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The findings reported in this paper show that perceptual measures based on conscious reports do not suffice to determine whether some information is or is not available to the visual system at large. Instead, motor and perceptual effects can be become perfectly dissociated. This indicates that relevant stimulus attributes are fully processed up to the level of response control but remain unavailable for conscious report. It is also clear that classical psychophysical measures do not necessarily reflect all information available to the visual system, and they should be supplemented by performance measures that do not tap perceptual awareness. We believe that our approach of contrasting direct and indirect performance measures and of dissociating perception and action by their time courses may provide, in conjunction with neurophysiological and functional brain imaging approaches, a more complete picture of information processing within the visual system. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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Motor responses can be facilitated by congruent visual stimuli and prolonged by incongruent visual stimuli that are made invisible by masking (direct motor priming). Recent studies on direct motor priming showed a reversal of these priming effects when a three-stimulus paradigm was used in which a prime was followed by a mask and a target stimulus was presented after a delay. A similar three-stimulus paradigm on nonmotor priming, however, showed no reversal of priming effects when the mask was used as a cue for processing of the following target stimulus (cue priming). Experiment 1 showed that the time interval between mask and target is crucial for the reversal of priming. Therefore, the time interval between mask and target was varied in three experiments to see whether cue priming is also subject to inhibition at a certain time interval. Cues indicated (1) the stimulus modality of the target stimulus, (2) the task to be performed on a multidimensional auditory stimulus, or (3) part of the motor response. Whereas direct motor priming showed the reversal of priming about 100 msec after mask presentation, cue priming effects simply decayed during the 300 msec after mask presentation. These findings provide boundary conditions for accounts of inverse priming effects. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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When participants must respond to a relevant central target and ignore irrelevant flanking stimuli, the flankers produce a flanker compatibility effect on behavioural measures. Current accounts of the flanker compatibility effect assume that both target and flanker stimuli affect response activation. This idea is supported by electrophysiological studies, which show that irrelevant flanker stimuli can affect the motor system. The present experiments examined the characteristics of flanker effects on the motor system by analysing the details of the motor output with response force measures. A total of 60 participants responded in the flanker task to arrows (Experiment 1) or letters (Experiment 2). Reaction time as well as response force increased on incompatible trials. Analyses of the distribution of incorrect activation revealed that both response times and correct motor output increased with the amount of incorrect activity. However, the flanker compatibility effect was only marginally modulated by incorrect activity. Results suggest that the largest part of the flanker compatibility effect cannot be attributed to response activation and competition at late levels of the response system. [ABSTRACT FROM AUTHOR]
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Der Abstract-Band zur 42. Tagung experimentell arbeitender Psychologen vom 3. bis 6. April 2000 in Braunschweig enthält 405 Kurzbeiträge aus Symposien, Referate- und Postergruppen. Die Beiträge verteilen sich auf folgende Themenfelder: (A) Referate. (1) Wahrnehmung, Aufmerksamkeit und Handlung (Wahrnehmung; auditive Wahrnehmung; visuelle Psychophysik; visuelle Suche; Aufmerksamkeit; exekutive Kontrolle; kognitive Kontrolle und Handungsplanung; Informationsverarbeitung und kognitive Kontrolle; Handlungseffekte; Psychomotorik). (2) Lernen und Gedächtnis (Lernen und Konditionieren, Gedächtnis, implizite kognitive Prozesse). (3) Motivation und Emotion. (4) Denken, Wissen und Sprache (Lesen und Worterkennung; Sprachproduktion; Wissenspsychologie; Denken und Problemlösen; Raumkognition). (5) Sozialpsychologie (selbstbezogene Kognition; emotionale Prozesse und soziale Aktivierung; Glaubwürdigkeit und Persuasion; soziale Schlüsse und Kategorien; Hilfsbereitschaft und soziale Wahrnehmung). (6) Klinische Psychologie, Diagnostik und Forschungsmethoden. (7) Biologische Psychologie. (8) Entwicklungspsychologie. (9) Verkehrspsychologie. (B) Symposien (Urteilsverzerrungen; implizite Messverfahren; kognitive Varianten bei verschiedenen Patientengruppen und Hirngesunden; Mehr-Komponenten-Konzeption von Einstellungen). (C) Poster. (10) Wahrnehmung, Aufmerksamkeit und Handlung (Wahrnehmung, Gesichtererkennung; Textursegmentierung und visuelle Suche; Aufmerksamkeitsmechanismen; kognitive Kontrolle; Psychomotorik). (11) Lernen und Gedächtnis (implizite kognitive Prozesse; Gedächtnis). (12) Denken, Wissen und Sprache (Denken, Problemlösen und Wissenspsychologie; Raumkognition; mentale Rotation; Worterkennung und Lesen; Psycholinguistik). (13) Beeinträchtigte kognitive Funktionen. (14) Sozialpsychologie. (15) Diagnostik und Forschungsmethodik. (15) Biopsychologie.
