Creating web applications for online psychological experiments: A hands-on technical guide including a template.

The present tutorial provides a technical overview of how to create web applications for online psychological experiments from scratch via the HTML/CSS/JavaScript framework. This approach allows virtually unlimited flexibility in accomplishing anything in an online experiment that a regular computer (or smartphone, etc.) is capable of. Apart from offering a fast introduction for complete beginners, this tutorial may also serve as a helpful guideline for more experienced programmers and researchers. Connected to the tutorial, a specific implementation is also given via the free and open-source template project at https://github.com/gasparl/expapp , intended to be improved by the community to always follow the latest technological advancements and general good practices.

Response time concealed information test using fillers in cybercrime and concealed identity scenarios.

The Response Time Concealed Information Test (RT-CIT) can reveal that a person recognises a relevant item (e.g., a murder weapon) among other control items, based on slower responses to the former compared to the latter ones. To date, the RT-CIT has been predominantly examined only in the context of scenarios that are very unlikely in real life, while sporadic assessment has shown that it suffers from low diagnostic accuracy in more realistic scenarios. In our study, we validated the RT-CIT in the new, realistic, and very topical mock scenario of a cybercrime (Study 1, n = 614; Study 2; n = 553), finding significant though moderate effects. At the same time (and expanded with a concealed identity scenario; Study 3, n = 250), we assessed the validity and generalizability of the filler items presented in the RT-CIT: We found similar diagnostic accuracies when using specific, generic, and even nonverbal items. However, the relatively low diagnostic accuracy in case of the cybercrime scenario reemphasizes the importance of assessments in realistic scenarios as well as the need for further improving the RT-CIT.

Precise display time measurement in JavaScript for web-based experiments.

Conducting research via the Internet is a formidable and ever-increasingly popular option for behavioral scientists. However, it is widely acknowledged that web-browsers are not optimized for research: In particular, the timing of display changes (e.g., a stimulus appearing on the screen), still leaves room for improvement. So far, the typically recommended best (or least bad) timing method has been a single (RAF) JavaScript function call within which one would give the display command and obtain the time of that display change. In our Study 1, we assessed two alternatives: Calling the RAF twice consecutively, or calling the RAF during a continually ongoing independent loop of recursive RAF calls. While the former has shown little or no improvement as compared to single RAF calls, with the latter we significantly and substantially improved overall precision, and achieved practically faultless precision in most practical cases. Our two basic methods for effecting display changes, plain text change and color filling, proved equally efficient. In Study 2, we reassessed the "RAF loop" timing method with image elements in combination with three different display methods: We found that the precision remained high when using either or changes - while drawing on a element consistently led to comparatively lower precision. We recommend the "RAF loop" display timing method for improved precision in future studies, and or changes when using image stimuli. We publicly share the easy-to-use code for this method, exactly as employed in our studies.

The good, the bad, and the red: implicit color-valence associations across cultures.

Cultural differences-as well as similarities-have been found in explicit color-emotion associations between Chinese and Western populations. However, implicit associations in a cross-cultural context remain an understudied topic, despite their sensitivity to more implicit knowledge. Moreover, they can be used to study color systems-that is, emotional associations with one color in the context of an opposed one. Therefore, we tested the influence of two different color oppositions on affective stimulus categorization: red versus green and red versus white, in two experiments. In Experiment 1, stimuli comprised positive and negative words, and participants from the West (Austria/Germany), and the East (Mainland China, Macau) were tested in their native languages. The Western group showed a significantly stronger color-valence interaction effect than the Mainland Chinese (but not the Macanese) group for red-green but not for red-white opposition. To explore color-valence interaction effects independently of word stimulus differences between participant groups, we used affective silhouettes instead of words in Experiment 2. Again, the Western group showed a significantly stronger color-valence interaction than the Chinese group in red-green opposition, while effects in red-white opposition did not differ between cultural groups. Our findings complement those from explicit association research in an unexpected manner, where explicit measures showed similarities between cultures (associations for red and green), our results revealed differences and where explicit measures showed differences (associations with white), our results showed similarities, underlining the value of applying comprehensive measures in cross-cultural research on cross-modal associations.

Speed versus accuracy instructions in the response time concealed information test.

