How expectancy violations facilitate learning to cope with pain – An experimental approach

Background: Expectations of painful sensations constitute a core feature of chronic pain. An important clinical question is whether such expectations are revised when disconfirming experiences are made (e.g., less pain than expected). The present study examined how people adjust their pain expectations when the experience of decreasing pain is expected vs. unexpected. Methods: In a novel experimental paradigm, people who frequently experience pain (N=73) were provided with painful thermal stimulations. Unbeknownst to participants, the temperature applied was decreased from trial to trial. Based on the experimental instructions provided, this experience of decreasing pain was expected in one condition (expectation-confirmation), whereas it was unexpected in another (expectation-disconfirmation). Results: Expectation violations were higher in the expectation-disconfirmation condition than in the expectation-confirmation condition, F(1, 69) = 6.339, p = .014, ηp² = .084. Participants from the expectation-confirmation condition showed a greater adjustment of their pain expectations than the expectation-disconfirmation condition, F(1.666, 114.929) = 7.486, p = .002, ηp² = .098. Across groups, expectation adjustment was related to increases in pain tolerance (r = .342, p = .004) and the ability to cope with pain (r = .234, p = .045) at a one-week follow-up. Conclusions: Participants were more likely to adjust their pain expectations when the experience of decreasing pain was expected. Though participants who experienced large discrepancies between expected and experienced pain were hesitant to adjust their pain expectations immediately, experiencing expectation violations increased their ability to cope with pain one week later, suggesting some beneficial longer-term effects of expectation violations.

Investigation of code-switching cost in conversation and self-paced reading tasks

Aims and objectives: Studies of code-switching (CS) in bilingual speakers using laboratory tasks have been equivocal on whether CS is cognitively demanding. The goal of this study was to examine time costs at the juncture of a CS in a more ecologically valid experimental paradigm. Methodology: English (L1)–French (L2) bilingual speakers performed two tasks. The primary experimental task was a novel paradigm that elicited voluntary code-switches in conversation with a bilingual interlocutor. A silent self-paced reading task was used to compare with a laboratory task with involuntary switches. Data and analysis: Intersyllabic durations (conversation task) and reading times (reading task) were analyzed. CS cost was the time difference between code-switches and matched non-switches. Cost-switching costs for each switch direction (English-to-French and French-to-English) and type of switch (alternations and insertions) were also compared. Findings: Code-switches in conversation were associated with a time cost, and the magnitude was comparable in both directions although speakers more frequently switched from French-to-English. In self-paced reading, switching costs were observed only for switches into the dominant language. Across both tasks, there were no differences in CS time cost between insertions and alternations. Originality: This study reports a novel measure of CS costs in conversation, intersyllabic duration, and provides a cross-task comparison in the same group of bilingual speakers to better inform theories of CS. Implications: Bilingual speakers experience a time cost when making voluntary switches in conversations. The symmetrical switch costs suggest that both languages have similar activation levels throughout the conversation, and the cognitive costs arise from the act of momentarily switching languages, irrespective of their dominance. In self-paced reading, cognitive costs arise from disturbing the status quo of relative activation-inhibition of each language adopted to perform the task. The comparable CS time cost for insertions and alternations suggests similar cognitive control and linguistic planning mechanisms for both types of switches.

Expectation violations produce error signals in mouse V1

Repeated exposure to visual sequences changes the form of evoked activity in the primary visual cortex (V1). Predictive coding theory provides a potential explanation for this, namely that plasticity shapes cortical circuits to encode spatiotemporal predictions and that subsequent responses are modulated by the degree to which actual inputs match these expectations. Here we use a recently developed statistical modeling technique called Model-Based Targeted Dimensionality Reduction (MbTDR) to study visually-evoked dynamics in mouse V1 in context of a previously described experimental paradigm called "sequence learning". We report that evoked spiking activity changed significantly with training, in a manner generally consistent with the predictive coding framework. Neural responses to expected stimuli were suppressed in a late window (100-150ms) after stimulus onset following training, while responses to novel stimuli were not. Omitting predictable stimuli led to increased firing at the expected time of stimulus onset, but only in trained mice. Substituting a novel stimulus for a familiar one led to changes in firing that persisted for at least 300ms. In addition, we show that spiking data can be used to accurately decode time within the sequence. Our findings are consistent with the idea that plasticity in early visual circuits is involved in coding spatiotemporal information.

Authoring esteem: Writing about vicarious and personal life story chapters boosts state self-esteem

Constructing personal life stories carries benefits for psychological adjustment. We examined whether writing about the life stories of parents (i.e., vicarious life stories) hold similar advantages. In Study 1, we adapted an established experimental paradigm to an online format. Participants wrote either about personal life story chapters or about famous persons (control condition) and completed pre- and post-measures of state self-esteem. We found the predicted interaction as self-esteem increased in the chapter but not in the control condition. In Studies 2 and 3, we added the critical condition of writing about vicarious chapters. Study 2 did not find the predicted interaction. Instead, all three conditions increased in self-esteem. Study 3, which used a new neutral control task (writing about historical events), showed that the two chapter conditions, but not the control condition, increased in self-esteem. This suggests that authoring life stories for both oneself and close others momentarily boosts self-esteem.

