Ultrasensitive electrochemical sensor for detection of salivary cortisol in stress conditions.

A natural stress response induces elevated cortisol levels in biological fluids, such as saliva. While current sensor technologies can detect cortisol in real time, their sensitivity and reliability for human subjects have not been assured. This is due to relatively low concentrations of salivary cortisol, which fluctuate throughout the day and vary significantly between individuals. To address these challenges, we present an improved electrochemical biosensor leveraging graphene's exceptional conductivity and physicochemical properties. A 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE-NHS)-modified commercial graphene foam (GF) electrode is presented to realize an ultra-sensitive biosensor for cortisol detection directly in human saliva. The biosensor fabrication process entails the attachment of anti-cortisol monoclonal antibodies (mAb-cort) onto a PBASE-NHS/GF electrode through noncovalent immobilization on the vertically stratified graphene foam electrode surface. This unique immobilization strategy preserves graphene's structural integrity and electrical conductivity while facilitating antibody immobilization. The binding of cortisol to immobilized mAb-cort is read out via differential pulse voltammetry using ferri/ferro redox reactions. The immunosensor demonstrates an exceptional dynamic range of 1.0 fg mL-1 to 10,000 pg mL-1 (R2 = 0.9914) with a detection limit of 0.24 fg mL-1 (n = 3) for cortisol. Furthermore, we have established the reliability of cortisol sensors in monitoring human saliva. We have also performed multiple modes of validation, one against the established enzyme-linked immunosorbent assay (ELISA) and a second by a third-party service Salimetric on 16 student volunteers exposed to different stress levels, showing excellent correlation (r = 0.9961). These findings suggest the potential for using mAb-cort/PBASE-NHS/GF-based cortisol electrodes for monitoring salivary cortisol in the general population.

Protecting memory from misinformation: Warnings modulate cortical reinstatement during memory retrieval.

Exposure to even subtle forms of misleading information can significantly alter memory for past events. Memory distortion due to misinformation has been linked to faulty reconstructive processes during memory retrieval and the reactivation of brain regions involved in the initial encoding of misleading details (cortical reinstatement). The current study investigated whether warning participants about the threat of misinformation can modulate cortical reinstatement during memory retrieval and reduce misinformation errors. Participants watched a silent video depicting a crime (original event) and were given an initial test of memory for the crime details. Then, participants listened to an auditory narrative describing the crime in which some original details were altered (misinformation). Importantly, participants who received a warning about the reliability of the auditory narrative either before or after exposure to misinformation demonstrated less susceptibility to misinformation on a final test of memory compared to unwarned participants. Warned and unwarned participants also demonstrated striking differences in neural activity during the final memory test. Compared to participants who did not receive a warning, participants who received a warning (regardless of its timing) demonstrated increased activity in visual regions associated with the original source of information as well as decreased activity in auditory regions associated with the misleading source of information. Stronger visual reactivation was associated with reduced susceptibility to misinformation, whereas stronger auditory reactivation was associated with increased susceptibility to misinformation. Together, these results suggest that a simple warning can modulate reconstructive processes during memory retrieval and reduce memory errors due to misinformation.

What the Acute Stress Response Suggests about Memory.

Research suggests that stress has immediate and long-term effects on attention and memory. Rather than disrupting memory formation and consolidation, acute stress has been shown to shift attention processes resulting in a tradeoff between prioritized and nonprioritized information. Both arousal and stress result in cognitive and neurobiological shifts that often support memory formation. When an acute stressor occurs, it can distort immediate attentional focus, increasing processing for high-priority features while reducing processing for extraneous features. The downstream cognitive consequences for this shift in attention are better memory for some features and poorer memory for others when compared to conditions of low stress. However, individual differences (e.g., sex, age, basal stress response, and stress reactivity) all impact the relationship between the acute stress response and memory. Although acute stress generally benefits memory formation, we suggest that forgetting and later recovery of stressful memories can better be understood by examining factors that influence the subjective experience of stress and stress reactivity.

Thinking about thinking about thinking & feeling: A model for metacognitive and meta-affective processes in task engagement.

