An action sequence withheld in memory can delay execution of visually guided actions: the generalization of response compatibility interference

Withholding an action plan in memory for later execution can delay execution of another action, if the actions share a similar (compatible) action feature (i.e., response hand). This phenomenon, termed compatibility interference (CI), was found for identity-based actions that do not require visual guidance. The authors examined whether CI can generalize to both identity-based and location-based actions that require visual guidance. Participants withheld a planned action based on the identity of a stimulus and then immediately executed a visually guided action (touch response) to a 2nd stimulus based on its color identity (Experiment 1), its spatial location (Experiment 2), or an intrinsic spatial location within an object (Experiment 3). Results showed CI for both left- and right-hand responses in Experiment 1. However, CI occurred for left- but not right-hand responses in Experiment 2 and 3. This suggests that CI can generalize to visually guided actions under cognitive control but not to actions that invoke automatic visual-control mechanisms where the left hemisphere may play a special role (C. Gonzalez, T. Ganel, & M. Goodale, 2006). The code occupation account for CI (G. Stoet & B. Hommel, 2002) is also discussed.     

Response-repetition effects in task switching with and without response execution

Previous research into the mechanisms of task switching has shown that repeating the same response in a different task context is associated with costs. To investigate whether such response-repetition costs occur even when the first of the two responses is not overtly executed, we used a variant of the change-signal paradigm. Subjects responded to a first stimulus by pressing a left or right response key. In half of the trials, a second stimulus occurred after a variable, adaptively adjusted delay, indicating to abandon the first response, and only respond to the second stimulus using another set of left and right response keys. In Experiment 1, different tasks had to be performed with the first and second stimulus (task-switch condition); in Experiment 2, the same task had to be performed with both stimuli (task-repetition condition). Response-repetition costs were obtained in Experiment 1, and response-repetition benefits in Experiment 2. Importantly, these costs and benefits were obtained even when the first of the two responses had not been overtly executed. The data support the idea that interference of task-specific response codes occurs at the level of abstract response codes. Interference of such response codes occurs even when the responses are not overtly executed.     

Visual field x response hand interactions and level priming in the processing of laterally presented hierarchical stimuli

Hemisphere-specific processing of laterally presented global and local stimulus levels was investigated by (a) examining interactions between the visual field of stimulus presentation and the response hand and (b) comparing intra- with inter-hemispheric effects of level priming (i.e. faster and more accurate performance when the target level repeats). Although in Experiment 1, which involved two-choice responses with left and right hands, performance costs occurred when the same hemisphere received the stimulus and controlled the response hand, further analyses suggest that these effects reflect spatial compatibility rather than intra-hemispheric interference. Consistent with the spatial compatibility interpretation, in Experiment 2 a similar visual field x response interaction was obtained with regard to left and right responses given with the same hand. Trial-to-trial level priming occurred in both experiments and was unaffected by the intra-hemispheric sequence of target levels. Implications regarding hemispheric processing mode are discussed.     

Locus of inhibition in the masked priming of response alternatives

Masked prime stimuli presented immediately before target stimuli in a choice reaction task give rise to behavioral costs when the primes and the target stimuli are mapped to the same response and result in benefits when they are mapped to opposite responses. Researchers assume that this negative compatibility effect reflects inhibitory processes in the control of perceptuomotor links. The authors investigated whether the inhibition operates at the level of abstract central codes or at effector-specific motor stages. In 2 experiments (N = 8 participants in each), left or right hand or foot responses were required to target stimuli that were preceded by masked arrow primes mapped to the same response side as the target stimuli in compatible trials and to the opposite response side in incompatible trials; the primes were irrelevant in neutral trials. In Experiment 1, when the masked primes determined both response side and modality, there was no transfer of negative compatibility effects across response modalities. That finding is inconsistent with a central abstract locus of inhibition and suggests that inhibition operates at effector-specific motor stages. In Experiment 2, primes conveyed only response side information but left response modality uncertain, and negative compatibility effects were elicited for both hand and foot responses, suggesting that partially informative masked primes can trigger a parallel activation and subsequent inhibition of response processes within separate effector systems.     

