Artificial Neural Network Simulations of Human Learning Suggest the Presence of Metastable Attractors in Visual Memory

The attractor hypothesis states that knowledge is encoded as topologically-defined, stable configurations of connected cell assemblies. Irrespective to its original state, a network encoding new information will thus self-organize to reach the necessary stable state. To investigate memory structure, a multimodular neural network architecture, termed Magnitron, has been developed. Magnitron is a biologically-inspired cognitive architecture that simulates digit recognition. It implements perceptual input, human visual long-term memory in the ventral visual pathway and, to a lesser extent, working memory processes. To test the attractor hypothesis a Monte Carlo simulation of 10,000 individuals has been run. Each simulated learner was trained in recognizing the ten digits from novice to expert stage. The results replicate several features of human learning. First, they show that random connectivity in long-term visual memory accounts for novices’ performance. Second, the learning curves revealed that Magnitron simulates the well-known psychological power law of practice. Third, after learning took place, performance departed from chance level and reached a minimum target of 95% of correct hits; hence simulating human performance in children (i.e., when digits are learned). Magnitron also replicates biological findings. In line with research using voxel-based morphometry, Magnitron showed that matter density increases while training is taken place. Crucially, the spatial analysis of the connectivity patterns in long-term visual memory supported the hypothesis of a stable attractor. The significance of these results regarding memory theory is discussed

The neural signature of emotional memories in serial crimes

Neural plasticity is the process whereby semantic information and emotional responses are stored in neural networks. It is hypothesized that the neural networks built over time to encode the sexual fantasies that motivate serial killers to act should display a unique, detectable activation pattern. The pathological neural watermark hypothesis posits that such networks comprise activation of brain sites that reflect four cognitive components: autobiographical memory, sexual arousal, aggression, and control over aggression. The neural sites performing these cognitive functions have been successfully identified by previous research. The key findings are reviewed to hypothesise the typical pattern of activity that serial killers should display. Through the integration of biological findings into one framework, the neural approach proposed in this paper is in stark contrast with the many theories accounting for serial killers that offer non-medical taxonomies. The pathological neural watermark hypothesis offers a new framework to understand and detect deviant individuals. The technical and legal issues are briefly discussed

Intuition in chess: a study with world-class players

Intuition plays a central role in cognition in general and expertise in particular. Dreyfus and Dreyfus’s (1986) and Gobet and Chassy’s (2008) theories of expert intuition propose that a characteristic feature of expert intuition is the holistic understanding displayed by experts. The ideal way to test this prediction is to use highly expert participants and short presentation times. Chess players (N = 63), ranging from candidate masters to world-class players, had to evaluate chess problems. Evaluating the problems required an understanding of the position as a whole. Results demonstrated an effect of skill (better players had better evaluations), complexity (simpler positions were better evaluated than complex positions) and balance (accuracy diminished when the true evaluations became more extreme). A regression analysis showed that skill accounted for 44% of the variance in evaluation error. These important results support the central role of holistic intuition in expertise

Habitual use of cognitive reappraisal to regulate emotions is associated with decreased amplitude of the late positive potential (LPP)

In contrast to our knowledge about instructed emotion regulation, rather little is known about the effects of habitual (or “spontaneous”) emotion regulation on neural processing. We analyzed the relationship between everyday use of cognitive reappraisal (measured by the Emotion Regulation Questionnaire, ERQ-R), and the amplitude of the late positive potential (LPP), which is sensitive to down-regulation of negative emotions via reappraisal. Participants viewed a series of neutral and threatening images, and rated them for level of threat. We found increased LPP amplitude for threatening compared to neutral pictures between 500 and 1,500 ms. Crucially, we found smaller LPP amplitudes to threatening versus neutral pictures for participants who used reappraisal more often in everyday life. This relationship between LPP amplitude and the ERQ-R was observed in the 1,000–1,500 ms interval of the LPP, over right centro-parietal 19 electrodes. The current findings indicate that habitual tendency to use reappraisal is associated with reduced amplitude of the LPP in response to threatening pictures, in the absence of any explicit instruction to regulate emotions