The response time concealed information test (RT-CIT) can reveal that a person recognizes a relevant item (probe) among other, irrelevant items, based on slower responding to the probe compared to the irrelevant items. Thereby, if this person is concealing knowledge about the relevance of this item (e.g., recognizing it as a murder weapon), this deception can be unveiled. In the present paper, we examined the impact of a speed versus accuracy instruction: Examinees (N = 235) were either presented with instructions emphasizing a focus on speed, with instructions emphasizing a focus on accuracy, or with no particular speed or accuracy instructions at all. We found that although participants responded to the probe and the irrelevants marginally faster when they had received instructions emphasizing speed, there was no significant difference between RTs of the different experimental groups and crucially no significant difference between the probe-irrelevant RT differences either. This means that such instructions are unlikely to benefit the RT-CIT, but it also suggests that related deliberate manipulation (focusing on speed on or accuracy) is unlikely to decrease the efficiency of the RT-CIT-contributing further evidence to the RT-CIT's resistance to faking.

A new type of pictorial database: The Bicolor Affective Silhouettes and Shapes (BASS).

We introduce the Bicolor Affective Silhouettes and Shapes (BASS): a set of 583 normed black-and-white silhouette images that is freely available via https://osf.io/anej6/ . Valence and arousal ratings were obtained for each image from US residents as a Western population (n = 777) and Chinese residents as an Asian population (n = 869). Importantly, the ratings demonstrate that, notwithstanding their visual simplicity, the images represent a wide range of affective content (from very negative to very positive, and from very calm to very intense). In addition, speaking to their cultural neutrality, the valence ratings correlated very highly between US and Chinese ratings. Arousal ratings were less consistent between the two samples, with larger discrepancies in the older age groups inviting further investigation. Due to their simplistic and abstract nature, our silhouette images may be useful for intercultural studies, color and shape perception research, and online stimulus presentation in particular. We demonstrate the versatility of the BASS by an example online experiment.

The mechanism of filler items in the response time concealed information test.

The response time concealed information test (RT-CIT) can reveal that a person recognizes a relevant (probe) item among other, irrelevant items, based on slower responding to the probe compared to the irrelevant items. Therefore, if this person is concealing the knowledge about the relevance of this item (e.g., recognizing it as a murder weapon), this deception can be unveiled. Adding familiarity-related filler items to the task has been shown to substantially increase the validity of the method, but assumptions for this effect have never been tested before. In the present series of three experiments (N = 511), we tested several factors, most of which were found to indeed influence the enhancing effects of fillers. First, larger enhancement is achieved when a smaller proportion of fillers shares the response key with the target. Second, familiarity context does play a role in the enhancement, and the target sharing its response key with the familiarity-referring fillers leads to larger enhancement. Third, mere symbolic fillers (such as simple arrow-like characters) also lead to enhancement, but filler words without task-relevant meaning are not effective. Fourth, small visual differences (lettercase or underlining) between fillers and the rest of the items have no significant influence. All this provides justification for the original structure of the fillers and also demonstrates that the enhancement is highly generalizable: Fillers have a potential to improve the RT-CIT regardless of deception scenario, item types, or the examinee's language comprehension.

Dispersion matters: Diagnostics and control data computer simulation in Concealed Information Test studies.

Binary classification has numerous applications. For one, lie detection methods typically aim to classify each tested person either as "liar" or as "truthteller" based on the given test results. To infer practical implications, as well as to compare different methods, it is essential to assess the diagnostic efficiency, such as demonstrating the number of correctly classified persons. However, this is not always straightforward. In Concealed Information Tests (CITs), the key predictor value (probe-irrelevant difference) for "truthtellers" is always similar (zero on average), and "liars" are always distinguished by a larger value (i.e., a larger number resulting from the CIT test, as compared to the zero baseline). Thereby, in general, the larger predictor values a given CIT method obtains for "liars" on average, the better this method is assumed to be. This has indeed been assumed in countless studies, and therefore, when comparing the classification efficiencies of two different designs, the mean difference of "liar" predictor values in the two designs were simply compared to each other (hence not collecting "truthteller" data to spare resources). We show, based on the meta-data of 12 different experimental designs collected in response time-based CIT studies, that differences in dispersion (i.e., variance in the data, e.g. the extent of random deviations from the zero average in case of "truthtellers") can substantially influence classification efficiency-to the point that, in extreme cases, one design may even be superior in classification despite having a larger mean "liar" predictor value. However, we also introduce a computer simulation procedure to estimate classification efficiency in the absence of "truthteller" data, and validate this procedure via a meta-analysis comparing outcomes based on empirical data versus simulated data.

