Table 1.

Inclusion and exclusion criteria for smokers and non-smokers.

Inclusion criteria

Aged 18–50 years

Fluent in English

Have a working telephone

Smokers

Smoke ≥5 cigarettes per day

Baseline expired carbon monoxide (CO) level >6 parts per million (ppm)

Non-smokers

Smoked <100 cigarettes in their lifetime

Baseline expired CO level <4 ppm

Exclusion criteria

Current psychiatric disorder (within 6 months, as established by self-report)

Current substance abuse (with the exception of smoking)

Current participation in a formal smoking-cessation activity

Current use of non-cigarette tobacco products (e.g., pipe tobacco, cigars, snuff, chewing  tobacco, and hookah)

Currently pregnant or breast-feeding

Use of psychotropic medication or illicit drug use (within 30 days)

History of seizures or a seizure disorder

A head injury with a loss of consciousness

Visual or auditory problems