Four empirical tests of Unconscious Thought Theory

According to Unconscious Thought Theory, people make better decisions after unconscious than after conscious thought (Dijksterhuis, Bos, Nordgren, & van Baaren, 2006a). Unconscious Thought Theory yields four specific predictions. First, an exact replication of Dijksterhuis et al. (2006a) study should indicate that unconscious decisions are superior to conscious decisions. Second, decisions should improve with duration of conscious thought. Third, unconscious decisions should be superior to conscious decisions, even if unconscious decisions are deliberated while having access to information. Fourth, unconscious decisions should be based on a weighting strategy. We report results of four studies, featuring 480 participants, that yield no evidence in favor of these predictions. Therefore our findings cast doubt on Unconscious Thought Theory and its advice to base decisions on unconscious thought. The results of our studies suggest that it is better to base decisions on conscious thought while having access to information.     

Perceptual awareness and categorical representation of faces: evidence from masked priming

How internal categories influence how we perceive the world is a fundamental question in cognitive sciences. Yet, the relation between perceptual awareness and perceptual categorization has remained largely uncovered so far. Here, we addressed this question by focusing on face perception during subliminal and conscious perception. We used morphed continua between two face identities and we assessed, through a masked priming paradigm, the perceptual processing of these morphed faces under subliminal and supraliminal conditions. We found that priming from subliminal faces followed linearly the information present in the primes, while priming from visible faces revealed a non-linear profile, indicating a categorical processing of face identities. Our results thus point to a special relation between perceptual awareness and categorical processing of faces, and support the dissociation between two modes of information processing: a subliminal mode involving analog treatment of stimuli information, and a supraliminal mode relying on discrete representation.     

Eye contact facilitates awareness of faces during interocular suppression

Eye contact captures attention and receives prioritized visual processing. Here we asked whether eye contact might be processed outside conscious awareness. Faces with direct and averted gaze were rendered invisible using interocular suppression. In two experiments we found that faces with direct gaze overcame such suppression more rapidly than faces with averted gaze. Control experiments ruled out the influence of low-level stimulus differences and differential response criteria. These results indicate an enhanced unconscious representation of direct gaze, enabling the automatic and rapid detection of other individuals making eye contact with the observer.     

Modeling and estimating recall processing capacity: Sensitivity and diagnostic utility in application to mild cognitive impairment

We investigate the potential for using latency-based measures of retrieval processing capacity to assess changes in performance specific to individuals with mild cognitive impairment (MCI), a reliable precursor state to Alzheimer’s Disease. Use of these capacity measures is motivated in part by exploration of the effects of atrophy on a computational model of a basic hippocampal circuit. We use this model to suggest that capacity may be a more sensitive indicator of the underlying atrophy than speed of processing, and test this hypothesis by adapting a standard behavioral measure of memory (the free and cued selective reminding test, FCSRT) to allow for the collection of cued recall latencies. Participants were drawn from five groups: college-aged, middle-aged, healthy elderly, those with a diagnosis of MCI, and a sample of MCI control participants. The measure of capacity is shown to offer increased classificatory sensitivity relative to the standard behavioral measures, and is also shown to be the behavioral measure that correlated most strongly with hippocampal volume.     

No evidence of age-related increases in unconscious plagiarism during free recall

In three experiments younger and older participants took part in a group generation task prior to a delayed recall task. In each, participants were required to recall the items that they had generated, avoiding plagiarism errors. All studies showed the same pattern: older adults did not plagiarise their partners any more than younger adults did. However, older adults were more likely than younger adults to intrude with entirely novel items not previously generated by anyone. These findings stand in opposition to the single previous demonstration of age-related increases in plagiarism during recall.     

Processing speed, intelligence, creativity, and school performance: Testing of causal hypotheses using structural equation models

According to mental speed theory of intelligence, the speed of information processing constitutes an important basis for cognitive abilities. However, the question, how mental speed relates to real world criteria, like school, academic, or job performance, is still unanswered. The aim of the study is to test an indirect speed-factor model in comparison to rivaling models explaining the relationships between different mental abilities and performance. In this speed-factor model, basic cognitive processing is assumed to influence higher mental abilities (IQ and creativity). Intelligence and creativity themselves should be valid predictors of school performance. We computed bivariate correlations and structural equation models to test this hypothesis, using indicators of processing speed [Zahlen-Verbindungs-Test (ZVT) and Coding Test], psychometric intelligence [Kognitiver Fähigkeits-Test (KFT) and Raven's Advanced Progressive Matrices (APM)], creativity [Verbaler Kreativitäts-Test (VKT) and Verwendungs-Test (VWT)] and school performance (grades). In a sample of 271 students from German gymnasiums (Class Levels 9 to 11) the speed-factor model can reproduce at best the empirical relationships between processing speed, intelligence, creativity, and school performance: It assumes that processing speed influences higher mental abilities (intelligence and creativity), which, in the sequel, influence school performance. Therefore, processing speed seems to have no direct effect on school performance; the effect is indirect as it operates via mediation through higher cognitive abilities.     

Enhanced processing fluency leads to biases in source memory

The present experiments were conducted to determine whether processing fluency affects source memory decisions. In the first three experiments, participants decided whether test items appeared in the same sensory modality (Experiments 1A, 1B) or perceptual form (font type, Experiment 2) at study and test. The results were consistent across the three studies and showed that perceptual priming leads to an increase in reports that stimuli were presented in the same sensory or perceptual form during the study and test phase. Experiment 3 showed that conceptual fluency affects source attributions in much the same way as perceptual fluency, and Experiment 4 showed that fluency is associated with a subjective experience of familiarity even when it might serve as a basis for source inference. These results are consistent with recent neuropsychological and neuroimaging evidence that familiarity-based processes contribute to source memory decisions under some circumstances, such as when items and contexts are unitized rather than merely bound together at encoding.