Modulation of defensive reflexes by contextual cues: Effect of environmental light-darkness

María Sánchez, María Carmen Fernández, Francisca López, Jaime Vila


The results of a study aimed to examine the effect of manipulating environmental lightdarkness on the amplitude of two defensive reflexes -the startle motor reflex and the cardiac defense response- are presented. Using a between group design, four light levels were manipulated: complete darkness (0 Lux), penumbra (11 lux), medium light (175 lux) and intense light (1225). 60 volunteer student women participated in the study (15 per group). Both reflexes were examined, presenting a white noise of 105 dB, 500 millisecond duration and instantaneous risetime five occasions. The results show a potentiation of the cardiac defense response under conditions of darkness-penumbra, as compared to conditions of medium-intense light. These results are discussed under of Peter J. Lang's motivational priming theory and the neurophysiological differentiation between fear and anxiety.


Startle; defense; heart rate; electromyography; fear; anxiety



  • There are currently no refbacks.

Copyright (c) 2015 Facultad de Psicología. Servicio de Psicología Aplicada.

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Attribution-NonCommercial  (CC BY-NC)This license lets others remix, tweak, and build upon your work non-commercially, and although their new works must also acknowledge you and be non-commercial, they don’t have to license their derivative works on the same terms.


Accion Psicologica

Applied Psychology Service (SPA), Faculty of Psychology (UNED).

C/ Juan del Rosal nº 10 28040 Madrid.


eISSN: 2255-1271