Polarities influence implicit associations between colour and emotion.

Colours are linked to emotional concepts. Research on the effect of red in particular has been extensive, and evidence shows that positive as well as negative associations can be salient in different contexts. In this paper, we investigate the impact of the contextual factor of polarity. According to the polarity-correspondence principle, negative and positive category poles are assigned to the binary response categories (here positive vs. negative valence) and the perceptual dimension (green vs. red) in a discrimination task. Response facilitation occurs only where the conceptual category (valence) and the perceptual feature (colour) share the same pole (i.e., where both are plus or both are minus). We asked participants (n = 140) to classify the valence of green and red words within two types of blocks: (a) where all words were of the same colour (monochromatic conditions) providing no opposition in the perceptual dimension, and (b) where red and green words were randomly mixed (mixed-colour conditions). Our results show that red facilitates responses to negative words when the colour green is present (mixed-colour conditions) but not when it is absent (monochromatic conditions). This is in line with the polarity-correspondence principle, but colour-specific valence-affect associations contribute to the found effects.

Item Roles Explored in a Modified P300-Based CTP Concealed Information Test.

In this study, we introduced familiarity-related inducer items (expressions referring to the participant's self-related, familiar details: "mine," "familiar"; and expressions referring to other, unfamiliar details, e.g., "other," "irrelevant") to the Complex Trial Protocol version of the P300-based Concealed Information Test (CIT), at the same time using different item categories with various levels of personal importance to the participants (forenames, birthdays, favorite animals). The inclusion of inducers did not significantly improve the overall efficiency of the method as we would have expected considering that these inducers should increase awareness of the denial of the recognition of the probes (the true details of the participants), and hence the subjective saliency of the items (Lukács in J Appl Res Mem Cognit, 6:283-284, 2017a). This may be explained by the visual similarity of inducers to the probe and irrelevant items and the consequent distracting influence of inducers on probe-task performance. On the other hand, the CIT effect (probe-irrelevant P300 differences) was always lower for less personally important (low-salient) and higher for more personally important (high-salient) items.

Methodological improvements of the association-based concealed information test.

The Association-Based Concealed Information Test (A-CIT) is a deception-detection method, in which participants categorize personally relevant items (e.g., their own surnames) as probes together with categorically similar but irrelevant items (e.g., others' surnames) by one key press A, while categorizing self-referring "inducer" items (e.g., "MINE" or "MY NAME") with an alternative key press B, thereby establishing an association between self-relatedness and B and an incongruence between the self-relatedness of probes and A (Lukács, Gula, Szegedi-Hallgató, & Csifcsák, 2017). The A-CIT's sensitivity to concealed information is reflected in an incongruence effect: slower responses to probes than to other surnames. To increase the relevance of categories, between trials of the original A-CIT, category-to-response mappings switched or repeated unpredictably. This, however, could have diminished incongruence effects, as the response labels were presented in the corners of the display, veering spatial attention away from the items at screen center. In the present online study (n = 294), we therefore tested two improved versions of the A-CIT that do not require spatial attention shifts to and from peripheral labels. One improved version presents per trial only one category label at screen center and requires comparison to the currently presented item. The other improved version is based on the Identification Extrinsic Affective Simon Task (ID-EAST), in which item categorization switches (or repeats) based on colors versus meanings of the central items. Both new versions outperformed the original A-CIT.

The first independent study on the complex trial protocol version of the P300-based concealed information test: Corroboration of previous findings and highlights on vulnerabilities.

More than a dozen studies of the Complex Trial Protocol (CTP) version of the P300-based Concealed Information Test have been published since its introduction (Rosenfeld et al., 2008), and it has been fairly consistently proven to provide high accuracy and strong resistance to countermeasures (Rosenfeld et al., 2013). However, no independent authors have verified these findings until now. In the present, first independent study, we corroborate the accuracy and countermeasure-resistance of the CTP, when the probe item (critical presented information, e.g., crime detail; P) vs. all irrelevant items (Iall) comparison is used for classifying participants as guilty or innocent, but we also show that the CTP is severely vulnerable to countermeasures, when the P vs. the irrelevant item with the largest P300 responses (Imax) comparison is used. This latter measure can be defeated by creating "oddball" items among the irrelevant items (through targeting them with covert responses), and thereby making their P300 responses statistically indistinguishable from those of the probe item. Practical implications are discussed.