Permutation Complexity and Coupling Measures in Hidden Markov Models

In [Haruna, T. and Nakajima, K., 2011. Physica D 240, 1370-1377], the authors introduced the duality between values (words) and orderings (permutations) as a basis to discuss the relationship between information theoretic measures for finite-alphabet stationary stochastic processes and their permutation analogues. It has been used to give a simple proof of the equality between the entropy rate and the permutation entropy rate for any finite-alphabet stationary stochastic process and show some results on the excess entropy and the transfer entropy for finite-alphabet stationary ergodic Markov processes. In this paper, we extend our previous results to hidden Markov models and show the equalities between various information theoretic complexity and coupling measures and their permutation analogues. In particular, we show the following two results within the realm of hidden Markov models with ergodic internal processes: the two permutation analogues of the transfer entropy, the symbolic transfer entropy and the transfer entropy on rank vectors, are both equivalent to the transfer entropy if they are considered as the rates, and the directed information theory can be captured by the permutation entropy approach.Comment: 26 page

The effect of atomoxetine on directed and random exploration in humans

The adaptive regulation of the trade-off between pursuing a known reward (exploitation) and sampling lesser-known options in search of something better (exploration) is critical for optimal performance. Theory and recent empirical work suggest that humans use at least two strategies for solving this dilemma: a directed strategy in which choices are explicitly biased toward information seeking, and a random strategy in which decision noise leads to exploration by chance. Here we examined the hypothesis that random exploration is governed by the neuromodulatory locus coeruleus-norepinephrine system. We administered atomoxetine, a norepinephrine transporter blocker that increases extracellular levels of norepinephrine throughout the cortex, to 22 healthy human participants in a double-blind crossover design. We examined the effect of treatment on performance in a gambling task designed to produce distinct measures of directed exploration and random exploration. In line with our hypothesis we found an effect of atomoxetine on random, but not directed exploration. However, contrary to expectation, atomoxetine reduced rather than increased random exploration. We offer three potential explanations of our findings, involving the non-linear relationship between tonic NE and cognitive performance, the interaction of atomoxetine with other neuromodulators, and the possibility that atomoxetine affected phasic norepinephrine activity more so than tonic norepinephrine activity

Risk Perception, Behavioural Response to COVID-19, and the Mediating Role of Information Sources in Zambia

The role of information sources in mediating the relationship between behavioural responses to COVID-19 and its determinants has hardly been studied. This study fills the knowledge gap with a focus on Zambia, a middle-income country. Data was collected using an online questionnaire. The key independent variables were risk perception of COVID-19, risk perception of the health care system (local and global), and risk perception of the big five global health problems (HIV/AIDS, cancer, injury from road traffic accidents, influenza, and diabetes). Risk perception of the health care system was measured by looking at whether or not the respondents trust the World Health Organisation (WHO) and Ministry of Health (MoH) backed COVID-19 vaccines. The three Independent Variables (IV) of risk perception predicted behavioural response as a Dependent Variable (DV). The behavioural response was found as an average of responses on a five-point Likert scale of questions, relating to safety measures taken by respondents against COVID 19. The relationship between IVs and the DV was hypothesised to be mediated by information sources. Information sources were measured by the frequency with which respondents obtained information about COVID-19 from various sources. A statistically significant positive relationship was found between risk perception of the health system and information sources. The same was not true for the other two independent variables. Further, a statistically significant indirect effect was found between risk perception of health systems and behavioural responses (mediated by information sources). Our findings can be used to influence policy, practice, and scholarship on sources of information for COVID-19 and expected behavioural responses. It is recommended that policy on sources of public health information be directed towards enhancing credible sources of information. Future studies must consider using longitudinal data. The big five health risks should include malaria and tuberculosis (TB), making it the big seven. Corruption’s role in risk perception of health systems should also be explored

Risk Perception, Behavioural Response to COVID-19, and the Mediating Role of Information Sources in Zambia

The role of information sources in mediating the relationship between behavioural responses to COVID-19 and its determinants has hardly been studied. This study fills the knowledge gap with a focus on Zambia, a middle-income country. Data was collected using an online questionnaire. The key independent variables were risk perception of COVID-19, risk perception of the health care system (local and global), and risk perception of the big five global health problems (HIV/AIDS, cancer, injury from road traffic accidents, influenza, and diabetes). Risk perception of the health care system was measured by looking at whether or not the respondents trust the World Health Organisation (WHO) and Ministry of Health (MoH) backed COVID-19 vaccines. The three Independent Variables (IV) of risk perception predicted behavioural response as a Dependent Variable (DV). The behavioural response was found as an average of responses on a five-point Likert scale of questions, relating to safety measures taken by respondents against COVID 19. The relationship between IVs and the DV was hypothesised to be mediated by information sources. Information sources were measured by the frequency with which respondents obtained information about COVID-19 from various sources. A statistically significant positive relationship was found between risk perception of the health system and information sources. The same was not true for the other two independent variables. Further, a statistically significant indirect effect was found between risk perception of health systems and behavioural responses (mediated by information sources). Our findings can be used to influence policy, practice, and scholarship on sources of information for COVID-19 and expected behavioural responses. It is recommended that policy on sources of public health information be directed towards enhancing credible sources of information. Future studies must consider using longitudinal data. The big five health risks should include malaria and tuberculosis (TB), making it the big seven. Corruption’s role in risk perception of health systems should also be explored

Playing with strangers: Which shared traits attract us most to new people?