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When participants must respond to a relevant central target and ignore irrelevant flanking stimuli the flanking stimuli produce a compatibility effect, with increased response speed and accuracy on compatible as compared to incompatible trials. This flanker effect is larger when compatible trials are more frequent than incompatible trials (the ratio effect). A potential explanation of this ratio effect is that the occurrence of frequent incompatible trials causes the focus of spatial attention to be set narrower than when there are frequent compatible trials. The present investigation tests this hypothesis by comparing the flanker effect with near and far flankers. The hypothesis predicts that the flanker distance should modulate the ratio effect more when incompatible trials are frequent than when compatible trials are frequent. The results, however, show the opposite pattern: Distance effects are larger in conditions with frequent compatible trials. Moreover, the effect of distance but not the ratio effect was eliminated when flanker distance remained fixed across blocks of trials, and also when participants had to attend to flanker stimuli in a go-no-go task. These results suggest that the ratio effect does not result from an adjustment of the focus of spatial attention. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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Visual stimuli may remain invisible but nevertheless produce strong and reliable effects on subsequent actions. How well features of a masked prime are perceived depends crucially on its physical parameters and those of the mask. We manipulated the visibility of masked stimuli and contrasted it with their influence on the speed of motor actions, comparing the temporal dynamics of visual awareness in metacontrast masking with that of action priming under the same conditions. We observed priming with identical time course for reportable and invisible prime stimuli, despite qualitative changes in the masking time course. Our findings indicate that experimental variations that modify the subjective visual experience of masked stimuli have no effect on motor effects of those stimuli in early processing. We propose a model that provides a quantitative account of priming effects on response speed and accuracy.
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The present experiments further examined the characteristics of flanker effects on the motor system. 60 participants responded in the flanker task to arrows (Experiment 1) or letters (Experiment 2). To examine time and extent of flanker effects on the motor system, target onset was delayed with blocked or random stimulus onset asynchronies (SOA). With SOA of 0 and 100 ms, flanker effects on behavioral measures were reduced in random as compared to blocked conditions, but enhanced with SOA of 400 ms. With SOA of 400 ms, flanker effects on the early lateralized readiness potentials (LRP) were reduced in blocked as compared to random conditions, indicating that the onset of flanker effects on the LRP was delayed. Response-locked LRPs suggest that flanker and target stimuli activate the motor system successively. Findings challenge current theories of the flanker compatibility effect.
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When observers view a rapidly moving stimulus they may see only a static streak. We report that there can be a transient percept of motion if such a moving stimulus is preceded or followed by a stationary image of that stimulus. A ring of dots was rotated so rapidly observers only saw a continuous outline circle and could not report its rotation direction. When an objectively stationary ring of dots preceded or followed this rotating ring, the stationary ring appeared to visibly launch into motion from a standstill or visibly rotate to a halt, principally in the same direction as the actual rapid rotation. Thus, motions too rapid to be consciously perceived as motion can nonetheless be processed by the visual system, and generate neural transition states that are consciously experienced as motion percepts. We suggest such transition states might serve a unifying function by bridging discontinuous motion states. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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A central question regarding the nature of cognitive control is the extent to which different tasks are controlled by a common system. We addressed this issue by comparing the cortical activation associated with the processing of an invalidly cued event with the activation associated with a validly cued event. In a perceptual cueing task, we cued the likely stimulus modality (visual or auditory), and in a motor cueing task, we cued the likely motor response (left or right hand). Event-related functional MRI revealed increased activation in the anterior cingulate cortex on valid and invalid trials in both tasks. In addition, a network of six regions, including the dorsal medial frontal cortex, showed increased activation on invalid trials irrespective of whether the invalid cue referred to the stimulus modality or response. Findings suggest that dorsal medial frontal cortex rather than the anterior cingulated cortex is involved in conflict monitoring operations. We summarize our findings in a model that links six modules for processing invalidly cued events. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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The interaction of two expectancies was examined. These were either two perceptual or two response-related expectancies. Perceptual expectancies were induced by combining spatial cuing with feature cuing on a trial-by-trial basis. Cues consisted either of two integrated parts, such as two arrows, or two separated pieces, such as an arrow and a word. Spatial-cuing effects were reduced on trials with invalid feature cues, as compared with valid ones. However, the interaction of spatial cuing and feature cuing was modulated by the type of cue used to induce expectancies. With integrated cues, spatial-cuing effects were reduced about twice as much as with separated cues. The same effect of type of cue was found in Experiment 2, although finger cuing was combined with hand cuing. With integrated cues, finger-cuing effects were much smaller on trials with invalid hand cues, as compared with valid ones. With separated cues, however, finger-cuing effects were additive to hand-cuing effects. The similarity of the results within perceptual- and motor-cuing tasks suggests that a general principle governs the combination of expectancies, such as that outlined in the framework of the proposed adjusted expectancy model. