Time course of the blindness to response-compatible stimuli

This article examines the time course of a deficit in identifying a stimulus sharing a compatible feature with a response that is executed in parallel ("blindness to response-compatible stimuli," J. Müsseler & B. Hommel, 1997a). In 5 experiments, participants performed a timed response, and the presentation point of time of a to-be-identified stimulus was varied in respect to response execution. A blindness effect was observed when the stimulus was presented between response cue offset and response execution. In contrast, the identification of a stimulus presented before the response cue or after response execution was not affected by stimulus-response compatibility--a finding that rules out a retention-based explanation. These results support an explanation that states that the perceptual processing of a stimulus feature is impaired as long as the shared perception-action feature code is integrated into the representation of a to-be-executed response.     

Inhibition and blindness to response-compatible stimuli: a reappraisal

Recent studies show that the preparation of an action can interfere with the concurrent detection and identification of objects that share features with this action, a phenomenon termed blindness to response-compatible stimuli. In order to account for the blindness effect, an integration mechanism for response features similar to the one suggested for object features has been proposed. In the present article, we propose an alternative explanation, namely an action-effect inhibition mechanism. This mechanism was demonstrated in two versions of a dual-task experiment using a primary stop-signal task. The results showed that when the primary response was withheld (signal-inhibit trials), this resulted in lower identification rates for compatible secondary task stimuli. On the other hand, we did not find any evidence for a blindness effect when the primary response was executed (no-signal trials). Additionally we found that identification rates depended on the time course of the inhibition process as estimated from our data. Consequently, the blindness effect seems to result from the requirement to inhibit the response, perhaps even if only temporary.     

Blindness to response-compatible stimuli in the psychological refractory period paradigm

This study investigated the conditions under which the processing in a speeded response task interferes with concurrent processing in a visual encoding task. Three experiments used a dual-task paradigm, in which a speeded left or right response to at one was combined with the identification of a masked left-or right pointing arrow following the tone with variable SOA. Two additional experiments tested the impact of the presentation of pure tone on visual encoding.There were four major findings. First, an unspecific decrease in identification accuracy was observed with decreasing SOA. Second, a blindness to response-compatible stimuli was observed with speeded responses. Third, a specific interference was found between low- and high-pitched tones and left- or right-pointing arrows. Fourth, the specific tone-arrow interference modulated the specific responsearrow interference when the task allowed both to occur simultaneously. The present findings, which suggest both procedural and structural interference between response preparation and stimulus encoding, are discussed in terms of a two-stage model of action planning.     

Detecting and identifying response-compatible stimuli

Previous work indicates that action-control processes influence perceptual processes: The identification probability of a left- or right-pointing arrow is reduced when it appears during the execution of a compatible left-right-key press (Müsseler & Hommel, in press). The present study addresses the question of whether this effect would also be observed in a detection task—that is, with judgments that do not require discriminating between left- and right-pointing arrows. Indeed, we found comparable effects in both the identification task and the detection task. This outcome is interpreted within a commoncoding framework, which holds that stimulus processing and action control operate on the same codes.     

Lengthening the duration of response execution does not modulate blindness to action-compatible stimuli.

Action-compatible blindness refers to the finding that target stimuli are perceived less frequently if they are presented during the planning or execution of a compatible action (e.g., a left arrow presented during a left manual key press) than during an incompatible action (Müsseler & Hommel, 1997 a, b). We investigated the effect of lengthening the response execution phase in the action-compatible blindness paradigm by requiring subjects to tap a response key once or three times on the assumption that tapping three times would increase the duration of the execution phase of the response. Prior research (e.g., Stevanovski, Oriet, & Jolicoeur, 2002; Wühr & Müsseler, 2001) has shown that larger blindness effects are observed for targets presented during the execution phase of a response than after the response has been made. We investigated whether a larger blindness effect would be observed in the three-tap condition than in the one-tap condition, or whether lengthening the duration of the response would extend the time course of the blindness effect. Neither of these possibilities was supported by the data irrespective of whether the number of taps to be made was blocked or mixed within a block of trials. The results are discussed in terms of current accounts of action-compatible blindness and the possible cognitive differences between making a single response and repeating a response.     

