Response Time Patterns Research Articles

Dissociating sub-processes of aftereffects of completed intentions and costs to the ongoing task in prospective memory: A mouse-tracking approach

In the present study, we used mouse tracking to investigate two processes underlying prospective memory (PM) retrieval: First, we aimed to explore to what extent spontaneous retrieval of already completed PM intentions is supported by reflexive-associative and discrepancy-plus-search processes. Second, we aimed to disentangle whether costs to an ongoing task during the pursuit of a PM intention are associated with presumably resource-demanding monitoring processes or with a presumably resource-sparing strategic delay of ongoing-task responses. Our third aim was to explore the interaction of processes underlying costs to the ongoing task and processes of spontaneous retrieval. Our analyses replicated response-time patterns from previous studies indicating aftereffects of completed intentions and costs to ongoing-task performance, as well as increased aftereffects while pursuing a PM intention. Notably, based on our mouse-tracking analyses, we argue that aftereffects of completed intentions are best explained by a reflexive initiation of an already completed intention. If the completed intention is not performed in its entirety (i.e., no commission error), the reflexive initiation of the completed intention is followed by a subsequent movement correction that most likely represents a time-consuming response-verification process. Regarding performance costs in the ongoing task, our analyses suggest that actively pursuing a PM intention most likely leads to a strategic delay of ongoing activities. Lastly, we found that pursuing a novel PM task after intention completion exacerbated orienting responses to all deviant stimuli, exacerbated the readiness to initiate the completed intention reflexively, and substantially prolonged the response-verification process following this reflexive intention retrieval.

Quantifying the Human Influence on the Intensity of Extreme 1- and 5-Day Precipitation Amounts at Global, Continental, and Regional Scales

Abstract This study provides a comprehensive analysis of the human contribution to the observed intensification of precipitation extremes at different spatial scales. We consider the annual maxima of the logarithm of 1-day (Rx1day) and 5-day (Rx5day) precipitation amounts for 1950–2014 over the global land area, four continents, and several regions, and compare observed changes with expected responses to external forcings as simulated by CanESM2 in a large-ensemble experiment and by multiple models from phase 6 of the Coupled Model Intercomparison Project (CMIP6). We use a novel detection and attribution analysis method that is applied directly to station data in the areas considered without prior processing such as gridding, spatial or temporal dimension reduction, or transformation to unitless indices and uses climate models only to obtain estimates of the space–time pattern of extreme precipitation response to external forcing. The influence of anthropogenic forcings on extreme precipitation is detected over the global land area, three continental regions (the western Northern Hemisphere, western Eurasia, and eastern Eurasia), and many smaller IPCC regions, including central North America, East Asia, east-central Asia, eastern Europe, eastern North America, northern Europe, and western Siberia for Rx1day, and central North America, eastern Europe, eastern North America, northern Europe, the Russian Arctic region, and western Siberia for Rx5day. Consistent results are obtained using forcing response estimates from either CanESM2 or CMIP6. Anthropogenic influence is estimated to have substantially decreased the approximate waiting time between extreme annual maximum events in regions where anthropogenic influence has been detected, which has important implications for infrastructure design and climate change adaptation policy. Significance Statement All previous detection and attribution studies of observed changes in extreme precipitation (i) use station data that has been heavily processed via gridding, transformation, and spatial and temporal averaging or other dimension reduction approaches, as well as using climate models to estimate the responses to external forcing, and (ii) also use models to estimate the unforced natural variability of extreme precipitation. Both aspects reduce user confidence in detection and attribution results. This study uses station data directly and avoids difficult to verify model-based estimates of the unforced variability of precipitation extremes. Results confirm findings from previous studies, and extend them to a number of subcontinental regions, thus substantially increasing confidence in detection and attribution findings precipitation.

Characterization of white spot lesions formed on human enamel under microcosm biofilm for different experimental periods.

