Publications by authors named "Christoph Stahl"

Introduction: Recommender systems, digital tools providing recommendations, and digital nudges increasingly affect our lives. The combination of digital nudges and recommender systems is very attractive for its application in preventing overweight and obesity. However, linking recommender systems with personalised digital nudges has a potential yet to be fully exploited.

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Researchers have become increasingly aware that data-analysis decisions affect results. Here, we examine this issue systematically for multinomial processing tree (MPT) models, a popular class of cognitive models for categorical data. Specifically, we examine the robustness of MPT model parameter estimates that arise from two important decisions: the level of data aggregation (complete-pooling, no-pooling, or partial-pooling) and the statistical framework (frequentist or Bayesian).

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Though a variety of eHealth/mHealth dietary solutions exist, many are ill-adapted to the target population and local eating habits. A specific need exists for the elderly, a growing vulnerable population with limited digital literacy. The LIFANA project aimed at developing a mobile nutrition solution, i.

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Attitude research has capitalized on evaluative conditioning procedures to gain insight into how evaluations are formed and may be changed. In evaluative conditioning, a conditioned stimulus (CS; e.g.

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Dual-systems theories of sequence learning assume that sequence learning may proceed within a unidimensional learning system that is immune to cross-dimensional interference because information is processed and represented in dimension-specific, encapsulated modules. Important evidence for such modularity comes from studies investigating the absence or presence of interference between multiple uncorrelated sequences (e.g.

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Evaluative conditioning is one of the most widely studied procedures for establishing and changing attitudes. The surveillance task is a highly cited evaluative-conditioning paradigm and one that is claimed to generate attitudes without awareness. The potential for evaluative-conditioning effects to occur without awareness continues to fuel conceptual, theoretical, and applied developments.

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Mnemonic discrimination is the ability to discriminate among similar memories, which requires separable representations of similar information. The neurocomputational process that assumedly decorrelates representations during encoding and consolidation is referred to as pattern separation. Deficits in pattern separation contribute to age-related declines in mnemonic functioning, which has motivated the development of targeted interventions.

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The evaluative conditioning (EC) phenomenon is central to the study of preference acquisition and attitude formation. Early studies have reported EC in the absence of awareness, but more recent work has questioned this conclusion. In previous work, using briefly presented and pattern-masked conditioned stimuli (CSs), we found that above-chance forced-choice identification of CSs is necessary for EC.

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Generalisation in learning means that learning with one particular stimulus influences responding to other novel stimuli. Such generalisation effects have largely been overlooked within research on attitude acquisition via Evaluative Conditioning (i.e.

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Evaluative conditioning (EC) changes the preference towards a formerly neutral stimulus (conditioned stimulus; CS), by pairing it with a valent stimulus (unconditioned stimulus; US), in the direction of the valence of the US. When the CS is presented suboptimally (i.e.

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In implicit sequence learning, a process-dissociation (PD) approach has been proposed to dissociate implicit and explicit learning processes. Applied to the popular generation task, participants perform two different task versions: instructions require generating the transitions that form the learned sequence; instructions require generating transitions other than those of the learned sequence. Whereas accurate performance under inclusion may be based on either implicit or explicit knowledge, avoiding to generate learned transitions requires controllable explicit sequence knowledge.

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Evaluative conditioning (EC) is a change in liking of neutral conditioned stimuli (CS) following pairings with positive or negative stimuli (unconditioned stimulus, US). A dissociation has been reported between US expectancy and CS evaluation in extinction learning: When CSs are presented alone subsequent to CS-US pairings, participants cease to expect USs but continue to exhibit EC effects. This dissociation is typically interpreted as demonstration that EC is resistant to extinction, and consequently, that EC is driven by a distinct learning process.

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Associative attitude learning is typically viewed as a low-level process that automatically registers mere co-occurrences between stimuli, independent of their validity and relational meaning. This view invites to critically examine how attitude formation conforms to four operating conditions (i.e.

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Research that dissociates different types of processes within a given task using a processing tree approach suggests that attitudes may be acquired through evaluative conditioning in the absence of explicit encoding of CS-US pairings in memory. This research distinguishes explicit memory for the CS-US pairings from CS-liking acquired without encoding of CS-US pairs in explicit memory. It has been suggested that the latter effect may be due to an implicit misattribution process that is assumed to operate when US evocativeness is low.

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Evaluative conditioning (EC) is proposed as a mechanism of automatic preference acquisition in dual-process theories of attitudes (Gawronski, B., & Bodenhausen, G. V.

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In the field of evaluative conditioning (EC), two opposing theories-propositional single-process theory versus dual-process theory-are currently being discussed in the literature. The present set of experiments test a crucial prediction to adjudicate between these two theories: Dual-process theory postulates that evaluative conditioning can occur without awareness of the contingency between conditioned stimulus (CS) and unconditioned stimulus (US); in contrast, single-process propositional theory postulates that EC requires CS-US contingency awareness. In a set of three studies, we experimentally manipulate contingency awareness by presenting the CSs very briefly, thereby rendering it unlikely to be processed consciously.

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In between-attribute Stroop matching tasks, participants compare the meaning (or the color) of a Stroop stimulus with a probe color (or meaning) while attempting to ignore the Stroop stimulus's task-irrelevant attribute. Interference in this task has been explained by two competing theories: A semantic competition account and a response competition account. Recent results favor the response competition account, which assumes that interference is caused by a task-irrelevant comparison.

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Previous research has claimed that evaluative conditioning (EC) effects may obtain in the absence of perceptual identification of conditioned stimuli (CSs). A recent meta-analysis suggested similar effect sizes for supra- and subliminal CSs, but this was based on a small body of evidence (k = 8 studies; Hofmann, De Houwer, Perugini, Baeyens, & Crombez, 2010). We critically discuss this prior evidence, and then report and discuss 6 experimental studies that investigate EC effects for briefly presented CSs using more stringent methods.

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We investigated potential biases affecting the validity of the process-dissociation (PD) procedure when applied to sequence learning. Participants were or were not exposed to a serial reaction time task (SRTT) with two types of pseudo-random materials. Afterwards, participants worked on a free or cued generation task under inclusion and exclusion instructions.

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Objectives: Although age-related differences in planning ability are well known, their cognitive foundations remain a matter of contention. To elucidate the specific processes underlying planning decrements in older age, the relative contributions of fluid reasoning, working memory (WM) capacity, and processing speed to accuracy on the Tower of London (TOL) planning task were investigated.

Method: Mediation analyses were used to relate overall and search depth-related TOL accuracy from older (N = 106; 60-89 years) and younger adults (N = 69; 18-54 years) to age and measures of fluid reasoning, WM capacity, and speed.

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In research investigating Stroop or Simon effects, data are typically analyzed at the level of mean response time (RT), with results showing faster responses for compatible than for incompatible trials. However, this analysis provides only limited information as it glosses over the shape of the RT distributions and how they may differ across tasks and experimental conditions. These limitations have encouraged the analysis of RT distributions using delta plots.

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