Wilfried Kunde

Response-effect compatibility in manual choice reaction tasks.

This study investigated whether compatibility between responses and their consistent sensorial effects influences performance in manual choice reaction tasks. In Experiment 1 responses to the nonspatial stimulus attribute of color were affected by the correspondence between the location of responses and the location of their visual effects. In Experiment 2, a comparable influence was found with nonspatial responses of varying force and nonspatial response effects of varying auditory intensity. Experiment 3 ruled out the hypothesis that acquired stimulus-effect associations may account for this influence of response-effect compatibility. In sum, the results show that forthcoming response effects influence response selection as if these effects were already sensorially present, suggesting that in line with the classical ideomotor theory, anticipated response effects play a substantial role in response selection.

Conscious control over the content of unconscious cognition

Visual stimuli (primes) presented too briefly to be consciously identified can nevertheless affect responses to subsequent stimuli - an instance of unconscious cognition. There is a lively debate as to whether such priming effects originate from unconscious semantic processing of the primes or from reactivation of learned motor responses that conscious stimuli afford during preceding practice. In four experiments we demonstrate that unconscious stimuli owe their impact neither to automatic semantic categorization nor to memory traces of preceding stimulus-response episodes, but to their match with pre-specified cognitive action-trigger conditions. The intentional creation of such triggers allows actors to control the way unconscious stimuli bias their behaviour.

Anticipated action effects affect the selection, initiation, and execution of actions.

This study investigated the impact of contingent action effects on response production. In Experiment 1 responses of varying intensity were initiated faster when contingently followed by auditory effects of corresponding rather than of noncorresponding intensity. This response–effect (R–E) compatibility influence was robust with respect to practice, and it was not due to persisting influences of preceding R–E episodes. These results support the conclusion that R–E compatibility reflects the impact of anticipatory effect representations in response production. Experiment 2 showed that anticipatory effect codes have an impact on early processes of response production (response selection) as well as on processes that immediately precede overt responding (response initiation). Finally, they also influence the way the actions are physically performed (response execution). The results support and specify ideo-motor theories of action control that assume movements to be controlled by anticipations of their sensorial effects.

Verbal response-effect compatibility.

Ideomotor theory states that motor responses are activated by an anticipation of their sensory effects. We assumed that anticipated effects would produce response-effect (R-E) compatibility when there is dimensional overlap of effects and responses. In a four-choice task, visual digit stimuli called for verbal responses (color names). Each response produced a written response-effect on the screen. In different groups, the response-effect was a colored color word (e.g.,blue in blue), a white color word, or a colored nonword (Xs in blue). In different blocks, the predictable effects were either incompatible (e.g., response “blue” → effect: green) or compatible with the response. We found faster responses with compatible than with incompatible R-E mappings. The compatibility effect was strongest with colored words, intermediate with white words, and smallest with colored nonwords. We conclude that effect anticipation influences response selection on both a perceptual level (related to the words color) and a conceptual level (related to the words meaning).

Sequential modulations of correspondence effects across spatial dimensions and tasks.

In two experiments, we explored sequential modulations of correspondence effects in a prime-target paradigm. In Experiment 1, the participants responded to the direction of target arrows that were preceded by prime arrows with a corresponding or noncorresponding direction. This produced a prime-target correspondence effect that was reduced when the preceding trial contained a noncorresponding prime-target event. This sequential modulation of the correspondence effect was observed even when neither stimuli nor responses were repeated from one trial to the next, ruling out explanations of sequential modulations in terms of stimulus or response repetitions. Experiment 2 combined the prime-target correspondence effect with a Simon-type correspondence effect. Both effects were reduced following noncorrespondence of the same type and, to a lesser extent, following noncorrespondence of the other type. Altogether, these results suggest that part of the sequential modulation of correspondence effects reflects an adaptation to a preceding response conflict independently of the peripheral stimulus events that produced this conflict.

The impact of anticipated action effects on action planning

Three experiments with a total of 72 participants investigated the assumption that motor actions are planned in terms of their sensorial effects. Participants had to prepare a certain action A that consistently led to a sensorial effect (a tone of certain pitch). Instead of (in Experiment 1) or before (in Experiments 2 and 3) the execution of the prepared action, another response B had to be carried out, which either resulted in the same or in a different auditory effect (a tone of same or different pitch). It was found that a to-be-executed response B was in general initiated more quickly when it resulted in the same effect as a concurrently prepared response A. The results are considered as evidence for the basic notion that the preparation and initiation even of very simple actions is mediated by an anticipation of their reafferences.