Attention and action: The role of response mappings in auditory attention switching

Switching auditory attention incurs a performance decrement (i.e. auditory attention-switch costs). Using an auditory attention-switching paradigm, we aimed to generalise these across different response mappings. In all three experiments, two number words, spoken by a female and male speaker, were presented dichotically via headphones. A visual cue indicated the gender of the to-be-attended speaker in each trial. The task was a magnitude judgement of the relevant number word (i.e. smaller vs. larger than 5). We additionally varied the interval between cue onset and auditory stimulus onset (cue-stimulus interval) to explore cue-based preparatory effects. In Experiment 1, attention switching was more costly with direct-verbal responses (e.g. ‘smaller’) than in the shadowing task (e.g. ‘three’). In Experiment 2, performance was largely similar for direct-verbal responses and abstract-verbal responses (e.g. ‘left’). In Experiment 3, performance was generally worse with abstract-verbal responses than with abstract-manual responses (e.g. left key press) and auditory attention-switch costs were similar for both response mappings. Overall, auditory switch costs occurred more or less invariably across response mappings in categorical (magnitude) judgements suggesting a minor role of the response mapping in auditory attention switching. Furthermore, verbal identity-based judgements (i.e. shadowing) generally seem to benefit from ideomotor compatibility.     

Response-based strengthening in task shifting: evidence from shift effects produced by errors

The hypothesis is introduced that 1 source of shift costs is the strengthening of task-related associations occurring whenever an overt response is produced. The authors tested this account by examining shift effects following errors and error compensation processes. The authors predicted that following a specific type of error, called task confusion, shift benefits instead of shift costs should result. A series of 3 experiments confirmed this prediction showing that task confusions produce shift benefits in subsequent trials (Experiment 1), even when the error is detected (Experiment 2). Moreover, only posterror processes that imply an error correction response produce shift costs (Experiment 3). These results additionally suggest that error detection cannot prevent errors from affecting subsequent performance.     

Response facilitation and inhibition in manual, vocal, and oculomotor performance: evidence for a modality-unspecific mechanism

In 2 experiments (N = 10, Experiment 1; N = 16, Experiment 2), the authors investigated whether evidence for response facilitation and subsequent inhibition elicited by masked prime stimuli can be observed for output modalities other than manual responding. Masked primes were followed by target stimuli that required a 2-choice manual, saccadic, or vocal response. Performance was measured for compatible trials in which primes and targets were identical and for incompatible trials in which they were mapped to opposite responses. When primes were presented centrally, performance benefits were obtained for incompatible trials; whereas for peripherally presented primes, performance benefits were found in compatible trials. That pattern of results was obtained for manual responses and for saccadic eye movements (Experiment 1), demonstrating that those effects are not mediated by specialized dorsal pathways involved in visuomanual control. An analogous pattern of effects was found when manual and vocal responses were compared (Experiment 2). Because vocal responding is controlled by the inferotemporal cortex, that result shows that prime-target compatibility effects are not primarily mediated by the dorsal stream, but appear to reflect modality-unspecific visuomotor links that allow rapid activation of motor responses that may later be subject to inhibition.     

Sticky rules: integration between abstract rules and specific actions

The authors manipulated repetitions and/or changes of abstract response rules and the specific stimulus- response (S-R) associations used under these rules. Experiments 1 and 2, assessing trial-to-trial priming effects, showed that repetition of complete S-R couplings produced only benefits when the rule also repeated (i.e., rule-S-R conjunctions) but costs when identical S-R couplings repeated while rules changed. In Experiments 3 and 4, the authors manipulated amount of experience with specific rule-S-R conjunctions and demonstrated integration between rules and S-R couplings in terms of cumulative practice effects. However, unlike short-term priming effects, cumulative practice supported generalization of experience with specific S-R couplings across rule boundaries (Experiment 4). Results are discussed in terms of constraints on models of hierarchical control and in terms of qualitatively different ways in which people profit from very recent experiences (i.e., all-or-none access to working memory representations) versus cumulative experience (i.e., similarity-based retrieval from long-term memory).     

