All around you
Pain relief provided by an outgroup member enhances analgesia
Grit Hein, Jan Engelmann & Philippe Tobler
Proceedings of the Royal Society: Biological Sciences, 26 September 2018
Abstract:
Pain feels different in different social contexts, yet the mechanisms behind social pain modulation remain poorly understood. To elucidate the impact of social context on pain processing, we investigated how group membership, one of the most important social context factors, shapes pain relief behaviourally and neurally in humans undergoing functional neuroimaging. Participants repeatedly received pain relief from a member of their own group (ingroup treatment) or a member of a disliked outgroup (outgroup treatment). We observed a decrease in pain ratings and anterior insula (AI) pain responses after outgroup treatment, but not after ingroup treatment. Moreover, path analyses revealed that the outgroup treatment induced a stronger relief learning in the AI, which in turn altered pain processing, in particular if the participant entered the treatment with a negative impression toward the outgroup individual. The finding of enhanced analgesia after outgroup treatment is relevant for intergroup clinical settings. More generally, we found that group membership affects pain responses through neural learning and we thus elucidate one possible mechanism through which social context impacts pain processing.
Reversing the causal arrow: Incidence and properties of negative backward magical contagion in Americans
Paul Rozin, Christopher Dunn & Natalie Fedotova
Judgment and Decision Making, September 2018, Pages 441-450
Abstract:
Backward magical contagion describes instances in which individuals (sources) express discomfort or pleasure when something connected to them (medium; e.g., hair, a diary) falls into the possession of a negatively- or positively-perceived individual (recipient). The reaction seems illogical, since it is made clear that the source will never experience the object again, and the psychological effect appears to reverse the standard forward model of causality. Backward magical contagion was originally believed to be a belief held only within traditional cultures. Two studies examined negative backward contagion in adult Americans in online surveys. Study 1 indicated that backward contagion effects occur commonly, particularly when a recipient knows of the medium's source. Study 2 showed that backward contagion effects tend to be neutralized when the recipient burns the object, as opposed to just possessing it or discarding it. Ironically, in traditional cultures, burning is a particularly potent cause of backward contagion.
Baseball's sight-audition farness effect (SAFE) when umpiring baserunners: Judging precedence of competing visual versus auditory events
Chandler Krynen & Michael McBeath
Journal of Experimental Psychology: Human Perception and Performance, forthcoming
Abstract:
Baseball umpires judge force-outs at first-base by comparing the sound of ball-mitt contact to the sight of foot-base contact. This study examines if distant observer judgments of the temporal order of visual versus auditory events are biased due to the slow speed of sound, or if judgments made from farther away systematically compensate for acoustic delays of sound. Seventy and 81 participants observed videos projected onto a gymnasium wall from 0, 100, or 200 feet, and made multisensory precedence judgments regarding which cue occurred first, visual ("safe") or auditory ("out"). Experiment 1 used visual flash versus auditory click; Experiment 2, colliding visual stimuli versus auditory click; Experiment 3, films of base-runners with basemen catching balls. Our findings confirm a sight-audition farness effect (SAFE) bias such that when visual information is impoverished, distant observers making multisensory precedence judgments typically do not fully compensate for acoustic delays due to the slow speed of sound, which can lead to disagreements. In short, distant fans will tend to have more of a bias to experience baserunners as safe, compared with nearby umpires.
The opportunity to choose enhances long-term episodic memory
Nuphar Rotem-Turchinski, Ayelet Ramaty & Avi Mendelsohn
Memory, forthcoming
Abstract:
Episodic memory is typically studied under conditions that treat participants as passive agents. Here we sought to explore how actively engaging in ongoing naturalistic occurrences affects long-term episodic memory. Participants viewed 40 short movie clips that depicted a protagonist that conversed with the participants. In each clip, they were either offered the chance to (supposedly) determine the clip's continuation (active condition), or let the computer decide for them (passive condition). Participants returned either two days or one week after the experience to undergo a true/false memory test for the clips' details and a two-alternative recognition test for the choices made. Memory performance for both groups was superior for information and choices conveyed in the active vs. passive condition. These findings suggest that the sense of actively influencing the unfolding of events is beneficial to long-term memory of the experience at large, baring potential interventions in the fields of education and cognitive enhancement.
Searching for answers in an uncertain world: Meaning threats lead to increased working memory capacity
Daniel Randles et al.