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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When participants use cues to prepare for a likely stimulus or a likely response, reaction times are facilitated by valid cues but prolonged by invalid cues. In studies on combined expectancy effects, two cues give information regarding two dimensions of the forthcoming task. When the two cues consist of two separable stimuli their effects are approximately additive. When cues are presented as an integrated stimulus, cueing effects interact. A model is presented that simulates effects like these. The model assumes that cues affect different processing stages. When implicit information suggests that expectancies are unrelated, as for instance with separated cues, cueing effects at early and late levels of processing remain independent. When implicit information suggests that expectancies are related, as with integrated cues, however, a mechanism that is sensitive to the validity of the early stage cue, leads to an adjustment of the cueing effect at the late stage. The model is based on neurophysiologically plausible assumptions, it is given explicitly in mathematical terms, and it provides a good fit to a large body of empirical data. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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Studies of combined expectancies have shown that spatial cueing effects are reduced on trials on which participants have to respond with an unexpected motor response. In the first two experiments the range of reduced expectancy effects is examined. Advance knowledge of the likely response was combined in a trial-by-trial procedure with modality cueing, object cueing, and task cueing. Effects of modality cueing were reduced on trials on which the target requested an unexpected response. However, effects of object cueing as well as effects of task cueing were unaffected by response cueing. Comparing experiments revealed that different types of cues were used in different experiments. To test the effect of type of cue on the interaction of expectancies the third experiment combined spatial cueing with response cueing. When integrated cues were used that cued the likely target location by an arrow and the likely response by an arrow too, spatial cueing effects were reduced on trials with unexpected responses. However, spatial cueing effects remained unaffected by response cueing when separated cues were used consisting in a word cueing the response and an arrow cueing target location. An account for the modulation of combined expectancies by the relation between cues is suggested in terms of the adjusted expectancy model. [ABSTRACT FROM AUTHOR]
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Background: When subjects use cues to prepare for a likely stimulus or a likely response, reaction times are facilitated by valid cues but prolonged by invalid cues. In studies on combined expectancy effects, two cues can independently give information regarding two dimensions of the forthcoming task. In certain situations, cueing effects on one dimension are reduced when the cue on the other dimension is invalid. According to the Adjusted Expectancy Model, cues affect different processing levels and a mechanism is presumed which is sensitive to the validity of early level cues and leads to online adjustment of expectancy effects at later levels. To examine the predictions of this model cueing of stimulus modality was combined with response cueing. Results: Behavioral measures showed the interaction of cueing effects. Electrophysiological measures of the lateralized readiness potential (LRP) and the N200 amplitude confirmed the predictions of the model. The LRP showed larger effects of response cues on response activation when modality cues were valid rather than invalid. N200 amplitude was largest with valid modality cues and invalid response cues, medium with invalid modality cues, and smallest with two valid cues. Conclusion: Findings support the view that the validity of early level expectancies modulates the effects of late level expectancies, which included response activation and response conflict in the present study. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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Visual stimuli that are made invisible by a following mask can nonetheless affect motor responses. To localize the origin of these target priming effects we used the psychological refractory period paradigm. Participants classified tones as high or low, and responded to the position of a visual target that was preceded by a prime. The stimulus onset asynchrony (SOA) between both tasks varied. In Experiment 1 the tone task was followed by the position task and SOA dependent target priming effects were observed. When the visual position task preceded the tone task in Experiment 2, with short SOA the priming effect propagated entirely to the tone task yielding faster responses to tones on visually congruent trials and delayed responses to tones on visually incongruent trials. Together, results suggest that target priming effects arise from processing before and at the level of the central bottleneck such as sensory analysis and response selection. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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We typically fixate targets such that they are projected onto the fovea for best spatial resolution. Macular degeneration patients often develop fixation strategies such that targets are projected to an intact eccentric part of the retina, called pseudofovea. A longstanding debate concerns which pseudofovea-location is optimal for non-foveal vision. We examined how pseudofovea position and eccentricity affect performance in visual search, when vision is restricted to an off-foveal retinal region by a gaze-contingent display that dynamically blurs the stimulus except within a small viewing window (forced field location). Trained normally sighted participants were more accurate when forced field location was congruent with the required scan path direction; this contradicts the view that a single pseudofovea location is generally best. Rather, performance depends on the congruence between pseudofovea location and scan path direction.
