Perception of danger signals: the role of control

How does the perceptual system process stimuli that signal aversive outcomes or dangers? Considering the functional links between perception, attention, and action regulation, we posit that when people can avoid the aversive consequences, sensitivity of the perceptual system to danger signals should be enhanced, whereas it should be reduced when there is no such option. To test this prediction, we used a search task in which tachistoscopically presented conjunctions of features had to be detected. Parameters of sensitivity and response bias were analyzed drawing on procedures from signal detection theory. Although the experimental procedure rewarded correct responses, the predicted asymmetry emerged. For stimuli that were linked to a negative consequence (loss of points in the experimental game), perceptual sensitivity was enhanced when participants had the opportunity to neutralize the loss in a second task; an opposite pattern emerged when they had no such opportunity.     

Inflation of conditional predictions

The authors report 7 experiments indicating that conditional predictions--the assessed probability that a certain outcome will occur given a certain condition--tend to be markedly inflated. The results suggest that this inflation derives in part from backward activation in which the target outcome highlights aspects of the condition that are consistent with that outcome, thus supporting the plausibility of that outcome. One consequence of this process is that alternative outcomes are not conceived to compete as fully as they should. Another consequence is that prediction inflation is resistant to manipulations that induce participants to consider alternative outcomes to the target outcome.     

Automatic vigilance for task-related information: Perseverance after failure and inhibition after success

In three experiments, the influence of failure and success on persistent automatic vigilance task-related information was investigated. Participants first had to work on a series of synonym selection problems for which negative and positive feedback was given independently of their performance. In the second part of the experiments, words from the synonym selection problems were presented as distractors in a dual task with speeded responses. Interference effects of the distractors served as a measure of automatic vigilance for the previous synonym selection problems that was unbiased by strategic processes. Interference effects were stronger for words from failure tasks than for words from success tasks. Comparing the success and failure conditions against a neutral baseline suggested that this difference was due to both a perseverance of automatic vigilance for failure tasks and an inhibition of cognitive accessibility after success.     

The influence of an external symbol system on number parity representation, or What’s odd about 6?

The aim of this study was to investigate whether language-specific properties influence mental number processing. German Sign Language (DGS) numbers differ from those in spoken German not only in terms of modality but also in their basic language structure. A group of 20 congenitally deaf German signers participated in a number parity (odd/even) judgment task with DGS and printed German number words. The results indicated that two-handed DGS number signs are processed in a decomposed way. This language-specific effect also generalized to another linguistic number notation, German number words, but not to Arabic digit notation. These differences are discussed with respect to two possible routes to number parity.     

Memory for fact, fiction, and misinformation: the Iraq War 2003

Media coverage of the 2003 Iraq War frequently contained corrections and retractions of earlier information. For example, claims that Iraqi forces executed coalition prisoners of war after they surrendered were retracted the day after the claims were made. Similarly, tentative initial reports about the discovery of weapons of mass destruction were all later disconfirmed. We investigated the effects of these retractions and disconfirmations on people's memory for and beliefs about war-related events in two coalition countries (Australia and the United States) and one country that opposed the war (Germany). Participants were queried about (a) true events, (b) events initially presented as fact but subsequently retracted, and (c) fictional events. Participants in the United States did not show sensitivity to the correction of misinformation, whereas participants in Australia and Germany discounted corrected misinformation. Our results are consistent with previous findings in that the differences between samples reflect greater suspicion about the motives underlying the war among people in Australia and Germany than among people in the United States.     

Evidence of separable spatial representations in a virtual navigation task

Three experiments investigated spatial orientation in a virtual navigation task. Subjects had to adjust a homing vector indicating their end position relative to the origin of the path. It was demonstrated that sparse visual flow was sufficient for accurate path integration. Moreover, subjects were found to prefer a distinct egocentric or allocentric reference frame to solve the task. "Turners" reacted as if they had taken on the new orientation during turns of the path by mentally rotating their sagittal axis (egocentric frame). "Nonturners," by contrast, tracked the new orientation without adopting it (allocentric frame). When instructed to use their nonpreferred reference frame, both groups displayed no decline in response accuracy relative to their preferred frame; even when presented with reaction formats based on either ego or allocentric coordinates, with format unpredictable on a trial, both groups responded highly accurately. These findings support the assumption of coexisting spatial representations during navigation.     

Binding and inhibition in working memory: individual and age differences in short-term recognition

Two studies investigated the relationship between working memory capacity (WMC), adult age, and the resolution of conflict between familiarity and recollection in short-term recognition tasks. Experiment 1 showed a specific deficit of young adults with low WMC in rejecting intrusion probes (i.e., highly familiar probes) in a modified Sternberg task, which was similar to the deficit found in old adults in a parallel experiment (K. Oberauer, 2001). Experiment 2 generalized these results to 3 recognition paradigms (modified Sternberg, local recognition, and n back tasks). Old adults showed disproportional performance deficits on intrusion probes only in terms of reaction times, whereas young adults with low WMC showed them only in terms of errors. The generality of the effect across paradigms is more compatible with a deficit in content-context bindings subserving recollection than with a deficit in inhibition of irrelevant information in working memory. Structural equation models showed that WMC is related to the efficiency of recollection but not of familiarity.     

Control of the contents of working memory--a comparison of two paradigms and two age groups

Two experiments investigated whether young and old adults can temporarily remove information from a capacity-limited central component of working memory (WM) into another component, the activated part of long-term memory (LTM). Experiment 1 used a modified Sternberg recognition task (S. Sternberg, 1969); Experiment 2 used an arithmetic memory-updating task. In both paradigms, participants memorized 2 lists, one of which was cued as temporarily irrelevant. Removal of the irrelevant list from capacity-limited WM was indexed by the disappearance of list-length effects of that list on latencies for concurrent processing tasks. Young adults could outsource the irrelevant list within 2-3 s and retrieve it back into the central part of WM later. Old adults showed the same flexibility in the arithmetic updating task but seemed somewhat less able or inclined to temporarily move information into the activated part of LTM in the modified Sternberg task.     

Past experience influences the processing of stimulus compounds in human Pavlovian conditioning

In two human skin conductance conditioning experiments we investigated whether processing of stimulus compounds can be influenced by past experience. Participants were either pre-trained with a discrimination problem that could be solved elementally (A+, B−, AB+, C− in Experiment 1 and A+, AB+, C−, CB− in Experiment 2) or one that required a configural solution (AB+, BC−, CD+, DA− in Experiment 1 and A−, AB+, C+, CB− in Experiment 2). After pre-training, participants were shown an EX+, FX− discrimination. Subsequently, responding to individual components (E and F) was tested. After elemental pre-training, participants showed larger responses to the component from the previously reinforced compound (E) than to the component from the nonreinforced compound (F) whereas no such difference was found after configural pre-training. This means that the kind of pre-training influenced whether the later discrimination problem was processed elementally or configurally. The results indicate that organisms can flexibly process stimulus compounds in different ways.