PLoS ONE, October 2018
Abstract:
The Meaning Maintenance Model posits that individuals seek to resolve uncertainty by searching for patterns in the environment, yet little is known about how this is accomplished. Four studies investigated whether uncertainty has an effect on people's cognitive functioning. In particular, we investigated whether meaning threats lead to increased working memory capacity. In each study, we exposed participants to either an uncertain stimulus used to threaten meaning in past studies, or a control stimulus. Participants then completed a working memory measure, where they either had to recall lists of words (Studies 1, 2), or strings of digits (Studies 3, 4). We used both a frequentist approach and Bayesian analysis to evaluate our findings. Across the four studies, we find a small but consistent effect, where participants in the meaning threat condition show improved performance on the working memory tasks. Overall, our findings were consistent with the hypothesis that working memory capacity increases when people experience a meaning threat, which may help to explain improved pattern recognition. Additionally, our results highlight the value of using a Bayesian analytic approach, particularly when studying phenomena with high variance.
Attribution Bias in Consumer Choice
Kareem Haggag et al.
Review of Economic Studies, forthcoming
Abstract:
When judging the value of a good, people may be overly influenced by the state in which they previously consumed it. For example, someone who tries out a new restaurant while very hungry may subsequently rate it as high quality, even if the food is mediocre. We produce a simple framework for this form of attribution bias that embeds a standard model of decision making as a special case. We test for attribution bias across two consumer decisions. First, we conduct an experiment in which we randomly manipulate the thirst of participants prior to consuming a new drink. Second, using data from thousands of amusement park visitors, we explore how pleasant weather during their most recent trip affects their stated and actual likelihood of returning. In both of these domains, we find evidence that people misattribute the influence of a temporary state to a stable quality of the consumption good. We provide evidence against several alternative accounts for our findings and discuss the broader implications of attribution bias in economic decision making.
Respiration modulates olfactory memory consolidation in humans
Artin Arshamian et al.
Journal of Neuroscience, forthcoming
Abstract:
In mammals, respiratory-locked hippocampal rhythms are implicated in the scaffolding and transfer of information between sensory and memory networks. These oscillations are entrained by nasal respiration and driven by the olfactory bulb. They then travel to the piriform cortex where they propagate further downstream to the hippocampus and modulate neural processes critical for memory formation. In humans, bypassing nasal airflow through mouth-breathing abolishes these rhythms and impacts encoding as well as recognition processes thereby reducing memory performance. It has been hypothesized that similar behavior should be observed for the consolidation process, the stage between encoding and recognition, were memory is reactivated and strengthened. However, direct evidence for such an effect is lacking in human and non-human animals. Here we tested this hypothesis by examining the effect of respiration on consolidation of episodic odor memory. In two separate sessions, female and male participants encoded odors followed by a one hour awake resting consolidation phase where they either breathed solely through their nose or mouth. Immediately after the consolidation phase, memory for odors was tested. Recognition memory significantly increased during nasal respiration compared to mouth respiration during consolidation. These results provide the first evidence that respiration directly impacts consolidation of episodic events, and lends further support to the notion that core cognitive functions are modulated by the respiratory cycle.
Dopaminergic basis for signaling belief updates, but not surprise, and the link to paranoia
Matthew Nour et al.
Proceedings of the National Academy of Sciences, 23 October 2018, Pages E10167-E10176
Abstract:
Distinguishing between meaningful and meaningless sensory information is fundamental to forming accurate representations of the world. Dopamine is thought to play a central role in processing the meaningful information content of observations, which motivates an agent to update their beliefs about the environment. However, direct evidence for dopamine's role in human belief updating is lacking. We addressed this question in healthy volunteers who performed a model-based fMRI task designed to separate the neural processing of meaningful and meaningless sensory information. We modeled participant behavior using a normative Bayesian observer model and used the magnitude of the model-derived belief update following an observation to quantify its meaningful information content. We also acquired PET imaging measures of dopamine function in the same subjects. We show that the magnitude of belief updates about task structure (meaningful information), but not pure sensory surprise (meaningless information), are encoded in midbrain and ventral striatum activity. Using PET we show that the neural encoding of meaningful information is negatively related to dopamine-2/3 receptor availability in the midbrain and dexamphetamine-induced dopamine release capacity in the striatum. Trial-by-trial analysis of task performance indicated that subclinical paranoid ideation is negatively related to behavioral sensitivity to observations carrying meaningful information about the task structure. The findings provide direct evidence implicating dopamine in model-based belief updating in humans and have implications for understating the pathophysiology of psychotic disorders where dopamine function is disrupted.