Homophily, the tendency for individuals to associate with those who are most similar to them, has been well documented. However, the influence of different kinds of similarity (e.g. relating to age, music taste, ethical views) in initial preferences for a stranger have not been compared. In the current study, we test for a relationship between sharing a variety of traits (i.e. having different kinds of similarity) with a stranger and the perceived likeability of that stranger. In two online experiments, participants were introduced to a series of virtual partners with whom they shared traits, and subsequently carried out activities designed to measure positivity directed towards those partners. Greater numbers of shared traits led to linearly increasing ratings of partner likeability and ratings on the Inclusion of Other in Self scale. We identified several consistent predictors of these two measures: shared taste in music, religion and ethical views. These kinds of trait are likely to be judged as correlates of personality or social group, and may therefore be used as proxies of more in-depth information about a person who might be socially more relevant

Mapping Smoking Addiction Using Effective Connectivity Analysis

Prefrontal and parietal cortex, including the default mode network (DMN; medial prefrontal cortex (mPFC), and posterior cingulate cortex, PCC), have been implicated in addiction. Nonetheless, it remains unclear which brain regions play a crucial role in smoking addiction and the relationship among these regions. Since functional connectivity only measures correlations, addiction-related changes in effective connectivity (directed information flow) among these distributed brain regions remain largely unknown. Here we applied spectral dynamic causal modeling (spDCM) to resting state fMRI to characterize changes in effective connectivity among core regions in smoking addiction. Compared to nonsmokers, smokers had reduced effective connectivity from PCC to mPFC and from RIPL to mPFC, a higher self-inhibition within PCC and a reduction in the amplitude of endogenous neuronal fluctuations driving the mPFC. These results indicate that spDCM can differentiate the functional architectures between the two groups, and may provide insight into the brain mechanisms underlying smoking addiction. Our results also suggest that future brain-based prevention and intervention in addiction should consider the amelioration of mPFC-PCC-IPL circuits

Web Acceptance and Usage Model: A Comparison between Goal-directed and Experiential Web Users

In this paper we analyse the Web acceptance and usage between goal-directed users and experiential users, incorporating intrinsic motives to improve the particular and explanatory TAM value –traditionally related to extrinsic motives-. A field study was conducted to validate measures used to operationalize model variables and to test the hypothesised network of relationships. The data analysis method used was Partial Least Squares (PLS).The empirical results provided strong support for the hypotheses, highlighting the roles of flow, ease of use and usefulness in determining the actual use of the Web among experiential and goal-directed users. In contrast with previous research that suggests that flow would be more likely to occur during experiential activities than goal-directed activities, we found clear evidence of flow for goal-directed activities. In particular the study findings indicate that flow might play a powerfulrole in determining the attitude towards usage,intention to useand, in turn,actual Web use among experiential and goal-directed users

The impact of Facebook use on micro-level social capital: a synthesis

The relationship between Facebook use and micro-level social capital has received substantial scholarly attention over the past decade. This attention has resulted in a large body of empirical work that gives insight into the nature of Facebook as a social networking site and how it influences the social benefits that people gather from having social relationships. Although the extant research provides a solid basis for future research into this area, a number of issues remain underexplored. The aim of the current article is twofold. First, it seeks to synthesize what is already known about the relationship between Facebook use and micro-level social capital. Second, it seeks to advance future research by identifying and analyzing relevant theoretical, analytical and methodological issues. To address the first research aim, we first present an overview and analysis of current research findings on Facebook use and social capital, in which we focus on what we know about (1) the relationship between Facebook use in general and the different subtypes of social capital; (2) the relationships between different types of Facebook interactions and social capital; and (3) the impact of self-esteem on the relationship between Facebook use and social capital. Based on this analysis, we subsequently identify three theoretical issues, two analytical issues and four methodological issues in the extant body of research, and discuss the implications of these issues for Facebook and social capital researchers

Less-structured time in children's daily lives predicts self-directed executive functioning.

Executive functions (EFs) in childhood predict important life outcomes. Thus, there is great interest in attempts to improve EFs early in life. Many interventions are led by trained adults, including structured training activities in the lab, and less-structured activities implemented in schools. Such programs have yielded gains in children's externally-driven executive functioning, where they are instructed on what goal-directed actions to carry out and when. However, it is less clear how children's experiences relate to their development of self-directed executive functioning, where they must determine on their own what goal-directed actions to carry out and when. We hypothesized that time spent in less-structured activities would give children opportunities to practice self-directed executive functioning, and lead to benefits. To investigate this possibility, we collected information from parents about their 6-7 year-old children's daily, annual, and typical schedules. We categorized children's activities as "structured" or "less-structured" based on categorization schemes from prior studies on child leisure time use. We assessed children's self-directed executive functioning using a well-established verbal fluency task, in which children generate members of a category and can decide on their own when to switch from one subcategory to another. The more time that children spent in less-structured activities, the better their self-directed executive functioning. The opposite was true of structured activities, which predicted poorer self-directed executive functioning. These relationships were robust (holding across increasingly strict classifications of structured and less-structured time) and specific (time use did not predict externally-driven executive functioning). We discuss implications, caveats, and ways in which potential interpretations can be distinguished in future work, to advance an understanding of this fundamental aspect of growing up

Information theoretic interpretation of frequency domain connectivity measures

To provide adequate multivariate measures of information flow between neural structures, modified expressions of Partial Directed Coherence (PDC) and Directed Transfer Function (DTF), two popular multivariate connectivity measures employed in neuroscience, are introduced and their formal relationship to mutual information rates are proved.Comment: 17 pages, 1 figur