Examining the cognitive costs of counterfactual language comprehension: Evidence from ERPs

Recent empirical research suggests that understanding a counterfactual event (e.g. ‘If Josie had revised, she would have passed her exams’) activates mental representations of both the factual and counterfactual versions of events. However, it remains unclear when readers switch between these models during comprehension, and whether representing multiple ‘worlds’ is cognitively effortful. This paper reports two ERP studies where participants read contexts that set up a factual or counterfactual scenario, followed by a second sentence describing a consequence of this event. Critically, this sentence included a noun that was either consistent or inconsistent with the preceding context, and either included a modal verb to indicate reference to the counterfactual-world or not (thus referring to the factual-world). Experiment 2 used adapted versions of the materials used in Experiment 1 to examine the degree to which representing multiple versions of a counterfactual situation makes heavy demands on cognitive resources by measuring individuals’ working memory capacity. Results showed that when reference to the counterfactual-world was maintained by the ongoing discourse, readers correctly interpreted events according to the counterfactual-world (i.e. showed larger N400 for inconsistent than consistent words). In contrast, when cues referred back to the factual-world, readers showed no difference between consistent and inconsistent critical words, suggesting that they simultaneously compared information against both possible worlds. These results support previous dual-representation accounts for counterfactuals, and provide new evidence that linguistic cues can guide the reader in selecting which world model to evaluate incoming information against. Crucially, we reveal evidence that maintaining and updating a hypothetical model over time relies upon the availability of cognitive resources

Complement set reference after implicitly small quantities: An event-related potentials study

An anaphoric reference to the complement-set is a reference to the set which does not fulfil the predicate of the preceding sentence. Preferred reference to the complement-set has been found in eye movements when a character’s implicit desire for a high amount has been denied using a negative emotion. We recorded ERPs to examine if, when a character’s desire is denied with a negative emotion, the complement-set is immediately available for reference. Analysis of the N400 over posterior regions showed that while readers favoured the reference-set following a positive emotion, there was no difference in responses between complement-set and reference-set references following a negative emotion. Processing of a complement-set reference did lead to an overall increase in negativity of the N400, suggesting that interpreting a complement-set reference incurred a general processing cost. This study provides novel data on the range of circumstances under which the complement-set is available

Adolescents are delayed at inferring complex social intentions in others, but not basic (false) beliefs: An eye movement investigation

Most developmental research on Theory of Mind (ToM) - our ability to infer the beliefs, intentions, and desires of others - has focused on the preschool years. This is unsurprising since it was previously thought that ToM skills are developed between the ages of 2 and 7 years old (Wellman, Cross, & Watson, 2001). Over the last couple of decades however, studies have provided evidence for significant structural and functional changes in the brain areas involved in ToM (the “social brain”) not only during childhood, but also during adolescence. Importantly, some of these findings suggest that the use of ToM shows a prolonged development through middle childhood and adolescence. Although evidence from previous studies suggests a protracted development of ToM, the factors that constrain performance during middle childhood and adolescence are only just beginning to be explored. In the current paper we report two visual world eye-tracking studies that focus on the timecourse of predictive inferences. We establish that when the complexity of ToM inferences are at a level which is comparable to standard change-of-location False-belief tasks, then adolescents and adults generate predictions for other agents’ behaviour in the same timecourse. However, when inferences are socially more complex, requiring inferences about higher-order mental states, adolescents generate predictive gaze bias at a marked delay relative to adults. Importantly, our results demonstrate that these developmental differences go beyond differences in executive functions (inhibitory control or working memory), and point to distinct expectations between groups and greater uncertainty when predicting actions based on conflicting desires

The neural basis of belief-attribution across the lifespan: False-belief reasoning and the N400 effect

