# Replacing the Classics? A Comparison of the ERPs Evoked by IAPS and OASIS Images During Emotional Processing

## TL;DR

This study compares how two image sets, IAPS and OASIS, affect brain responses during emotional processing, finding that both elicit similar emotional reactions.

## Contribution

The study directly compares ERP responses to IAPS and OASIS images, revealing differences in neural processing during emotional tasks.

## Key findings

- Emotional OASIS images elicited larger Cue-P300 amplitudes than IAPS images.
- Both IAPS and OASIS images produced a robust LPP modulation, with IAPS showing a stronger effect for unpleasant images.
- Self-reported emotional ratings were similar across IAPS and OASIS images.

## Abstract

Emotional visual stimuli presented in laboratory settings reliably elicit prototypical patterns of subjective and psychophysiological responses. These responses likely serve distinct functions and reflect the engagement of appetitive and defensive motivational systems, making them a valuable tool for examining emotional processing in both healthy individuals and those with mental disorders. Event‐related potentials (ERPs), such as the Cue‐P300, Stimulus Preceding Negativity (SPN), and Late Positive Potential (LPP), provide valuable temporal insight into anticipatory and elaborative stages of emotional processing. While these components have been extensively studied using the International Affective Picture System (IAPS), concerns about its dated content have prompted the development of alternative image sets, such as the Open Affective Standardized Image Set (OASIS). Yet, ERP responses to OASIS images remain underexplored. This study aimed to compare psychophysiological and subjective responses elicited by images from the IAPS and OASIS databases, matched for valence and arousal. Twenty‐three participants completed two emotional S1–S2 tasks—one using IAPS images and the other using OASIS images—while undergoing EEG recording. In each task, a cue (S1) predicted the valence (pleasant, neutral, unpleasant) of an upcoming emotional image (S2). The SPN, Cue‐P300, and the LPP components were analyzed. Results revealed that emotional (pleasant, unpleasant) OASIS images elicited larger Cue‐P300 amplitudes than IAPS emotional images, whereas no SPN component was observed for either database. In addition, both IAPS and OASIS images elicited a robust LPP modulation, with this effect more pronounced for IAPS than OASIS unpleasant images. Together, these results indicate that both IAPS and OASIS images elicit the expected emotional responses. Self‐reported ratings were similar across the two databases, alongside the LPP modulation by emotional content. Although further research is needed to clarify how image selection may influence emotional anticipation, the integration of the two databases appears to be a future viable approach.

This study provides novel insights about the role of stimulus selection in shaping neural and subjective responses during different emotional processing stages. By directly comparing event‐related potentials elicited by two standardized image sets—the International Affective Picture System (IAPS) and the more recent Open Affective Standardized Image Set (OASIS)—the findings indicate that both image sets elicit the expected emotional responses at the elaboration stage, suggesting that the integration of the two databases might be a future approach in studies employing emotional pictures. However, further research is needed to clarify whether they also elicit similar anticipatory processes.