The Neural Representation of Events Is Dominated by Elements that Are Most Reliably Present

An episodic memory is specific to an event that occurred at a particular time and place. However, the elements that comprise the event—the location, the people present, and their actions and goals—might be shared with numerous other similar events. Does the brain preferentially represent certain elements of a remembered event? If so, which elements dominate its neural representation: those that are shared across similar events, or the novel elements that define a specific event? We addressed these questions by using a novel experimental paradigm combined with fMRI. Multiple events were created involving conversations between two individuals using the format of a television chat show. Chat show “hosts” occurred repeatedly across multiple events, whereas the “guests” were unique to only one event. Before learning the conversations, participants were scanned while viewing images or names of the (famous) individuals to be used in the study to obtain person-specific activity patterns. After learning all the conversations over a week, participants were scanned for a second time while they recalled each event multiple times. We found that during recall, person-specific activity patterns within the posterior midline network were reinstated for the hosts of the shows but not the guests, and that reinstatement of the hosts was significantly stronger than the reinstatement of the guests. These findings demonstrate that it is the more generic, familiar, and predictable elements of an event that dominate its neural representation compared with the more idiosyncratic, event-defining, elements.

Validity and Reliability of a Protocol to Establish Human Critical Environmental Limits (PSU HEAT)

The PSU HEAT protocol has been used to determine critical environmental limits, i.e., those combinations of ambient temperature and humidity above which heat stress becomes uncompensable and core temperature rises continuously. However, no studies have rigorously investigated the reliability and validity of this experimental protocol. Here, we assessed the (1) between-visit reliability and (2) validity of the paradigm. Twelve subjects (5M/7W; 25±4 yr) completed a progressive heat stress protocol during which they walked on a treadmill (2.2 mph, 3% gradient) in a controllable environmental chamber. After an equilibration period, either dry-bulb temperature (Tdb) was increased every 5 min while ambient water vapor pressure (Pa) was held constant (Tcrit experiments) or Pa was increased every 5 min while Tdb was held constant (Pcrit experiments) until an upward inflection in gastrointestinal temperature (Tgi) was observed. For reliability experiments, 11 subjects repeated the same protocol on a different day. For validity experiments, 10 subjects performed a Tcrit experiment at their previously determined Pcrit or vice versa. The between-visit reliability (intraclass correlation coefficient, ICC) for critical environmental limits was 0.98. Similarly, there was excellent agreement between original and validity trials for Tcrit (ICC = 0.95) and Pcrit (ICC = 0.96). Further, the wet-bulb temperature at the Tgi inflection point was not different during reliability (p = 0.78) or validity (p = 0.32) trials compared to original trials. These findings support the reliability and validity of this experimental paradigm for the determination of critical environmental limits for maintenance of human heat balance.

Leaders are made: Learning acquisition of consistent leader-follower relationships depends on implicit haptic interactions.

Are leaders made or born? Leader-follower roles have been well characterized in social science, but they remain somewhat obscure in sensory-motor coordination. Furthermore, it is unknown how and why leader-follower relationships are acquired, including innate versus acquired controversies. We developed a novel asymmetrical coordination task in which two participants (dyad) need to collaborate in transporting a simulated beam while maintaining its horizontal attitude. This experimental paradigm was implemented by twin robotic manipulanda, simulated beam dynamics, haptic interactions, and a projection screen. Clear leader-follower relationships were learned despite participants not being informed that they were interacting with each other, but only when strong haptic feedback was introduced. For the first time, we demonstrate the emergence of consistent leader-follower relationships in sensory-motor coordination, and further show that haptic interaction is essential for dyadic co-adaptation. These results provide insights into neural mechanisms responsible for the formation of leader-follower relationships in our society.

Cognitive diversity promotes social learning - but only when cognitive differences are obscured

Cognitive diversity is often assumed to catalyze creativity and innovation by promoting social learning. Yet the learning benefits of cognitive diversity often fail to materialize. Why does cognitive diversity promote social learning in some contexts but not in others? We propose that the answer partly lies in the complex interplay between cognitive diversity and cognitive homophily: The likelihood of individuals learning from one another, and thus changing their views about a substantive issue, depends crucially on whether they are aware of the cognitive similarities and differences that exist between them. When social identities and cognitive associations about concepts related to a focal issue are obscured, we theorize that cognitive diversity will promote social learning by exposing people to novel ideas. When cognitive diversity is instead made salient, we anticipate that a cognitive homophily response is activated that extinguishes cognitive diversity’s learning benefits---even when social identity cues and other categorical distinctions are suppressed. To evaluate these ideas, we introduce a novel experimental paradigm and report the results of four pre-registered studies (N=1,325) that lend support to our theory. We discuss implications for research on social influence, collective intelligence, and cognitive diversity in groups.