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Investigated cumulative repetition priming of words and pseudowords presented in a rapid serial visual stream in a series of 6 experiments. A total of 88 college students (14 male, aged 18-41 years) participated in the experiments in which they were required to count forenames occurring in a visually presented word stream of 200 words and pseudowords and then perform lexical decision tasks for words and pseudowords which had or had not previously been seen. The experiments provided clear evidence of cumulative repetition priming, with repetition effects proving greater with increasing presentation frequency. While words consistently showed facilitatory priming, priming was consistently inhibitory for pseudowords. For pseudowords, repetition priming was generally smaller than that found for words. The experiments yielded no evidence of priming differences for pseudowords with different frequencies. In contrast, word frequency effects were obtained when the prime was processed for 250 but not for 80 ms. Results suggest that massive repetition priming does not appear to depend on conscious recollection at test and also demonstrated that priming does not decay even when measured after 7 minutes. The findings of an experiment with delays of 1 day revealed the significance of response learning and also demonstrated a clear dissociation between word and pseudoword repetition priming. In closing, implications of the findings are discussed.
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Hundreds of studies have found that humans’ decisions are strongly influenced by the opinions of others, even when making simple perceptual decisions. In this study, we aimed to clarify whether this effect can be explained by social influence biasing (early) perceptual processes. We employed stimulus evoked potentials, lateralized readiness potentials (LRPs) and a diffusion model analysis of reaction time data to uncover the neurocognitive processes underlying social conformity in perceptual decision-making. The diffusion model analysis showed that social conformity was due to a biased uptake of stimulus information and accompanied by more careful stimulus processing. As indicated by larger N1- amplitudes, social influence increased early attentional resources for stimulus identification and discrimination. Furthermore, LRP analyses revealed that stimulus processing was biased even in cases of non-conformity. In conclusion, our results suggest that the opinion of others can cause individuals to selectively process stimulus information supporting this opinion, thereby inducing social conformity. This effect is present even when individuals do not blindly follow the majority but rather carefully process stimulus information. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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Need for cognition (NFC) refers to dispositional differences in cognitive motivation and has been frequently found to predict higher-order cognition, such as attitude formation and decision making. Based on recent evidence, this study examined whether NFC already relates to relatively early perceptual processes. Using a metacontrast masking paradigm (N = 137), we found that high-NFC individuals were more likely to use target-specific perceptual cues providing valid information for target discrimination, while low-NFC individuals were more likely to use less reliable heuristic cues for their judgement. Intriguingly, our results suggest that core mechanisms of NFC (focussed/elaborative vs. peripheral/heuristic processing by differential utilization of environmental cues) can not only be found in reflective higher-order cognition, but similarly in behavioral indicators of early visual processing. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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Our ability to identify even complex scenes in rapid serial visual presentation (RSVP) is astounding, but memory for such items seems lacking. Rather than pictures, we used streams of more than 200 verbal stimuli, rushing by on the screen at a rate of more than 12 items per second while participants had to detect infrequent names (Experiments 1 and 2) or words written in capitals (Experiment 3). By direct and indirect tests, we investigated what is remembered of these masses of task-irrelevant distractor words and pseudowords embedded in an RSVP stream. Lexical decision, the indirect test applied either immediately after each stimulus train or with a delay, revealed strong long-term priming effects. Relative to stimuli not shown before, lexical decisions were faster and more accurate to words but slower to pseudowords. The size of these effects mirrored how often words and pseudowords had occurred in a stream, suggesting that memory traces are strengthened with successive presentations and survive for several minutes at least. Moreover, in a direct test (old–new categorization), words as well as pseudowords benefited from prior occurrence in an RSVP stream if they had occurred more than once. These findings parallel recent physiological and behavioral evidence for memory consolidation of distractor pictures in RSVP and highlight that, despite huge numbers of interfering stimuli, distractor words and pseudowords exhibit long-lasting memory effects. Consolidation seems to progress at higher cognitive levels at the same time that subsequent stimuli are perceptually processed. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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Metacontrast masking occurs when a mask follows a target stimulus in close spatial proximity. Target visibility varies with stimulus onset asynchrony (SOA) between target and mask in individually different ways leading to different masking functions with corresponding phenomenological reports. We used individual differences to determine the processes that underlie metacontrast masking. We assessed individual masking functions in a masked target discrimination task using different masking conditions and applied factor-analytical techniques on measures of sensitivity. Results yielded two latent variables that (1) contribute to performance with short and long SOA, respectively, (2) relate to specific stimulus features, and (3) differentially correlate with specific subjective percepts. We propose that each latent variable reflects a specific process. Two additional processes may contribute to performance with short and long SOAs, respectively. Discrimination performance in metacontrast masking results from individually different weightings of two to four processes, each of which contributes to specific subjective percepts. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
