We examined emotional memory enhancement (EEM) for negative and positive pictures while manipulating encoding and retrieval conditions. Two groups of 40 participants took part in this study. Both groups performed immediate implicit (categorization task) and explicit (recognition task) retrieval, but for one group the tasks were preceded by incidental encoding and for the other group by intentional encoding. As indicated by the sensitivity index (d'), after incidental encoding positive stimuli were easier to recognize than negative and neutral stimuli. Participants' response criterion was more liberal for negative stimuli than for both positive and neutral ones, independent of encoding condition. In the implicit retrieval task, participants were slower in categorizing positive than negative and neutral stimuli. However, the priming effect was larger for emotional than for neutral stimuli. These results are discussed in the context of the idea that the effect of emotion on immediate memory enhancement may depend on the intentionality to encode and retrieve information.

In the present study we examined whether categorization difficulty regarding a food is related to its likability. For this purpose, we produced stimulus images by morphing photographs of a tomato and a strawberry. Subjects categorized these images as either a tomato or a strawberry and in separate sessions evaluated the food's eatability or the subject's willingness to eat (Experiments 1 and 2) and the likeliness of existence of each food (Experiment 2). The lowest score for ca- tegorization confidence coincided with the lowest scores for eatability, willingness to eat, and likeliness of existence. In Experiment 3, we found that food neophobia, a trait of ingestion avoidance of novel foods, modulated food likability but not categorization confidence. These findings suggest that a high categorization difficulty generally co-occurs with a decrease in food likability and that food neophobia modulates likability. This avoidance of difficult-to-categorize foods seems ecologically valid because before eating we have little information regarding whether a food is potentially harmful.

The contributions of feature recognition, object categorization, and recollection of episodic memories to the re-identification of a perceived object as the very same thing encountered in a previous perceptual episode are well understood in terms of both cognitive-behavioral phenomenology and neurofunctional implementation. Human beings do not, however, rely solely on features and context to re-identify individuals; in the presence of featural change and similarly-featured distractors, people routinely employ causal constraints to establish object identities. Based on available cognitive and neurofunctional data, the standard object-token based model of individual re-identification is extended to incorporate the construction of unobserved and hence fictive causal histories (FCHs) of observed objects by the pre-motor action planning system. It is suggested that functional deficits in the construction of FCHs are associated with clinical outcomes in both autism spectrum disorders and later-stage stage Alzheimer's disease.

The effect of the emotional quality of study-phase background music on subsequent recall for happy and sad facial expressions was investigated. Undergraduates (N = 48) viewed a series of line drawings depicting a happy or sad child in a variety of environments that were each accompanied by happy or sad music. Although memory for faces was very accurate, emotionally incongruent background music biased subsequent memory for facial expressions, increasing the likelihood that happy faces were recalled as sad when sad music was previously heard, and that sad faces were recalled as happy when happy music was previously heard. Overall, the results indicated that when recalling a scene, the emotional tone is set by an integration of stimulus features from several modalities.

We investigated influences of item generation and emotional valence on retrieval-induced forgetting. Drawing on postulates of the three-factor theory of generation effects, generation tasks differentially affecting the processing of inter-item relations were applied. Whereas retrieval-induced forgetting of freely generated items was moderated by the emotional valence as well as retrieval-induced forgetting of read items, even though in the reverse direction (Experiment 1), fragment completion eliminated the moderation of retrieval-induced forgetting by emotional valence (Experiment 2). The results corroborate the assumption that the processing of inter-item relations is crucial for the immunization against retrieval-induced forgetting. Moreover, differential processing of inter-item relations may clarify the mixed results on moderating factors of retrieval-induced forgetting that have been reported.

Semantic priming refers to the phenomenon that participants typically respond faster to targets following semantically related primes as compared to semantically unrelated primes. In contrast, Wentura and Frings (2005) found a negatively signed priming effect (i.e., faster responses to semantically unrelated as compared to semantically related targets) when they used (a) a special masking technique for the primes and (b) categorically related prime-target-pairs (e.g., fruit-apple). The negatively signed priming effect was most pronounced for participants with random prime discrimination performance, whereas participants with high prime discrimination performance showed a positive effect. In the present study we analyzed the after-effects of masked category primes in audition. A comparable pattern of results as in the visual modality emerged: The poorer the individual prime discrimination, the more negative is the semantic priming effect. This result is interpreted as evidence for a common mechanism causing the semantic priming effect in vision as well as in audition instead of a perceptual mechanism only working in the visual domain.

