Table 2.

Mean ± SD of accuracy and reaction time (msec) on 2BT

Measure	Placebo	Nicotine
Smokers (n = 11)
PCT correct†	88.3  ± 4.3	89.9  ± 5.5*
PCT incorrect‡	11.2  ± 4.6	9.8  ± 5.3*
RT all§	456.3  ± 78.7	431.7  ± 59.8
SD-RT all¶	96.9  ± 29.7	85.7  ± 19.3
RT c‖	529.6  ± 118.0	517.4  ± 121.3
SD-RT c**	162.8  ± 41.9	149.2  ± 30.1*
Ex-smokers (n = 11)
PCT correct	89.0  ± 9.1	85.5  ± 15.6
PCT incorrect	12.4  ± 7.5	10.7  ± 6.6
RT all	447.7  ± 80.5	440.3  ± 76.3
SD-RT all	106.6  ± 41.3	92.2  ± 27.0
RT c	481.9  ± 137.1	512.4  ± 128.2
SD-RT c	151.7  ± 62.5	157.6  ± 59.5

^*, P < 0.05, placebo vs. nicotine. 

^† Percentage of correct responses. 

^‡ Percentage of incorrect responses. 

^§ Reaction time to all stimuli. 

^¶ Variability (SD) of reaction time to all stimuli. 

^‖ Reaction time to correct responses. 

^**Variability (SD) of reaction time to correct responses.