The initial characteristics of white spot lesion (WSLs), such as the degree of integrated mineral loss (ΔZ), depth and pattern of mineral distribution, have an impact on further demineralization and remineralization. However, these lesion parameters have not been evaluated in WSLs produced from microcosm biofilms.Objective:This study characterized artificial white spot lesions produced on human enamel under microcosm biofilm for different experimental periods.Methodology:In total, 100 human enamel specimens (4x4mm) were assigned to 5 distinct groups (n=20/group) differing according to the period of biofilm formation (2, 4, 6, 8 or 10 days). Microcosm biofilm was produced on the specimens from a mixture of human and McBain saliva at the first 8h. Enamel samples were then exposed to McBain saliva containing 0.2% sucrose. WSLs formed were characterized by quantitative light-induced fluorescence (QLF) and transverse microradiography (TMR). Data were analyzed by ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p<0.05).Results:A clear time-response pattern was observed for both analyses, but TMR was able to better discriminate among the lesions. Regarding QLF analysis, median (95%CI; %) changes in fluorescence ∆Z were -7.74(-7.74:-6.45)a, -8.52(-8.75:-8.00)ab, -9.17(-10.00:-8.71)bc, -9.58(-10.53:-8.99)bc and -10.01(-11.44:-9.72)c for 2, 4, 6, 8, and 10 days, respectively. For TMR, median (95%CI; vol%.µm) ∆Z were 1410(1299-1479)a, 2420(2327-2604)ab, 2775(2573-2899)bc, 3305(3192-3406)cd and 4330(3972-4465)d, whereas mean (SD; µm) lesion depth were 53.7(12.3)a, 71.4(12.0)a, 103.8(24.8)b, 130.5(27.2)bc, 167.2(39.3)c for 2, 4, 6, 8 and 10 days, respectively.Conclusion:The progression of WSLs formed on human enamel under microcosm biofilm can be characterized over 2-10 days, both by QLF and TMR analyses, although the latter provides better discrimination among the lesions.

Can the early visual processing of others' actions be related to social power and dominance?

Although goals often drive action understanding, this ability is also prone to important variability among individuals, which may have its origin in individual social characteristics. The present study aimed at evaluating the relationship between the tendency to prioritize goal information over grip information during early visual processing of action and several social dimensions. Visual processing of grip and goal information during action recognition was evaluated in 64 participants using the priming protocol developed by Decroix and Kalénine (Exp Brain Res 236(8):2411-2426, 2018). Object-directed action photographs were primed by photographs sharing the same goal and/or the same grip. The effects of goal and grip priming on action recognition were evaluated for different prime durations. The same participants further fulfilled questionnaires characterizing the way individuals deal with their social environment, namely their sense of social power, dominance, perspective taking, and construal level. At the group level, results confirmed greater goal than grip priming effects on action recognition for the shortest prime duration. Regression analyses between the pattern of response times in the action priming protocol and scores at the questionnaires further showed that the advantage of goal over grip priming was associated with higher sense of social power, and possibly to lower dominance. Overall, data confirm that observers tend to prioritize goal-related information when processing visual actions but further indicate that this tendency is sensitive to individual social characteristics. Results suggest that goal information may not always drive action understanding and point out the connection between low-level processing of observed actions and more general individual characteristics.

An In-Depth Case Description of Gaze Patterns of an Individual With Cortical Visual Impairment to Stimuli of Varying Complexity: Implications for Augmentative and Alternative Communication Design

Purpose: Many individuals with cortical visual impairment (CVI) are unable to meet their daily communication needs through natural speech. Augmentative and alternative communication (AAC) provides supports for individuals with complex communication needs, including those with CVI. However, many forms of AAC involve access via a visual modality. This presents specific challenges for assessment and intervention of individuals with CVI using AAC. Method: This study used an automated eye tracking technology to analyze the gaze patterns of one individual with CVI to stimuli of varying complexity. The automated eye tracking technology captured the point of gaze of the participant every 16 ms (60 Hz), allowing for a detailed evaluation of what captured the participant's attention. Results: Variations in stimulus complexity resulted in changes in visual attention. Overall, the participant engaged significantly faster to and longer with simpler images both when presented one at a time and also during a preferential looking task when two stimuli were presented. Additionally, one stimulus displayed a teddy bear, with an animated face. The participant gazed at the face for the majority of her looking time to that stimulus, rather than the colorful foot pads. Conclusions: The participant demonstrated clear patterns of quicker response times and longer gaze times when the stimuli were simpler in design. This has implications for AAC interventions and choice of symbols. Additionally, the participant's ability to engage with the face of the teddy bear image suggests her visual processing was consistent with the score she received on the CVI Range, an assessment tool that describes functional vision in individuals with CVI.

Coherence shifts in attribute evaluations.