The current study examined how social cognition – specifically, belief-state processing – changes across the lifespan, using a large sample (N = 309) of participants aged 10-86 years. Participants completed an event-related brain potential study in which they listened to stories involving a character who held either a true- or false-belief about the location of an object, and then acted in a manner consistent or inconsistent to this belief-state. Analysis of the N400 revealed that when the character held a true-belief, inconsistent outcomes led to a more negative-going N400 waveform than consistent outcomes. In contrast, when the character held a false-belief, consistent outcomes led to a more negative-going N400 waveform than inconsistent outcomes, indicating that participants interpreted the character’s actions according to their own more complete knowledge of reality. Importantly, this egocentric bias was not modulated by age in an early time window (200-400ms post-stimulus onset), meaning that initial processing is grounded in reality, irrespective of age. However, this egocentric effect was correlated with age in a later time window (400-600ms post-stimulus onset), as older adults continued to consider the story events according to their own knowledge of reality, but younger participants had now switched to accommodate the character’s perspective. In a final 600-1000ms time window, this age modulation was no longer present. Interestingly, results suggested that this extended egocentric processing in older adults was not the result of domain-general cognitive declines, as no significant relationship was found with executive functioning (inhibitory control and working memory)

Plausibility and perspective influence the processing of counterfactual narratives

Previous research has established that readers’ eye movements are sensitive to the difficulty with which a word is processed. One important factor that influences processing is the fit of a word within the wider context, including its plausibility. Here we explore the influence of plausibility in counterfactual language processing. Counterfactuals describe hypothetical versions of the world, but are grounded in the implication that the described events are not true. We report an eye-tracking study that examined the processing of counterfactual premises that varied the plausibility of a described action and manipulated the narrative perspective (“you” vs. “he/she”). Results revealed a comparable pattern to previous plausibility experiments. Readers were sensitive to the inconsistent thematic relation in anomalous and implausible conditions. The fact that these anomaly detection effects were evident within a counterfactual frame suggests that participants were evaluating incoming information within the counterfactual world, and did not suspend processing based on an inference about reality. Interestingly, perspective modulated the speed with which anomalous but not implausible words were detected

Characterization of DNA binding, transcriptional activation, and regulated nuclear association of recombinant human NFATp

BACKGROUND: NFATp is one member of a family of transcriptional activators whose nuclear accumulation and hence transcriptional activity is regulated in mammalian cells. Human NFATp exists as a phosphoprotein in the cytoplasm of naive T cells. Upon antigen stimulation, NFATp is dephosphorylated, accumulates in nuclei, and functions to regulate transcription of genes including those encoding cytokines. While the properties of the DNA binding domain of NFATp have been investigated in detail, biochemical studies of the transcriptional activation and regulated association with nuclei have remained unexplored because of a lack of full length, purified recombinant NFATp. RESULTS: We developed methods for expressing and purifying full length recombinant human NFATp that has all of the properties known to be associated with native NFATp. The recombinant NFATp binds DNA on its own and cooperatively with AP-1 proteins, activates transcription in vitro, is phosphorylated, can be dephosphorylated by calcineurin, and exhibits regulated association with nuclei in vitro. Importantly, activation by recombinant NFATp in a reconstituted transcription system required regions of the protein outside of the central DNA binding domain. CONCLUSIONS: We conclude that NFATp is a bona fide transcriptional activator. Moreover, the reagents and methods that we developed will facilitate future studies on the mechanisms of transcriptional activation and nuclear accumulation by NFATp, a member of an important family of transcriptional regulatory proteins

Behavioural Improvement in Minimally Conscious State After Caloric Vestibular Stimulation: Evidence from two single case studies.

Objective: To investigate whether caloric vestibular stimulation, a non-invasive form of neuro-modulation, alters level of awareness in people residing in minimally conscious state. Design: Single-case (n=2), prospective, controlled (ABAB) efficacy study. Setting: Tertiary, neuro-rehabilitation in-patient ward within a university hospital Participants: Two individuals in minimally conscious state Intervention: Left ear caloric vestibular stimulation was performed in two four/five-week blocks interleaved with two four/five-week blocks of sham stimulation. Session duration and frequency gradually increased within each block from once per day for 10 minutes (week 1) to once per day for 20 minutes (week 2) to 20 minutes twice per day in the remaining weeks. Measures: Wessex Head Injury Matrix, JFK Coma Recovery Scale – Revised. Results: Both participants’ Wessex Head Injury Matrix scores indicated a transition from involuntary (i.e. mechanical vocalization) to voluntary (i.e. gesture making, selective responses to family members) behaviour that was time-locked to the onset of active stimulation. In one participant, this improvement persisted for at least 4 weeks after active stimulation while in the other it diminished 2 weeks after stimulation. Allied, although less dramatic, changes were seen on the arousal and auditory subscales of the JFK Coma Recovery Scale – Revised. Conclusion: The data provide the first evidence that vestibular stimulation may help improve outcome in low awareness state although further studies are needed to replicate effect and determine longer-term benefit

