Comments on the Institute of Medicine's 2002 report on the safety of anthrax vaccine

In April 2002, the prestigious Institute of Medicine of the National Academy of Sciences issued a final report on the safety and effectiveness of the anthrax vaccine currently in use by the United States military. It concluded that the present vaccine was completely safe and effective, but ignored evidence of several recent research studies from three different nations that have implicated vaccines, often including anthrax vaccine, in the epidemiology of Gulf War illnesses. Omissions and limitations of that report are discussed.     

Age and skilled performance: contributions of working memory and processing speed

In this study, we examined the interrelationships among age, working memory (WM), processing speed, and the development of skilled performance. Younger (M=20.5) and older (M=68.9) adults were trained on an alphabet arithmetic task (Haider & Frensch, 1996) administered across three consecutive days. Although older adults were slower than younger adults, both age groups' response latencies decreased as a result of practice. Contrary to expectations, WM and processing speed were significantly correlated with performance late in training. Partial correlations suggested that age differences in performance at the end of training were mediated by individual differences in cognitive processing speed.     

Emotion-modulated performance and activity in left dorsolateral prefrontal cortex

Functional MRI (fMRI) was used to examine the relationship between processing of pleasant and unpleasant stimuli and activity in prefrontal cortex. Twenty volunteers identified the colors in which pleasant, neutral, and unpleasant words were printed. Pleasant words prompted more activity bilaterally in dorsolateral prefrontal cortex (DLPFC) than did unpleasant words. In addition, pleasant words prompted more activity in left than in right DLPFC. Response speed to pleasant words was correlated with DLPFC activity. These data directly link positive affect, enhanced performance, and prefrontal activity, providing some of the first fMRI evidence supporting models of emotional valence and frontal brain asymmetry based on electroencephalography (EEG).     

Can robots make good models of biological behaviour?

How should biological behaviour be modelled? A relatively new approach is to investigate problems in neuroethology by building physical robot models of biological sensorimotor systems. The explication and justification of this approach are here placed within a framework for describing and comparing models in the behavioural and biological sciences. First, simulation models--the representation of a hypothesis about a target system--are distinguished from several other relationships also termed "modelling" in discussions of scientific explanation. Seven dimensions on which simulation models can differ are defined and distinctions between them discussed: 1. Relevance: whether the model tests and generates hypotheses applicable to biology. 2. Level: the elemental units of the model in the hierarchy from atoms to societies. 3. Generality: the range of biological systems the model can represent. 4. Abstraction: the complexity, relative to the target, or amount of detail included in the model. 5. Structural accuracy: how well the model represents the actual mechanisms underlying the behaviour. 6. Performance match: to what extent the model behaviour matches the target behaviour. 7. Medium: the physical basis by which the model is implemented. No specific position in the space of models thus defined is the only correct one, but a good modelling methodology should be explicit about its position and the justification for that position. It is argued that in building robot models biological relevance is more effective than loose biological inspiration; multiple levels can be integrated; that generality cannot be assumed but might emerge from studying specific instances; abstraction is better done by simplification than idealisation; accuracy can be approached through iterations of complete systems; that the model should be able to match and predict target behaviour; and that a physical medium can have significant advantages. These arguments reflect the view that biological behaviour needs to be studied and modelled in context, that is, in terms of the real problems faced by real animals in real environments.     

Distinguishing indeterminate belief from “risk-averse” preferences

I focus my discussion on the well-known Ellsberg paradox. I find good normative reasons for incorporating non-precise belief, as represented by sets of probabilities, in an Ellsberg decision model. This amounts to forgoing the completeness axiom of expected utility theory. Provided that probability sets are interpreted as genuinely indeterminate belief (as opposed to “imprecise” belief), such a model can moreover make the “Ellsberg choices” rationally permissible. Without some further element to the story, however, the model does not explain how an agent may come to have unique preferences for each of the Ellsberg options. Levi (1986, Hard choices: Decision making under unresolved conflict. Cambridge, New York: Cambridge University Press) holds that the extra element amounts to innocuous secondary “risk” or security considerations that are used to break ties when more than one option is rationally permissible. While I think a lexical choice rule of this kind is very plausible, I argue that it involves a greater break with xpected utility theory than mere violation of the ordering axiom.     

