Showing papers in "Frontiers in Psychology in 2014"

Using Bayes to get the most out of non-significant results

Abstract: No scientific conclusion follows automatically from a statistically non-significant result, yet people routinely use non-significant results to guide conclusions about the status of theories (or the effectiveness of practices). To know whether a non-significant result counts against a theory, or if it just indicates data insensitivity, researchers must use one of: power, intervals (such as confidence or credibility intervals), or else an indicator of the relative evidence for one theory over another, such as a Bayes factor. I argue Bayes factors allow theory to be linked to data in a way that overcomes the weaknesses of the other approaches. Specifically, Bayes factors use the data themselves to determine their sensitivity in distinguishing theories (unlike power), and they make use of those aspects of a theory’s predictions that are often easiest to specify (unlike power and intervals, which require specifying the minimal interesting value in order to address theory). Bayes factors provide a coherent approach to determining whether non-significant results support a null hypothesis over a theory, or whether the data are just insensitive. They allow accepting and rejecting the null hypothesis to be put on an equal footing. Concrete examples are provided to indicate the range of application of a simple online Bayes calculator, which reveal both the strengths and weaknesses of Bayes factors.

A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability.

Abstract: Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges’ polyvagal theory, Thayer and colleagues’ neurovisceral integration model, Lehrer et al.’s resonance frequency model, and the Institute of HeartMath’s coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain.

An ERP study on L2 syntax processing: When do learners fail?

Abstract: Event-related brain potentials (ERPs) can reveal online processing differences between native speakers and second language (L2) learners during language comprehension. Using the P600 as a measure of native-likeness, we investigated processing of grammatical gender agreement in highly proficient immersed Romance L2 learners of Dutch. We demonstrate that these late learners consistently fail to show native-like sensitivity to gender violations. This appears to be due to a combination of differences from the gender marking in their L1 and the relatively opaque Dutch gender system. We find that L2 use predicts the effect magnitude of non-finite verb violations, a relatively regular and transparent construction, but not that of gender agreement violations. There were no effects of age of acquisition, length of residence, proficiency or offline gender knowledge. Additionally, a within-subject comparison of stimulus modalities (written vs. auditory) shows that immersed learners may show some of the effects only in the auditory modality; in non-finite verb violations, an early native-like N400 was only present for auditory stimuli. However, modality failed to influence the response to gender. Taken together, the results confirm the persistent problems of Romance learners of Dutch with online gender processing and show that they cannot be overcome by reducing task demands related to the modality of stimulus presentation.

Mindfulness-based interventions in schools - A systematic review and meta-analysis

Abstract: Mindfulness programs for schools are popular. We systematically reviewed the evidence regarding the effects of school-based mindfulness interventions on psychological outcomes, using a comprehensive search strategy designed to locate both published and unpublished studies. Systematic searches in 12 databases were performed in August 2012. Further studies were identified via hand search and contact with experts. Two reviewers independently extracted the data, also selecting information about intervention programs (elements, structure etc.), feasibility, and acceptance. Twenty-four studies were identified, of which 13 were published. Nineteen studies used a controlled design. In total, 1,348 students were instructed in mindfulness, with 876 serving as controls, ranging from grade 1 to 12. Overall effect sizes were Hedge's g = 0.40 between groups and g = 0.41 within groups (p < 0.0001). Between group effect sizes for domains were: cognitive performance g = 0.80, stress g = 0.39, resilience g = 0.36, (all p < 0.05), emotional problems g = 0.19 third person ratings g = 0.25 (both n.s.). All in all, mindfulness-based interventions in children and youths hold promise, particularly in relation to improving cognitive performance and resilience to stress. However, the diversity of study samples, variety in implementation and exercises, and wide range of instruments used require a careful and differentiated examination of data. There is great heterogeneity, many studies are underpowered, and measuring effects of Mindfulness in this setting is challenging. The field is nascent and recommendations will be provided as to how interventions and research of these interventions may proceed.

What do verbal fluency tasks measure? Predictors of verbal fluency performance in older adults

Abstract: The study examined the contributions of verbal ability and executive control to verbal fluency performance in older adults (n=82). Verbal fluency was assessed in letter and category fluency tasks, and performance on these tasks was related to indicators of vocabulary size, lexical access speed, updating, and inhibition ability. In regression analyses the number of words produced in both fluency tasks was predicted by updating ability, and the speed of the first response was predicted by vocabulary size and, for category fluency only, lexical access speed. These results highlight the hybrid character of both fluency tasks, which may limit their usefulness for research and clinical purposes.

The grit effect: predicting retention in the military, the workplace, school and marriage.

Abstract: Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g. intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time.

