Effects of ethanol and promethazine on awareness of errors and judgements of performance
Kim Acons1,
Li-San Chan1,
Gordon Drummond2,
Brian Tiplady2*
1 Division of Neuroscience, University of Edinburgh, Edinburgh, UK
2 Division of Anaesthesia, Critical Care and Pain Medicine, University of
Edinburgh, Edinburgh, UK
* To whom correspondence should be addressed.
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Abstract |
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Ethanol may affect detection and processing of errors in performance tasks, and
thus influence the speed accuracy trade-off. In this double-blind study, 11 volunteers,
(seven female, four male) took part in four sessions in which they received ethanol
(Eth; mean blood alcohol concentration at 60 min: 87.3, SD: 18.4), placebo (Pla),
promethazine 20 mg (P20) and 30 mg (P30) in randomized order. A computerized four choice
reaction time test (FCRT), other performance measures and visual analogue scales (VAS)
were administered before dosing and at intervals up to 2.5 h after. During the FCRT
volunteers reported errors verbally. These reports were recorded together with error
signals from the computer. The overall pattern of effects was as expected for Eth, with
increases in errors for most tasks, and subjective drowsiness. P30 affected only the
FCRT, and both P30 and P20 caused drowsiness. The number of errors made by the
volunteers in the FCRT was significantly increased for both Eth (N = 5.20, p
< 0.01) and P30 (N = 3.81, p < 0.01) compared to Pla (1.84) with
no significant change in response speed. The proportion of errors detected was slightly
but not significantly reduced (Pla 68%, Eth 63%, P30 57%). These results show that error
processing is not significantly impaired by ethanol, and a reduction in awareness of
errors cannot account for the increased errors which occur when performance is impaired
by ethanol.
Key Words:
ethanol, promethazine, speed-accuracy tradeoff, error detection
