DOCUMENTS

Muhle-Karbe, P.S., Duncan, J., De Baene, W., Mitchell, D.J., & Brass, M. (2016). Neural Coding for Instruction-Based Task Sets in Human Frontoparietal and Visual Cortex. Cerebral Cortex.


Task preparation has traditionally been thought to rely upon persistent representations of instructions that permit their execution after delays. Accumulating evidence suggests, however, that accurate retention of task knowledge can be insufficient for successful performance. Here, we hypothesized that instructed facts would be organized into a task set; a temporary coding scheme that proactively tunes sensorimotor pathways according to instructions to enable highly efficient “reflex-like” performance. We devised a paradigm requiring either implementation or memorization of novel stimulus–response mapping instructions, and used multivoxel pattern analysis of neuroimaging data to compare neural coding of instructions during the pretarget phase. Although participants could retain instructions under both demands, we observed striking differences in their representation. To-be-memorized instructions could only be decoded from mid-occipital and posterior parietal cortices, consistent with previous work on visual short-term memory storage. In contrast, to-be-implemented instructions could also be decoded from frontoparietal “multiple-demand” regions, and dedicated visual areas, implicated in processing instructed stimuli. Neural specificity in the latter moreover correlated with performance speed only when instructions were prepared, likely reflecting the preconfiguration of instructed decision circuits. Together, these data illuminate how the brain proactively optimizes performance, and help dissociate neural mechanisms supporting task control and short-term memory storage.

Caspar, E., De Beir, A., Magalhaes de Saldanha Da Gama, P., Yernaux, F., Cleeremans, A. & Vanderborght, B.
Behaviour Research Methods - doi:10.3758/s13428-014-0498-3

The rubber hand illusion is an experimental para- digm in which participants consider a fake hand to be part of their body. This paradigm has been used in many domains of psychology (i.e., research on pain, body ownership, agency) and is of clinical importance. The classic rubber hand para- digm nevertheless suffers from limitations, such as the ab- sence of active motion or the reliance on approximate mea- surements, which makes strict experimental conditions diffi- cult to obtain. Here, we report on the development of a novel technology—a robotic, user- and computer-controllable hand—that addresses many of the limitations associated with the classic rubber hand paradigm. Because participants can actively control the robotic hand, the device affords higher realism and authenticity. Our robotic hand has a comparative- ly low cost and opens up novel and innovative methods. In order to validate the robotic hand, we have carried out three experiments. The first two studies were based on previous research using the rubber hand, while the third was specific to the robotic hand. We measured both sense of agency and ownership. Overall, results show that participants experienced a “robotic hand illusion” in the baseline conditions. Furthermore, we also replicated previous results about agency and ownership.

Atas, A., Faivre, N., Timmermans, B., Cleeremans, A., & Kouider, S. (in press). Nonconscious learning from crowded sequences. Psychological Science.


Can people learn complex information without conscious awareness? Implicit learning—learning without awareness of what has been learned—has been the focus of intense investigation over the last 50 years. However, it remains controversial whether complex knowledge can be learned implicitly. In the research reported here, we addressed this challenge by asking participants to differentiate between sequences of symbols they could not perceive consciously. Using an operant-conditioning task, we showed that participants learned to associate distinct sequences of crowded (nondiscriminable) symbols with their respective monetary outcomes (reward or punishment). Overall, our study demonstrates that sensitivity to sequential regularities can arise through the nonconscious temporal integration of perceptual information.

Doyen, S., Klein, O., Simons, D.J., & Cleeremans, A. (in press). On the other side of the mirror: Priming in cognitive and social psychology. Social Cognition.

Over the past several years, two largely separate traditions have collided, leading to controversy over claims about priming. We describe and contrast the main accounts of priming effects in cognitive and social psychology, focusing especially on the role of awareness. In so doing, we consider one of the core points of contention, claims about the effects of subliminal priming. Whereas cognitive psychologists often are interested in exploring how priming operates with and without awareness, social psychologists more commonly assume subliminality in order to bolster claims about the automaticity of priming. We discuss the criteria necessary to claim that a stimulus was processed entirely without awareness, noting the challenges in meeting those criteria. Finally, we identify three sources of conflict between the fields: awareness, replicability, and the nature of the underlying processes. We close by proposing resolutions for each of them.

Doyen, S., Klein, O., Simons, D., & Cleeremans, A. (2014). On the other side of the mirror: Priming in cognitive and social psychology. Social Cognition, 32 (Supplement: Understanding priming effects in social psychology), 12-32.

Abstract:

Over the past several years, two largely separate traditions have collided, leading to controversy over claims about priming. We describe and contrast the main accounts of priming effects in cognitive and social psychology, focusing especially on the role of awareness. In so doing, we consider one of the core points of contention, claims about the effects of subliminal priming. Whereas cognitive psychologists often are interested in exploring how priming operates with and without awareness, social psychologists more commonly assume subliminality in order to bolster claims about the automaticity of priming. We discuss the criteria necessary to claim that a stimulus was processed entirely without awareness, noting the challenges in meeting those criteria. Finally, we identify three sources of conflict between the fields: awareness, replicability, and the nature of the underlying processes. We close by proposing resolutions for each of them. "

Mertens, G., & De Houwer, J. (2016). Potentiation of the startle reflex is in line with contingency reversal instructions rather than the conditioning history. Biological Psychology, 113, 91-99.