Talking while looking: On the encapsulation of output system representations

The idea that the human mind can be divided into distinct (but interacting) functional modules is an important presupposition in many theories of cognition. While previous research on modularity predominantly studied input domains (e.g., vision) or central processes, the present study focused on cognitive representations of output domains. Specifically, we asked to what extent output domain representations are encapsulated (i.e., immune to influence from other domains, representing a key feature of modularity) by studying determinants of interference between simultaneous action demands (oculomotor and vocal responses). To examine the degree of encapsulation, we compared single- vs. dual-response performance triggered by single stimuli. Experiment 1 addressed the role of stimulus modality under dimensionally overlapping response requirements (stimuli and responses were spatial and compatible throughout). In Experiment 2, we manipulated the presence of dimensional overlap across responses. Substantial performance costs associated with dual-response (vs. single-response) demands were observed across response modalities, conditions, and experiments. Dimensional overlap combined with shared spatial codes across responses enabled response-code priming (i.e., beneficial crosstalk between output domains). Overall, the results are at odds with the idea of strong encapsulation of output system representations and show how processing content determines the extent of interdependency between output domains in cognition.     

Holding a manual response sequence in memory can disrupt vocal responses that share semantic features with the manual response

Holding an action plan in memory for later execution can delay execution of another action if the actions share a similar (compatible) feature. This compatibility interference (CI) occurs for actions that share the same response modality (e.g., manual response). We investigated whether CI can generalize to actions that utilize different response modalities (manual and vocal). In three experiments, participants planned and withheld a sequence of key-presses with the left- or right-hand based on the visual identity of the first stimulus, and then immediately executed a speeded, vocal response (‘left’ or ‘right’) to a second visual stimulus. The vocal response was based on discriminating stimulus color (Experiment 1), reading a written word (Experiment 2), or reporting the antonym of a written word (Experiment 3). Results showed that CI occurred when the manual response hand (e.g., left) was compatible with the identity of the vocal response (e.g., ‘left’) in Experiment 1 and 3, but not in Experiment 2. This suggests that partial overlap of semantic codes is sufficient to obtain CI unless the intervening action can be accessed automatically (Experiment 2). These findings are consistent with the code occupation hypothesis and the general framework of the theory of event coding (Behav Brain Sci 24:849–878, 2001a; Behav Brain Sci 24:910–937, 2001b).     

Response Facilitation and Inhibition in Manual,Vocal, and Oculomotor Performance: Evidence for a Modality-Unspecific Mechanism

In 2 experiments (N = 10, Experiment 1; N = 16, Experiment 2), the authors investigated whether evidence for response facilitation and subsequent inhibition elicited by masked prime stimuli can be observed for output modalities other than manual responding. Masked primes were followed by target stimuli that required a 2-choice manual, saccadic, or vocal response. Performance was measured for compatible trials in which primes and targets were identical and for incompatible trials in which they were mapped to opposite responses. When primes were presented centrally, performance benefits were obtained for incompatible trials; whereas for peripherally presented primes, performance benefits were found in compatible trials. That pattern of results was obtained for manual responses and for saccadic eye movements (Experiment 1), demonstrating that those effects are not mediated by specialized dorsal pathways involved in visuomanual control. An analogous pattern of effects was found when manual and vocal responses were compared (Experiment 2). Because vocal responding is controlled by the inferotemporal cortex, that result shows that prime-target compatibility effects are not primarily mediated by the dorsal stream, but appear to reflect modality-unspecific visuomotor links that allow rapid activation of motor responses that may later be subject to inhibition.     

An action sequence held in memory can interfere with response selection of a target stimulus,but does not interfere with response activation of noise stimuli

Withholding an action plan in memory for later execution can delay execution of another action if the actions share a similar (compatible) action feature (e.g., response hand). We investigated whether this phenomenon, termed compatibility interference (CI), occurs for responses associated with a target as well as responses associated with distractors in a visual selection task. Participants planned and withheld a sequence of keypress responses (with their right or left hand), according to the identity of a stimulus (A), and then immediately executed a keypress response (with their right or left hand) to a second stimulus (B), according to the identity of a target letter appearing alone or among distractor letters. Distractor letters were either response compatible or incompatible with the target and appeared either simultaneously with the target (Experiments 1A and 2) or 100 msec before the target (Experiment 1B). Also, stimulus-response mapping was either 1:1 (Experiment 1) or 2:1 (Experiment 2). Results showed that the response to the Stimulus B target was delayed when it required the same response hand as Stimulus A, as opposed to a different hand. Also, the target reaction time for Stimulus B was greater when the target was flanked by incompatible distractors than when it was flanked by compatible distractors. Moreover, the degree of CI was consistent across the compatible-, incompatible-, and no-distractor conditions, indicating that CI generalizes to responses associated with a target, but not to those associated with distractors. Thus, CI occurs at a response selection, not at a response activation stage. Implications for the code occupation account for CI (e.g., Stoet & Hommel, 1999, 2002) and an alternative account for CI are discussed.     