Goal-congruency in bimanual object manipulation

In 3 experiments, the authors investigated the impact of action goals on the production of discrete bimanual responses. Similar to a bartender putting 2 glasses simultaneously on a shelf, participants placed 2 objects into either parallel or opposite orientations by carrying out either mirror-symmetrical or mirror-asymmetrical movements. In Experiment 1, performance was strongly affected by the congruency of the intended object orientations but was essentially unaffected by movement symmetry. Experiment 2 replicated this instrumental goal-congruency effect (and the absence of motor-symmetry effects) when actions were cued in advance. Experiment 3 revealed substantial motor-symmetry effects, provided the movements themselves became the action goal. The authors concluded that performance in bimanual choice reaction tasks is constrained by the creation and maintenance of goal codes rather than by properties inherent in the neuromuscular system that carries out these responses. These goals can relate to either body-intrinsic states or to body-extrinsic states according to the actors current intentions.

Spatial Compatibility Effects With Tool Use

Objective: We explored constraints in responding to spatially variable stimuli when hand movements are transformed into inverse movements of a tool. Background: Generally, the spatial compatibility between stimuli and responses is a powerful determinant of performance. However, many tasks require the use of simple tools such as first-class levers that transform hand movements into inverted movements of a tool. What types of compatibility effects arise with such tools? Method: Participants moved the tip of a pointer to the left or right according to the color of a stimulus. The pointer was manipulated either directly, so that a hand movement caused a pointer movement in the corresponding direction, or indirectly, so that the hand moved the pointer in the opposite direction. Results: Responding was faster when the location of stimulus and the movement direction of the tool corresponded than when they did not correspond, independent of the movement direction of the hand. This occurred when stimulus location was task relevant (Experiment 1) as well as when it was task irrelevant (Experiment 2). Furthermore, responding was delayed when the hand and the relevant end of the tool moved in noncorresponding rather than corresponding directions. Conclusion: These results point to two distinct compatibility effects in tool use: one that relates to the transformation of stimuli into goals and one that relates to the transformation of goals into movements. Application: Potential applications of this research include the prediction and possibly manipulation of unwanted “fulcrum effects” in laparoscopic surgery and other first-class lever movements.

Evidence for task-specific resolution of response conflict

When a target requires different responses to a relevant and to an irrelevant task in a task-switching paradigm, there is response conflict. This target-induced response conflict was combined with conflict caused by a subliminally presented prime presented prior to the target. We found that target-related conflict reduced prime-induced conflict effects within the same trial. However, target-related conflict modified prime-related conflict effects according to the irrelevant stimulus-response (S-R) rule, but not according to the relevant S-R rule. Moreover, trial-to-trial modulations of the target congruency effect were observed in task repetition trials, but not in task switch trials. These results indicate that conflict resolution mechanisms, at least under the present circumstances, operate in a strictly task-specific manner.

Mechanisms of subliminal response priming

Subliminal response priming has been considered to operate on several stages, e.g. perceptual, central or motor stages might be affected. While primes’ impact on target perception has been clearly demonstrated, semantic response priming recently has been thrown into doubt (e.g. Klinger, Burton, & Pitts, 2000). Finally, LRP studies have revealed that subliminal primes evoke motor processes. Yet, the premises for such prime-evoked motor activation are not settled. A transfer of priming to stimuli that have never been presented as targets appears particularly interesting because it suggests a level of processing that goes beyond a reactivation of previously acquired S-R links. Yet, such transfer has not always withstood empirical testing. To account for these contradictory results, we proposed a two-process model (Kunde, Kiesel, & Hoffmann, 2003): First, participants build up expectations regarding imperative stimuli for the required responses according to experience and/or instructions. Second, stimuli that match these “action triggers” directly activate the corresponding motor responses irrespective of their conscious identification. In line with these assumptions, recent studies revealed that non-target primes induce priming when they fit the current task intentions and when they are expected in the experimental setting.