM. Participants rated static visual emotional and neutral scenes on measures of arousal, valence, and semantic relatedness. These measures were used to create a novel stimulus set, which – in addition to demonstrating significant differences in measures of valence and arousal – also controlled for within-set semantic relatedness; thus resolving a crucial issue that has not previously been addressed in the use of visual emotional stimuli. As an added advantage, the stimulus set developed here are controlled for measures of objective visual complexity, also implicated as confounding to the investigation of memory. This article introduces a collection of emotional and neutral colour images which can be organised flexibly according to experimental requirements. These stimuli are made freely available for non-commercial use within the scientific community.