Symbolic- and response-related contributions to blindness to compatible stimuli

Blindness to compatible stimuli refers to poorer target identification (e.g., right-pointing arrowhead) following compatible stimuli (e.g., right arrows; Stevanovski, Oriet, & Jolic?ur, 2003) and compatible responses (e.g., right key press; Müsseler & Hommel, 1997a and 1997b). To clarify the role of the response in this effect, we examined the impact of adding or removing an overt response. In three experiments, subjects saw an arrow cue (that sometimes required a response) followed by a brief, masked arrowhead, which was reported on all trials. In all experiments, making a response increased the magnitude of the blindness effect. Furthermore, “no response” performance was unaffected by whether subjects had previously responded to the cue. Results favour a two-factor symbolic- plus response-related activation model over a purely symbolic activation model.     

Action blindness in response to gradual changes

The goal of this study is to characterize observers’ abilities to detect gradual changes and to explore putative dissociations between conscious experience of change and behavioral adaptation to a changing stimulus. We developed a new experimental paradigm in which, on each trial, participants were shown a dot pattern on the screen. Next, the pattern disappeared and participants had to reproduce it. In some conditions, the target pattern was incrementally rotated over successive trials and participants were either informed or not of this change. We analyzed both awareness of the changes and the dynamics of behavioral adaptation, in a way that makes it possible to assess both variability and accuracy as they change over time. Results indicate a dissociation between change awareness and behavioral adaptation to the changes, and support the notion that unconscious representations of visual stimuli are more precise and detailed than previously suggested. We discuss the implications of these results for theories of change detection.     

Double response to Stroop stimuli.

To reexamine Klein's 1964 findings we carried out two experiments on the double response made to Stroop stimuli. In Exp. 1 incongruent color-word stimuli were presented on a CRT online with a microcomputer. A color-word card was used in Exp. 2. Subjects were asked to read words before naming colors or, conversely, to name colors before reading words. An analysis of variance (the task x the type of task) was performed on response times in both experiments. Two main effects and interactions were nonsignificant. Some subjects made an error-like reverse-order response on the double-response task. The present findings do not support Klein's findings or the competition explanation of the Stroop effect.     

Spatial summation in the evoked cortical response to auditory stimuli

Six Ss were presented monaurally and binaurally with stimuli of 0.5, 2.0, and 4.0 kHz at 40 and 70 dB sensation levels. Their computer averaged evoked potentials indicated substantially larger amplitudes (N₁ -P₂) with bilateral stimulation, regardless of frequency. Stimulation at 70 dB SL gave greater responses than that to 40 dB.     

Developmental changes in response preparation to visual stimuli

We examined how preparation to respond changes with age. Subjects from four age groups (5- to 7-, 8- to 11-, 12- to 17-, and 18- to 24-yr.-olds) were given a simple visual RT task with foreperiod duration varied between 300 and 2000 msec. Analysis showed that in addition to the expected effects of age and foreperiod, there were qualitative differences between the performance of adults and children: 5- to 7-yr.-olds reacted quickest after a foreperiod shorter than that required by adults to perform best. Conversely, preadolescents' optimal foreperiod was relatively longer than that of either older or younger subjects. In addition, the youngest subjects showed an inability to maintain preparation as efficiently as older subjects. Implications for the development of response preparation are discussed.     

Culture and sensory response to visual stimuli

This study investigated the influence of culture on people's sensory responses, such as smell, taste, sound and touch to visual stimuli. The sensory feelings of university students from four countries (Japan, South Korea, Britain and France) to six images were evaluated. The images combined real and abstract objects and were presented on a notebook computer. Overall, 280 participants (144 men and 136 women; n = 70/country) were included in the statistical analysis. The chi‐square independence analysis showed differences and similarities in the sensory responses across countries. Most differences were detected in smell and taste, whereas few variations were observed for sound responses. Large variations in the response were observed for the abstract coral and butterfly images, but few differences were detected in response to the real leaf image. These variations in response were mostly found in the British and Japanese participants.     

