Alzheimer's disease and natural cognitive aging may represent adaptive metabolism reduction programs

The present article examines several lines of converging evidence suggesting that the slow and insidious brain changes that accumulate over the lifespan, resulting in both natural cognitive aging and Alzheimer's disease (AD), represent a metabolism reduction program. A number of such adaptive programs are known to accompany aging and are thought to have decreased energy requirements for ancestral hunter-gatherers in their 30s, 40s and 50s. Foraging ability in modern hunter-gatherers declines rapidly, more than a decade before the average terminal age of 55 years. Given this, the human brain would have been a tremendous metabolic liability that must have been advantageously tempered by the early cellular and molecular changes of AD which begin to accumulate in all humans during early adulthood. Before the recent lengthening of life span, individuals in the ancestral environment died well before this metabolism reduction program resulted in clinical AD, thus there was never any selective pressure to keep adaptive changes from progressing to a maladaptive extent

A Computational Architecture for Machine Consciousness and Artificial Superintelligence: Updating Working Memory Iteratively

This theoretical article examines how to construct human-like working memory and thought processes within a computer. There should be two working memory stores, one analogous to sustained firing in association cortex, and one analogous to synaptic potentiation in the cerebral cortex. These stores must be constantly updated with new representations that arise from either environmental stimulation or internal processing. They should be updated continuously, and in an iterative fashion, meaning that, in the next state, some items in the set of coactive items should always be retained. Thus, the set of concepts coactive in working memory will evolve gradually and incrementally over time. This makes each state is a revised iteration of the preceding state and causes successive states to overlap and blend with respect to the set of representations they contain. As new representations are added and old ones are subtracted, some remain active for several seconds over the course of these changes. This persistent activity, similar to that used in artificial recurrent neural networks, is used to spread activation energy throughout the global workspace to search for the next associative update. The result is a chain of associatively linked intermediate states that are capable of advancing toward a solution or goal. Iterative updating is conceptualized here as an information processing strategy, a computational and neurophysiological determinant of the stream of thought, and an algorithm for designing and programming artificial intelligence

Psychological correlates of certainty strength: Measuring the relative influence of evidence, opinion of personal contacts & importance to self-identity

This research examines the psychological foundations of personal belief by measuring how different determinants of belief formulation contribute to certainty strength. Together, two studies collected data from over 400 undergraduate students regarding how physical, social and religious beliefs are formulated. Participants rated their strength of belief in these domains relative to the following determinants: the importance of substantiating evidence, the perceived logic inherent in a belief, the importance to self-identity, the influence of personal contacts, the social community and authority figures and the expected permanence, perceived relevance and personal likeability of the belief. The present research found that strength of certainty can be predicted by the quality of empirical evidence that people can offer to support the belief, by their estimates of their parent's certainty in the belief and by the perceived importance of the belief to their sense of self-identity

Assessing the psychological correlates of belief strength: Contributing factors and role in behavior

This dissertation examines the psychological foundations of personal belief by conducting a review of classical and contemporary thought about belief, by hypothesizing about ways to conceptualize belief and by presenting new evidence about belief from empirical studies. Two studies measured the contributions of various constructs to belief strength in an effort to examine the determinants and functions of personal belief. Study 1 collected data from over 250 child-parent pairs regarding how beliefs are formulated. Participants rated their strength of belief in statements relative to the following determinants: the importance of substantiating evidence, the perceived logic inherent in a belief, the importance to self-identity, the influence of parents, the social community and authority figures. Study 1 found that strength of certainty can be best predicted by one's estimate of their family member's belief, the quality of empirical evidence that the person can offer to support the belief, and the perceived importance of the belief to their sense of self-identity. Study 2 investigated whether people's weight management beliefs predicted diet and exercise behaviors and whether these behaviors in turn predicted BMI. These expected results were strongly supported by the data gathered from 996 participants, who responded to a questionnaire, reporting their height, weight, beliefs about various aspects of weight management, and personal weight-management behaviors, including exercise activities and eating habits. Overall, 40% of the variance in BMI within our sample, including 49% of the variance in BMI in individuals older than 25, could be predicted by a combination of health beliefs and their associated eating and exercise behavior