HUMAN COGNITION

Human Cognition

Human Cognition

Hegel's own pithy account of the nature of philosophy given in the "Preface" to his Elements of the Philosophy of Right captures a characteristic tension in his philosophical approach and, in particular, in his approach to the nature and limits of human cognition. "Philosophy", he says there, "is its own time raised to the level of thought".

On the one hand we can clearly see in the phrase "its own time" the suggestion of a historical or cultural conditionedness and variability which applies even to the highest form of human cognition, philosophy itself -- the contents of philosophical knowledge, we might suspect, will come from the historically changing contents of contemporary culture.

It is well established that nicotine has a very important role in tobacco use (Russell and U). A dose of nicotine can have effects on mood, arousal, and cognition in humans, and these psychological effects may promote and sustain tobacco use in humans through either direct reinforcement or relief of withdrawal (Stolerman, 1991). Previous research has described these psychological effects in psychopharmacological terms (e.g., dose-response relationships). Different nicotine delivery devices (e.g., cigarettes, subcutaneous injection, and nasal spray) have been used in different subject groups (e.g., nicotine-deprived smokers and never-smokers). Factors which can affect the size of a given effect have also been examined (e.g., acute tolerance). Given that basic data on nicotine's psychological effects have now been collected, we examine here a new question: are nicotine's acute effects on the different psychological dimensions direct effects, or is an effect on one dimension mediated through effects on other dimensions (i.e., “indirect” effects)?

To address this question, we shall note the large number of factors which can potentially affect the size of a given effect of nicotine. We also acknowledge the difficulties in interpreting whether these effects represent psychological benefits when nicotine is administered to smokers. But our main focus is the interrelationships between the effects. In particular, given that we know from the discipline of psychology that the dimensions of mood, arousal, and cognition represent interacting constructs in humans, how can we know whether a nicotine effect on one dimension is a direct effect, or an indirect effect from another dimension, or both? To examine this question in detail, we choose to focus on the question of whether the cognitive effects of nicotine are direct effects, or whether they are mediated by nicotine's effects on mood and arousal. We outline five ways in which direct and indirect effects can be distinguished. En route, we suggest some experimental ideas. Finally, we address the analogous issue for nicotine withdrawal. First, to gain a foothold on these issues, we briefly review some of the recent literature documenting nicotine's psychological effects in humans.

If there are positive effects on mood and arousal as well as cognition, interpretation is more difficult. There may be just a direct route to cognition, just an indirect route (via mood and/or arousal), or both direct and indirect routes. However, one could distinguish between these models by examining ...