Emotional modulation of the startle reflex in twins: Preliminary findings

Scott R. Carlson, Joanna Katsanis, William G. Iacono, Matt McGue

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


This study investigated twin similarity in general startle reflex reactivity and emotional modulation. Seventeen monozygotic (MZ) and 12 dizygotic (DZ) male twin pairs received startling acoustic stimuli while viewing emotionally positive, negative and neutral slides. Electromyographic (EMG) responses were recorded from the orbicularis oculi. Members of MZ twin pairs had similar response amplitudes under all three valence conditions. In addition, modulation scores for the positive and negative conditions, representing the percent change in response amplitude between the affective and the neutral conditions, also showed significant similarity within MZ twin pairs. Overall, members of DZ twin pairs were not found to be significantly similar on any of the measures. These preliminary findings suggest that emotional modulation of the startle reflex shows familial resemblance within MZ pairs. Given the lack of resemblance between DZ twins, it is tentatively suggested that affective modulation may be under partial genetic control.

Original languageEnglish (US)
Pages (from-to)235-246
Number of pages12
JournalBiological Psychology
Issue number3
StatePublished - Oct 10 1997


  • Affect
  • Blink reflex modification
  • Electromyography
  • Emotion
  • Startle
  • Twin studies

ASJC Scopus subject areas

  • General Neuroscience
  • Neuropsychology and Physiological Psychology


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