The Emergence of Miller's Magic Number on a Sparse Distributed Memory

Human memory is limited in the number of items held in one's mind—a limit known as “Miller's magic number”. We study the emergence of such limits as a result of the statistics of large bitvectors used to represent items in memory, given two postulates: i) the Sparse Distributed Memory; and ii) chunking through averaging. Potential implications for theoretical neuroscience are discussed

What is the nature of the mind's pattern-recognition process?

If we look at the human mind as a pattern-recognition device, what is the nature of its pattern-recognizing? And how does it differ from the majority of pattern-recognition methods we have collectively devised over the decades? These broad philosophical questions emerge from the studies of chess thought, and we propose that a major task of the mind is to engage in 'experience recognition' (Linhares & Freitas, 2010). One of the basic tenets of that proposal is that pattern recognition, in cognitive science and related disciplines, does not accurately reflect human psychology. As an example, the well-known article by Chase and Simon, 'perception in chess', and the benchmark cognitive computational models of chess, by Gobet et al. were criticized. Lane and Gobet (2011) provide serious skepticism concerning some of those arguments, and here we take the opportunity to respond and expand the theoretical constructs of 'experience recognition'. We postulate that the mind's pattern-recognizing process holds the following properties: it is a highly path-dependent process; it prioritizes internal encodings; it is a self-organizing process in constant change; and it constructs its future information-processing pathways by continuously recognizing the possibilities that lie within the adjacent possible. © 2012 Elsevier Ltd

Sparse distributed memory: understanding the speed and robustness of expert memory

How can experts, sometimes in exacting detail, almost immediately and very precisely recall memory items from a vast repertoire? The problem in which we will be interested concerns models of theoretical neuroscience that could explain the speed and robustness of an expert's recollection. The approach is based on Sparse Distributed Memory, which has been shown to be plausible, both in a neuroscientific and in a psychological manner, in a number of ways. A crucial characteristic concerns the limits of human recollection, the “tip-of-tongue” memory event—which is found at a non-linearity in the model. We expand the theoretical framework, deriving an optimization formula to solve this non-linearity. Numerical results demonstrate how the higher frequency of rehearsal, through work or study, immediately increases the robustness and speed associated with expert memory

Preserved items as a function of ; selected values of .

<p>Preserved items as a function of ; selected values of .</p

Threshold values.

<p>Thresholds given plausible success factors and dimension combinations.</p

Cardiac autonomic activity predicts dominance in verbal over spatial reasoning tasks : results from a preliminary study

Abstract: The present study sought to determine whether autonomic activity is associated with dominance in verbal over spatial reasoning tasks. A group of 19 healthy adults who performed a verbal and spatial aptitude test was evaluated. Autonomic function was assessed by means of heart rate variability analysis, before and during the tasks. The results showed that a better relative performance in verbal over spatial reasoning tasks was associated with vagal prevalence in normal subjects

Heart rate nonlinear dynamics during sudden hypoxia at 8,230 m simulated altitude

Background: Acute hypobaric hypoxia is associated with autonomic changes that bring a global reduction of linear heart rate variability (HRV). Although changes in nonlinear HRV can be associated with physiological stress and are relevant predictors of fatal arrhythmias in ischemic heart disease, to what extent these components vary in sudden hypobaric hypoxia is not known. Methods: Twelve military pilots were supplemented with increasing concentrations of oxygen during decompression to 8,230 m in a hypobaric chamber. Linear and nonlinear HRV was evaluated at 8,230 m altitude before, during and after oxygen flow deprivation. Linear HRV was assessed through traditional time- and frequency- domain analysis. Nonlinear HRV was quantified through the short term fractal correlation exponent alpha (αs) and the Sample Entropy index (SampEn). Results: Hypoxia was related to a decrease in linear heart rate variability indexes at all frequency levels. A non significant decrease in αs (basal: 1.39 ± 0.07, hypoxia: 1.11 ± 0.13, recovery: 1.41 ± 0.05, p = 0.054) and a significant increase in SampEn (basal: 1.07 ± 0.11, hypoxia: 1.45 ± 0.12, recovery: 1.43 ± 0.09, p = 0.018) were detected. Conclusions: The observed pattern of diminished linear heart rate variability and increased nonlinear heart rate variability is similar to that seen in subjects undergoing heavy exercise or in patients with ischemic heart disease and high risk for ventricular fibrillation