Nonlinear dynamics: theoretical perspectives and application to suicidology

Despite decades of research, the prediction of suicidal behavior remains limited. As a result, searching for more specific risk factors and testing their predictive power are central in suicidology. This strategy may be of limited value because it assumes linearity to the suicidal process that is most likely nonlinear by nature and which can be more adequately described and analyzed with nonlinear dynamics. The goal of moving nonlinear dynamics from theory to practice and to real-world phenomena can now be realized with Internet-based monitoring systems such as the Synergetic Navigation System.     

Attachment Styles and Employee Performance: The Mediating Role of Burnout

Researchers are becoming increasingly interested in how early experiences within the family are relevant to an individual’s behavior at work. Drawing on Bowlby’s attachment theory, the present study addresses this topic by examining the relationship between attachment in adulthood and job performance, and the mediating role of burnout in that relationship. We used data from two samples (201 Dutch employees and 178 Romanian working students) and structural equation modeling to test this mediation model and its possible invariance across both samples. The results showed that in both samples, attachment-related anxiety was positively related to burnout, which was in turn negatively related to job performance. Attachment-related avoidance was not significantly associated with burnout or performance. These results were similar in both samples, thus increasing their validity. The results suggest that childhood and early socialization experiences play a role in shaping the employee’s behavior and well-being at work. The study is one of the few examining attachment styles in relation to burnout and performance.     

Framing decisions: Hypothetical and real

This paper addresses the general issue of whether the practice of investigating human decision making in hypothetical choice situations is at all warranted, or under what conditions. A particularly relevant factor that affects the match between real decisions and hypothetical decisions is the importance of a decision’s consequences. In the literature experimental gambles tend to confound the reality of the decision situation with the size of the payoffs: hypothetical decisions tend to offer large payoffs, and real decisions tend to offer only small payoffs. Using the well-known framing effect (a tendency of risk-aversion for gains and of risk-seeking for losses) we find that the framing effect depends on payoff size but hypothetical choices match real choices for small as well as large payoffs. These results appear paradoxical unless size of incentive is clearly distinguished from the reality status of decision (real versus hypothetical). Since the field lacks a general theory of when hypothetical decisions match real decisions, the discussion presents an outline for developing such a theory.     

Developmental aspects of consciousness: how much theory of mind do you need to be consciously aware?

When do children become consciously aware of events in the world? Five possible strategies are considered for their usefulness in determining the age in question. Three of these strategies ask when children show signs of engaging in activities for which conscious awareness seems necessary in adults (verbal communication, executive control, explicit memory), and two of the strategies consider when children have the ability to have the minimal form of higher-order thought necessary for access consciousness and phenomenal consciousness, respectively. The tentative answer to the guiding question is that children become consciously aware between 12 and 15 months (+/-3 months).     

Listen up,eye movements play a role in verbal memory retrieval

People fixate on blank spaces if visual stimuli previously occupied these regions of space. This so-called “looking at nothing” (LAN) phenomenon is said to be a part of information retrieval from internal memory representations, but the exact nature of the relationship between LAN and memory retrieval is unclear. While evidence exists for an influence of LAN on memory retrieval for visuospatial stimuli, evidence for verbal information is mixed. Here, we tested the relationship between LAN behavior and memory retrieval in an episodic retrieval task where verbal information was presented auditorily during encoding. When participants were allowed to gaze freely during subsequent memory retrieval, LAN occurred, and it was stronger for correct than for incorrect responses. When eye movements were manipulated during memory retrieval, retrieval performance was higher when participants fixated on the area associated with to-be-retrieved information than when fixating on another area. Our results provide evidence for a functional relationship between LAN and memory retrieval that extends to verbal information.     

The "minimal self" in psychopathology: re-examining the self-disorders in the schizophrenia spectrum

The notion of minimal, basic, pre-reflective or core self is currently debated in the philosophy of mind, cognitive sciences and developmental psychology. However, it is not clear which experiential features such a self is believed to possess. Studying the schizophrenic experience may help exploring the following aspects of the minimal self: the notion of perspective and first person perspective, the 'mineness' of the phenomenal field, the questions of transparency, embodiment of point of view, and the issues of agency and ownership, considered as different and less fundamental than the feeling of mineness. Two clinical vignettes of patients with the diagnosis of schizophrenia will be presented: the first one, illustrating early illness stages, and the second case, of chronic schizophrenia, symptomatically marked by persistent hallucinations. Through their analysis, we will discuss the experiential dimensions of minimal self.     

Remember judgments and the constraint of direct experience

The most direct assessment of episodic memory is provided by Remember versus Know judgments of recalled or recognised items. We investigate whether Remember judgments reflect episodic memories as a re-experience of formerly experienced events (mental time travel). If they do, they must obey the direct experience constraint: only directly experienced events can be re-experienced but not when the event is known through indirectly conveyed information. In two Experiments participants saw simple events in Power Point, e.g. a car exploding. In the direct experience condition these events were directly perceived. In three further conditions information about the object (particular car), the kind of event (explosion), or both were verbally conveyed. After controlling for a potential encoding specificity effect in Experiment 1, the frequency of Remember judgments was twice as high in the direct experience condition than in the other three conditions. This suggests that Remember judgments are—at least to some degree—subject to the direct experience constraint.     

Automatic analysis of altered gait in arylsulphatase A-deficient mice in the open field

In current research with laboratory animals, observing their dynamic behavior or locomotion is a laborintensive task. Automatic continuous monitoring can provide quantitative data on each animal’s condition and coordination ability. The objective of the present work is to develop an automated mouse observation system integrated with a conventional open-field test for motor function evaluation. Data were acquired from 86 mice having a targeted disruption of the arylsulphatase A (ASA) gene and having lowered coordinated locomotion abilities as a symptom. The mice used were 36 heterozygotes (12 females) and 50 knockout mice (30 females) at the age of 6 months. The mice were placed one at a time into the test setup, which consisted of a Plexiglas cage (53× 34.5 × 26 cm) and two fluorescent bulbs for proper illumination. The transparent cage allowed images to be captured from underneath the cage, so image information could be obtained about the dynamic variation of the positions of the limbs of the mice for gait reconstruction. Every mouse was recorded for 10 min. Background subtraction and color filtering were used to measure and calculate image features, which are variables that contain crucial information, such as the mouse’s position, orientation, body outline, and poßible locations for the mouse’s paws. A set of heuristic rules was used to prune implausible paw features and label the remaining ones as front/hind and left/right. After we had pruned the implausible paw features, the paw features that were consistent over subsequent images were matched to footprints. Finally, from the measured footprint sequence, eight parameters were calculated in order to quantify the gait of the mouse. This automatic observation technique can be integrated with a regular open-field test, where the trajectory and motor function of a free-moving mouse are measured simultaneously.