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.     

Students' ratings of teaching effectiveness: a laughing matter?

Gump in 2004 identified a positive significant relationship between awareness of daily class objectives and ratings of the instructor's overall teaching effectiveness. The idea that rating of teaching effectiveness can be related to other non-teaching related attributes of the lecturer was further examined. Correlations based on ratings of teaching effectiveness from 453 undergraduate students (M=21 yr., SD= 5.5; 73% women) showed that another nonteaching related variable, namely, how funny the instructor was perceived, was significantly related to indicators of teaching effectiveness.     

The relation of phoneme discrimination, lexical access, and short-term memory: A case study and interactive activation account

A brain-damaged patient (AP) is reported who had a strong tendency to identify nonwords as words on auditory lexical decision and to lexicalize nonwords in repetition, yet who showed a normal ability to perceive individual phonemes. It was initially hypothesized that these findings could be accounted for in terms of disrupted lexical phonological representations. This hypothesis was rejected on the basis of an interactive activation model of word recognition which revealed that modifications at the lexical level did not mimic the patient's pattern of results. Instead, it was found that increasing the rate of decay of activation at the phoneme level produced output that was consistent with the phoneme discrimination, lexical decision, and repetition results. This hypothesis of increased phoneme level decay led to the prediction that speech discrimination would decline with increased interstimulus interval and that short-term memory performance would be impaired. Both predictions were confirmed. The results of this study provide support for an interactive activation model of word recognition with feedback from the lexical to the phonemic level and for a close connection between the processes involved in word recognition and short-term memory.     

Effects of semantic context in the naming of pictures and words

Two experiments investigated whether lexical retrieval for speaking can be characterized as a competitive process by assessing the effects of semantic context on picture and word naming in German. In Experiment 1 we demonstrated that pictures are named slower in the context of same-category items than in the context of items from various semantic categories, replicating findings by Kroll and Stewart (Journal of Memory and Language, 33 (1994) 149). In Experiment 2 we used words instead of pictures. Participants either named the words in the context of same- or different-category items, or produced the words together with their corresponding determiner. While in the former condition words were named faster in the context of same-category items than of different-category items, the opposite pattern was obtained for the latter condition. These findings confirm the claim that the interfering effect of semantic context reflects competition in the retrieval of lexical entries in speaking.     

Relational processing and working memory capacity in comprehension of relative clause sentences

Previous research has indicated that the cognitive load imposed by tasks in various content domains increases with the complexity of the relational information processed. Sentence comprehension entails processing noun-verb relations to determine who did what to whom. The difficulty of object-extracted relative clause sentences might stem from the complex noun-verb relations they entail. Across three studies, participants read 16 types of object- and subject-extracted relative clause sentences at their own pace and then responded to a comprehension question for each sentence. Relational processing was assessed using a premise integration task or a Latin square task. These tasks predicted comprehension of object-relatives before and after controlling for subject-relatives. Working memory (WM) capacity was assessed using reading span or forward and backward digit span tests. WM tasks predicted comprehension of object-relatives before but not after controlling for subject-relatives. Comprehension of object-relatives relied more heavily on a domain-general capacity to process complex relations than on WM capacity.     

An exploratory study of perceived discrimination and homesickness: a comparison of international students and American students

The authors examined group differences in perceived discrimination and homesickness in a sample of 439 college students (198 international and 241 U.S. students) from 2 campuses of the same university. Within the international student group, the authors also examined relationships between homesickness, discrimination, age, English proficiency, and years of residence in the United States. Results indicated that international students experienced higher levels of discrimination and homesickness than did U.S. students. Age, English proficiency, and perceived discrimination predicted homesickness among the international students. Younger students, students with lower levels of English proficiency, and students with higher levels of perceived discrimination reported having higher levels of homesickness. Also, years of residence and race or ethnicity predicted international students' level of perceived discrimination. Being a European international student predicted lower levels of perceived discrimination than did being an international student from other regions of the world. The authors discuss implications for higher-education institutions and counseling personnel.     

Perfectionistic concerns predict increases in adolescents’ anxiety symptoms: a three-wave longitudinal study

Background and Objectives: Although perfectionism has been proposed to be a risk factor for the development of anxiety, research on perfectionism and anxiety symptoms in adolescents is scarce and inconclusive. The aim of the present study was to investigate whether the two higher-order dimensions of perfectionism – perfectionistic strivings and perfectionistic concerns – predict the development and maintenance of anxiety symptoms. An additional aim of the present study was to examine potential reciprocal effects of anxiety symptoms predicting increases in perfectionism.

Design: The study used a longitudinal design with three waves spaced 4–5 months apart.

Methods: A non-clinical sample of 489 adolescents aged 12–19 years completed a paper-and-pencil questionnaire.

Results: As expected, results showed a positive effect from perfectionistic concerns to anxiety symptoms, but the effect was restricted to middle-to-late adolescents (16–19 years old): Perfectionistic concerns predicted longitudinal increases in adolescents’ anxiety symptoms, whereas perfectionistic strivings did not. Furthermore, anxiety symptoms did not predict increases in perfectionism.

Conclusions: Implications for the understanding of the relationship between perfectionism and anxiety symptoms are discussed.     

Why People Who Have Sex with Animals Believe That It Is Their Sexual Orientation—A Grounded Theory Study of Online Communities of Zoophiles

This study explores online spaces of zoophiles. Relevant discussion forums, specializing in mental health, were identified through having threads on “sexuality,” “paraphilias,” and “zoophilia.” Thematic analysis includes responses of 138 participants (135 exclusive zoophiles, and three zoophiles with pedophilic tendencies). Trend analysis identified most frequently discussed topics: animals as an object of love; emotional closeness with animals; what are paraphilias; can animals consent to sex with humans; misunderstanding terminology of zoophilia/bestiality. First, zoophiles frequently ask why zoophilia is considered an act of bestiality if the term to them means “to murder.” Second, zoophiles believe that animals have an intrinsic ability to consent to sexual behaviors involving people. Third, most messages pointed to the lack of emotional support from the family and widespread public contempt.