Subjective antedating of a sensory experience and mind-brain theories: reply to Honderich (1984)

Honderich claims that our "delay-and-antedating" hypothesis, of a delay in cerebral production combined with a subjective antedating of a conscious sensory experience, involves self-contradiction which may cast doubt on some of our experimental findings and on the hypothesis. This claim misses the distinction between the phenomenological subjective mental content of an experience and the physical-neuronal configuration that elicits the experience; also, it cannot explain the experimentally observed discrepancy, between subjective timing and the empirically delayed time for cerebral adequacy for eliciting the experience, found when stimulating a subcortical sensory pathway. Honderich usefully distinguishes between our stated (delay-and-antedating) hypothesis and a different though unacceptable one which would have serious implications for mind-brain theories. The delay-and-antedating hypothesis does not provide a formally definitive contradiction of monist-identity theory (of the mind-brain relationship). However, our experimentally based hypothesis does dissociate subjective/mental timing from the actual physical/neuronal time of an experience. This phenomenon, though conceptually strange, must be encompassed by any mind-brain theory.     

The implications of accepting untestedhypotheses: a review of the effectsof purple loosestrife (Lythrum salicaria)in North America

The acceptance of poorly tested hypotheses has adverse scientific consequences, and may have adverse ecological and social consequences. The hypothesis that purple loosestrife (Lythrum salicaria) has deleterious effects on North American wetlands is an example. We traced the history of purple loosestrife and its control in North America and found little scientific evidence consistent with the hypothesis that purple loosestrife has deleterious effects. The most commonly cited study of the effects of purple loosestrife on native flora and fauna produced inconclusive results. The general acceptance of this hypothesis, however, has resulted in the introduction of nonindigenous insects for biological control. Efforts to control purple loosestrife may be misplayed and may have long-term ecological consequences if loosestrife does not have the impact it is believed to have. The acceptance of this hypothesis using scientific justifications may affect future scientific credibil ity. Careful evaluation of the precautionary principle is necessary when considering the control of nonindigenous organisms.     

Biological nonlocality and the mind-brain interaction problem: comments on a new empirical approach

Up to now, we have been faced with an age old fundamental dilemma posed by the mind-brain interaction problem, i.e. how is it that the mind which is subjective and immaterial, can interact with the brain which is objective and material? Analysis of recent experiments appears to indicate that quantum mechanics may have a role to play in the resolution of the mind-brain interaction problem in the form of biological entanglement and nonlocality. In addition to this analysis, when coupled with ongoing and proposed experiments, may help us to simultaneously resolve related issues such as whether mental events can initiate neural events, the transference of conscious subjective experience, the measurement problem and the binding problem.     

Restriction in the cleavage activity of hammerhead ribozymes ensures ongoing evolution in prebiotic RNA world

Self-cleaving infectious RNAs found in many plant viruses and viroids can also cleave intrans and form hammerhead type secondary structure. It has been observed that the cleavage site must contain the triplet GUC. Also, in other cases, the sequence XUY holds good where X = A, C, G, U and Y = A, C, U but not G. The high electronegative nature of guanosine holds the key to its resistance to cleavage which does not allow hybrid formation between the ribozyme and substrate strands. Guanosine resistance to cleavage might have been the starting thrust for the evolution of a translational initiation codon from XUG. A hypothesis is proposed in this regard and its evolutionary consequences are discussed briefly. Presented at the National Symposium on Evolution of Life.     

Invasion success and threat status: two sides of a different coin?

The characteristics possessed by invasive species have been suggested to be the reverse of those possessed by species threatened with extinction, such that relationships of species’ traits to invasion success should be opposite in sign to relationships of the same traits to extinction threat. A recent study (Jeschke, J. M. and Strayer, D. L. 2008. Are threat status and invasion success two sides of the same coin? – Ecography 31: 124–130) found no evidence for this “two‐sides‐of‐the‐same‐coin” hypothesis but compared characteristics of species in each taxon that were invasive to a control group consisting of all other species. A different view of the “two‐sides‐of‐the‐same‐coin” hypothesis may be obtained if the characters of invasive species are compared to those of a control group consisting of species that have not invaded despite actually being introduced. Here, we show that changing the control group for comparison with invasive species does not change the lack of support for the “two‐sides‐of‐the‐same‐coin” hypothesis but does change views about which specific traits are consistent with the hypothesis.     