The relationship between nature connectedness and happiness: a meta-analysis

Abstract: Research suggests that contact with nature can be beneficial, for example leading to improvements in mood, cognition, and health. A distinct but related idea is the personality construct of subjective nature connectedness, a stable individual difference in cognitive, affective, and experiential connection with the natural environment. Subjective nature connectedness is a strong predictor of pro-environmental attitudes and behaviours that may also be positively associated with subjective well-being. This meta-analysis was conducted to examine the relationship between nature connectedness and happiness. Based on 30 samples (n = 8,523), a fixed-effect meta-analysis found a small but significant effect size (r = .19). Those who are more connected to nature tended to experience more positive affect, vitality, and life satisfaction compared to those less connected to nature. Publication status, year, average age, and percentage of females in the sample were not significant moderators. Vitality had the strongest relationship with nature connectedness (r = .24), followed by positive affect (r = .22) and life satisfaction (r = .17). In terms of specific nature connectedness measures, associations were the strongest between happiness and inclusion of nature in self (r = .27), compared to nature relatedness (r = .18) and connectedness to nature (r = .18). This research highlights the importance of considering personality when examining the psychological benefits of nature. The results suggest that closer human-nature relationships do not have to come at the expense of happiness. Rather, this meta-analysis shows that being connected to nature and feeling happy are, in fact, connected.

Quality-space theory in olfaction

Abstract: Quality-space theory (QST) explains the nature of the mental qualities distinctive of perceptual states by appeal to their role in perceiving. QST is typically described in terms of the mental qualities that pertain to color. Here we apply QST to the olfactory modalities. Olfaction is in various respects more complex than vision, and so provides a useful test case for QST. To determine whether QST can deal with the challenges olfaction presents, we show how a quality space (QS) could be constructed relying on olfactory perceptible properties and the olfactory mental qualities then defined by appeal to that QS of olfactory perceptible properties. We also consider how to delimit the olfactory QS from other modalities. We further apply QST to the role that experience plays in refining our olfactory discriminative abilities and the occurrence of olfactory mental qualities in non-conscious olfactory states. QST is shown to be fully applicable to and useful for understanding the complex domain of olfaction.

Heart rate variability biofeedback: how and why does it work?

Abstract: In recent years there has been substantial support for heart rate variability biofeedback (HRVB) as a treatment for a variety of disorders and for performance enhancement (Gevirtz, 2013). Since conditions as widely varied as asthma and depression seem to respond to this form of cardiorespiratory feedback training, the issue of possible mechanisms becomes more salient. The most supported possible mechanism is the strengthening of homeostasis in the baroreceptor (Vaschillo et al., 2002; Lehrer et al., 2003). Recently, the effect on the vagal afferent pathway to the frontal cortical areas has been proposed. In this article, we review these and other possible mechanisms that might explain the positive effects of HRVB.

The influences of age on olfaction: a review.

Abstract: Decreased olfactory function is very common in the older population, being present in over half of those between the ages of 65 and 80 years and in over three quarters of those over the age of 80 years. Such dysfunction significantly influences physical well-being and quality of life, nutrition, the enjoyment of food, as well as everyday safety. Indeed a disproportionate number of the elderly die in accident gas poisonings each year. As described in this review, multiple factors contribute to such age-related loss, including altered nasal engorgement, increased propensity for nasal disease, cumulative damage to the olfactory epithelium from viral and other environmental insults, decrements in mucosal metabolizing enzymes, ossification of cribriform plate foramina, loss of selectivity of receptor cells to odorants, changes in neurotransmitter and neuromodulator systems, and neuronal expression of aberrant proteins associated with neurodegenerative disease. It is now well established that decreased smell loss can be an early sign of such neurodegenerative diseases as Alzheimer's disease and sporadic Parkinson's disease. In this review we provide an overview of the anatomy and physiology of the aging olfactory system, how this system is clinically evaluated, and the multiple pathophysiological factors that are associated with its dysfunction.

Food-pics: an image database for experimental research on eating and appetite.

Abstract: Our current environment is characterized by the omnipresence of food cues. The sight and smell of real foods, but also graphically depictions of appetizing foods, can guide our eating behavior, for example, by eliciting food craving and influencing food choice. The relevance of visual food cues on human information processing has been demonstrated by a growing body of studies employing food images across the disciplines of psychology, medicine, and neuroscience. However, currently used food image sets vary considerably across laboratories and image characteristics (contrast, brightness, etc.) and food composition (calories, macronutrients, etc.) are often unspecified. These factors might have contributed to some of the inconsistencies of this research. To remedy this, we developed food-pics, a picture database comprising 568 food images and 315 non-food images along with detailed meta-data. A total of N = 1988 individuals with large variance in age and weight from German speaking countries and North America provided normative ratings of valence, arousal, palatability, desire to eat, recognizability and visual complexity. Furthermore, data on macronutrients (g), energy density (kcal), and physical image characteristics (color composition, contrast, brightness, size, complexity) are provided. The food-pics image data base is freely available under the creative commons license with the hope that the set will facilitate standardization and comparability across studies and advance experimental research on the determinants of eating behavior.