Eliminating the cost of task set reconfiguration

With insufficient time to fully prepare for a switch in task, a deterioration in performance on the first trial of a new task would be expected. The interest of researchers has been captured by the residual switch costs that, surprisingly, remain despite sufficient time to prepare. We used avery simple task to investigate the costs to reaction time and accuracy associated with changing between two different instructional sets every eight trials. Subjects responded to left and right visual targets by making either spatially compatible or incompatible eye movements (Experiment 1) or buttonpress responses (Experiment 2). The subjects were cued as to whether to make the compatible or the incompatible response by the color of a border appearing on the perimeter of the display. In cases in which the subject alternated between making pro- and antisaccades, the large costs to reaction time and accuracy at the short cue-target stimulus onset asynchrony were completely eliminated when sufficient time was provided to prepare for the switch. This complete elimination of residual switch costs was not obtained when the same alternation was applied to manual responses. This pattern of results links residual costs to response selection processes and suggests that they are not a necessary component of the switch process. We propose that the elimination of "stubborn" residual switch costs is rooted in our use of a hypercompatible task (making saccades toward targets) that places minimal demands on response selection.     

A central-peripheral asymmetry in masked priming

Masked primes presented prior to a target result in behavioral benefits on incompatible trials (in which the prime and the target are mapped onto opposite responses) when they appear at fixation, but in behavioral benefits on compatible trials (in which the prime and the target are mapped onto the same response) when appearing peripherally. In Experiment 1, the time course of this central-peripheral asymmetry (CPA) was investigated. For central primes, compatible-trial benefits at short stimulus onset asynchronies (SOAs) turned into incompatible-trial benefits at longer SOAs. For peripheral primes, compatible-trial benefits at short SOAs increased in size with longer SOAs. Experiment 2 showed that these effects also occur when primes and targets are physically dissimilar, ruling out an interpretation in terms of the perceptual properties of the stimulus material. In Experiments 3 and 4, the question was investigated as to whether the CPA is related to visual-spatial attention and/or retinal eccentricity per se. The results indicate that the CPA is independent of attentional factors but strongly related to the physiological inhomogeneity of the retina. It is argued that central and peripheral primes trigger an initial motor activation, which is inhibited only if primes are presented at retinal locations of sufficiently high perceptual sensitivity. The results are discussed in terms of an activation threshold model.     

Response inhibition under task switching: its strength depends on the amount of task-irrelevant response activation

Under task switch conditions, response repetitions usually produce benefits if the task also repeats, but costs if the task switches. So far, it is largely undecided how to account for these effects. In the present study, we provide additional evidence in favor of the account that each response is inhibited in order to prevent its accidental re-execution. To test this hypothesis, the risk of an accidental re-execution of a given response was manipulated by modulating the activation of the response in the previous task. In Experiment 1, this was done by means of congruent and incongruent stimuli. As expected, on task switch trials, the repetition costs were larger if a congruent rather than an incongruent stimulus occurred in the previous task. In Experiment 2, the same effect occurred for stimulus-response compatible versus incompatible stimuli in the previous task. In Experiment 3, both manipulations were applied together, which produced almost additive effects. Altogether, the results support the inhibition account for the response repetition effects under task switch conditions.     

Flowers and spiders in spatial stimulus-response compatibility: does affective valence influence selection of task-sets or selection of responses?

The present study examined the effect of stimulus valence on two levels of selection in the cognitive system, selection of a task-set and selection of a response. In the first experiment, participants performed a spatial compatibility task (pressing left and right keys according to the locations of stimuli) in which stimulus-response mappings were determined by stimulus valence. There was a standard spatial stimulus-response compatibility (SRC) effect for positive stimuli (flowers) and a reversed SRC effect for negative stimuli (spiders), but the same data could be interpreted as showing faster responses when positive and negative stimuli were assigned to compatible and incompatible mappings, respectively, than when the assignment was opposite. Experiment 2 disentangled these interpretations, showing that valence did not influence a spatial SRC effect (Simon effect) when task-set retrieval was unnecessary. Experiments 3 and 4 replaced keypress responses with joystick deflections that afforded approach/avoidance action coding. Stimulus valence modulated the Simon effect (but did not reverse it) when the valence was task-relevant (Experiment 3) as well as when it was task-irrelevant (Experiment 4). Therefore, stimulus valence influences task-set selection and response selection, but the influence on the latter is limited to conditions where responses afford approach/avoidance action coding.     