Metacognition, or thinking about thinking, is a phenomenon that has received much attention across the numerous fields of Psychological Science. The overarching goal has centered on understanding how humans monitor their internal mental processes and exert control over these processes. However, discipline-focused approaches with little generalized discussion across the field have yielded an incomplete understanding of the construct of metacognition. Consider, for example, the cognitive approach: from this perspective, researchers have developed predictive models and useful frameworks. Further, the field has produced sophisticated techniques to measure monitoring accuracy and define attributes that contribute to monitoring assessments and control process selection. However, the impact of this research has been relatively limited and isolated from metacognitive investigations that consider other important constructs such as motivation and affect. The approaches taken in subfields, such as educational psychology, emotion, and neuropsychology when combined with the cognitive approach, may result in a more complete picture and thorough understanding of metacognition. In this article, we present an argument that the study of metacognition should bridge the various subfields of psychological inquiry. We present a framework toward an integrative approach to understanding metacognition as a complementary process to meta-affect and encourage researchers to consider the study of metacognition from a broader perspective. This article is categorized under: Psychology > Memory Psychology > Emotion and Motivation.

White (but Not Black) Americans Continue to See Racism as a Zero-Sum Game; White Conservatives (but Not Moderates or Liberals) See Themselves as Losing.

In a 2011 article in this journal entitled "Whites See Racism as a Zero-Sum Game That They Are Now Losing" (Perspectives on Psychological Science, 6, 215-218), Norton and Sommers assessed Black and White Americans' perceptions of anti-Black and anti-White bias across the previous 6 decades-from the 1950s to the 2000s. They presented two key findings: White (but not Black) respondents perceived decreases in anti-Black bias to be associated with increases in anti-White bias, signaling the perception that racism is a zero-sum game; White respondents rated anti-White bias as more pronounced than anti-Black bias in the 2000s, signaling the perception that they were losing the zero-sum game. We collected new data to examine whether the key findings would be evident nearly a decade later and whether political ideology would moderate perceptions. Liberal, moderate, and conservative White (but not Black) Americans alike believed that racism is a zero-sum game. Liberal White Americans saw racism as a zero-sum game they were winning by a lot, moderate White Americans saw it as a game they were winning by only a little, and conservative White Americans saw it as a game they were losing. This work has clear implications for public policy and behavioral science and lays the groundwork for future research that examines to what extent racial differences in perceptions of racism by political ideology are changing over time.

The Dynamic and Fragile Nature of Eyewitness Memory Formation: Considering Stress and Attention.

Eyewitnesses are often susceptible to recollection failures and memory distortions. These failures and distortions are influenced by several factors. The present review will discuss two such important factors, attention failures and stress. We argue that acute stress, often experienced by eyewitnesses and victims of crimes, directly influences attentional processes, which likely has downstream consequences for memory. Attentional failures may result in individuals missing something unusual or important in a complex visual field. Amongst eyewitnesses, this can lead to individuals missing details, even unusual or important central details, regarding the crime. Surprisingly, few studies have investigated attentional failures in eyewitness scenarios, and none have investigated the relationship between stress, attention, and witness memory. This review will discuss the impact of attentional failures, mainly those resulting from inattentional blindness, in applied contexts in order to bridge to eyewitness scenarios. In addition, we will integrate the applied literature on attentional failures with literature that examines the influences of arousal and stress on attention. We will conclude by presenting how future research may tease apart the independent contributions of arousal and stress on attentional failures and successes and how this research may inform understanding of eyewitness reliability.

Stealing and sharing memories: Source monitoring biases following collaborative remembering.

People experience difficulties tracking the source of their memories following collaborative remembering. This results in a variety of source monitoring errors. Researchers have typically focused on one of these errors - instances of adopting information from external sources as one's own memories. They have failed to investigate the frequency of other possible source monitoring errors. Because of this, it is impossible to say whether observed instances of mistakenly adopting external information represent a true bias in remembering or whether these errors simply reflect one of many memory errors that have an equal likelihood of occurring. In two studies, we teased apart these two possibilities. Members of dyads individually studied pictures with some items appearing in both participants' pictures and some unique to each one's pictures. Participants then collaboratively recalled what items were present. After the collaborative recall, participants completed individual source monitoring tests. We found that participants displayed biases in their source monitoring errors for information discussed during collaborative remembering. They were more likely to adopt information from partners as their own memories than attribute their contributions to their partners. They also more often believed their memories (rather than their partner's) were shared, representing a false consensus. Importantly, these biases only occurred following collaborative remembering and not when individuals received comparable information in a non-social setting. These results illuminate the importance of investigating the relative, and not just absolute, frequency of source monitoring errors and provide insight into how collaborative remembering changes individual memories over time.