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The role of alpha oscillations in resisting distraction.
The role of alpha oscillations (8-13 Hz) in suppressing distractors is extensively debated. One debate concerns whether alpha oscillations suppress anticipated visual distractors through increased power. Whereas some studies suggest that alpha oscillations support distractor suppression, others do not. We identify methodological differences that may explain these discrepancies. A second debate concerns the mechanistic role of alpha oscillations. We and others previously proposed that alpha oscillations implement gain reduction in early visual regions when target load or distractor interference is high. Here, we suggest that parietal alpha oscillations support gating or stabilization of attentional focus and that alpha oscillations in ventral attention network (VAN) support resistance to attention capture. We outline future studies needed to uncover the precise mechanistic role of alpha oscillations.
Fast Feature- and Category-Related Parafoveal Previewing Support Free Visual Exploration.
While humans typically saccade every ∼250 ms in natural settings, studies on vision tend to prevent or restrict eye movements. As it takes ∼50 ms to initiate and execute a saccade, this leaves only ∼200 ms to identify the fixated object and select the next saccade goal. How much detail can be derived about parafoveal objects in this short time interval, during which foveal processing and saccade planning both occur? Here, we had male and female human participants freely explore a set of natural images while we recorded magnetoencephalography and eye movements. Using multivariate pattern analysis, we demonstrate that future parafoveal images could be decoded at the feature and category level with peak decoding at ∼110 and ∼165 ms, respectively, while the decoding of fixated objects at the feature and category level peaked at ∼100 and ∼145 ms. The decoding of features and categories was contingent on the objects being saccade goals. In sum, we provide insight on the neuronal mechanism of presaccadic attention by demonstrating that feature- and category-specific information of foveal and parafoveal objects can be extracted in succession within a ∼200 ms intersaccadic interval. These findings rule out strict serial or parallel processing accounts but are consistent with a pipeline mechanism in which foveal and parafoveal objects are processed in parallel but at different levels in the visual hierarchy.
How much conversation content is actually social: Human conversational behaviour revisited
Our study explores aspects of human conversation within the framework of evolutionary psychology, focusing on the proportion of 'social' to 'non-social' content in casual conversation. Building upon the seminal study by Dunbar et al. (1997, Human Nature, 8, 231-246), which posited that two-thirds of conversation gravitates around social matters, our findings indicate an even larger portion, approximately 85% being of a social nature. Additionally, we provide a nuanced categorisation of 'social' rooted in the principles of evolutionary psychology. Similarly to Dunbar et al.'s findings, our results support theories of human evolution that highlight the importance of social interactions and information exchange and the importance of the exchange of social information in human interactions across various contexts.
Modelling Agency Perception in a Multi-agent Context in Depression Using Active Inference
A reduced sense of agency is a primary symptom of depression. This study investigates how agency is learned and perceived in a multi-agent environment, comparing depressed and non-depressed individuals. Participants explored their control over an on-screen outcome via button presses across multiple trials, while observing a simulated agent’s button presses. They rated each agent’s control after each block of trials. Experimental conditions varied which agent had control and the type/direction of control (positive/excitatory, negative/inhibitory, or none). We applied an active inference model to the behavioural data to understand action and perceptual processes in forming agentic beliefs. Results showed all participants identified the controlling agent but incorrectly attributed control to the non-controlling agent in the opposite direction. Depressed participants consistently perceived themselves and others as having less agency, while viewing the other agent as having positive control across all conditions. The model suggested stronger prior beliefs about agents having opposing directions of control. Depressed participants, however, perceived their control to match that of external agents, while non-depressed participants perceived their control to be independent of the external agent. Despite perceiving reduced agency, depressed participants increased their agentic action over time, suggesting heightened but potentially aimless environmental sampling. The model reflected this as a higher prior for acting and a lower preference for observing outcomes. This study provides novel insights into how individuals with and without depression perceive agency differently within the same environment through differing biases in perceptual and action processes. Depressed individuals may not learn about other agents in the same way as non-depressed individuals. These findings could inform future therapeutic strategies and deepen our understanding of depression.
A novel 14mer peptide, T14, is associated with age-dependent behaviour in female mice.
Age-related cognitive decline presents a healthcare challenge. While age-related mechanisms are mainly studied in humans, animal models provide key insights. Despite evidence of sex-specific differences in aging and cognition, the impact of age on female rodent behaviour is underexplored. This study investigated age-related behavioural changes in female C57BL/6 mice over 8 months, alongside neurochemical markers amyloid, Tau, and T14, a novel peptide from acetylcholinesterase (AChE) that promotes cell growth/renewal. Behavioural assessments showed an age-dependent decline in nest-building ability and familiar odour discrimination from 10 months. Spatial learning declined at 10 and 13 months, while object recognition memory remained intact from 5 to 13 months of age. Neurochemical analyses revealed a decline in T14 and its receptor α7-AChR during postnatal development and adulthood. However, there was a disparity between AChE expression and its enzymatic activity. T14 levels correlated with phosphorylated tau, but not amyloid, and negatively with nest-building scores, suggesting a role of T14 in age-related behavioural changes. This study highlights early behavioural and molecular indicators of cognitive decline in middle-aged female mice.
