Friday, September 22, 2017

Mnemonic transmission, social contagion, and emergence of collective memory: Influence of emotional valence, group structure, and information distribution

Choi, H.-Y., Kensinger, E. A., & Rajaram, S. (2017). Mnemonic transmission, social contagion, and emergence of collective memory: Influence of emotional valence, group structure, and information distribution. Journal of Experimental Psychology: General, 146(9), 1247-1265.

Abstract: Social transmission of memory and its consequence on collective memory have generated enduring interdisciplinary interest because of their widespread significance in interpersonal, sociocultural, and political arenas. We tested the influence of 3 key factors—emotional salience of information, group structure, and information distribution—on mnemonic transmission, social contagion, and collective memory. Participants individually studied emotionally salient (negative or positive) and nonemotional (neutral) picture–word pairs that were completely shared, partially shared, or unshared within participant triads, and then completed 3 consecutive recalls in 1 of 3 conditions: individual–individual–individual (control), collaborative–collaborative (identical group; insular structure)–individual, and collaborative–collaborative (reconfigured group; diverse structure)–individual. Collaboration enhanced negative memories especially in insular group structure and especially for shared information, and promoted collective forgetting of positive memories. Diverse group structure reduced this negativity effect. Unequally distributed information led to social contagion that creates false memories; diverse structure propagated a greater variety of false memories whereas insular structure promoted confidence in false recognition and false collective memory. A simultaneous assessment of network structure, information distribution, and emotional valence breaks new ground to specify how network structure shapes the spread of negative memories and false memories, and the emergence of collective memory.

Check: Social contagion of memory. HENRY L. ROEDIGER III, MICHELLE L. MEADE, and ERIK T. BERGMAN. Psychonomic Bulletin & Review, 2001, 8 (2), 365-371,

Abstract: We report a new paradigm for studying false memories implanted by social influence, a process we call the social contagion of memory. A subject and confederate together saw six common household scenes (e.g., a kitchen) containing many objects, for either 15 or 60 sec. During a collaborative recall test, the 2 subjects each recalled six items from the scenes, but the confederate occasionally made mistakes by reporting items not from the scene. Some intrusions were highly consistent with the scene schema (e.g., a toaster) while others were less so (e.g., oven mitts). After a brief delay, the individual subject tried to recall as many items as possible from the six scenes. Recall of the erroneous items suggested by the confederate was greater than in a control condition (with no suggestion). Further, this social contagion effect was greater when the scenes were presented for less time (15 sec) and when the intruded item was more schema consistent (e.g., the toaster). As with other forms of social influence, false memories are contagious; one person’s memory can be infected by another person’s errors.

Tattooed targets, especially women, were rated as stronger and more independent, but more negatively

Tattoo or taboo? Tattoo stigma and negative attitudes toward tattooed individuals. Kristin A Broussard & Helen C Harton. The Journal of Social Psychology,

ABSTRACT: Tattoos are common in the United States; however, tattooed persons may be perceived as having more negative character and as more deviant than people without tattoos. College students (Study 1) and community members (Study 2) viewed images of men and women with tattoos or the same images with the tattoos digitally removed and rated the targets’ characteristics. Half of the participants viewed a target with a tattoo, and half viewed that target without it, allowing for both within- (participants all rated one male and one female target with a tattoo and another without) and between-participants (participants rated either the tattooed or non-tattooed version of a single target) comparisons. Tattooed targets, especially women, were rated as stronger and more independent, but more negatively on other character attributes than the same target images with the tattoos removed. The stigma associated with tattoos appears to still exist, despite the prevalence of tattoos in modern culture.

KEYWORDS: Tattoo, stigma, gender, stereotypes

Tattooed people also judge negatively other tattooed individuals, like the non-tattooed do.

How many laypeople holding a popular opinion are needed to counter an expert opinion?

How many laypeople holding a popular opinion are needed to counter an expert opinion? Jos Hornikx, Adam J. L. Harris & Jordy Boekema. Thinking & Reasoning,

Abstract: In everyday situations, people regularly receive information from large groups of (lay) people and from single experts. Although lay opinions and expert opinions have been studied extensively in isolation, the present study examined the relationship between the two by asking how many laypeople are needed to counter an expert opinion. A Bayesian formalisation allowed the prescription of this quantity. Participants were subsequently asked to assess how many laypeople are needed in different situations. The results demonstrate that people are sensitive to the relevant factors identified for determining how many lay opinions are required to counteract a single expert opinion. People's assessments were fairly good in line with Bayesian predictions.

