Flexible target templates improve visual search accuracy for faces depicting emotion

Good-enough attentional guidance

Theories of attention posit that attentional guidance operates on information held in a target template within memory. The template is often thought to contain veridical target features, akin to a photograph, and to guide attention to objects that match the exact target features. However, recent evidence suggests that attentional guidance is highly flexible and often guided by non-veridical features, a subset of features, or only associated features. We integrate these findings and propose that attentional guidance maximizes search efficiency based on a 'good-enough' principle to rapidly localize candidate target objects. Candidates are then serially interrogated to make target-match decisions using more precise information. We suggest that good-enough guidance optimizes the speed-accuracy-effort trade-offs inherent in each stage of visual search.

Long-term memory interference is resolved via repulsion and precision along diagnostic memory dimensions

When memories share similar features, this can lead to interference, and ultimately forgetting. With experience, however, interference can be resolved. This raises the important question of how memories change, with experience, to minimize interference. Intuitively, interference might be minimized by increasing the precision and accuracy of memories. However, recent evidence suggests a potentially adaptive role for memory distortions. Namely, similarity can trigger exaggerations of subtle differences between memories (repulsion). Here, we tested whether repulsion specifically occurs on feature dimensions along which memories compete and whether repulsion is predictive of reduced memory interference. To test these ideas, we developed synthetic faces in a two-dimensional face space (affect and gender). This allowed us to precisely manipulate similarity between faces and the feature dimension along which faces differed. In three experiments, participants learned to associate faces with unique cue words. Associative memory tests confirmed that when faces were similar (face pairmates), this produced interference. Using a continuous face reconstruction task, we found two changes in face memory that preferentially occurred along the feature dimension that was "diagnostic" of the difference between face pairmates: (1) there was a bias to remember pairmates with exaggerated differences (repulsion) and (2) there was an increase in the precision of feature memory. Critically, repulsion and precision were each associated with reduced associative memory interference, but these were statistically dissociable contributions. Collectively, our findings reveal that similarity between memories triggers dissociable, experience-dependent changes that serve an adaptive role in reducing interference.

Sharper attentional tuning with target templates in long-term compared to working memory

Theories of attention postulate the existence of an attentional template containing target features in working or long-term memory. Previous research has shown that these internal representations of target features in memory are shifted away from nontarget features and that attention is tuned to the shifted feature especially when the target appeared with similar nontarget items. While previous studies have shown that the target-nontarget relationship has influence on the attentional selection and the representation shift when attentional template is maintained in long-term memory, there is little evidence for such effects when attentional template is stored in working memory. To address this issue, we asked participants to search for a target, which varied from trial to trial (working memory attentional template), or look for the target being stable across trials (long-term memory attentional template). We found that the shifted target features captured attention and that the representations of target features were deviated away from nontarget features when the target template was stored in either working memory or long-term memory. However, such effects were found to be greater for the attentional template in long-term memory. The present results provide evidence that one can encode the target-nontarget relationship even though the target varies from trial to trial, and such contextual information influences attentional selection and target representation shift even under this dynamically changing environment.