In five experiments, people repeatedly judged individual options with respect to both overall value and attribute values. When required to choose between two snacks, each differing in two attributes (pleasure and nutrition), people9s assessments of value shifted from pre- to post-choice in the direction that spread the alternatives further apart so as to favor the winner, thereby increasing confidence in the choice. This shift was observed not only for ratings of overall value, but also for each of the two individual attributes. The magnitude of the coherence shift increased with choice difficulty as measured by the difference in initial ratings of overall value for the two options, as well as with a measure of attribute disparity (the degree to which individual attributes disagree with one another as to which option is superior). In Experiments 2-5, tasks other than explicit choice generated the same qualitative pattern of value changes, confidence, and response time. These findings support the hypothesis that active consideration of options, whether or not explicitly related to value, automatically refines the mental value representations for the options, which in turn allows them to be more precisely distinguished when later included in a value-based choice set.

Qualitative speed-accuracy tradeoff effects can be explained by a diffusion/fast-guess mixture model

Rafiei and Rahnev (2021) presented an analysis of an experiment in which they manipulated speed-accuracy stress and stimulus contrast in an orientation discrimination task. They argued that the standard diffusion model could not account for the patterns of data their experiment produced. However, their experiment encouraged and produced fast guesses in the higher speed-stress conditions. These fast guesses are responses with chance accuracy and response times (RTs) less than 300 ms. We developed a simple mixture model in which fast guesses were represented by a simple normal distribution with fixed mean and standard deviation and other responses by the standard diffusion process. The model fit the whole pattern of accuracy and RTs as a function of speed/accuracy stress and stimulus contrast, including the sometimes bimodal shapes of RT distributions. In the model, speed-accuracy stress affected some model parameters while stimulus contrast affected a different one showing selective influence. Rafiei and Rahnev’s failure to fit the diffusion model was the result of driving subjects to fast guess in their experiment.

Development of an Online Telepharmacy Service in the Philippines and Analysis of Its Usage During the COVID-19 Pandemic

Background: To augment traditional sources of health information at a time of reduced accessibility, a free online telepharmacy service was developed during the COVID-19 pandemic. Objectives: This study details the process of developing and operating an online telepharmacy service, analyzes its usage, and assesses users’ health information-seeking patterns. Methods: The service utilized various platforms for receiving and processing queries, communication, and promotion. Submissions received from March 20 to May 31, 2020 were processed for analysis. Parameters analyzed were time patterns of query submission, response time, service feedback, user and patient demographics, and subjects of inquiry. Results: A total of 271 queries were analyzed. Query frequency decreased over time, consistent with relaxation of quarantine restrictions and increasing availability of information. Peak hours of query influx were outside typical business hours. The majority of users were from the general public (93.8%) and preferred to receive responses through text (61.2%). The majority of users from the general public belonged to the 15- to 25-year-old age group (41.1%) and sought information for oneself. Most submissions mentioned COVID-related topics. From the general public, there was greatest interest in drug indications and vitamins, supplements, and herbal products, and from healthcare professionals, in drug procurement. Users who provided feedback (n = 12) all expressed satisfaction with the service and the information they received. Conclusion: Transition to the “new normal” entails adopting alternative platforms to augment traditional sources of health information. An online telepharmacy service may be utilized to provide and clarify medication information as part of primary care.

I Am Looking for Your Mind: Pupil Dilation Predicts Individual Differences in Sensitivity to Hints of Human-Likeness in Robot Behavior.

The presence of artificial agents in our everyday lives is continuously increasing. Hence, the question of how human social cognition mechanisms are activated in interactions with artificial agents, such as humanoid robots, is frequently being asked. One interesting question is whether humans perceive humanoid robots as mere artifacts (interpreting their behavior with reference to their function, thereby adopting the design stance) or as intentional agents (interpreting their behavior with reference to mental states, thereby adopting the intentional stance). Due to their humanlike appearance, humanoid robots might be capable of evoking the intentional stance. On the other hand, the knowledge that humanoid robots are only artifacts should call for adopting the design stance. Thus, observing a humanoid robot might evoke a cognitive conflict between the natural tendency of adopting the intentional stance and the knowledge about the actual nature of robots, which should elicit the design stance. In the present study, we investigated the cognitive conflict hypothesis by measuring participants’ pupil dilation during the completion of the InStance Test. Prior to each pupillary recording, participants were instructed to observe the humanoid robot iCub behaving in two different ways (either machine-like or humanlike behavior). Results showed that pupil dilation and response time patterns were predictive of individual biases in the adoption of the intentional or design stance in the IST. These results may suggest individual differences in mental effort and cognitive flexibility in reading and interpreting the behavior of an artificial agent.