Overselective response to social stimuli by autistic children

Previous studies have shown that when presented with a complex stimulus input, autistic children typically respond to only one of the elements of the complex. This phenomenon was called stimulus overselectivity (or overselective attention). The present investigation sought to determine if this overselectivity might be a possible basis for the deviant social behavior in autistic children. Autistic and normal children were trained to discriminate between clothed girl and boy doll figures. After the children had acquired this discrimination, the individual clothing components and the heads were systematically interchanged between the figures. Thus, it could be determined which component(s) the children had used to make the discrimination. The autistic children demonstrated stimulus overselectivity in that they formed the discrimination between the boy and girl figures on the basis of only one component or of peculiar combinations of components. For example, one child discriminated the figures on the basis of shoes. In contrast, the normal children responded primarily to the figures' heads but could also respond correctly to other parts. These findings are consistent with previous research on stimulus overselectivity and have implications for understanding the difficulty autistic children show in forming meaningful social relationships.This investigation was supported by U.S. Public Health Service Research Grant 11440 from the National Institute of Mental Health.The authors express their appreciation to James Q. Simmons, Associate Chief, Mental Retardation and Child Mental Health Programs, Neuropsychiatric Institute, University of California, Los Angeles; and Norbert Rieger, Superintendent of Children's Services, Camarillo State Hospital, Camarillo, California. They are also grateful to Robert Koegel and to Thomas Willis for their valuable suggestions and to Meredith Gibbs for her assistance in data collection.     

Diminished response to pleasant stimuli by depressed women

This study examined the self-report and facial expressions of emotional response to pictorial stimuli and the incidental learning of pleasant and unpleasant words by depressed (n = 20) and nondepressed (n = 20) women. Depression was associated with reports of diminished emotional response and reduced frequency and intensity of facial expressions only to pleasant stimuli. The 2 groups did not differ in response to hedonically unpleasant stimuli, even those specifically relevant to the emotion of sadness. In a similar vein, depressed and nondepressed participants showed differences in incidental recall for only pleasant self-referential terms. There was no difference in recall of unpleasant words. These findings suggest the importance of hedonic deficits on psychological processes in clinical depression.     

Burying by rats in response to aversive and nonaversive stimuli

Previous investigations have shown that rats bury a variety of conditioned and unconditioned aversive stimuli. Such burying has been considered as a species-typical defensive reaction. In the present studies, rats buried spouts filled with Tabasco sauce, or condensed milk to which a taste aversion was conditioned, but did not bury water-filled spouts or spouts filled with a palatable novel food (apple juice) to which a taste aversion was not conditioned. However, in other experiments rats consistently and repeatedly buried Purina Rat Chow, Purina Rat Chow coated with quinine, and glass marbles. This indicates that a variety of stimuli, not all aversive or novel, evoke burying by rats. Whereas the behavior may reasonably be considered as a species-typical defensive behavior in some situations, the wide range of conditions that occasion burying suggests that the behavior has no single biological function.     

Respiratory sinus arrhythmia in response to fear-relevant and fear-irrelevant stimuli

Heart period variability and heart rate were studied in 15 women and 15 men while they were viewing negatively (snakes/spiders), neutrally (scenic views), and positively (cats and kittens/puppies and dogs) valenced films. Time-frequency analyses of the heart period variability power spectrum in the high frequency region (0.12-0.4 Hz), reflecting respiratory sinus arrhythmia (RSA), were carried out during 5 minutes in each condition. The main finding showed that RSA-magnitude (high frequency power) was inversely related to emotional valence: lowest magnitudes were found in response to positive films, and highest magnitude to negative films. The findings were interpreted as reflecting motor or behavioral inhibition, and increased attention to negatively valenced, stimuli.