Psychological Research

 In two-choice reaction time experiments, participants were instructed within a variable precueing interval to speed up responding in 20% of trials and to maintain their basic level of performance in the remaining trials. The achievement of this goal was rewarded by a monetary bonus. The requirement to speed up was signaled at varying intervals before the onset of the imperative stimulus. The main questions to be answered were whether participants would be able to dynamically adjust their response speed, and if so, whether a speed up would be due to enhanced effort with a genuine improvement of performance or due to an adjusted response criterion, accompanied by a speed-accuracy trade-off. The data of both experiments suggest that participants were able to invest some extra effort, the amount of which varied as a function of the length of the precueing interval. This speed-up was evident already in the fastest bins of the reaction time distribution, indicating a continuous modulation of processing efficiency. Only in the first experiment was there clear evidence for a speed-accuracy trade-off in addition to effort mobilization.

Traditional models of face perception (e.g. Bruce and Young 1986) stress independent routes for processing identity and emotional expression. We investigated the interplay between familiarity and emotional expression by systematically varying both factors. In contrast to earlier studies which used binary forced-choice decisions, participants had to judge the familiarity of the presented face and the emotional hedonic valence and emotional arousal of its expressed emotion (angry, happy or neutral), using rating scales. The results demonstrated symmetric, strong interactions between familiarity and expressed emotion. Thus, this study supports more recent models of face perception (Haxby et al. 2000) that were mostly based on brain imaging data. These data together with our behavioural results emphasize the interaction of emotional expression and personal identity and support approaches that propose a relative segregation of these processes, rather than completely independent coding (Calder and Young 2005).

A series of experiments is reported concerning implicit memory in imaginal processing. In the standard condition, subjects had to encode word images before spelling a word. The spelling task was repeated in the test phase with the same words and with additional control words. Spelling times were registered after the image encoding. Implicit memory has been detected if repeated words can be spelled faster than control words. Experiment 1 showed that levels of processing manipulations (such as the additional generation of meaning images at encoding or variations in word concreteness) favor explicit memory, but do not show up in implicit memory. Experiment 2 demonstrated that implicit memory disappears if spelling at encoding took place on visually present words. Experiment 3 investigated whether the focusing of specific letter positions within the image may contribute to the effect, but this was not found. According to a processing view that underlies our task analysis, implicit memory depends on transfer-appropriate processing and is attributed to processes of image encoding or generation and image reconstruction or regeneration.

The incorporation of editors and monitors in models of language production has become a common practice over the past ten years or so. However, there is much confusion in the psycholinguistics literature about these two control mechanisms. A monitor is redefined as a television viewer who can spot problems on the screen but cannot do anything about it. An editor, in contrast, is powerful enough to change the programme so as to produce fewer and less anomalous errors. Although there is no doubt that our speech is internally monitored, it is far from clear that this is achieved via editing. Not only can editing models be shown to suffer from serious defects, but also the data which motivated the introduction of editors in the first place lend themselves more plausibly to a reanalysis in terms of evidencing properties of the regular programming process. It is argued that McClelland and Rumelhart's interactive activation model accommodates the monitoring function quite nicely without any additional theoretical apparatus. Monitoring is carried out by a mechanism called non-local feedback which results automatically from bottom-up information flow in a parallel processing system. All the speaker has to do is to check the activation levels of the nodes in his internal network. He discovers problems whenever the levels of activation are too low with respect to the idea he wishes to communicate.

It has been proposed that sudden insight into the solutions of problems can enhance long-term memory for those solutions. However, the nature of insight has been operationalized differently across studies. Here, we examined two main aspects of insight problem-solving—the generation of a solution and the subjective “aha!” experience—and experimentally evaluated their respective relationships to long-term memory formation (encoding). Our results suggest that generation (generated solution vs. presented solution) and the “aha!” experience (“aha!” vs. no “aha!”) are independently related to learning from insight, as well as to the emotional response towards understanding the solution during encoding. Moreover, we analyzed the relationship between generation and the “aha!” experience and two different kinds of later memory tests, direct (intentional) and indirect (incidental). Here, we found that the generation effect was larger for indirect testing, reflecting more automatic retrieval processes, while the relationship with the occurrence of an “aha!” experience was somewhat larger for direct testing. Our results suggest that both the generation of a solution and the subjective experience of “aha!” indicate processes that benefit long-term memory formation, though differently. This beneficial effect is possibly due to the intrinsic reward associated with sudden comprehension and the detection of schema-consistency, i.e., that novel information can be easily integrated into existing knowledge.

Subjects performed a timed-response task in which they attempted to synchronize a rapid flexion of the index finger of their preferred hand with the last of a train of four regularly spaced acoustic clicks. The task was used to stabilize the execution time of a simple voluntary response in order to facilitate psychophysical judgments about the subjects' perception of having responded and of having intended to respond. In the first experiment, male subjects (N = 6) adjusted the appearance time of a reference stimulus (a brief percutaneous pulse to the responding finger) until it appeared to be simultaneous with their perception of having made the response. All subjects adjusted the reference stimulus to appear after response onset during the latter half of the force impulse. This finding suggests that the perception of having responded is based on peripheral feedback from the response. In the second experiment, male subjects (N = 6) performed the same motor task, but adjusted the time of the reference stimulus so that it appeared to be simultaneous with their intention to respond. Two subjects were not able to do the task successfully; the remaining four subjects adjusted the reference stimulus to appear from 101 to 145 ms before response onset. This finding suggests that the intention to respond is perceptually separable from the response itself and occurs at a measurable time before response onset.

In everyday life, navigators often consult a map before they navigate to a destination (e.g., a hotel, a room, etc.). However, not much is known about how humans gain spatial knowledge from seeing a map and direct navigation together. In the present experiments, participants learned a simple multiple corridor space either from a map only, only from walking through the virtual environment, first from the map and then from navigation, or first from navigation and then from the map. Afterwards, they conducted a pointing task from multiple body orientations to infer the underlying reference frames. We constructed the learning experiences in a way such that map-only learning and navigation-only learning triggered spatial memory organized along different reference frame orientations. When learning from maps before and during navigation, participants employed a map- rather than a navigation-based reference frame in the subsequent pointing task. Consequently, maps caused the employment of a map-oriented reference frame found in memory for highly familiar urban environments ruling out explanations from environmental structure or north preference. When learning from navigation first and then from the map, the pattern of results reversed and participants employed a navigation-based reference frame. The priority of learning order suggests that despite considerable difference between map and navigation learning participants did not use the more salient or in general more useful information, but relied on the reference frame established first.

We are less prone today than in Köhler's time to believe in a unified science. The Gestalt program could therefore safely abandon the psychophysical isomorphism heuristic if it wished to. Indeterminacy of the heuristic might be a reason for doing so. The determination of the components involved in the isomorphism of the visual field as well as the electrocortical events would have to occur simultaneously. In the Gestalt program, however, components are determined by their position in the whole. They can therefore not be compared in different contexts, so no independent test of a candidate heuristic is possible.