Eating behavior and stress: a pathway to obesity (Review)

Abstract: Stress causes or contributes to a huge variety of diseases and disorders. Recent evidence suggests obesity and other eating-related disorders may be among these. Immediately after a stressful event is experienced, there is a corticotropin-releasing-hormone (CRH)-mediated suppression of food intake. This diverts the body's resources away from the less pressing need to find and consume food, prioritizing fight, flight, or withdrawal behaviors so the stressful event can be dealt with. In the hours following this, however, there is a glucocorticoid-mediated stimulation of hunger and eating behavior. In the case of an acute stress that requires a physical response, such as a predator-prey interaction, this hypothalamic-pituitary-adrenal (HPA) axis modulation of food intake allows the stressful event to be dealt with and the energy used to be replaced afterward. In the case of ongoing psychological stress, however, chronically elevated glucocorticoids can lead to chronically stimulated eating behavior and excessive weight gain. In particular, stress can enhance the propensity to eat high calorie "palatable" food via its interaction with central reward pathways. Activation of this circuitry can also interact with the HPA axis to suppress its further activation, meaning not only can stress encourage eating behavior, but eating can suppress the HPA axis and the feeling of stress. In this review we will explore the theme of eating behavior and stress and how these can modulate one another. We will address the interactions between the HPA axis and eating, introducing a potential integrative role for the orexigenic hormone, ghrelin. We will also examine early life and epigenetic modulation of the HPA axis and how this can influence eating behavior. Finally, we will investigate the clinical implications of changes to HPA axis function and how this may be contributing to obesity in our society.

Emotion categorization of body expressions in narrative scenarios

Abstract: Humans can recognise emotions expressed through body motion with high accuracy even when the stimuli are impoverished. However, most of the research on body motion has relied on exaggerated displays of emotions. In this paper we present two experiments where we investigated whether emotional body expressions could be recognised when they were recorded during natural narration. Our actors were free to use their entire body, face and voice to express emotions, but our resulting visual stimuli used only the upper body motion trajectories in the form of animated stick figures. Observers were asked to perform an emotion recognition task on short motion sequences using a large and balanced set of emotions (amusement, joy, pride, relief, surprise, anger, disgust, fear, sadness, shame and neutral). Even with only upper body motion available, our results show recognition accuracy significantly above chance level and high consistency rates among observers. In our first experiment, that used more classic emotion induction setup, all emotions were well recognised. In the second study that employed narrations, four basic emotion categories (joy, anger, fear and sadness), three non-basic emotion categories (amusement, pride and shame) and the "neutral" category were recognised above chance. Interestingly, especially in the second experiment, observers showed a bias towards anger when recognising the motion sequences for emotions. We discovered that similarities between motion sequences across the emotions along such properties as mean motion speed, number of peaks in the motion trajectory and mean motion span can explain a large percent of the variation in observers' responses. Overall, our results show that upper body motion is informative for emotion recognition in narrative scenarios.

