Cognitive biases, which are tendencies to systematically process, select and remember certain information (e.g., jumping to conclusions), are exacerbated in schizophrenia and associated with delusions.
View Article and Find Full Text PDFMany quantitative cross-cultural research studies assume that cultural groups consist of anyone born and raised in the same country. Applying these criteria to the formation of study samples may produce cohorts that share a country but are heterogeneous in relevant domains of culture. For example, in Canada, Franco- and Anglo-Canadians are generally assumed to represent different linguistic groups but the same cultural group.
View Article and Find Full Text PDFBackground: Lack of insight is a frequent characteristic of psychotic disorders, both in patients who recently experienced a first episode of psychosis (FEP) and those who experience recurrent multiple episodes (MEP). Insight is a multifaceted construct: its clinical form notably includes the unawareness of being ill, of symptoms, and of the need for treatment. Cognitive capacity is among the key determinants of insight into symptoms, but less is known about whether stage of illness (FEP vs.
View Article and Find Full Text PDFBackground: Patients in every stage of the psychosis continuum can present with negative symptoms. While no treatment is currently available to address these symptoms, a more refined characterization of their course over the lifetime could help in elaborating interventions. Previous reports have separately investigated the prevalence of negative symptoms within each stage of the psychosis continuum.
View Article and Find Full Text PDFCognitive impairments in psychotic disorders (PD) present heterogeneously across patients. Between 2 and 5 clusters have been identified in previous studies with first-episode (FEP) and multiple-episodes of psychosis (MEP) patients suggesting different profiles of impairment. Past findings suggest there are differences between FEP and MEP patients regarding severity and number of affected cognitive domains.
View Article and Find Full Text PDFContext sometimes helps make objects more recognizable. Previous studies using functional magnetic resonance imaging (fMRI) have examined regional neural activity when objects have strong or weak associations with their contexts. Such studies have demonstrated that activity in the parahippocampal cortex (PHC) generally corresponds with strong associations between objects and their spatial contexts while retrosplenial cortex (RSC) activity is linked with episodic memory.
View Article and Find Full Text PDFContextual information allows the human brain to make predictions about the identity of objects that might be seen and irregularities between an object and its background slow down perception and identification processes. Bar and colleagues modeled the mechanisms underlying this beneficial effect suggesting that the brain stocks information about the statistical regularities of object and scene co-occurrence. Their model suggests that these recurring regularities could be conceptualized along a continuum in which the probability of seeing an object within a given scene can be high (probable condition), moderate (improbable condition) or null (impossible condition).
View Article and Find Full Text PDFNeuropsychology
September 2016
Objective: Schizophrenia is associated with poor spatial attention. However, although this deficit undermines the perception of target information, it may be helpful for ignoring irrelevant inputs. The present study examined whether event-related brain potential (ERP) indices of visual spatial attention predicted the magnitude of the brain response to interference in schizophrenia.
View Article and Find Full Text PDFMany objects seen for the first time look familiar because they resemble known objects. To overcome this feeling of familiarity and detect novelty, memories of known objects must be recollected and compared to new objects. This experiment examines whether recollection performed when perceiving new items (i.
View Article and Find Full Text PDFWe are used to seeing objects in specific settings, and in association with other related objects. This contextual information allows for fast and efficient object recognition and influences brain-related processes. The influence of scene context has been studied using event-related potentials (ERPs) in order to further our understanding of the underlying brain mechanisms.
View Article and Find Full Text PDFResearchers have only recently started to take advantage of the developments in technology and communication for sharing data and documents. However, the exchange of experimental material has not taken advantage of this progress yet. In order to facilitate access to experimental material, the Bank of Standardized Stimuli (BOSS) project was created as a free standardized set of visual stimuli accessible to all researchers, through a normative database.
View Article and Find Full Text PDFIn the domain of cognition, an increasing number of researchers are interested in the role of objects' motor affordances in cognitive processing. However, outside of the existing norms on the objects' levels of manipulability (e.g.
