PROBING AFFECTIVE PICTURES - ATTENDED STARTLE AND TONE PROBES

Reflexive eyeblinks to a startle probe vary with the pleasantness of a ffective pictures, whereas the corresponding P300 varies with emotiona l arousal. The impact of attention to the probe on these effects was e xamined by varying task and probe type. Probes were either nonstartlin g tones or startling noises presented during affective picture viewing . Half the participants performed a task requiring attention to the pr obes; the other participants were told to ignore the probes. Blinks to the startle probe varied with picture pleasantness for both task and nontask conditions. In contrast, P300 magnitudes for both startle and tone probes were reduced during emotionally arousing pictures, irrespe ctive of pleasantness, in task and nontask conditions. Further attendi ng to the startle probe prompted an augmentation of N100 during unplea sant pictures. The data suggest that affective modulation of probe res ponses reflects obligatory processes in picture perception.