Is the frontal lobe involved in conscious perception

Abstract: When studying the neural mechanisms underlying conscious perception we should be careful not to misinterpret evidence, and delineate these mechanisms from activity which could reflect the prerequisites or consequences of conscious experiences (Aru et al., 2012; De Graaf et al., 2012). However, at the same time, we need to be careful not to exclude any relevant evidence about the phenomenon. Recently, novel paradigms have attempted to dissociate activity related to conscious perception from activity reflecting its prerequisites and consequences. In particular, one of these studies focused on resolving the role of frontal lobe in conscious perception (Frassle et al., 2014). Through a clever experimental design that contrasted blood-oxygen-level-dependent (BOLD) activity elicited during binocular rivalry with and without behavioral reports, Frassle et al. (2014) suggested that frontal lobe, or a large part of it, may not be necessary for conscious perception per se. Rather frontal areas are involved in processing the consequences of conscious perception like monitoring the perceptual content in order to elicit the appropriate report of the subjective experience. In particular, Frassle et al. showed that behavioral reports of conscious experiences resulted in increased and more widespread activity of the frontal lobe compared to a condition without behavioral reports, where spontaneous transitions in the content of consciousness were estimated through the objective measures like optokinetic nystagmus (OKN) and pupil dilation. The authors of this study concluded that “frontal areas are associated with active report and introspection rather than with rivalry per se.” Therefore, activity in prefrontal regions could be considered as a consequence rather than a direct neural correlate of conscious experience. However, a previous study (Panagiotaropoulos et al., 2012) that measured directly neural activity in the macaque lateral prefrontal cortex (LPFC) using extracellular electrophysiological recordings could help to narrow down the role of frontal activity in conscious perception and exclude the contribution of cognitive or motor consequences in prefrontal neural activity during visual awareness. Specifically, the activity of feature selective neurons in the macaque LFPC was shown to be modulated in accordance with the content of subjective perception, without any confound from motor action (i.e., behavioral reports). Using binocular flash suppression (BFS), a paradigm of robust, externally induced perceptual suppression and without any requirement of behavioral reports, neurons in the LPFC were found to increase or decrease their discharge activity when their preferred stimulus was perceptually dominant or suppressed, respectively. Therefore, since neuronal discharges in the LPFC follow the content of conscious perception even without any motor action, the conclusion of Frassle et al. (2014) about the role of frontal lobe activity in rivalrous perception needs to be refined. Prefrontal activity can indeed reflect the content of conscious perception under conditions of rivalrous stimulation and this activity should not be necessarily considered as the result of a motor action or self-monitoring required for active report. Moreover, the results obtained by Frassle et al. (2014) do not anatomically preclude the entire prefrontal cortex from having a role in conscious perception. Specifically, the BOLD activity related to rivalry in their experiment is still present in the right inferior frontal lobe and right superior frontal lobe (Zaretskaya and Narinyan, 2014). Further, activation of dorso- LPFC in conscious perception of Mooney images was also reported in a study that explicitly controlled for activity elicited by motor action (Imamoglu et al., 2012). It is true that the BFS-related prefrontal activity cannot conclude on a mechanistic, causal involvement of prefrontal activity in driving spontaneous transitions in conscious perception. This is because BFS is a paradigm of externally induced perceptual suppression and is therefore not directly informative about the role of recorded activity in spontaneous transitions. Therefore, the possibility remains open that the kind of prefrontal activity observed in the macaque LPFC during BFS is not a causal factor for conscious perception but rather reflects some other aspects of monitoring that are not directly related to motor action. For example, prefrontal activity could just reflect a read-out from other areas like the inferior temporal cortex (Sheinberg and Logothetis, 1997) that also reliably reflects the content of conscious perception. However, if this is the case, it triggers the question why this activity that closely follows the content of subjective perception is observed in the LPFC even in the absence of any behavioral report. Overall, it motivates further investigation to understand whether prefrontal activity has a mechanistic role in conscious perception or it might underlie some monitoring functions that are not necessarily bound to motor action. Similar to this debate on the role of LPFC in visual awareness, the last decade witnessed disagreement on whether activity in primary visual cortex reflects subjective perception as monitored with electrophysiology and fMRI (Leopold and Logothetis, 1996; Tong, 2003; Maier et al., 2008; Keliris et al., 2010; Leopold, 2012). Measuring both electrophysiological activity and the BOLD signal in the same macaques engaged in an identical task of perceptual suppression finally provided the solution (Maier et al., 2008; Leopold, 2012). Therefore, in order to investigate and resolve the role of PFC in visual perception, one must take a similar approach that utilizes multiple measurement techniques simultaneously or in the same animal along with a careful experimental design. The experimental tasks should not only segregate the effect of various cognitive processes such as attention or introspection in comparison to awareness (Watanabe et al., 2011; Frassle et al., 2014), but also use an objective criterion to decode the content of conscious experience (Frassle et al., 2014), therefore separating perception-related activities from the subsequent behavioral report. Such an approach could therefore robustly delineate the prerequisites and consequences of conscious experience and reveal the true correlates of conscious perception. Lastly, although such a multimodal approach could provide us substantial insights into the activity underlying the representation of conscious content, whether or not this activity has a causal role in mediating perception remains to be understood. Although a number of studies indeed point to a causal involvement of prefrontal cortex in conscious perception (reviewed in Dehaene and Changeux, 2011), a systematic study which directly interferes with prefrontal activity during a task of subjective perception is currently, to the best of our knowledge, missing. While utilizing objective criteria as indicators of perceptual transitions, systematic perturbation of the PFC (such as cooling, transcranial magnetic stimulation, microstimulation, or optogenetics) and observing concomitant changes in the temporal dynamics of perceptual transitions could reveal its causal contribution. Indeed, patients with frontal lesions are impaired in their ability to switch from one subjective view of an ambiguous figure to the other (for example see Ricci and Blundo, 1990, but also see a different case study from Valle-Inclan and Gallego, 2006). We would like to conclude that in formulating our conclusions related to prerequisites, consequences and true correlates of conscious experiences, we need to have an integrative view on the available evidence. Our investigations and conclusions about the neural correlates of consciousness must not only entail better-designed experiments but also diverse experimental techniques (e.g., BOLD fMRI, electrophysiology) that could measure brain activity on different spatial and temporal scales (Panagiotaropoulos et al., 2014). Such a multi-modal approach holds great promise in refining our current understanding of conscious processing.

Is threat the only modulator of attentional selectivity? Redefining the Easterbrook hypothesis