Accounts of statistical learning, both implicit and explicit, often invoke predictive processes as central to learning, yet practically all experiments employ non-predictive measures during training. We argue that the common theoretical assumption of anticipation and prediction needs clearer, more direct evidence for it during learning. We offer a novel experimental context to explore prediction, and report results from a simple sequential learning task designed to promote predictive behaviors in participants as they responded to a short sequence of simple stimulus events. Predictive tendencies in participants were measured using their computer mouse, the trajectories of which served as a means of tapping into predictive behavior while participants were exposed to very short and simple sequences of events. A total of 143 participants were randomly assigned to stimulus sequences along a continuum of regularity. Analysis of computer-mouse trajectories revealed that (a) participants almost always anticipate events in some manner, (b) participants exhibit two stable patterns of behavior, either reacting to vs. predicting future events, (c) the extent to which participants predict relates to performance on a recall test, and (d) explicit reports of perceiving patterns in the brief sequence correlates with extent of prediction. We end with a discussion of implicit and explicit statistical learning and of the role prediction may play in both kinds of learning.

Implicit learning is often assumed to be an effortless process. However, some artificial grammar learning and sequence learning studies using dual tasks seem to suggest that attention is essential for implicit learning to occur. This discrepancy probably results from the specific type of secondary task that is used. Different secondary tasks may engage attentional resources differently and therefore may bias performance on the primary task in different ways. Here, we used a random number generation (RNG) task, which may allow for a closer monitoring of a participant's engagement in a secondary task than the popular secondary task in sequence learning studies: tone counting (TC). In the first two experiments, we investigated the interference associated with performing RNG concurrently with a serial reaction time (SRT) task. In a third experiment, we compared the effects of RNG and TC. In all three experiments, we directly evaluated participants' knowledge of the sequence with a subsequent sequence generation task. Sequence learning was consistently observed in all experiments, but was impaired under dual-task conditions. Most importantly, our data suggest that RNG is more demanding and impairs learning to a greater extent than TC. Nevertheless, we failed to observe effects of the secondary task in subsequent sequence generation. Our studies indicate that RNG is a promising task to explore the involvement of attention in the SRT task.

Over the last 20 years researchers have used the serial reaction time (SRT) task to investigate the nature of spatial sequence learning. They have used the task to identify the locus of spatial sequence learning, identify situations that enhance and those that impair learning, and identify the important cognitive processes that facilitate this type of learning. Although controversies remain, the SRT task has been integral in enhancing our understanding of implicit sequence learning. It is important, however, to ask what, if anything, the discoveries made using the SRT task tell us about implicit learning more generally. This review analyzes the state of the current spatial SRT sequence learning literature highlighting the stimulus-response rule hypothesis of sequence learning which we believe provides a unifying account of discrepant SRT data. It also challenges researchers to use the vast body of knowledge acquired with the SRT task to understand other implicit learning literatures too often ignored in the context of this particular task. This broad perspective will make it possible to identify congruences among data acquired using various different tasks that will allow us to generalize about the nature of implicit learning.

In two experiments, we investigated the impact of spatial attributes on the representation acquired during a serial reaction time task. Two sequences were used, in which structural regularities occurred either in the horizontal or in the vertical locations of successive stimuli. After training with the dominant hand, participants were required to respond with the non-dominant hand to either the original sequence or to a mirror-ordered version of the original sequence that required finger movements homologous to those used during training. We observed that a difference in reaction times between the two transfer conditions was smaller in the vertical sequence than in the horizontal sequence. This pattern of results was independent of whether three fingers (Experiment 1) were used or only one finger (Experiment 2) was used for responding. This result suggests that perceptual and motor learning mechanisms may be weighted differently depending on the context in which the stimulus is presented.