The negative compatibility effect with nonmasking flankers: a case for mask-triggered inhibition hypothesis

Visual targets which follow a prime stimulus and a mask can be identified faster when they are incompatible rather than compatible with the prime (negative compatibility effect--NCE). According to the self-inhibition hypothesis, the initial activation of the motor response is elicited by the prime based on its identity. This activation leads to benefits for compatible trials and costs for incompatible trials. This motor activation is followed by an inhibition phase, leading to an NCE if perceptual evidence of the prime is immediately removed by the mask. The object-updating and mask-triggered inhibition hypotheses emphasize the role of the mask content (i.e. whether the mask possesses target-like features). We show that the NCE may appear even if nonmasking neutral flankers are presented instead of a mask. Moreover, although with target-like flankers the NCE is larger, it occurred if flankers and targets are built from dissimilar elements. Therefore, masks/flankers can evoke an inhibition phase independently of whether or not they remove evidence for the prime and whether they are similar to the targets.     

Task selection cost asymmetry without task switching

The switch cost asymmetry (i.e., larger costs when switching from a nondominant into a dominant task than vice versa) has been explained in terms of the trial-to-trial carryover of activation levels required for the dominant versus the nondominant task. However, there is an open question about whether an actual switch in task is in fact necessary to obtain a “selection” cost asymmetry. In Experiments 1 and 2, we modified an alternatingruns paradigm to include either long or short response-to-stimulus intervals (RSIs) after each pair of trials (i.e., AA-AA-BB-BB), thereby inducing selection costs not only at the point of a task switch (i.e., AA-BB), but also between same-task pairs (i.e., AA-AA). Using spatially compatible versus incompatible response rules (Experiment 1) and Stroop word versus color naming (Experiment 2), we found asymmetric effects not only at task-change transitions, but also at task-repeat transitions when the RSI was long (presumably inducing frequent losses of set). In Experiments 3A and 3B, a cost asymmetry for long RSIs was obtained even when competing tasks were separated into alternating single task blocks, but not when the tasks were compared in a betweensubjects design. This general pattern cannot be explained by activation carryover models, but is consistent with the idea that the asymmetry arises as a result of interference from long-term memory traces.     

Switching between tasks and responses: a developmental study

Task switching requires the ability to flexibly switch between task rules and responses, and is sensitive to developmental change. We tested the hypothesis that developmental changes in task switch performance are associated with changes in the facilitating or interfering effect of the previously retrieved stimulus-response (S-R) association. Three age groups (7-8-year-olds, 10-12-year-olds and 20-25-year-olds) performed a two-choice reaction time (RT) task in which spatially compatible or incompatible responses were required. The RT costs associated with switching between tasks were larger when responses were repeated than when responses were alternated. Younger children showed a greater cost than adults when switching between tasks but repeating responses. This age difference decreased when the interval between the previous response and the upcoming stimulus increased. Switch costs were larger when switching to the compatible task than to the incompatible task, but this effect did not differ between age groups. These findings suggest that young children build up stronger transient associations between task sets and response sets, which interfere with their ability to switch to currently intended actions. A similar pattern has previously been observed for older adults (Mayr, 2001), suggesting a common contributor to task switching deficits across the life span.     

Inhibition of return for target discriminations: the effect of repeating discriminated and irrelevant stimulus dimensions

Inhibition of return (IOR) refers to slowed reaction times when a target repeats in the same location as a preceding stimulus. In four experiments, the participants were presented with two successive stimuli, S1 and S2. In Experiments 1 and 2, the participants made a speeded discrimination of the identity or orientation of both S1 and S2 (Experiment 1) or of S2 only (Experiment 2). An IOR effect occurred for the repetition of stimulus location, but a facilitatory effect occurred if the stimulus remained unchanged or if an overt response was repeated. In Experiments 3 and 4, the participants localized S1 and S2 (Experiment 3) or S2 only (Experiment 4) to the left or right of center. In this case, repeating the same stimulus had no effect: IOR occurred any time stimulus location repeated. These results demonstrate that the expression of IOR is modulated by the repetition of a target object, but only when the task requires the discrimination of that object; when no discrimination is required, IOR is unaffected.