Social intelligence, human intelligence and niche construction

This paper is about the evolution of hominin intelligence. I agree with defenders of the social intelligence hypothesis in thinking that externalist models of hominin intelligence are not plausible: such models cannot explain the unique cognition and cooperation explosion in our lineage, for changes in the external environment (e.g. increasing environmental unpredictability) affect many lineages. Both the social intelligence hypothesis and the social intelligence-ecological complexity hybrid I outline here are niche construction models. Hominin evolution is hominin response to selective environments that earlier hominins have made. In contrast to social intelligence models, I argue that hominins have both created and responded to a unique foraging mode; a mode that is both social in itself and which has further effects on hominin social environments. In contrast to some social intelligence models, on this view, hominin encounters with their ecological environments continue to have profound selective effects. However, though the ecological environment selects, it does not select on its own. Accidents and their consequences, differential success and failure, result from the combination of the ecological environment an agent faces and the social features that enhance some opportunities and suppress others and that exacerbate some dangers and lessen others. Individuals do not face the ecological filters on their environment alone, but with others, and with the technology, information and misinformation that their social world provides.     

Calcium: just a chemical switch?

The calcium-signature hypothesis has evolved as a concept to explain specificity in signaling pathways that utilise calcium as a second messenger. In plant biology, this hypothesis was purely conceptual and based only upon correlative observations until recently. In the past few years, however, empirical data have emerged from experiments that were specifically designed to tackle the question of how specificity is encoded by calcium. In light of the attractive calcium-signature hypothesis, other potential explanations for signalling specificity have been overshadowed and ignored: it has been assumed that the calcium-signature dogma will explain all plant calcium signaling. However, there is a good deal of evidence supporting a counter-hypothesis in which calcium does not itself encode specificity but is merely an essential 'switch' in signaling. At the very least, both hypotheses are likely to be true in different situations, and it may well be that the calcium-signature hypothesis describes the exception rather than the rule.     

The biological foundations of culture and morality

Two aspects are discussed: first, the mechanism of learning, and second, the generation of culture and morality. Both aspects are analyzed in relation to the evolution of the mind-brain system. As to the first aspect, I suggest that the use of the concept of innatism requires a re-examination of the genome-dependent effects on the mind-brain system particularly for what concerns the time scale of these effects. The reason is that the information in the genome of the parents is transmitted to the embryo during fertilization of the egg and then into the structures of neuronal cells at the very early stage of ontogenesis, whereas organization of the mind-brain system occurs at a much later time and after an extensive reorganization of the brain structure. The problem is, then, that while during the early stages of the ontogenetic development the neuronal cells maintain their genome determined properties, the full expression of these genome properties within the mind-brain organization undergo fundamental changes which depend not on the properties of the genomic information but rather on the evolution of the operational conditions which are generated in the brain organization and which determine the expression of the genomic potentialities. These operational conditions may become markedly different because of a number of on-going processes due to the formation of new synapses, axons, dendrites and neuronal networks; these phenomena are, to a large extent due to interaction with the environment. Using the Fodor’s language, the effect of the innate properties over the horizontal neuronal networks (the innatism that operates during the whole ontogenesis) assumes a much more important role in the mind-brain than in all other physiological systems. As to the second aspect, I suggest that the development of cultural andmoral worlds are products of the histories of human minds and societies, and depend on the evolutionary nature of these histories.To explain the generation of these worlds I shall discuss a basic problem. How can the neuronal networks of the mind-brain system — usually dealing with phenomena of the natural world and being themselves natural structures obeying the principles and rules of the natural phenomena, where no transition from is to ought or from facts to values is allowed — be able to generate cultural and moral concepts and generate moral behaviours? The solution here proposed is that some sort of modularitydominates in the whole structure of the mind-brain system and that the effect of this modularity is that the neurophysiological processes dealing with the processes of human cultural, moral and social life are structurally associated with emotions, intentions and values. In brief, it is suggested that the mind-brain systems contain, in addition to the division introduced by Fodor, other innate types of neurophysiological processes: some types of processes and of neuronal networks deal with the problems of the natural world and provide answers which are right or wrong, wheras other types of processes and neuronal networks deal with problems of human cultural and social life and provide answers which are adapt on non-adapt.The latter types of neuronal networks are suited to generate the cultural and moral worlds in the course of development and evolution of the Homo sapiens sapiens species and of the single individual. Finally, in view of recent findings on the patterns of mental diseases and the relations of these patterns with alterations of the frontal lobes of the mind brain system, I suggest that the particular types of processes responsible for the moral behaviour of human beings are localized in the frontal lobes. The consequence is that alterations of this type of neurophysiological processes lead to the development of various types of mental diseases.      

