Memory sensitivity improves with larger image size during naturalistic encoding

We have recently found that people remember bigger images more than smaller images during naturalistic-like encoding. Since these findings were established with accuracy levels which may be confounded by response biases, and since memory performance was apparently low, here we addressed these issues. In a new set of experiments (n=199), we estimated accuracy to test replication of our earlier findings, dprime memory-sensitivity that accounts for potential response biases (criterion), and RT-based ROC measures. Our findings, consistent across experiments, that overall memory as estimated by dprime and ROC-based analyses was significantly above chance, indicate that information was encoded and learnt. Furthermore, larger images (in the 3 to15.5 degrees range) were better remembered as evident in dprime and accuracy. Memory for 1.5 degrees images did not differ from that of 3degrees images and memory for images bigger than 15.5 degrees dropped, likely reflecting limitations of display size. Memorability also increased with image size. Our findings provide converging measures supporting the idea that image size plays an important role in image memory during naturalistic encoding for images in the size range of 3 to 15.5 degrees. Our study also emphasizes the importance of testing an effect across multiple measures and methods.