In the context of fear conditioning, different psychophysiological measures have been related to different learning processes. Specifically, skin conductance responses (SCRs) have been related to cognitive expectancy learning, while fear potentiated startle (FPS) has been proposed to reflect affective learning that operates according to simple associative learning principles. On the basis of this two level account of fear conditioning we predicted that FPS should be less affected by verbal instructions and more affected by direct experience than SCRs. We tested this hypothesis by informing participants that contingencies would be reversed after a differential conditioning phase. Our results indicate that contingency reversal instructions led to an immediate and complete reversal of FPS regardless of the previous conditioning history. This change was accompanied by similar changes on US expectancy ratings and SCRs. These results conform with an expectancy model of fear conditioning but argue against a two level account of fear conditioning.

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Atas, A., Vermeiren, A., & Cleeremans, A. (2013). Repeating a strongly masked stimulus increases priming and awareness. Consciousness and Cognition, 22, 1422-1430.


Previous studies [Marcel, A. J. (1983). Conscious and unconscious perception: Experiments on visual masking and word recognition. Cognitive Psychology, 15(2), 197–237; Wentura, D., & Frings, C. (2005). Repeated masked category primes interfere with related exemplars: New evidence for negative semantic priming. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31(1), 108–120] suggested that repeatedly presenting a masked stimulus improves priming without increasing perceptual awareness. However, neural the- ories of consciousness predict the opposite: Increasing bottom-up strength in such a par- adigm should also result in increasing availability to awareness. Here, we tested this prediction by manipulating the number of repetitions of a strongly masked digit. Our results do not replicate the dissociation observed in previous studies and are instead sug- gestive that repeating an unconscious and attended masked stimulus enables the progres- sive emergence of perceptual awareness.

Blocking is the most important phenomenon in the history of associative learning theory: For over 40 years, blocking has inspired a whole generation of learning models. Blocking is part of a family of effects that are typically termed “cue competition” effects. Common amongst all cue competition effects is that a cue-outcome relation is poorly learned or poorly expressed because the cue is trained in the presence of an alternative predictor or cause of the outcome. We provide an overview of the cognitive processes involved in cue competition effects in humans and propose a stage framework that brings these processes together. The framework contends that the behavioral display of cue competition is cognitively construed following three stages that include (1) an encoding stage, (2) a retention stage, and (3) a performance stage. We argue that the stage framework supports a comprehensive understanding of cue competition effects.

Sidarus, N., & Haggard, P. (2016). Difficult action decisions reduce the sense of agency: A study using the Eriksen flanker task. Acta Psychologica, 166, 1–11.

The sense of agency refers to the feeling that we are in control of our actions and, through them, of events in the outside world. Much research has focused on the importance of retrospectively matching predicted and actual action outcomes for a strong sense of agency. Yet, recent studies have revealed that a metacognitive signal about the fluency of action selection can prospectively inform our sense of agency. Fluent, or easy, action selection leads to a stronger sense of agency over action outcomes than dysfluent, or difficult, selection. Since these studies used subliminal priming to manipulate action selection, it remained unclear whether supraliminal stimuli affecting action selection would have similar effects.

We used supraliminal flankers to manipulate action selection in response to a central target. Experiment 1 revealed that conflict in action selection, induced by incongruent flankers and targets, led to reduced agency ratings over an outcome that followed the participant's response, relative to neutral and congruent flanking conditions. Experiment 2 replicated this result, and extended it to free choice between alternative actions. Finally, Experiment 3 varied the stimulus onset asynchrony (SOA) between flankers and target. Action selection performance varied with SOA. Agency ratings were always lower in incongruent than congruent trials, and this effect did not vary across SOAs. Sense of agency is influenced by a signal that tracks conflict in action selection, regardless of the visibility of stimuli inducing conflict, and even when the timing of the stimuli means that the conflict may not affect performance.

Sidarus, N., Chambon, V. & Haggard, P. 2013 Priming of actions increases sense of control over unexpected outcomes. Consciousness and Cognition, 22, 1403–1411.

Sense of agency (SoA) refers to the feeling that we are in control of our own actions and, through them, events in the outside world. SoA depends partly on retrospectively matching outcomes to expectations, and partly on prospective processes occurring prior to action, notably action selection.
To assess the relative contribution of these processes, we factorially varied subliminal priming of action selection and expectation of action outcomes. Both factors affected SoA, and there was also a significant interaction. Compatible action primes increased SoA more strongly for unexpected than expected outcomes. Outcome expectation had strong effects on SoA following incompatible action priming, but only weak effects following compatible action priming. Prospective and retrospective SoA may have distinct and complementary functions.