View Article and Find Full Text PDFBackground: Dysfunctional reward processing is present in individuals with schizophrenia-spectrum disorders (SSD) and may confer vulnerability to addiction. Our objective was to identify a deficit in patients with SSD on response to rewarding stimuli and determine whether this deficit predicts cannabis use.
Methods: We divided a group of patients with SSD and nonpsychotic controls into cannabis users and nonusers.
The role of objects' motor affordances in cognition is a topic that has gained in popularity over the last decades. However, few studies exist that have normed the different motor dimensions of the objects; this limits researchers regarding usable stimuli, as well as comparability between studies. In the present study, we normed a set of 560 objects on four motor dimensions: the ease with which they can be grasped, moved, and pantomimed and the number of actions they afford.
View Article and Find Full Text PDFPictorial stimuli are commonly used by scientists to explore central processes; including memory, attention, and language. Pictures that have been collected and put into sets for these purposes often contain visual ambiguities that lead to name disagreement amongst subjects. In the present work, we propose new norms which reflect these sources of name disagreement, and we apply this method to two sets of pictures: the Snodgrass and Vanderwart (S&V) set and the Bank of Standardized Stimuli (BOSS).
View Article and Find Full Text PDFPictures of objects have been shown to automatically activate affordances, that is, actions that could be performed with the object. Similarly, pictures of faces are likely to activate social affordances, that is, interactions that would be possible with the person whose face is being presented. Most interestingly, if it is the face of a real person that is shown, one particular type of social interactions can even be carried out while event-related potentials (ERPs) are recorded.
View Article and Find Full Text PDFThroughout the last decades, numerous picture data sets have been developed, such as the Snodgrass and Vanderwart (1980) set, and have been normalized for variables such as name and familiarity; however, due to cultural and linguistic differences, norms can vary from one country to another. The effect due specifically to culture has already been demonstrated by comparing samples from different countries where the same language is spoken. On the other hand, it is still not clear how differences between languages may affect norms.
View Article and Find Full Text PDFFaces of unknown persons are processed to infer the intentions of these persons not only when they depict full-blown emotions, but also at rest, or when these faces do not signal any strong feelings. We explored the brain processes involved in these inferences to test whether they are similar to those found when judging full-blown emotions. We recorded the event-related brain potentials (ERPs) elicited by faces of unknown persons who, when they were photographed, were not asked to adopt any particular expression.
View Article and Find Full Text PDFStudies have shown that symmetric stimuli are recognized better than asymmetric stimuli but evidence suggests that this advantage may result from a familiarity bias induced by symmetry. We used a classic episodic memory paradigm to test this bias and see if it truly accounts for the symmetry advantage. Subjects first encoded symmetric and asymmetric figures.
View Article and Find Full Text PDFThe present study was carried out to examine how the event-related potentials to fragmentation predict recognition success. Stimuli were abstract meaningless figures that were either complete or fragmented to various extents but still recoverable. Stimuli were first encoded as part of a symmetry discrimination task.
View Article and Find Full Text PDFAtten Percept Psychophys
August 2010
Visual perception is often challenged by various difficulties that act concomitantly and whose respective impacts may therefore be hard to distinguish. We used event-related potentials to dissociate the impact of target saliency, generated by occlusion, from that of interference produced by incongruent nontargets. In one block, the target (a square) partially occluded another square tilted by 45 degrees.
View Article and Find Full Text PDFThere are currently stimuli with published norms available to study several psychological aspects of language and visual cognitions. Norms represent valuable information that can be used as experimental variables or systematically controlled to limit their potential influence on another experimental manipulation. The present work proposes 480 photo stimuli that have been normalized for name, category, familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability.
View Article and Find Full Text PDFRepetition has often been associated with a reduction or a suppression of semantic effects. However, several studies have reported that semantic processing can still be effective for repeated target stimuli when the context, prime word or sentence frame, changes from trial to trial. This type of context-target designs allows to study semantic associations between repeated words.
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