Abstract: A repeated finding in the emotion literature is that threatening stimuli are capable of capturing attention in some way; that is, the observer narrows their attentional focus on the objects of threat in their environment. While this finding makes sense from an evolutionary perspective, a key question is: which particular mechanism is responsible for the modulation of such attentional selectivity? The common interpretation of Easterbrook's (1959) hypothesis suggests that the mechanism in question is arousal, although Easterbrook himself described the mechanism as the drive or motivation to withdraw. According to the Yerkes–Dodson's law, the relationship between arousal and performance resembles an inverted U-shape curve with a moderate level of arousal being associated with an optimal level of performance (Yerkes and Dodson, 1908). Recently, van Steenbergen et al. (2011) have presented a study that seems to challenge Easterbrook's widely accepted hypothesis. Using pictures from the International Affective Picture System as emotional stimuli, pupil dilation as a measure of arousal, and an anti-saccade task as a measure of attentional selectivity, the authors found that both positive and negative pictures produced an increase in arousal whereas only negative pictures produced an increase in attentional selectivity. The authors conclude that arousal is a necessary but not a sufficient condition for attentional selectivity. Although this study presents an interesting challenge to the Easterbrook hypothesis, it does not rule out an alternative interpretation of the underlying mechanisms. First, we need to determine whether or not arousal is capable of increasing attentional selectivity independently of any emotional manipulation. Our laboratory has developed an arousal manipulation which is based on observer expectancy and thus potentially unconfounded by emotional valence (see Vangkilde et al., 2012, Exp. 3; but also see Berlyne, 1966). In a whole and partial report setup, the temporal onset of the stimulus display is varied in accordance with a certain cue (Sorensen et al., 2014). Given that we use a blocked design, we hypothesize that this manipulation modulates the participant's cortical arousal in a tonic rather than a phasic fashion by means of brain arousal systems such as the Reticular Activation System (RAS). Using the Theory of Visual Attention (TVA; Bundesen, 1990) as a theoretical framework, we are able to model the impact of this arousal on specific attentional parameters (Dyrholm et al., 2011). Significantly, we have found that participants in a heightened state of arousal consistently assign higher attentional weights to the target stimuli (w) and are better at distinguishing the target stimuli from the distractors (α), in comparison with the low arousal condition. In addition, we have found that as the level of participants' arousal increases the capacity of their visual short-term memory (K) tends to decrease (Sorensen and Bundesen, 2011; McAvinue et al., 2012; Sorensen et al., 2014). These results are consistent with both the Easterbrook hypothesis and the Yerkes–Dodson law: for example, raising the level of arousal to a certain point improves the observer's capacity to attend to relevant objects by effectively boosting the salience of the target stimuli. Following the Yerkes–Dodson law, however, too much arousal is a bad thing: if the salience of the target stimuli is already at ceiling, then the only possible effect of adding yet more arousal will be to increase the salience of the distractors, thus leading to an overall decrease in performance. If arousal is capable of increasing attentional selectivity independently of any emotional manipulation, then why do van Steenbergen and colleagues find a difference between the positive and negative conditions in their study? (Previous studies by, e.g., McNamara and Fisch, 1964, have shown a similar pattern, with negative arousal mediated by threat tending to have a larger impact on performance than positive arousal mediated by monetary reward.) In order to answer this question, we need to turn to the research on visual attention and emotion. Behavioral studies using paradigms such as the flanker task (Fenske and Eastwood, 2003; Barratt and Bundesen, 2012) and the visual search task (Ohman et al., 2001) suggest that threatening stimuli are capable of capturing attention to a greater extent than both positive and neutral stimuli. Neurobiological studies have pinpointed limbic structures such as the amygdala as playing a crucial role in the appraisal of threat (LeDoux, 1998; Ohman, 2005). The amygdala is thought to generate at least three potential outputs of relevance to the current question. First, the amygdala may trigger bodily arousal via the autonomic nervous system, resulting in the increases in heart rate, respiration, and perspiration typically associated with a fear response (and in the pupil dilation measured by van Steenbergen et al.). Second, the amygdala may trigger cortical arousal via various brain arousal systems such as the RAS, thus increasing the general sensitivity of cortical neurons and ensuring that the observer is in a relatively alert state. The key, however, lies in the third and final output. Significantly, evidence suggests that the amygdala may send an attentional weight (w) signal to the visual cortex via reciprocal neural connections, thus ensuring that a threatening object in the visual field receives a greater allocation of attentional processing resources (e.g., Sugase et al., 1999). In principle, then, arousal and attentional selectivity can be separated, although arousal serves to increase the effects of attentional selectivity. We propose that a general increase in cortical arousal modulated via brain arousal systems such as the RAS is sufficient to cause a narrowing of the attentional focus in line with the Easterbrook hypothesis. On top of this, however, the appearance of threatening stimuli in an otherwise neutral environment (cf. McNamara and Fisch, 1964; van Steenbergen et al., 2011) is capable of triggering a specific calculation of attentional weights which results in the faster and more efficient processing of threatening stimuli relative to neutral stimuli. If, for example, the cortical neurons involved in the processing of threatening stimuli are relatively active in comparison with those neurons coding for neutral stimuli, then this activity will be boosted further by a general level of arousal—an engineering “trick” of evolutionary significance (cf. LeDoux, 1998, p. 288).

Predictors of early growth in academic achievement: the head-toes-knees-shoulders task

Abstract: Children’s behavioral self-regulation and executive function (EF; including attentional or cognitive flexibility, working memory, and inhibitory control) are strong predictors of academic achievement. The present study examined the psychometric properties of a measure of behavioral self-regulation called the Head-Toes-Knees-Shoulders (HTKS) by assessing construct validity, including relations to EF measures, and predictive validity to academic achievement growth between prekindergarten and kindergarten. In the fall and spring of prekindergarten and kindergarten, 208 children (51% enrolled in Head Start) were assessed on the HTKS, measures of cognitive flexibility, working memory (WM), and inhibitory control, and measures of emergent literacy, mathematics, and vocabulary. For construct validity, the HTKS was significantly related to cognitive flexibility, working memory, and inhibitory control in prekindergarten and kindergarten. For predictive validity in prekindergarten, a random effects model indicated that the HTKS significantly predicted growth in mathematics, whereas a cognitive flexibility task significantly predicted growth in mathematics and vocabulary. In kindergarten, the HTKS was the only measure to significantly predict growth in all academic outcomes. An alternative conservative analytical approach, a fixed effects analysis (FEA) model, also indicated that growth in both the HTKS and measures of EF significantly predicted growth in mathematics over four time points between prekindergarten and kindergarten. Results demonstrate that the HTKS involves cognitive flexibility, working memory, and inhibitory control, and is substantively implicated in early achievement, with the strongest relations found for growth in achievement during kindergarten and associations with emergent mathematics.