Active avoidance conditioning in zebrafish (Danio rerio)

The zebrafish represents a potentially useful organism for studying genes involved in learning and memory function in vertebrates, because a number of genetic techniques in zebrafish have been developed to produce a wide variety of genetic mutants. While zebrafish mutants are being developed, behavioral studies on learning and memory function in zebrafish are in urgent need. The present study investigated active avoidance conditioning in normal zebrafish. Zebrafish were trained to swim from a lighted (CS) compartment to a dark compartment to avoid an electrical body shock (US) in a shuttle-box that consisted of a water-filled tank separated by an opaque barrier into two equal compartments. By varying the number of trials per training session and the duration of the intertrial interval, Experiments 1 and 2 showed that, with the CS, US, and intertrial interval being 12s, zebrafish learned avoidance responses within a training session consisting of 30 trials and retained the avoidance responses. Experiment 3 showed that zebrafish learned avoidance responses following the association between the CS of light and the US of shock in the avoidance conditioning paradigm. Using the avoidance conditioning paradigm, Experiment 4 investigated the amnestic effects of N-methyl-D-aspartate receptor antagonist MK-801 and nitric oxide synthase inhibitor L-NAME in zebrafish. Experiment 4 showed that post-training injection of L-NAME significantly impaired retention of avoidance responses while MK-801 did not, confirming previous results with other vertebrates. The results of the present study suggest the similar involvements of neurochemicals in learning and memory among vertebrates. Thus, future studies with zebrafish mutants may identify genes involved in learning and memory in vertebrates.     

The contributory role of worry in emotion generation and dysregulation in generalized anxiety disorder

The role of worry in generalized anxiety disorder (GAD) has been posited to serve as an avoidance of emotional experience, and emotion regulation deficits in GAD have been found in several previous studies. It remains unclear whether those with GAD experience more dysregulated emotions during periods of euthymia and positive affect or whether these deficits occur only during periods of worry. Individuals with GAD (with and without co-occurring dysphoria) and non-anxious controls were randomly assigned to receive a worry, neutral, or relaxation induction. Following the induction, all participants viewed a film clip documented to elicit sadness. Intensity of emotions and emotion regulation were examined following the induction period and film clip. The results revealed that, regardless of co-occurring dysphoria, individuals with GAD in the worry condition experienced more intense depressed affect than GAD participants in the other conditions and controls participants. In contrast, presence of worry appeared to have less impact on indices of emotion dysregulation, which were greater in participants with GAD compared to controls, but largely insensitive to contextual effects of worry or of relaxation. Following film viewing, both GAD participants with and without dysphoria displayed poorer understanding, acceptance, and management of emotions than did controls. However, acceptance and management deficits were most pronounced in individuals with both GAD and co-occurring dysphoria. Implications for the role of emotions in conceptualization and treatment of GAD are discussed.     

Evidence for kind representations in the absence of language: experiments with rhesus monkeys (Macaca mulatta)

How do we come to recognize and represent different kinds of objects in the world? Some developmental psychologists have hypothesized that learning language plays a crucial role in this capacity. If this hypothesis were correct, then non-linguistic animals should lack the capacity to represent objects as kinds. Previous research with rhesus monkeys (Macaca mulatta) has shown that this species can successfully individuate different kinds of objects - monkeys who saw one kind of object hidden inside a box searched longer after finding a different kind of object. However, in these studies and the infant studies on which they were based, the objects to be individuated differed both in kind and in properties. Thus, subjects in these experiments may not be representing the kinds of objects per se, but instead only their immediate perceptual properties. Here, we show that rhesus monkeys successfully individuate different kinds of objects even when their perceptual properties are held constant. Although these data provide the best evidence to date that language is not necessary to represent kinds, we discuss our findings in terms of possible associative hypotheses as well.     

The Erotic Eucharist

Pope Benedict XVI's encyclical Deus Caritas Est continues the magisterium's twentieth‐century shift from an act‐oriented, procreative approach to sexual ethics to what I will term a heterosexually personalistic one. Situating a heterosexual anthropology within a heterosexual cosmology, Benedict argues that just as God loves humanity with heterosexual eros, so must human beings love each other heterosexually. Although Benedict depends upon the explanatory power of heterosexuality, he perhaps unwittingly ends up depicting God's love not as iconically heterosexual, but as queer. In casting God's love as queer, I do not, even analogously, impute to God a type of homosexuality as Benedict does a heterosexuality. Instead, by drawing attention to the discursive specificity and historical instability of both homosexuality and heterosexuality, I use “queer” to recognize God's love as beyond categorization and as strange; it cannot be corralled into or contained by the historically specific notions of heterosexual and homosexual. But this essay does not merely deconstruct Benedict's heterosexually personalistic cosmology. It uncovers in Benedict's Eucharistic transfiguration of marital love a new and promising way of situating discussions about the ethics of sex.