From “satisfaction of search” to “subsequent search misses”: a review of multiple-target search errors across radiology and cognitive science

For over 50 years, the satisfaction of search effect has been studied within the field of radiology. Defined as a decrease in detection rates for a subsequent target when an initial target is found within the image, these multiple target errors are known to underlie errors of omission (e.g., a radiologist is more likely to miss an abnormality if another abnormality is identified). More recently, they have also been found to underlie lab-based search errors in cognitive science experiments (e.g., an observer is more likely to miss a target ‘T’ if a different target ‘T’ was detected). This phenomenon was renamed the subsequent search miss (SSM) effect in cognitive science. Here we review the SSM literature in both radiology and cognitive science and discuss: (1) the current SSM theories (i.e., satisfaction, perceptual set, and resource depletion theories), (2) the eye movement errors that underlie the SSM effect, (3) the existing efforts tested to alleviate SSM errors, and (4) the evolution of methodologies and analyses used when calculating the SSM effect. Finally, we present the attentional template theory, a novel mechanistic explanation for SSM errors, which ties together our current understanding of SSM errors and the attentional template literature.

A novel, unbiased approach to evaluating subsequent search misses in dual target visual search

Research in radiology and visual cognition suggest that finding one target during visual search may result in increased misses for a second target, an effect known as subsequent search misses (SSM). Here, we demonstrate that the common method of calculating second-target detection performance is biased and could produce spurious SSM effects. We describe the source of that bias and document factors that influence its magnitude. We use a modification of signal-detection theory to develop a novel, unbiased method of calculating the expected value for dual-target performance under the null hypothesis. We then apply our novel method to two of our data sets that showed modest SSM effects when calculated in the traditional manner. Our correction reduced the effect size to the point that there was no longer a significant SSM effect. We then applied our method to a published data set that had a larger effect size when calculated using the traditional calculation as well as when using an alternative calculation that was recently proposed to account for biases in the traditional method. We find that both the traditional method and the recently proposed alternative substantially overestimate the magnitude of the SSM effect in these data, but a significant SSM effect persisted even with our calculation. We recommend that future SSM studies use our method to ensure accurate effect-size estimates, and suggest that the method be applied to reanalyze published results, particularly those with small effect sizes, to rule out the possibility that they were spurious.

Object working memory load and perceptual similarity in visual search for multiple targets

Subsequent search misses can occur during visual search for several targets. SSM is a decrease in accuracy at finding a second target after successful detection of a first one. Two experiments investigated the effect of object working memory load, target stimuli similarity and the similarity of stimuli in visual search task and working memory tasks on the SSM. It was found that targets perceptual similarity is significant, as well as memory load in case of working memory task and visual search task stimuli similarity. In addition, we found a significant interaction between working memory load and number of shared features between two target stimuli, which may indicate a common mechanism underlying the role of working memory load and perceptual similarity factors.

Stimuli similarity in subsequent search misses

The role of targets categorical similarity in subsequent search misses (SSM) effect, which assumes second target omission after the first target was found in visual search task, was observed. Participant’s task was to search for the targets (even or odd digits) among distracters (odd or ever digits, respectively). On each trial, it could be two, one or no targets. In dual target condition, the targets could be equal digits or different. 22 participants were tested, mean age — 18.73. Accuracy at detecting the second target after the first one was found was compared. Targets similarity had the significant effect on second target detection performance, F (1, 30) = 9.69, p = 0.002, ηp2 = 0.316, and on the search time, F (1, 31) = 28.29, p < 0.000, ηp2 = 0.574. In two dissimilar targets condition the participants missed the second target more often and found it slowly as compared to two similar targets condition. The results are discussed in the context perceptual set and resource depletion theories.