Relationship between flanker identifiability and compatibility effect

What is the relation between the identifiability of masked flankers and their ability to induce compatibility effects in a letter classification task? Using a within-subjects design (n=8), we first determined identification performance for two flankers (H or N) around an irrelevant target letter as a function of the time (stimulus onset asynchrony, or SOA) after which the flankers were masked. In a second condition, subjects classified the central letter of the same stimulus patterns irrespectively of the identity of the flankers. The compatibility effects increased with increasing identification performance as a function of SOA, and we found a significant compatibility effect even at an SOA at which the identifiability of the flankers did not differ significantly from zero. We discuss the statistical power of our design and an interpretation of our results in terms of a dissociation between perceptual processes and processes directly activating the motor system (direct parameter specification; cf. Neumann, 1990).     

Sequence learning in a dual-stimulus setting

Is sequence learning an autonomous process that relies on independent resources? In this paper, I attempt to answer this question by exploring whether sequence learning occurs even despite the availability of reliable explicit information about the material to be learned. I report on a series of experiments during which participants performed a sequential choice reaction task. On each trial, participants were exposed to a stimulus and to a cue of varying validity which, when valid, indicated where the next stimulus would appear. Participants could therefore optimize their performance either by implicitly encoding the sequential constraints contained in the material or by explicitly relying on the information conveyed by the cue. Some theories assume that implicit learning does not rely on the same processing resources as those involved in explicit learning. Such theories would thus predict that sensitivity to sequential constraints should not be affected by the presence of reliable explicit information about sequence structure. Other theories, by contrast, would predict that implicit learning would not occur in such cases. The results are consistent with the former theories, but simulation work meant to enable the implications of these contrasting theories to be explored suggests that such results are also obtainable in architectures in which two processing pathways share resources.     

Contextual modulation of prime response retrieval processes: Evidence from auditory negative priming

Contextual similarity between learning and test phase has been shown to be beneficial for memory retrieval. Negative priming is known to be caused by multiple processes; one of which is episodic retrieval. Therefore, the contextual similarity of prime and probe presentations should influence the size of the negative priming effect. This has been shown for the visual modality. In Experiment 1, an auditory four-alternative forced choice reaction time task was used to test the influence of prime-probe contextual similarity on negative priming and the processes underlying the modulation by context. The negative priming effect was larger when the auditory context was repeated than when it was changed from prime to probe. The modulation by context was exclusively caused by an increase in prime response retrieval errors in ignored repetition trials with context repetition, whereas repeating only the context but not the prime distractor did not lead to an increase in prime response retrieval. This exact pattern of results was replicated in Experiment 2. The findings suggest that contextual information is integrated with prime distractor and response information. Retrieval of the previous episode, including prime distractor, prime response, and context (event file), can be triggered when the former prime distractor is repeated, whereas a context cue alone does not retrieve the event file. This suggests an event file structure that is more complicated than its usually assumed binary structure.     

Further evidence on the similarity of memory processes in the process dissociation procedure and in source monitoring

Buchner, Erdfelder, Steffens, and Martensen (1997) proposed that the memory processes involved in recognition judgments in the process dissociation procedure are the same as those involved in standard source monitoring tasks. Two extensions of that research are presented here. First, following a line of reasoning recently brought forward by Jacoby (1998), the instructions in the earlier study could have triggered different processes from those triggered by his instructions. However, with instructions conforming as closely as possible to those reported by Jacoby (1991), Experiment 1 replicated the earlier recognition judgment finding almost perfectly. Second, the memory processes underlying fame judgments in the process dissociation procedure could also resemble those involved in source monitoring tasks. Indeed, the results of Experiment 2 are compatible with the hypothesis that the same processes are involved in fame judgments given a source monitoring or a process dissociation procedure.     

The efficiency of holistic template matching in the recognition of unconstrained handwritten digits

Summary Psychological evidence suggests that simple visual patterns can be recognized by the use of internal representations as holistic templates, but the efficiency of holistic template matching in the recognition of real-life patterns, such as handwritten characters, has been doubted. To clarify this issue, we measured the efficiency of holistic template matching in machine recognition of totally unconstrained handwritten digits. Our learning and recognition algorithm was simple; no previous knowledge of handwritten digits was presupposed, and preprocessing was limited to Gaussian smoothing and normalization with respect to position, size, and orientation. For patterns presented in a known orientation, recognition rates were .69, .77, and .88, respectively, when about 5, 10, or 50 templates had been learned for each type of digit. For patterns presented in unknown orientations, recognition rates were slightly lower. High levels of reliability could be attained by the discounting of classifications based on weak evidence. Apparently, in high reliability recognition, holistic template matching can be used as a first operation by which recognition is achieved for most of the handwritten digits that are seen in real life.     

The dependency of the validity of information integration on cognitive variables and the judgement task

Simple models of information integration focus essentially on the combination of the components of information. This research investigated whether cognitive variables in the constructs of intelligence and cognitive complexity, as well as concentration, could predict the conditions of simple models of judgement. As additional predictors, the two qualitative variables [type of information] and [experience of the judgement task] were introduced. Subjects judged three types of stimuli using the pair comparison method. The conditions of the judgement models were analysed in the framework of the conjoint-measurement approach. Five different regression functions provided mediocre approximations to the 10 conditions of the models, when the 9 cognitive variables were considered. The small differences did not favour one of the five functions. The introduction of the qualitative predictor [type of information] improved the estimations more clearly than the experience of the judgement task, the effect of which was small.