Impacts of climate change on malaria vector control in Africa

There has been extensive consideration of how climate change may impact the distribution of vector-borne diseases; with a particular focus on malaria risk in Africa. Such analyses primarily consider how the ‘malaria map’ will shift in response to changes in the environmental determinants of transmission, but rarely consider the equally if not more important question of whether climate change will impact the effectiveness of vector control measures. Here we hypothesize that the efficacy and ability to implement core vector control interventions for malaria could be significantly impacted by climate change due to direct and indirect impacts on mosquito vectors and interventions. We review current knowledge on the environmental dependency of current core interventions for malaria vector control including Insecticide Treated Nets, Indoor Residual Spraying and larviciding. We explore how anticipated changes in temperature, rainfall and humidity could impact vector ecology, behaviour and resistance mechanisms; and the knock on effects of these changes for intervention efficacy. Finally we review potential indirect impacts of climate change on the ability to finance, implement and sustain vector control; with a focus on changes in human behaviour, land use, socioeconomic conditions and health systems. We conclude by highlighting the need to build ‘climate-proof’ strategies into future vector control planning

An improved mosquito electrocuting trap that safely reproduces epidemiologically relevant metrics of mosquito human-feeding behaviours as determined by human landing catch

Background: Reliable quantification of mosquito host—seeking behaviours is required to determine the efficacy of vector control methods. For malaria, the gold standard approach remains the risky human landing catch (HLC). Here compare the performance of an improved prototype of the mosquito electrocuting grid trap (MET) as a safer alternative with HLC for measuring malaria vector behaviour in Dar es Salaam, Tanzania. Methods: Mosquito trapping was conducted at three sites within Dar es Salaam representing a range of urbanicity over a 7-month period (December 2012–July 2013, 168 sampling nights). At each site, sampling was conducted in a block of four houses, with two houses being allocated to HLC and the other to MET on each night of study. Sampling was conducted both indoors and outdoors (from 19:00 to 06:00 each night) at all houses, with trapping method (HLC and MET) being exchanged between pairs of houses at each site using a crossover design. Results: The MET caught significantly more Anopheles gambiae sensu lato than the HLC, both indoors (RR [95 % confidence interval (CI)]) = 1.47 [1.23–1.76], P < 0.0001 and outdoors = 1.38 [1.14–1.67], P < 0.0001). The sensitivity of MET compared with HLC did not detectably change over the course of night for either An. gambiae s.l. (OR [CI]) = 1.01 [0.94–1.02], P = 0.27) or Culex spp. (OR [CI]) = 0.99 [0.99–1.0], P = 0.17) indoors and declined only slightly outdoors: An. gambiae s.l. (OR [CI]) = 0.92 [0.86–0.99], P = 0.04), and Culex spp. (OR [CI]) = 0.99 [0.98–0.99], P = 0.03). MET-based estimates of the proportions of mosquitoes caught indoors (P i ) or during sleeping hours (P fl ), as well as the proportion of human exposure to bites that would otherwise occurs indoors (π i ), were statistically indistinguishable from those based on HLC for An. gambiae s.l. (P = 0.43, 0.07 and 0.48, respectively) and Culex spp. (P = 0.76, 0.24 and 0.55, respectively). Conclusions: This improved MET prototype is highly sensitive tool that accurately quantifies epidemiologically-relevant metrics of mosquito biting densities, behaviours and human exposure distribution