Give us a hand, mate! A holistic review of research on human-machine teaming.
Defence has a significant interest in the use of artificial intelligence (AI)-based technologies to address some of the challenges it faces. At the core of future military advantage will be the effective integration of humans and AI into human-machine teams (HMT) that leverages the capabilities of people and technologies to outperform adversaries. Realising the full potential of these technologies will depend on understanding the relative strengths of humans and machines, and how we design effective integration to optimise performance and resilience across all use cases and environments.Since the first robot appeared on the assembly line, machines have effectively augmented human capability and performance; however, they fall short of being a team member-someone you can ask to give you a hand! Working in teams involves collaboration, adaptive and dynamic interactions between team members to achieve a common goal. Currently, human-machine partnership is typically one of humans and machines working alongside each other, with each conducting discrete functions within predicable process and environments. However, with recent advances in neuroscience and AI, we can now envisage the possibility of HMT, not just in physical applications, but also complex cognitive tasks.This paper provides a holistic review of the research conducted in the field of HMT from experts working in this area. It summarises completed and ongoing studies and research in the UK and USA by a broad group of researchers. This work was presented in the HMT thematic session at the Sixth International Congress on Soldiers' Physical Performance (ICSPP23 London).
Impulse Control Disorders and Effort-Based Decision-Making in Parkinson's Disease Patients with Subthalamic Nucleus Deep Brain Stimulation.
BACKGROUND: Impulse control disorders (ICD) are common side effects of dopaminergic treatment in Parkinson's disease (PD). Whereas some studies show a reduction in ICD after subthalamic nucleus deep brain stimulation (STN-DBS), others report worsening of ICD or impulsivity. OBJECTIVE: The aim was to study ICD in the context of STN-DBS using an objective measure of decision-making. METHODS: Ten PD patients performed an effort-based decision-making task alongside neuropsychiatric and cognitive evaluation before and 4 months after STN-DBS. Further, 33 PD patients underwent the same experimental procedures just once after an average 40 months of chronic STN-DBS. Participants were examined preoperatively in the medication on state and postoperatively in the medication on/stimulation ON state. Mixed linear models were used to assess the impact of ICD and STN-DBS on acceptance rate and decision time in the task while controlling for motor symptom burden, cognitive measures, and dopaminergic medication. RESULTS: Results revealed an increased willingness to exert high levels of effort in return for reward in patients with ICD, but acceptance rate was not modulated by chronic STN-DBS. Further, ICD, cognitive processing speed, and STN-DBS were all identified as positive predictors for faster decision speed. ICD scores showed a tendency to improve 4 months after STN-DBS, without an increase in apathy scores. CONCLUSIONS: Chronic STN-DBS and ICD facilitate effort-based decision-making by speeding up judgment. Furthermore, ICD enhances the willingness to exert high levels of effort for reward. Both STN-DBS and dopaminergic medication impact motivated behavior and should be titrated carefully to balance neuropsychiatric symptoms.
Reactivating and reorganizing activity-silent working memory: two distinct mechanisms underlying pinging the brain
Abstract Recent studies have proposed that visual information in working memory (WM) can be maintained in an activity-silent state and reactivated by task-irrelevant high-contrast visual impulses (“ping”). Although pinging the brain has become a popular tool for exploring activity-silent WM, its underlying mechanisms remain unclear. In the current study, we directly compared the neural reactivation effects and behavioral consequences of spatial-nonmatching and spatial-matching pings to distinguish the noise-reduction and target-interaction hypotheses of pinging the brain. Initially, in an electroencephalogram study, our neural decoding results showed that spatial-nonmatching pings reactivated activity-silent WM transiently without changing the original WM representations or recall performance. Conversely, spatial-matching pings reactivated activity-silent WM more durably and further reorganized WM information by decreasing neural representations’ dynamics. Notably, only the reactivation strength of spatial-matching pings correlated with recall performance and was modulated by the location of memorized items, with neural reactivation occurring only when both items and pings were presented horizontally. Consistently, in a follow-up behavioral study, we found that only spatial-matching, horizontal pings impaired recall performance compared to no ping. Together, our results demonstrated two distinct mechanisms underlying pinging the brain, highlighting the critical role of the ping’s context (i.e. spatial information) in reactivating and reorganizing activity-silent WM.
Confidence regulates feedback processing during human probabilistic learning.