Publication bias and the limited strength model of self-control: has the evidence for ego depletion been overestimated?

Abstract: Few models of self-control have generated as much scientific interest as has the limited strength model. One of the entailments of this model, the depletion effect, is the expectation that acts of self-control will be less effective when they follow prior acts of self-control. Results from a previous meta-analysis concluded that the depletion effect is robust and medium in magnitude (d = 0.62). However, when we applied methods for estimating and correcting for small-study effects (such as publication bias) to the data from this previous meta-analysis effort, we found very strong signals of publication bias, along with an indication that the depletion effect is actually no different from zero. We conclude that until greater certainty about the size of the depletion effect can be established, circumspection about the existence of this phenomenon is warranted, and that rather than elaborating on the model, research efforts should focus on establishing whether the basic effect exists. We argue that the evidence for the depletion effect is a useful case study for illustrating the dangers of small-study effects as well as some of the possible tools for mitigating their influence in psychological science.

Mood, food, and obesity

Abstract: Food is a potent natural reward and food intake is a complex process. Reward and gratification associated with food consumption leads to dopamine (DA) production, which in turn activates reward and pleasure centers in the brain. An individual will repeatedly eat a particular food to experience this positive feeling of gratification. This type of repetitive behavior of food intake leads to the activation of brain reward pathways that eventually overrides other signals of satiety and hunger. Thus, a gratification habit through a favorable food leads to overeating and morbid obesity. Overeating and obesity stems from many biological factors engaging both central and peripheral systems in a bi-directional manner involving mood and emotions. Emotional eating and altered mood can also lead to altered food choice and intake leading to overeating and obesity. Research findings from human and animal studies support a two-way link between three concepts, mood, food, and obesity. The focus of this article is to provide an overview of complex nature of food intake where various biological factors link mood, food intake, and brain signaling that engages both peripheral and central nervous system signaling pathways in a bi-directional manner in obesity.

Music and social bonding: "self-other" merging and neurohormonal mechanisms.

Abstract: It has been suggested that a key function of music during its development and spread amongst human populations was its capacity to create and strengthen social bonds amongst interacting group members. However, the mechanisms by which this occurs have not been fully discussed. In this paper we review evidence supporting two thus far independently investigated mechanisms for this social bonding effect: self-other merging as a consequence of inter-personal synchrony, and the release of endorphins during exertive rhythmic activities including musical interaction. In general, self-other merging has been experimentally investigated using dyads, which provide limited insight into large-scale musical activities. Given that music can provide an external rhythmic framework that facilitates synchrony, explanations of social bonding during group musical activities should include reference to endorphins, which are released during synchronised exertive movements. Endorphins (and the Endogenous Opioid System (EOS) in general) are involved in social bonding across primate species, and are associated with a number of human social behaviours (e.g. laughter, synchronised sports), as well as musical activities (e.g. singing and dancing). Furthermore, passively listening to music engages the EOS, so here we suggest that both self-other merging and the EOS are important in the social bonding effects of music. In order to investigate possible interactions between these two mechanisms, future experiments should recreate ecologically valid examples of musical activities.

Considerations in the assessment of heart rate variability in biobehavioral research

Abstract: Heart rate variability (HRV) refers to various methods of assessing the beat-to-beat variation in the heart over time, in order to draw inference on the outflow of the autonomic nervous system. Easy access to measuring HRV has led to a plethora of studies within emotion science and psychology assessing autonomic regulation, but significant caveats exist due to the complicated nature of HRV. Firstly, both breathing and blood pressure regulation have their own relationship to social, emotional and cognitive experiments – if this is the case are we observing heart rate changes as a consequence of breathing changes? Secondly, experiments often have poor internal and external controls. In this review we highlight the interrelationships between heart rate and respiration, as well as presenting recommendations for researchers to use when collecting data for HRV assessment. Namely, we highlight the superior utility of within-subjects designs along with the importance of establishing an appropriate baseline and monitoring respiration.

Rationality: a social-epistemology perspective

Abstract: Both in philosophy and in psychology, human rationality has traditionally been studied from an 'individualistic' perspective. Recently, social epistemologists have drawn attention to the fact that epistemic interactions among agents also give rise to important questions concerning rationality. In previous work, we have used a formal model to assess the risk that a particular type of social-epistemic interactions lead agents with initially consistent belief states into inconsistent belief states. Here, we continue this work by investigating the dynamics to which these interactions may give rise in the population as a whole.

From the heart to the mind: cardiac vagal tone modulates top-down and bottom-up visual perception and attention to emotional stimuli.

