Self-organisation in dynamical systems: a limiting result

There is presently considerable interest in the phenomenon of “self-organisation” in dynamical systems. The rough idea of self-organisation is that a structure appears “by itself” in a dynamical system, with reasonably high probability, in a reasonably short time, with no help from a special initial state, or interaction with an external system. What is often missed, however, is that the standard evolutionary account of the origin of multi-cellular life fits this definition, so that higher living organisms are also products of self-organisation. Very few kinds of object can self-organise, and the question of what such objects are like is a suitable mathematical problem. Extending the familiar notion of algorithmic complexity into the context of dynamical systems, we obtain a notion of “dynamical complexity”. A simple theorem then shows that only objects of very low dynamical complexity can self organise, so that living organisms must be of low dynamical complexity. On the other hand, symmetry considerations suggest that living organisms are highly complex, relative to the dynamical laws, due to their large size and high degree of irregularity. In particular, it is shown that since dynamical laws operate locally, and do not vary across space and time, they cannot produce any specific large and irregular structure with high probability in a short time. These arguments suggest that standard evolutionary theories of the origin of higher organisms are incomplete.     

False recognition in Lewy-body disease and frontotemporal dementia

The primary goal of this study was to evaluate the false recognition phenomenon in persons with frontotemporal dementia (FTD) and those with Lewy-body disease (LBD). Patients with LBD (n=10) or FTD (n=15) and their corresponding controls (n=30) were subjected to the Deese-Roediger-McDermott (DRM) paradigm to induce false recognition. Patients were first presented with items semantically related to a nonpresented critical target. The critical target was later included in a word list shown to patients to assess level of recognition. Both groups of patients showed a reduced level of false recognition of the critical target when controlling for their overall level of false alarms. This reduction was greater in persons with LBD than in those with FTD. Correlational analyses of performance on neuropsychological tests and the DRM variables indicated that the reduced DRM effect was associated with inhibition deficits in patients with LBD and with inhibition deficits and verbal memory in those with FTD. Our results support current models suggesting that these cognitive components contribute to the false recognition effect.     

Combating stereotype threat: The effect of self-affirmation on women’s intellectual performance

The present studies were designed to investigate the effects of self-affirmation on the performance of women under stereotype threat. In Study 1, women performed worse on a difficult math test when it was described as diagnostic of math intelligence (stereotype threat condition) than in a non-diagnostic control condition. However, when women under stereotype threat affirmed a valued attribute, they performed at levels comparable to men and to women in the no-threat control condition. In Study 2, men and women worked on a spatial rotation test and were told that women were stereotyped as inferior on such tasks. Approximately half the women and men self-affirmed before beginning the test. Self-affirmation improved the performance of women under threat, but did not affect men’s performance.     

Interstimulus interval and delivery cues influence timed conditioned responding in rats

Appetitive contextual excitation supported by intertrial unconditioned stimuli was more easily overcome by timed conditioned responding in rats using quiet (Experiment 1) rather than noisy (Experiment 2) food pellet deliveries. Head-entry responding in acquisition peaked above the contextual baseline when pellet delivery occurred 10, 30, 60, or 90 s after the onset of the 120-s white-noise conditioned stimulus (CS). Special tests in extinction revealed CS onset and offset were conditioned by pellet delivery at 0 and 120 s, respectively. Responding was not undermined in Experiment 3 when noisy pellet deliveries replaced quiet pellet deliveries. Our results suggest that micro-stimuli occasioned at different times during the CS are vulnerable to overshadowing, but do not lose strength if they are already predictive.     

Domestic violence and sexual assault services: Inside the black box

Research examining the efficacy of community-based domestic violence and sexual assault services is yielding promising findings; however, little is known about the structure, components, and content of these services. Although service guidelines exist, a critical gap persists because review, comparison, and synthesis of these recommendations have not been undertaken. This research addresses this knowledge gap through a review of the domestic violence and sexual assault services literature. We gathered relevant literature by conducting systematic searches of databases, and by soliciting the service guidelines and training manuals from all the Domestic Violence and Sexual Assault Coalitions in the United States. These efforts yielded 43 articles, books, or manuals for review. The findings show strong consensus on core services for survivors, including crisis services, legal and medical advocacy, support groups, individual counseling, and shelter. This article presents the review results in tables comparing the service goals, intervention strategies, and recommendations for service delivery. We also found areas of contention (e.g., whether to continuously staff domestic violence shelters, and whether combined agencies can effectively offer both domestic violence and sexual assault services). Building upon the review findings, we discuss the implications for domestic violence and sexual assault services and intervention research.     

Oxytocin responsivity in mothers of infants: a preliminary study of relationships with blood pressure during laboratory stress and normal ambulatory activity.

The neuropeptide oxytocin (OT) enhances maternal behavior and decreases blood pressure (BP) and stress responses in animals. Thus, the relationship of OT responsivity to BP in 14 breast- and 11 bottle-feeding mothers of infants was examined. Laboratory BP was assessed during baseline, speech preparation, active speech, and recovery on 2 days, 1 in which baseline and speech were separated by 10 min of baby holding and the other by no baby contact. Systolic BP reactivity to speech was lower after baby contact. Plasma OT change from baseline to speech after baby contact defined OT increase, minimal OT change, and OT decrease groups. OT increase mothers were primarily breast-feeders, and they had lower BP throughout both stress sessions and after baby feeding at home than OT decrease mothers, who also had greater BP reactivity to preparation and recovery. These results suggest that oxytocin has antistress and BP-lowering effects in humans.     

The Role of Negative Information in Distributional Semantic Learning

Distributional models of semantics learn word meanings from contextual co‐occurrence patterns across a large sample of natural language. Early models, such as LSA and HAL (Landauer & Dumais, 1997; Lund & Burgess, 1996), counted co‐occurrence events; later models, such as BEAGLE (Jones & Mewhort, 2007), replaced counting co‐occurrences with vector accumulation. All of these models learned from positive information only: Words that occur together within a context become related to each other. A recent class of distributional models, referred to as neural embedding models, are based on a prediction process embedded in the functioning of a neural network: Such models predict words that should surround a target word in a given context (e.g., word2vec; Mikolov, Sutskever, Chen, Corrado, & Dean, 2013). An error signal derived from the prediction is used to update each word's representation via backpropagation. However, another key difference in predictive models is their use of negative information in addition to positive information to develop a semantic representation. The models use negative examples to predict words that should not surround a word in a given context. As before, an error signal derived from the prediction prompts an update of the word's representation, a procedure referred to as negative sampling. Standard uses of word2vec recommend a greater or equal ratio of negative to positive sampling. The use of negative information in developing a representation of semantic information is often thought to be intimately associated with word2vec's prediction process. We assess the role of negative information in developing a semantic representation and show that its power does not reflect the use of a prediction mechanism. Finally, we show how negative information can be efficiently integrated into classic count‐based semantic models using parameter‐free analytical transformations.     

Clinical concepts

In this section authors have written about the Winnicottian concept that they value most in their everyday working lives. This provides a valuable insight into the ways in which Winnicott's work is being used as a springboard for new ideas, as well as enlightening familiar ground. It is striking to see how the original Winnicottian idea takes on new form as it is taken up by new generations of clinicians. Despite the absence of a Winnicottian training school, his pervasive impact continues to influence current theory and practice.