Bayesian inference for psychology. Part II: Example applications with JASP

Bayesian hypothesis testing presents an attractive alternative to p value hypothesis testing. Part I of this series outlined several advantages of Bayesian hypothesis testing, including the ability to quantify evidence and the ability to monitor and update this evidence as data come in, without the need to know the intention with which the data were collected. Despite these and other practical advantages, Bayesian hypothesis tests are still reported relatively rarely. An important impediment to the widespread adoption of Bayesian tests is arguably the lack of user-friendly software for the run-of-the-mill statistical problems that confront psychologists for the analysis of almost every experiment: the t-test, ANOVA, correlation, regression, and contingency tables. In Part II of this series we introduce JASP (http://www.jasp-stats.org), an open-source, cross-platform, user-friendly graphical software package that allows users to carry out Bayesian hypothesis tests for standard statistical problems. JASP is based in part on the Bayesian analyses implemented in Morey and Rouder’s BayesFactor package for R. Armed with JASP, the practical advantages of Bayesian hypothesis testing are only a mouse click away.     

Mindfulness Based Flourishing Program: A Cross-Cultural Study of Hong Kong Chinese and British Participants

The Mindfulness Based Flourishing Program (MBFP) is an online 8-week intervention developed for enhancing wellbeing with the use of mindfulness practices, through targeting a range of positive variables. The efficacy of the MBFP has been demonstrated in a randomized controlled trial, and in order to further establish it as an intervention with widespread application, cross-cultural validation is warranted. The current study was conducted with the primary aim of testing the validity of the MBFP with a Hong Kong Chinese population, as well as verifying its positive effects. A randomized wait-list controlled design was adopted with 115 participants (92 females, mean age = 31.50). Intervention outcomes were compared between Hong Kong Chinese and British participants. Five positive variables were examined (self-compassion, meaning in life, positive and negative emotions, gratitude, and mindfulness), and measures were taken pre- and post-intervention. Significant gains in wellbeing measures were observed in both the Hong Kong Chinese and the British experimental groups. Levels of wellbeing post-intervention were also higher for the two experimental groups as compared to their control counterparts. The current study provides preliminary evidence for the MBFP’s cross-cultural validity, and strengthens previous claims for its efficacy as a new, accessible alternative for enhancing wellbeing.     

What to expect from your remote eye-tracker when participants are unrestrained

The marketing materials of remote eye-trackers suggest that data quality is invariant to the position and orientation of the participant as long as the eyes of the participant are within the eye-tracker’s headbox, the area where tracking is possible. As such, remote eye-trackers are marketed as allowing the reliable recording of gaze from participant groups that cannot be restrained, such as infants, schoolchildren and patients with muscular or brain disorders. Practical experience and previous research, however, tells us that eye-tracking data quality, e.g. the accuracy of the recorded gaze position and the amount of data loss, deteriorates (compared to well-trained participants in chinrests) when the participant is unrestrained and assumes a non-optimal pose in front of the eye-tracker. How then can researchers working with unrestrained participants choose an eye-tracker? Here we investigated the performance of five popular remote eye-trackers from EyeTribe, SMI, SR Research, and Tobii in a series of tasks where participants took on non-optimal poses. We report that the tested systems varied in the amount of data loss and systematic offsets observed during our tasks. The EyeLink and EyeTribe in particular had large problems. Furthermore, the Tobii eye-trackers reported data for two eyes when only one eye was visible to the eye-tracker. This study provides practical insight into how popular remote eye-trackers perform when recording from unrestrained participants. It furthermore provides a testing method for evaluating whether a tracker is suitable for studying a certain target population, and that manufacturers can use during the development of new eye-trackers.     

Saved by the blush: being trusted despite defecting

This study examined whether blushing after a sociomoral transgression remediates trustworthiness in an interdependent context. Participants (N = 196) played a computerized prisoner's dilemma game with a virtual opponent who defected in the second round of the game. After the defection, a photograph of the opponent was shown, displaying a blushing or a nonblushing face. In a subsequent Trust Task, the blushing opponent was entrusted with more money than the nonblushing opponent. In further support of the alleged remedial properties of the blush, participants also indicated that they trusted the blushing opponent more, expected a lower probability that she would defect again, and judged the blushing opponent more positively.     

The effect of foregone outcomes on choices from experience

We examined the relative weight given to obtained and foregone outcomes (i.e., outcomes from the non-chosen options) in repeated choices using cognitive modeling. Previous modeling studies have yielded mixed results. When participants' choices are analyzed by models that predict the next choice ahead in a sequence of decisions, the results imply that people give less weight to foregone than to obtained outcomes. In contrast, in simulation models of n trials ahead, the results imply that, on average, people give equal weight to foregone and obtained outcomes. Using datasets of experience-based binary choices with fixed (stationary) payoff distributions (Erev & Haruvy, in press) and dynamic (nonstationary) payoff distributions (Rakow & Miler, 2009), we employed generalization tests at the individual level to examine whether the findings derived from the one-step-ahead method are due to overfitting. The results of trial-ahead model fitting implied that for the nonstationary tasks only, foregone outcomes received lower weight. However, when this dataset was assessed via generalization criteria at the individual level, equal weighting of foregone and obtained outcomes was the best assumption. This implies that overfitting is implicated in the superior fit of models that assume discounting of foregone outcomes.     

Compositionality: A Connectionist Variation on a Classical Theme

Connectionism has been attacked on the grounds that it does not employ compositionally structured representations (e.g., Fodor & Pylyshyn, 1988). This article develops the response that Connectionist models can, and in fact sometimes do, employ compositionally structured representations without, thereby, simply implementing a Classical “Language of Thought.” Focusing on the mode of combination employed in constructing representations, it distinguishes concatenative compositionality, essential to the Classical approach, from a merely functional counterpart increasingly common in Connectionist research. On the basis of this distinction it is possible to demonstrate that Connectionist representations can be compositional without being Classical, and further, that Fodor and Pylyshyn's supposedly conclusive arguments in favor of the Classical approach do not in fact support that approach over the Connectionist alternative (as opposed to an “ossociotionist” straw man).     

When encoding fails: Instructions,feedback, and registration without learning

Four experiments replicated and extended the registration-without-learning effect, in which there is little improvement in the ability to discriminate an old target (X) from a highly similar test item (Y) after the first few presentations of X, even though judgments of frequency continue to rise in an openended fashion. Forced-choice testing revealed the anomalous form of the learning curve for X-Y discrimination (faster and then slower than the exponential). Effects of several different learning instructions were compared, but these appeared to affect only the level of initial learning, and to do little to promote X-Y discrimination learning on later presentations. The opportunity for self-testing with feedback during study provided no benefits when responding was covert, but did when overt anticipation was required. The findings are discussed in relation to the roles of bottom-up and topdown processing in memory encoding, and to the importance of error-correcting feedback in further structural learning of materials, once the materials have become familiar.