Abstract: The neurovisceral integration model (Thayer & Lane, 2000) posits that cardiac vagal tone, indexed by heart rate variability (HRV), can indicate the functional integrity of the neural networks implicated in emotion-cognition interactions. Our recent findings begin to disentangle how HRV is associated with both top-down and bottom-up cognitive processing of emotional stimuli. Higher resting HRV is associated with more adaptive and functional top-down and bottom-up cognitive modulation of emotional stimuli, which may facilitate effective emotion regulation. Conversely, lower resting HRV is associated with hyper-vigilant and maladaptive cognitive responses to emotional stimuli, which may impede emotion regulation. In the present paper, we recapitulate the neurovisceral integration model and review recent findings that shed light on the relationship between HRV and top-down and bottom-up visual perception and attention to emotional stimuli, which may play an important role in emotion regulation. Further implications of HRV on individual well-being and mental health are discussed.

Does language dominance affect cognitive performance in bilinguals? Lifespan evidence from preschoolers through older adults on card sorting, Simon, and metalinguistic tasks

Abstract: This study explores the extent to which a bilingual advantage can be observed for three tasks in an established population of fully fluent bilinguals from childhood through adulthood. Welsh-English simultaneous and early sequential bilinguals, as well as English monolinguals, aged 3 years through older adults, were tested on three sets of cognitive and executive function tasks. Bilinguals were Welsh-dominant, balanced, or English-dominant, with only Welsh, Welsh and English, or only English at home. Card sorting, Simon, and a metalinguistic judgment task (650, 557, and 354 participants, respectively) reveal little support for a bilingual advantage, either in relation to control or globally. Primarily there is no difference in performance across groups, but there is occasionally better performance by monolinguals or persons dominant in the language being tested, and in one case-in one condition and in one age group-lower performance by the monolinguals. The lack of evidence for a bilingual advantage in these simultaneous and early sequential bilinguals suggests the need for much closer scrutiny of what type of bilingual might demonstrate the reported effects, under what conditions, and why.

Is there a bilingual advantage in the ANT task? Evidence from children.

Abstract: Bilinguals have been shown to outperform monolinguals in a variety of tasks that do not tap into linguistic processes. The origin of this bilingual advantage has been questioned in recent years. While some authors argue that the reason behind this apparent advantage is bilinguals’ enhanced executive functioning, inhibitory skills and/or monitoring abilities, other authors suggest that the locus of these differences between bilinguals and monolinguals may lie in uncontrolled factors or incorrectly matched samples. In the current study we tested a group of 180 bilingual children and a group of 180 carefully matched monolinguals in a child-friendly version of the ANT task. Following recent evidence from similar studies with children, our results showed no bilingual advantage at all, given that the performance of the two groups in the task and the indices associated with the individual attention networks were highly similar and statistically indistinguishable.

Eating behavior and stress: a pathway to obesity

Abstract: Stress causes or contributes to a huge variety of diseases and disorders. Recent evidence suggests obesity and other eating-related disorders may be among these. Immediately after a stressful event is experienced, there is a corticotropin-releasing-hormone (CRH)-mediated suppression of food intake. This diverts the body’s resources away from the less pressing need to find and consume food, prioritizing fight, flight, or withdrawal behaviours so the stressful event can be dealt with. In the hours following this, however, there is a glucocorticoid-mediated stimulation of hunger and eating behaviour. In the case of an acute stress that requires a physical response, such as a predator-prey interaction, this hypothalamic-pituitary-adrenal (HPA) axis modulation of food intake allows the stressful event to be dealt with and the energy used to be replaced afterwards. In the case of ongoing psychological stress, however, chronically elevated glucocorticoids can lead to chronically stimulated eating behaviour and excessive weight gain. In particular, stress can enhance the propensity to eat high calorie “palatable” food via its interaction with central reward pathways. Activation of this circuitry can also interact with the HPA axis to suppress its further activation, meaning not only can stress encourage eating behaviour, but eating can suppress the HPA axis and the feeling of stress. In this review we will explore the theme of eating behaviour and stress and how these can modulate one another. We will address the interactions between the HPA axis and eating, introducing a potential integrative role for the orexigenic hormone, ghrelin. We will also examine early life and epigenetic modulation of the HPA axis and how this can influence eating behaviour. Finally, we will investigate the clinical implications of changes to HPA axis function and how this may be contributing to obesity in our society.

Embodied affectivity: on moving and being moved

Abstract: There is a growing body of research indicating that bodily sensation and behaviour strongly influences one’s emotional reaction towards certain situations or objects. On this background, a framework model of embodied affectivity is suggested: we regard emotions as resulting from the circular interaction between affective qualities or affordances in the environment and the subject’s bodily resonance, be it in the form of sensations, postures, expressive movements or movement tendencies. Motion and emotion are thus intrinsically connected: one is moved by movement (perception; impression; affection ) and moved to move (action; expression; e-motion). Through its resonance, the body functions as a medium of emotional perception: it colours or charges self-experience and the environment with affective valences while it remains itself in the background of one’s own awareness. This model is then applied to emotional social understanding or interaffectivity which is regarded as an intertwinement of two cycles of embodied affectivity, thus continuously modifying each partner’s affective affordances and bodily resonance. We conclude with considerations of how embodied affectivity is altered in psychopathology and can be addressed in psychotherapy of the embodied self.