The Effect of Item Preknowledge on Response Time: Analysis of Two Datasets Using the Multiple‐Group Lognormal Response Time Model with a Gating Mechanism

AbstractResponse time information has recently attracted significant attention in the literature as it may provide meaningful information about item preknowledge. The methods that use response time information to identify examinees with potential item preknowledge make an implicit assumption that the examinees with item preknowledge differ in their response time patterns when compared to examinees without item preknowledge. This study uses a multiple‐group extension of van der Linden's Lognormal Response Time Model with a gated mechanism to quantify the differences in latent speed between examinees with and without item preknowledge when responding to compromised and uncompromised items. Our findings indicate that there may be a wide range for potential effect of item preknowledge on response time. The effect of item preknowledge on response times is likely to be contextual and depends on many factors such as characteristics of test‐takers, the nature of item preknowledge, and item characteristics. We recommend that researchers systematically quantify the effect sizes in their studies, and if possible, manipulate the effect size for a wide range while studying the effectiveness of already existing or new methods to detect examinees with item preknowledge through simulation.

Influence of emotional prosody, content, and repetition on memory recognition of speaker identity.

Recognising individuals through their voice requires listeners to form an invariant representation of the speaker's identity, immune to episodic changes that may occur between encounters. We conducted two experiments to investigate to what extent within-speaker stimulus variability influences different behavioural indices of implicit and explicit identity recognition memory, using short sentences with semantically neutral content. In Experiment 1, we assessed how speaker recognition was affected by changes in prosody (fearful to neutral, and vice versa in a between-group design) and speech content. Results revealed that, regardless of encoding prosody, changes in prosody, independent of content, or changes in content, when prosody was kept unchanged, led to a reduced accuracy in explicit voice recognition. In contrast, both groups exhibited the same pattern of response times (RTs) for correctly recognised speakers: faster responses to fearful than neutral stimuli, and a facilitating effect for same-content stimuli only for neutral sentences. In Experiment 2, we investigated whether an invariant representation of a speaker's identity benefitted from exposure to different exemplars varying in emotional prosody (fearful and happy) and content (Multi condition), compared to repeated presentations of a single sentence (Uni condition). We found a significant repetition priming effect (i.e., reduced RTs over repetitions of the same voice identity) only for speakers in the Uni condition during encoding, but faster RTs when correctly recognising old speakers from the Multi, compared to the Uni, condition. Overall, our findings confirm that changes in emotional prosody and/or speech content can affect listeners' implicit and explicit recognition of newly familiarised speakers.

Guided Search 6.0: An updated model of visual search.

This paper describes Guided Search 6.0 (GS6), a revised model of visual search. When we encounter a scene, we can see something everywhere. However, we cannot recognize more than a few items at a time. Attention is used to select items so that their features can be "bound" into recognizable objects. Attention is "guided" so that items can be processed in an intelligent order. In GS6, this guidance comes from five sources of preattentive information: (1) top-down and (2) bottom-up feature guidance, (3) prior history (e.g., priming), (4) reward, and (5) scene syntax and semantics. These sources are combined into a spatial "priority map," a dynamic attentional landscape that evolves over the course of search. Selective attention is guided to the most active location in the priority map approximately 20 times per second. Guidance will not be uniform across the visual field. It will favor items near the point of fixation. Three types of functional visual field (FVFs) describe the nature of these foveal biases. There is a resolution FVF, an FVF governing exploratory eye movements, and an FVF governing covert deployments of attention. To be identified as targets or rejected as distractors, items must be compared to target templates held in memory. The binding and recognition of an attended object is modeled as a diffusion process taking > 150 ms/item. Since selection occurs more frequently than that, it follows that multiple items are undergoing recognition at the same time, though asynchronously, making GS6 a hybrid of serial and parallel processes. In GS6, if a target is not found, search terminates when an accumulating quitting signal reaches a threshold. Setting of that threshold is adaptive, allowing feedback about performance to shape subsequent searches. Simulation shows that the combination of asynchronous diffusion and a quitting signal can produce the basic patterns of response time and error data from a range of search experiments.

Does Attention Increase the Value of Choice Alternatives?

A growing recognition of the role of attention in decision-making has been driven by both the technology of eye tracking and the development of models that explicitly incorporate attention. One result of this convergence is the arresting claim that attention, by itself, can increase the perceived value of a decision alternative. In this review, we cover the origins of that claim, its empirical foundation, and the reasoning that supports it. The conclusion is that, to date, there is not sufficient evidence to support the claim. Alternative explanations for the extant evidentiary base are discussed, as is the balance between the bottom-up influence of empirical evidence and the top-down commitment to a conceptual framework.