Anticodon conformation and accessibility in wild-type and suppressor tryptophan tRNA from E. coli.

The association between Trp-tRNA and Pro-tRNA, which have complementary anticodon sequences, has been used as a probe of anticodon conformation. It is unaffected, however, by the base change in the D-stem present in UGA-suppressor Trp-tRNA. This does not support the hypothesis that UGA suppression depends upon a conformational change induced in the anticodon. The stable denatured form of wild-type Trp-tRNA no longer interacts with Pro-tRNA; the structure of the anticodon region must therefore be quite different in the denatured form.     

Punching above their weight: low-biomass non-native plant species alter soil properties during primary succession

Non‐native invasive plants can greatly alter community and ecosystem properties, but efforts to predict which invasive species have the greatest impacts on these properties have been generally unsuccessful. An hypothesis that has considerable promise for predicting the effects of invasive non‐native plant species is the mass ratio hypothesis (i.e. that dominant species exert the strongest effects). We tested this hypothesis using data from a four year removal experiment in which the presence of two dominant shrub species (one native and the other not), and subordinate plant species, were manipulated in factorial combinations over four years in a primary successional floodplain system. We measured the effects of these manipulations on the plant community, soil nutrient status and soil biota in different trophic levels of the soil food web. Our experiment showed that after four years, low‐biomass non‐native plant species exerted disproportionate belowground effects relative to their contribution to total biomass in the plant community, most notably by increasing soil C, soil microbial biomass, altering soil microbial community structure and increasing the abundance of microbial‐feeding and predatory nematodes. Low‐biomass, non‐native plant species had distinct life history strategies and foliar traits (higher foliar N concentrations and higher leaf area per unit mass) compared with the two dominant shrub species (97% of total plant mass). Our results have several implications for understanding species’ effects in communities and on soil properties. First, high‐biomass species do not necessarily exert the largest impacts on community or soil properties. Second, low‐biomass, inconspicuous non‐native species can influence community composition and have important trophic consequences belowground through effects on soil nutrient status or resource availability to soil biota. Our finding that low‐biomass non‐native species influence belowground community structure and soil properties more profoundly than dominant species demonstrates that the mass ratio hypothesis does not accurately predict the relative effects of different coexisting species on community‐ and ecosystem‐level properties.     

The most common diet results in low reproduction in a generalist seabird

Dietary specialization has been described across a wide range of taxa in the animal kingdom. Fitness consequences are, however, not well documented. We examined the reproductive consequences of different dietary specializations in the herring gull Larus argentatus, an omnivorous seabird, using an extensive dataset which includes breeding and dietary data of 10 successive years. We hypothesized that pairs that focused on prey of higher energetic value would yield higher fledging rates. An alternative hypothesis is that pairs that relied on more resources simultaneously would reproduce better. The novelty of this study is that we used continuous measurements representing dietary composition and degree of specialization rather than restricting our analysis to predefined categories. By relating these two continuous measurements for diet to several proxies for reproductive success, we show clear consequences of dietary choice. Most pairs concentrated on bivalves, a prey type not particularly rich in energy. Pairs feeding on energy‐rich prey (e.g., “domestic refuse and fishery discards”) during chick rearing were found to have a higher reproductive success, supporting the first hypothesis. Pairs that used more resources did not clearly have a higher reproductive success. The majority of the pairs did not switch to energy‐rich prey during chick rearing, despite low breeding outcome. We discuss how trade‐offs between factors such as resource availability, predictability, and the time and energy needed to obtain certain prey species may influence resource selection.     