Uncertainty presents a key challenge when learning how best to act to attain a desired outcome. People can report uncertainty in the form of confidence judgments, but how such judgments contribute to learning and subsequent decisions remains unclear. In a series of three experiments employing an operant learning task, we tested the hypothesis that confidence plays a central role in learning by regulating resource allocation to the seeking and processing of feedback. We predicted that, as participants' confidence in their task knowledge grew, they would discount feedback when it was provided and be correspondingly less willing to pay for it when it was costly. Consistent with these predictions, we found that higher confidence was associated with reduced electrophysiological markers of feedback processing and decreased updating of beliefs following feedback receipt. Bayesian modeling suggests that this decrease in processing was due to a drop in the expected informative value of novel information when participants were highly confident. Thus, when choosing whether to pay a fee to receive further feedback, participants' subjective confidence, rather than the objective accuracy of their decisions, guided their choices. Overall, our results suggest that confidence regulates learning and subsequent decision making. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
Learning new words via reading: The influence of emotional narrative context on learning novel adjectives.
People learn new words in narrative contexts, but little is known about how the emotional valence of the narrative influences word learning. In a pre-registered experiment, 76 English-speaking adults read 30 novel adjectives embedded in 60 short narratives (20 positive, 20 negative, and 20 neutral valence). Both immediately after and 24 hr later, participants completed a series of post-tests, including speeded recognition, sentence completion, meaning generation, and valence judgement. Results showed that participants learned both the novel word form and its meaning. Compared with novel words experienced in the neutral contexts, those read in the emotional contexts (both positive and negative) showed better learning of orthographic form in the immediate post-test, but only those read in the negative context were recognised with greater accuracy in the delayed post-test. Furthermore, the valence of the context was reflected in the word meanings participants generated for each novel word, suggesting that word valence can be inferred from the valence of the contexts. Results from sentence completion and valence judgement were mixed, depending on the task demands. These findings are discussed with reference to theories of affective embodiment and the implications for learning abstract words are considered.
‘Hot stuff’: Making food more desirable with animated temperature cues
Nothing beats a comforting image of a bowl of hot soup with whisps of rising steam unless it is the actual soup itself. The current paper investigates the influence of food photography on people's food expectations. Despite the recognition of the importance of the food temperature depicted in food images, the effectiveness of using visual cues on food photography to indicate temperature and potential managerial outcomes of so doing has barely been researched. This study explored whether the addition of visual temperature cues to food images was effective in activating relevant temperature associations, leading to downstream consequences, including food desirability, freshness perception and willingness to pay (WTP), with a focus on thermal temperature cues. Three online experimental studies were conducted showing that animated traces of steam added to food images not only induced hot temperature perception of the food, but also increased food desirability and freshness perception. Meanwhile, implied animation (i.e., static picture of rising steam) did not produce any such effect. Further, food image appeal was found to be a boundary condition for the effect of hot temperature cues: that is, when the food images is of low appeal, traces of steam which increased hot temperature perception, in turn enhanced freshness perception and food desirability, but not WTP. The effectiveness of animated steam textures crossmodally enhancing thermal temperature perception and food desirability underscores the potential in digital food creation and marketing.
Sensory acuity: Impact of aging and chronic disease
Chemosensory abilities decline as a result of aging, chronic disease, and the medicines/treatments that are often used to address these conditions. The flavor of food and drink normally results from the multisensory integration of gustatory, retronasal olfactory, and trigeminal cues. Given that most of what we think we taste, we actually smell, it is the olfactory decline that may be expected to have the most adverse impact on the loss of the taste/flavor of, and pleasure in consuming, food and drink. The loss of sensory acuity, together with the dysgeusia that affects a number of individuals may well lead to a range of unhealthy eating behaviors ranging from anorexia at one end through to the overconsumption of salt and sugar at the other. Various sensory strategies have been put forward to tackle the loss of chemosensory acuity, including the greater use of herbs and spices (such as chili), flavor enhancers such as monosodium glutamate, as well as greater use of oral-somatosensory thermal cues (e.g., by formulating nutritionally beneficial ice cream). It is important not to forget the desirable sonic attributes of crisp and crunchy foods, as well as the importance of visual presentation, while also ensuring adequate contrast between the food and the plateware. However, looking to the future, effective intervention strategies for those suffering from a loss of chemosensory acuity will need to move beyond a narrow focus on meeting nutritional requirements in a tasty and pleasant manner to consider the more social/emotional role that commensality can play, especially for those living alone and/or in care.
Multisensory feature integration
Several theoretical accounts have been put forward to help explain feature integration, including Treisman’s Feature Integration Theory and Bayesian causal inference. However, there may be some important differences between multisensory feature integration (MFI) in the spatial and chemical senses. While several of the same factors undoubtedly do appear to modulate MFI, regardless of the combination of senses under consideration (such as attention and crossmodal correspondences, or congruency), there are also a number of salient differences; these include the phenomenon of oral referral in the chemical senses, and the fact that olfactory stimuli tend to take on the sensory properties of the tastes with which they happen to be regularly paired. As such, it may not be possible to account for all cases of MFI within a single theoretical framework.