Relative Clause Sentence Processing in Korean-Speaking School-Aged Children With and Without Specific Language Impairment.

Purpose The goal of this study was to examine online and off-line sentence processing using Korean language relative clause sentences between children with specific language impairment (SLI) and children with typical development (TD). Method Twenty-four children with TD and 19 children with SLI participated in this study. Children completed online and off-line sentence-processing tasks using relative clause sentences. The response time (RT) data obtained from the online processing task were analyzed at each word position and between adjacent words for items answered both correctly and incorrectly on the off-line comprehension task. A linear mixed-effects model and a generalized linear mixed-effects model were used to analyze the performances on the online/off-line sentence-processing task between the two groups. Results The results revealed that the processing pattern of RTs on the online processing task differed between the two groups, such that the SLI group did not show the predicted RT increase while the TD group did. Also, the SLI group processed each word with comparable or faster reading rates than the TD group. On the off-line comprehension task, the SLI group performed poorly compared to the TD group. Conclusions Processing of syntactically complex sentences differed between the TD and SLI groups, such that the SLI group had lower accuracy on the off-line comprehension task and was less efficient on the online processing task as compared to the TD group. These results mainly support the syntactic deficit account in children with SLI.

Laterality judgements in patients with frequent episodic migraine

IntroductionMigraine is a cyclic disorder but also a chronic pain condition. Left-right recognition tasks have been shown to be impaired in patients with chronic pain. ObjectivesTo investigate whether laterality judgements of migraine patients depend on the status within the migraine cycle. Methods34 episodic migraine patients completed a laterality recognition task on 30 consecutive days using the Recognise™ software. Reaction time and number of mistakes of recognising the left or right side of a face or neck movements to the right or left were recorded and analysed longitudinally. Ictal days (48 h and 24 h prior to the attack; during the headache phase; 24 h after the attack) were contrasted against interictal days using repeated measures ANOVAs. 4 headache-free controls served to investigate the natural fluctuation over time and to compare migraine versus non-migraine data in a secondary exploratory analysis. Results1691 data sets from migraine patients and 183 from control participants were included in the analyses. Results indicated that performance varied throughout the migraine cycle but only showed a clear pattern of prolonged response times for images of movements to the right (F(4,1690) = 2.412; p = 0.047), while data for frequency of correct answers and for the left side remained inconclusive. Migraine patients had a reduced frequency of correct answers (right: F(1,1873) = 11.426; p = 0.001; left: F(1,1873) = 5.873; p = 0.015). Response times where unaffected. Laterality judgements were not correlated with the dominant headache side. ConclusionsThe current data shows that laterality judgements can depend on the status within the migraine cycle. Laterality judgements of migraine patients where comparable to other chronic pain conditions.

Testing the drift-diffusion model.

The drift-diffusion model (DDM) is a model of sequential sampling with diffusion signals, where the decision maker accumulates evidence until the process hits either an upper or lower stopping boundary and then stops and chooses the alternative that corresponds to that boundary. In perceptual tasks, the drift of the process is related to which choice is objectively correct, whereas in consumption tasks, the drift is related to the relative appeal of the alternatives. The simplest version of the DDM assumes that the stopping boundaries are constant over time. More recently, a number of papers have used nonconstant boundaries to better fit the data. This paper provides a statistical test for DDMs with general, nonconstant boundaries. As a by-product, we show that the drift and the boundary are uniquely identified. We use our condition to nonparametrically estimate the drift and the boundary and construct a test statistic based on finite samples.

Examining aging and numerosity using an integrated diffusion model.

Two experiments are presented that use tasks common in research in numerical cognition with young adults and older adults as subjects. In these tasks, one or two arrays of dots are displayed, and subjects decide whether there are more or fewer dots of one kind than another. Results show that older adults, relative to young adults, tend to rely more on the perceptual feature, area, in making numerosity judgments when area is correlated with numerosity. Also, convex hull unexpectedly shows different effects depending on the task (being either correlated with numerosity or anticorrelated). Accuracy and response time (RT) data are interpreted with the integration of the diffusion decision model with models for the representation of numerosity. One model assumes that the representation of the difference depends on the difference between the numerosities and that standard deviations (SDs) increase linearly with numerosity, and the other model assumes a log representation with constant SDs. The representational models have coefficients that are applied to differences between two numerosities to produce drift rates and SDs in drift rates in the decision process. The two tasks produce qualitatively different patterns of RTs: One model fits results from one task, but the results are mixed for the other task. The effects of age on model parameters show a modest decrease in evidence driving the decision process, an increase in the duration of processes outside the decision process (nondecision time), and an increase in the amount of evidence needed to make a decision (boundary separation). (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Twenty-four or four-and-twenty: Language modulates cross-modal matching for multidigit numbers in children and adults