Phytochemicals and Insect Control: An Antifeedant Approach

Plants based pest control agents have long been touted as alternatives to synthetic chemicals for integrated pest management. Such phytochemicals reputedly pose little threat to the environment or to human health. Bioactivity of plant-based compounds is well documented in literature and is a subject of increasing importance. An antifeedant approach for insect control has been extensively studied, at least at laboratory level, though only a handful of plant-based compounds are currently used in agriculture. The known active plant-based antifeedants belong to groups like chromenes, polyacetylenes, saponins, quassinoids, cucurbitacins, cyclopropanoid acids, phenolics, alkaloids, various types of terpenes and their derivatives etc., and each insect species may process these allomones in a thoroughly idiosyncratic way, so that the same compound may have very different fates and consequences in different species of insects, thus pointing to different mechanisms involved in antifeedant action. It can also be visualized that insect feeding deterrents may be perceived either by stimulation of specialized deterrent receptors or by distortion of the normal function of neurons, which perceive phagostimulating compounds. Some plant antifeedants influence the feeding activity through a combination of these two principal modes of action. Only a few highly active antifeedants have been looked into from a commercial point of view, which makes it impossible to systemize or to predict any molecular motifs in feeding inhibition. Structure activity relationship studies also do not point to any generalization. “Mix and Match” systems may help in developing a cocktail of feeding inhibitors that can be used in developing a customized formulation against a specific category of pests. Application of such products will be broad and will not be limited to targeted pests and to plant parts. Decreased deterrence resulting from habituation has been suggested that could pose different implications for pest management than does decreased deterrence resulting from increased tolerance to toxic substances. Genetically modified plants, which could produce the active antifeedant substances in amounts high enough to protect the plants from further herbivorous damage, could be a possibility in the future.     

A critical look at the embodied cognition hypothesis and a new proposal for grounding conceptual content.

Many studies have demonstrated that the sensory and motor systems are activated during conceptual processing. Such results have been interpreted as indicating that concepts, and important aspects of cognition more broadly, are embodied. That conclusion does not follow from the empirical evidence. The reason why is that the empirical evidence can equally be accommodated by a 'disembodied' view of conceptual representation that makes explicit assumptions about spreading activation between the conceptual and sensory and motor systems. At the same time, the strong form of the embodied cognition hypothesis is at variance with currently available neuropsychological evidence. We suggest a middle ground between the embodied and disembodied cognition hypotheses--grounding by interaction. This hypothesis combines the view that concepts are, at some level, 'abstract' and 'symbolic', with the idea that sensory and motor information may 'instantiate' online conceptual processing.     

Molecular abnormalities in leukemia: the 11q23 story so far

Various hematopoietic malignant disorders have been shown to bear chromosome abnormalities of the 11q23 band, which can be rearranged with many different chromosomal regions in a wide variety of different leukemia subtypes. Several laboratories have identified a trithorax-related gene that is involved in most of the 11q23 abnormalities. Although some patterns and associations between the partner genes are beginning to emerge, it is not yet possible to frame a single unifying hypothesis for 11q23 leukaemic transformation. The aim of this review is to summarise the recent data concerning these 11q23 rearrangements and the understanding of their consequences.     

Evolutionary implication of genetic code deviations

We formulate the following hypothesis: Life's origin may have occurred during the lower Archaean at a time when the environmental temperature was higher than it is at present. Preliminary consequences of this hypothesis are studied from the point of view of molecular evolution. We restrict our attention to implications regarding the genetic code. We conclude that alternative assignment of termination codons may be understood in terms of: (a) the elevated temperatures to which the progenote may initially have been exposed; and (b) the subsequent response of its genome to the opportunity provided by the eventual loss of hyperthermal genetic expression during a thermal transition (TT) period, which was triggered off by the evolution of the dynamic Earth.     

A quantitative threshold for nest-mate recognition in a paper social wasp

Nest-mate recognition is fundamental for protecting social insect colonies from intrusion threats such as predators or social parasites. The aggression of resident females towards intruders is mediated by their cuticular semiochemicals. A positive relation between the amount of cues and responses has been widely assumed and often taken for granted, even though direct tests have not been carried out. This hypothesis has important consequences, since it is the basis for the chemical insignificance strategy, the most common explanation for the reduction in the amount of semiochemicals occurring in many social parasites. Here we used the social wasp Polistes dominulus, a model species in animal communication studies and host of three social parasites, to test this hypothesis. We discovered that different amounts of cuticular hydrocarbons (CHC) of a foreign female evoke quantitatively different behavioural reactions in the resident foundress. The relation between CHC quantity and the elicited response supports the idea that a threshold exists in the chemical recognition system of this species. The chemical insignificance hypothesis thus holds in a host–parasite system of Polistes wasps, even though other explanations should not be discarded.     

