Abstract:

Previous research has suggested that faces can produce robust conjunction and feature effects at item recognition in the feature-conjunction paradigm. However, whether such two effects are affected when the task and contextual details are manipulated, has not been described yet. Also, the contribution of external facial features versus internal facial features to feature effect needs further exploration. Thus, the first goal of the present study was to investigate to what extent that the two effects were affected by task type (the two aspects of episodic memory, i.e., item recognition and source retrieval) for unfamiliar faces in the feature-conjunction paradigm. The second goal was to explore the interaction between the consistency of presentation location and task type. Third, we would study the possible difference between external facial features and internal facial features in the case of feature effect. Thirty-one subjects participated in this experiment. The formal stimuli were 720 headshots of unfamiliar individuals, half male and half female. In the study stage, subjects were asked to learn some unfamiliar faces that were either presented on the left side or on the right side of the screen. In the test stage, five types of faces were displayed, left or right: old faces, conjunction faces, old external feature faces, old internal feature faces, and totally new faces; and two types of tasks were randomly presented: the item recognition task during which subjects only had to make old/new judgments, and the source retrieval task which required an additional discrimination towards the location of old faces (i.e., subjects were instructed to differentiate the old faces that were displayed on the same location between study and test from the old faces on different locations and other faces). The results showed that both tasks elicited robust conjunction effect and feature effect for faces, but they were larger in source retrieval task. The interaction between location consistency and task type was significant in terms of memory performance: At recognition, location consistency facilitated both effects, while no such facilitation was observed at source retrieval. The feature effect in old external faces was similar to that in internal feature faces. These results strongly demonstrate that both conjunction effect and feature effect are sensitive to task type, and suggests an important role of high familiarity compared with recollection in such two effects, consistent with the dual-process model. The discrimination of conjunction and feature faces is regulated by the interaction of whether the presentation location is consistent or not between study and test and task type. Additionally, old external facial features and old internal facial features play similar roles in the contribution to feature effect.

Key words: conjunction effect, feature effect, task type, recognition, source retrieval, face