KEYWORDS: Expert opinion, popular opinion, Bayesian argumentation

Invasive interventions are associated with substantially large placebo effects

Route of Placebo Administration: Robust Placebo Effects in Laboratory and Clinical Settings. Tao Liu. Neuroscience & Biobehavioral Reviews,

•    Pivotal role of placebo administration in subsequent placebo responses.
•    Robust placebo analgesia in the context of anticipating an upcoming pain.
•    Enhanced placebo effects associated with invasive procedures

Abstract: Recent advances in laboratory and clinical research have greatly enhanced our understanding of placebo effects. However, little progress has been made in translational research that can well integrate these findings. This article examines pivotal role of placebo administration in subsequent placebo responses, providing a unified framework that accounts for robust placebo effects in both laboratory and clinical settings.

Keywords: placebo effects; placebo administration; route of administration; pain; pain anticipation; learning; conditioning; verbal suggestion; belief; reward expectation; appetitive motivation; emotion; anxiety; brain mechanisms; descending pain modulation; RCTs; invasive placebo; sham invasive procedure; acupuncture; clinical practice

Depression is not due to interaction of genetics and childhood trauma -- study of 5,765 subjects from the Psychiatric Genomics Consortium

Does childhood trauma moderate polygenic risk for depression? A meta-analysis of 5,765 subjects from the Psychiatric Genomics Consortium. Wouter J. Peyrot, et al. Biological Psychiatry,


Background: The heterogeneity of genetic effects on Major Depressive Disorder (MDD) may be partly attributable to moderation of genetic effects by environment, such as exposure to childhood trauma (CT). Indeed, previous findings in two independent cohorts showed evidence for interaction between polygenic risk scores (PRS) and CT, albeit in opposing directions. This study aims to meta-analyze MDD-PRSxCT interaction results across these two and other cohorts, while applying more accurate PRS based on a larger discovery sample.

Methods and Materials: Data were combined from 3,024 MDD cases and 2,741 controls from nine cohorts contributing to the MDD Working Group of the Psychiatric Genomics Consortium. MDD-PRS were based on a discovery sample of approximately 110,000 independent individuals. CT was assessed as exposure to sexual or physical abuse during childhood. In a subset of 1957 cases and 2002 controls, a more detailed 5-domain measure additionally included emotional abuse, physical neglect and emotional neglect.

Results: MDD was associated with the MDD-PRS (OR=1.24, p=3.6e-5, R2=1.18%) and with CT (OR=2.63, p=3.5e-18 and OR=2.62, p=1.4e-5 for the 2- and 5-domain measures respectively). No interaction was found between MDD-PRS and the 2-domain and 5-domain CT measure (OR=1.00, p=0.89 and OR=1.05, p=0.66).

Conclusions: No meta-analytic evidence for interaction between MDD-PRS and CT was found. This suggests that the previously reported interaction effects, although both statistically significant, can best be interpreted as chance findings. Further research is required, but this study suggests that the genetic heterogeneity of MDD is not attributable to genome-wide moderation of genetic effects by CT.

The Ugly Truth About Ourselves and Our Robot Creations: The Problem of Bias and Social Inequity

As a preventive measure against possible complains in the future about bias, I share this:

The Ugly Truth About Ourselves and Our Robot Creations: The Problem of Bias and Social Inequity. Ayanna Howard and Jason Borenstein. Science and Engineering Ethics,

Abstract: Recently, there has been an upsurge of attention focused on bias and its impact on specialized artificial intelligence (AI) applications. Allegations of racism and sexism have permeated the conversation as stories surface about search engines delivering job postings for well-paying technical jobs to men and not women, or providing arrest mugshots when keywords such as “black teenagers” are entered. Learning algorithms are evolving; they are often created from parsing through large datasets of online information while having truth labels bestowed on them by crowd-sourced masses. These specialized AI algorithms have been liberated from the minds of researchers and startups, and released onto the public. Yet intelligent though they may be, these algorithms maintain some of the same biases that permeate society. They find patterns within datasets that reflect implicit biases and, in so doing, emphasize and reinforce these biases as global truth. This paper describes specific examples of how bias has infused itself into current AI and robotic systems, and how it may affect the future design of such systems. More specifically, we draw attention to how bias may affect the functioning of (1) a robot peacekeeper, (2) a self-driving car, and (3) a medical robot. We conclude with an overview of measures that could be taken to mitigate or halt bias from permeating robotic technology.