Face-to-face or face-to-screen? Undergraduates' opinions and test performance in classroom vs. online learning.

Abstract: As electronic communication becomes increasingly common, and as students juggle study, work, and family life, many universities are offering their students more flexible learning opportunities. Classes once delivered face-to-face are often replaced by online activities and discussions. However, there is little research comparing students' experience and learning in these two modalities. The aim of this study was to compare undergraduates' preference for, and academic performance on, class material and assessment presented online vs. in traditional classrooms. Psychology students (N = 67) at an Australian university completed written exercises, a class discussion, and a written test on two academic topics. The activities for one topic were conducted face-to-face, and the other online, with topics counterbalanced across two groups. The results showed that students preferred to complete activities face-to-face rather than online, but there was no significant difference in their test performance in the two modalities. In their written responses, students expressed a strong preference for class discussions to be conducted face-to-face, reporting that they felt more engaged, and received more immediate feedback, than in online discussion. A follow-up study with a separate group (N = 37) confirmed that although students appreciated the convenience of completing written activities online in their own time, they also strongly preferred to discuss course content with peers in the classroom rather than online. It is concluded that online and face-to-face activities can lead to similar levels of academic performance, but that students would rather do written activities online but engage in discussion in person. Course developers could aim to structure classes so that students can benefit from both the flexibility of online learning, and the greater engagement experienced in face-to-face discussion.

Is adding more indicators to a latent class analysis beneficial or detrimental? Results of a Monte-Carlo study

Abstract: The purpose of this study was to examine in which way adding more indicators or a covariate influences the performance of latent class analysis (LCA). We varied the sample size (100 ≤ N ≤ 2000), number, and quality of binary indicators (between 4 and 12 indicators with conditional response probabilities of [0.3, 0.7], [0.2, 0.8], or [0.1, 0.9]), and the strength of covariate effects (zero, small, medium, large) in a Monte Carlo simulation study of 2- and 3-class models. The results suggested that in general, a larger sample size, more indicators, a higher quality of indicators, and a larger covariate effect lead to more converged and proper replications, as well as fewer boundary parameter estimates and less parameter bias. Furthermore, interactions among these study factors demonstrated how using more or higher quality indicators, as well as larger covariate effect size, could sometimes compensate for small sample size. Including a covariate appeared to be generally beneficial, although the covariate parameters themselves showed relatively large bias. Our results provide useful information for practitioners designing an LCA study in terms of highlighting the factors that lead to better or worse performance of LCA.

A construct divided: prosocial behavior as helping, sharing, and comforting subtypes.

Abstract: The development and maintenance of prosocial, other-oriented behaviors has been of considerable recent interest. Though it is clear that prosocial behaviors emerge early and play a uniquely important role in the social lives of humans, there is less consensus regarding the mechanisms that underlie and maintain these fundamental acts. The goal of this paper is to clarify inconsistencies in our understanding of the early emergence and development of prosocial behavior by proposing a taxonomy of prosocial behavior anchored in the social-cognitive constraints that underlie the ability to act on behalf of others. I will argue that within the general domain of prosocial behavior, other-oriented actions can be categorized into three distinct types (helping, sharing, and comforting) that reflect responses to three distinct negative states (instrumental need, unmet material desire, and emotional distress). In support of this proposal, I will demonstrate that the three varieties of prosocial behavior show unique ages of onset, uncorrelated patterns of production, and distinct patterns of individual differences. Importantly, by differentiating specific varieties of prosocial behavior within the general category, we can begin to explain inconsistencies in the past literature and provide a framework for directing future research into the ontogenetic origins of these essential social behaviors.

Approach, avoidance, and affect: a meta-analysis of approach-avoidance tendencies in manual reaction time tasks.

Abstract: Approach action tendencies toward positive stimuli and avoidance tendencies from negative stimuli are widely seen to foster survival. Many studies have shown that approach and avoidance arm movements are facilitated by positive and negative affect, respectively. There is considerable debate whether positively and negatively valenced stimuli prime approach and avoidance movements directly (i.e., immediate, unintentional, implicit, automatic, and stimulus-based), or indirectly (i.e., after conscious or non-conscious interpretation of the situation). The direction and size of these effects were often found to depend on the instructions referring to the stimulus object or the self, and on explicit vs. implicit stimulus evaluation. We present a meta-analysis of 29 studies included for their use of strongly positive and negative stimuli, with 81 effect sizes derived solely from the means and standard deviations (combined N = 1538), to examine the automaticity of the link between affective information processing and approach and avoidance, and to test whether it depends on instruction, type of approach-avoidance task, and stimulus type. Results show a significant small to medium-sized effect after correction for publication bias. The strongest arguments for an indirect link between affect and approach-avoidance were the absence of evidence for an effect with implicit evaluation, and the opposite directions of the effect with self and object-related interpretations. The link appears to be influenced by conscious or non-conscious intentions to deal with affective stimuli.