Scene identification and emotional response: which spatial frequencies are critical ?

Emotional responses are regulated by basic motivational systems (appetitive and defensive), which allow for adaptive response to opportunities and threats in the environment once they are detected. Detection of an emotional stimulus depends on scene identification, which is achieved through the interaction of bottom-up and top-down processes. Recently, it has been suggested that an emotional response can be preferentially elicited, based on low spatial frequencies. However, it is unclear whether spatial frequency information may allow to distinguish emotional from non-emotional scenes. The present study aimed at examining the role of low and high spatial frequencies in the affective modulation of the late positive potential (LPP), a well-known event-related potentials (ERPs) signature of emotional processing. To this end, the content of an initial degraded (low- or high-passed) picture was progressively revealed in a sequence of 16 successive steps by adding high or low spatial frequencies to the initial degraded picture. Participants responded as to whether they identified the gist of the image. Results showed that LPP affective modulation varied with picture identification, similarly for low-passed and high-passed pictures. Emotional response, indexed by the LPP, did not critically depend on the availability of either low or high spatial frequencies.