Does number–word structure have a long-lasting impact on transcoding? Contrary to English, German number words comprise decade–unit inversion (e.g., vierundzwanzig is literally translated as four-and-twenty). To investigate the mental representation of numbers, we tested the effect of visual and linguistic–morphological characteristics on the development of verbal–visual transcoding. In a longitudinal cross-linguistic design, response times (RTs) in a number-matching experiment were analyzed in Grade 2 (119 German-speaking and 179 English-speaking children) and in Grade 3 (131 German-speaking and 160 English-speaking children). To test for long-term effects, the same experiment was given to 38 German-speaking and 42 English-speaking adults. Participants needed to decide whether a spoken number matched a subsequent visual Arabic number. Systematic variation of digits in the nonmatching distractors allowed comparison of three different transcoding accounts (lexicalization, visual, and linguistic–morphological). German speakers were generally slower in rejecting inverted number distractors than English speakers. Across age groups, German speakers were more distracted by Arabic numbers that included the correct unit digit, whereas English speakers showed stronger distraction when the correct decade digit was included. These RT patterns reflect differences in number–word morphology. The individual cost of rejecting an inverted distractor (inversion effect) predicted arithmetic skills in German-speaking second-graders only. The moderate relationship between the efficiency to identify a matching number and arithmetic performance could be observed cross-linguistically in all age groups but was not significant in German-speaking adults. Thus, findings provide consistent evidence of a persistent impact of number–word structure on number processing, whereas the relationship with arithmetic performance was particularly pronounced in young children.

Divergent response-time patterns in vigilance decrement tasks.

Performance on tasks tends to change with time-on-task, usually for the worse. Two seemingly contradictory patterns of behavior are reported for these "vigilance decrements." Over the past 70 years, the more common vigilance decrement involves a decrease in signal detection associated with an increase in response times. In contrast, search tasks such as industrial inspection or X-ray screening produce vigilance decrements that involve a decrease in signal detection associated with a decrease in response times. Subjects respond faster with increasing time-on-task. Three experiments reported here were designed to explain these contrasting performance patterns. The results rule out task-type (search vs. nonsearch detection) and whether trials were paced versus unpaced by the computer as causes of these divergent response-time patterns. Instead, response structure-how subjects respond to the presence and absence of the critical signal-is the primary cause of this phenomenon. These results do not support traditional resource-depletion or under-stimulation theories of the vigilance decrement. Instead, I propose a dynamic-allocation resource theory in which the attention system uses various tactics to strategically disengage from tasks that provide low payoff across time-on-task. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Evidence for Mixed Processes in Normal/Mirror Discrimination of Rotated Letters: A Bayesian Model Comparison Between Single‐ and Mixed‐Distribution Models1

AbstractWhen determining whether a rotated letter is normal or mirrored, an observer mentally rotates the letter to its canonical orientation. To account for patterns of response times (RTs) for the normal/mirror discrimination of rotated letters, previous research formulated a model that postulated a mixture of trials with and without mental rotation. While this model could explain the curvilinear relationship that has been found between averaged RT and letter orientations, the curved RT function is still open to alternative explanations without assuming mixed processes. To address this issue and test the mixed‐process hypothesis more directly, we analyzed trial‐by‐trial RT data instead of averaged RTs by employing a Bayesian model comparison technique. If rotation and non‐rotation trials are mixed, trial‐by‐trial RTs for letters in a particular orientation should not follow a single distribution but a mixed one formed from the superposition of two separate distributions, one for rotation and one for non‐rotation trials. In the present study, we compared single‐ and mixed‐distribution models. Bayes‐factor analysis showed decisive support for the mixed‐distribution model over the single‐distribution model. In addition, using the widely applicable information criterion (WAIC), the predictive accuracy of the mixed‐distribution model was found to be as high as that of the single‐distribution model. These results indicated the involvement of mixed processes in normal/mirror discrimination of rotated letters. The usefulness of statistical modeling in psychological study and necessary precautions to take in the interpretation of the parameters of unconfirmed models are also discussed.