The effects of eyelid closure on affective imagery and eyeblink startle

A number of recent investigations have demonstrated affective modulation of the eyeblink startle response during emotional imagery. The present study investigated the effects of eyelid position on imagery vividness baseline EMG and startle responses among 24 undergraduate participants in an affective imagery paradigm. Startles were reliably larger during negatively valent and highly arousing imagery regardless of eyelid position and lid position had no effect on rated imagery vividness. Baseline EMG was higher and startle latencies were reduced with eyes closed as well as during high arousal imagery. Statistical partialing of baseline EMG levels suggested that the latency effects - but not the magnitude effects - were mediated by changes in tonic contraction of orbicularis oculi. Recommendations are made for future research that uses imagery to explore the affective modulation of startle.