Measuring Chess Experts' Single-Use Sequence Knowledge: An Archival Study of Departure from ‘Theoretical’ Openings

The respective roles of knowledge and search have received considerable attention in the literature on expertise. However, most of the evidence on knowledge has been indirect – e.g., by inferring the presence of chunks in long-term memory from performance in memory recall tasks. Here we provide direct estimates of the amount of monochrestic (single use) and rote knowledge held by chess players of varying skill levels. From a large chess database, we analyzed 76,562 games played in 2008 by individuals ranging from Class B players (average players) to Masters to measure the extent to which players deviate from previously known initial sequences of moves (“openings”). Substantial differences were found in the number of moves known by players of different skill levels, with more expert players knowing more moves. Combined with assumptions independently made about the branching factor in master games, we estimate that masters have memorized about 100,000 opening moves. Our results support the hypothesis that monochrestic knowledge is essential for reaching high levels of expertise in chess. They provide a direct, quantitative estimate of the number of opening moves that players have to know to reach master level

Visual search in ecological and non-ecological displays: Evidence for a non-monotonic effect of complexity on performance

Copyright @ 2013 PLoSThis article has been made available through the Brunel Open Access Publishing Fund.Considerable research has been carried out on visual search, with single or multiple targets. However, most studies have used artificial stimuli with low ecological validity. In addition, little is known about the effects of target complexity and expertise in visual search. Here, we investigate visual search in three conditions of complexity (detecting a king, detecting a check, and detecting a checkmate) with chess players of two levels of expertise (novices and club players). Results show that the influence of target complexity depends on level of structure of the visual display. Different functional relationships were found between artificial (random chess positions) and ecologically valid (game positions) stimuli: With artificial, but not with ecologically valid stimuli, a “pop out” effect was present when a target was visually more complex than distractors but could be captured by a memory chunk. This suggests that caution should be exercised when generalising from experiments using artificial stimuli with low ecological validity to real-life stimuli.This study is funded by Brunel University and the article is made available through the Brunel Open Access Publishing Fund

Risk Taking in Brinkmanship

Judgement and decision making are essential functions of the cognitive system. The present paper exposes key elements of the psychological theory which best accounts for human decision making. Decision making can be a flawed process. Loss aversion, framing effects, and differences across individuals are presented to highlight the irrational aspect of human risk taking. We reveal evidence of various cognitive distortions as compared to normalised decisions. It has been shown that expertise acquisition can compensate part of these cognitive distortions. Yet, recent evidence shows that experts in different civilizations retain civilizational risk propensities. Such evidence thus challenges the notion that knowledge is sufficient for perfect rationality in decision making; throwing the idea that politics is served by informed individuals making rational decisions under a severe cloud. The consequences of flawed human decisions regarding risk taking at a grand scale and by educated individuals is discussed. It is demonstrated that risk tolerance in different civilizations leads to different actions. This basic phenomenon is used to demonstrate how powerful states may misread potential reactions of less powerful states, which historically, can and has led to costly wars. Understanding the opponents’ psychology is a well-known factor for chess players, which, so far, has not been explored much in political psychology

The role of memory templates in experts strategic thinking

There is ample evidence that experts’ performance is mostly due to domain specific knowledge. Some complex memory structures, termed templates, have been theorised to underpin strategic thinking in expert chess players. A behavioural study and computer simulations have been used to test this hypothesis. The behavioural study is the first to show that experts identify strategic systems with more accuracy than novices do. A new artificial neural network model is introduced to implement visuospatial templates. The simulations indicate that templates adequately model identification of strategies in novice and expert players. Both results support the view that templates underpin strategic thinking. The findings constitute a demonstration of the dependence of strategic thinking on memory processes and open the door for a new theoretical approach to understand high-level cognition