Participants studied naturalistic pictures presented for varying brief durations and then received a recognition test on which they indicated whether each picture was old or new and rated their confidence. In 1 experiment they indicated whether each "old"/"new" response was based on memory for a specific feature in the picture or instead on the picture's general familiarity; in another experiment, we defined pictures that tended to elicit feature versus familiarity responses. Thus, feature/familiarity was a dependent variable in 1 experiment and an independent variable in the other. In both experiments feature-based responses were more accurate than those that were familiarity based, and confidence and accuracy increased with duration for both response types. However, when confidence was controlled for, mean accuracy was higher for familiarity-based than for feature-based responses. The theoretical implication is that confidence and accuracy arise from different underlying information. The applied implication is that confidence differences should not be taken as implying accuracy differences when the phenomenal basis of the memory reports differ.

Using naturalistic scenes, we recently demonstrated that confidence-accuracy relations differ depending on whether recognition responses are based on memory for a specific feature or instead on general familiarity: When confidence is controlled for, accuracy is higher for familiarity-based than for feature-based responses. In the present experiment, we show that these results generalize to face recognition. Subjects studied photographs of scenes and faces presented for varying brief durations and received a recognition test on which they (1) indicated whether each picture was old or new, (2) rated their confidence in their response, and (3) indicated whether their response was based on memory for a feature or on general familiarity. For both stimulus types, subjects were more accurate and more confident for their feature-based than for their familiarity-based responses. However, when confidence was held constant, accuracy was higher for familiaritybased than for feature-based responses. These results demonstrate an important similarity between face and scene recognition and show that for both types of stimuli, confidence and accuracy are based on different information.Keywords Human memory . Face recognition . Recollection . FamiliarityAlthough confidence and accuracy tend to be correlated in recognition memory experiments, the relation is far from perfect. One reason why confidence is not always a good predictor of accuracy is that confidence and accuracy are not always based on the same underlying information. For instance, there is good evidence that metacognitive assumptions sometimes influence confidence in ways that are unrelated to accuracy; for instance, Busey, Tunnicliff, Loftus, and Loftus (2000) found that increasing the luminance of test items in a recognition experiment produced an increase in recognition confidence but no corresponding accuracy increase. The likely reason is that increasing luminance caused the items to become more salient, and subjects assumed that salient items were more likely to be correctly remembered.Reinitz, Peria, Séguin, and Loftus (2011) specifically tested the proposal that accuracy and confidence are based in part on different underlying informational components. Many previous studies have shown that recognition responses are sometimes based on memory for a visual feature, and sometimes on general familiarity. Featurebased responses tend to be more accurate that familiaritybased responses (e.g., Loftus & Bell, 1975;Loftus & Kallman, 1979;Yonelinas, 2002); however, none of these earlier authors measured recognition confidence. Using naturalistic scenes, Reinitz et al. (2011) Psychon Bull Rev (2012) 19:1085-1093 which, in turn, allowed us to produce confidence-accuracy scatterplots, with one point corresponding to each of the 12 response type-duration conditions. Figure 1 includes an example of such a plot, using the natural-scene data from Reinitz et al. (2011). As with all other graphs in this article, up-facing, solid triangles indicate feature-based respons...

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<p>Activation and attention have opposite effects on time perception. Emotion can both increase physiological activation (which leads to overestimation of time) and attract attention (which leads to underestimation of time). Although the effect of emotion on time perception has received a growing amount of attention, the use of different time estimation tasks and stimuli makes it difficult to compare findings across studies. The effect of emotion on the temporal perception of complex stimuli (e.g. scenes) is particularly under-researched. This thesis presents a systematic assessment of the effect of two key emotional dimensions, arousal and valence, on time perception for visual stimuli. Studies were designed to control for factors that may modulate emotion effects, such as image repetition and carry over from one emotion to another. The stimuli were complex images standardized for arousal (high or low) and valence (positive or negative) as well as neutral images. The first study compared three time estimation tasks to determine which were sensitive to emotion effects. The selected task, temporal bisection, was used to test time perception in three duration ranges: short (400 to 1600ms), middle (1000 to 4000ms), and long (2000 to 6000ms). Results of bisection point analyses revealed that the duration of attention-capturing stimuli (e.g. high arousal or negative images) was underestimated compared to that of other stimuli (e.g. low arousal or neutral images). These findings are at odds with activational effects of emotion (overestimation of emotional stimuli), which are typically found in studies of time perception for facial expression. Better temporal sensitivity in the long range than in short and middle ranges suggests that participants used different timing strategies to perform the bisection task at longer stimulus durations. To test the effect of emotion on time perception using a discrete rather than dimensional classification of emotion, experiments were replicated using emotional facial expressions as stimuli. Time estimates in the short and middle ranges did not show attentional effects, but pointed to activational effects of emotion. Facial expression had no impact on time perception in the long duration range. Taken together, these experiments show that the effect of emotion on time perception varies according to both duration and stimulus type. Emotional facial expressions have short lived activational effects whereby the duration of arousing stimuli is overestimated, whereas complex emotional scenes have protracted attentional effects through which the duration of attention-capturing stimuli is underestimated.</p>