Prevalence and penetrance variation of male-killing Wolbachia across Indo-Pacific populations of the butterfly Hypolimnas bolina

Male-killing bacteria are generally thought to attain low to intermediate prevalence in natural populations, with only mild effects on the host population sex ratio. This view was recently challenged by reports of extremely high infection frequencies in three butterfly species, raising the prospect that male killers, by making males rare, might drive many features of host ecology and evolution. To assess this hypothesis, it is necessary to evaluate how often male killers actually produce a highly female-biased population sex ratio in nature, which requires both high prevalence of infection and high penetrance of action. To this end, we surveyed South Pacific and Southeast Asian populations of Hypolimnas bolina, a butterfly in which extreme prevalence of male-killing Wolbachia bacteria has recently been recorded. Our results indicate that highly female-biased populations are common in Polynesia, with 6 out of 12 populations studied having in excess of 70% of females infected with a fully efficient male killer. However, heterogeneity is extreme in Polynesia, with the male-killing Wolbachia absent from three populations. In contrast to the Polynesian situation, Wolbachia does not kill males in any of the three Southeast Asian populations studied, despite its very high prevalence there. We conclude that male killers are likely to have significant ongoing ecological and evolutionary impact in 6 of the 15 populations surveyed. The causes and consequences of the observed spatial variation are discussed with respect to host resistance evolution, host ecology and interference with additional symbionts.     

A kinetic analysis of the changes in membrane permeability induced by fertilization in the egg of the sea urchin Sphaerechinus granularis

Fertilization-induced modifications in egg membrane permeability to labeled adenine and l-leucine substrates have been studied by the initial rate-pulse technique, using the sea urchin Sphaerechinus granularis. Kinetic parameters have been determined for unfertilized eggs as well as for fertilized eggs at various developmental stages. Samples were usually processed according to a centrifuge-wash technique, since Millipore filtration was found to be inadequate in the case of leucine.Several arguments are presented which support the view that the uptake of adenine occurs through a process of simple physical diffusion across the cell membrane. It has been demonstrated, on the other hand, that the transport of l-leucine involves a carrier-mediated exchange-diffusion process.Kinetic data point to the existence of major fluctuations in general egg membrane permeability which appear to be largely independent of the mitotic cycle and of the mechanisms involved in the transport of the substrates studied. A unitary hypothesis is presented to account for these fertilization-induced changes in membrane permeability and which does not involve the synthesis or recruitment of previously inactive carriers.     

An assessment of the impact of hafting on Paleoindian point variability

It has long been argued that the form of North American Paleoindian points was affected by hafting. According to this hypothesis, hafting constrained point bases such that they are less variable than point blades. The results of several studies have been claimed to be consistent with this hypothesis. However, there are reasons to be skeptical of these results. None of the studies employed statistical tests, and all of them focused on points recovered from kill and camp sites, which makes it difficult to be certain that the differences in variability are the result of hafting rather than a consequence of resharpening. Here, we report a study in which we tested the predictions of the hafting hypothesis by statistically comparing the variability of different parts of Clovis points. We controlled for the potentially confounding effects of resharpening by analyzing largely unused points from caches as well as points from kill and camp sites. The results of our analyses were not consistent with the predictions of the hypothesis. We found that several blade characters and point thickness were no more variable than the base characters. Our results indicate that the hafting hypothesis does not hold for Clovis points and indicate that there is a need to test its applicability in relation to post-Clovis Paleoindian points.     

Continuous deep sedation at the end of life and the 'natural death' hypothesis

Surveys in different countries (e.g. the UK, Belgium and The Netherlands) show a marked recent increase in the incidence of continuous deep sedation at the end of life (CDS). Several hypotheses can be formulated to explain the increasing performance of this practice. In this paper we focus on what we call the 'natural death' hypothesis, i.e. the hypothesis that acceptance of CDS has spread rapidly because death after CDS can be perceived as a 'natural' death by medical practitioners, patients' relatives and patients. We attempt to show that the label 'natural' cannot be unproblematically applied to the nature of this end-of-life practice. We argue that the labeling of death following CDS as 'natural' death is related to a complex set of mechanisms which facilitate the use of this practice. However, our criticism does not preclude the view that CDS may be clinically and ethically justified in many cases.