Recreational cocaine use is associated with attenuated latent inhibition.

INTRODUCTION: Evidence has linked chronic cocaine use with various cognitive deficits; however few studies have investigated the effects of recreational (non-dependent) use. The present study aimed to assess whether recreational users show deficits in latent inhibition (LI: a measure of delayed learning of an association between 2 stimuli, one of which has been previously exposed (PE) without consequence and thus deemed irrelevant). METHODS: Using a quasi-experimental between groups design, recreational cocaine users (n = 21), poly-drug users (n = 17) and drug-naive controls (n = 18) were compared on a LI task. Questionnaires assessing psychological health and drug use were also completed. RESULTS: There was a statistically significant interaction between condition (PE vs non PE) and group (cocaine, polydrug and control); cocaine users scored lower in the PE condition compared to polydrug users and controls, indicating quicker learning. CONCLUSIONS: Recreational cocaine users show attenuated LI reflecting reduced ability to filter out irrelevant stimuli enabling faster learning of a PE irrelevant and novel stimuli association. This does not appear to be a result of schizotypy and/or other drug use. Thus even at recreational levels, cocaine use may be sufficient to affect inhibitory attentional processes.

The little known Mineral and Chemical History of Iron and A History of Brass by an eighteenth-century technologist, William Lewis (1708-1781).

Sometime during the 1920s, Cardiff Public Libraries (later to become Cardiff Central Library) acquired a six-volume handwritten manuscript collection entitled Mineral & Chemical History of Iron. The author of the manuscripts is named as William Lewis. Now uniformly bound in half-leather and cloth boards, this impressive holding provides, in more than a thousand handwritten pages, an early attempt to produce a full-scale treatise in English on the history of iron.' This note traces the route by which the collection reached Cardiff, and also presents evidence for the existence of a hitherto unknown work on the history of brass by the same author.