Edited by: David Sobel, Brown University, USA
Reviewed by: Matthew Schlesinger, Southern Illinois University, USA; Marissa Greif, Florida Atlantic University, USA
*Correspondence: Bernhard Hommel, Leiden University, Department of Psychology, Cognitive Psychology Unit, Wassenaarseweg 52, 2333 XZ Leiden, Netherlands. e-mail:
This article was submitted to Frontiers in Developmental Psychology, a specialty of Frontiers in Psychology.
This is an open-access article distributed under the terms of the
Ideomotor theories claim that carrying out a movement that produces a perceivable effect creates a bidirectional association between the two, which can then be used by action control processes to retrieve the associated action by anticipating its outcome. Previous implicit-learning studies have shown that practice renders novel but action-contingent stimuli effective retrieval cues of the action they used to follow, suggesting that experiencing sequences of actions and effects creates bidirectional action–effect associations. We investigated whether action–effect associations are also acquired under explicit learning conditions and whether familiar action–effect relations (such as between a trumpet and a trumpet sound) are learned the same way as novel, arbitrary relations are. We also investigated whether these factors affect adults and 4-year-old children equally. Findings suggest that explicit learning produces the same bidirectional action–effect associations as implicit-learning does, that non-arbitrary relations improve performance without affecting learning
James’ (
Ideomotor approaches to action planning and action control recently regained interest (Hommel,
In an acquisition phase of this design subjects freely choose among several actions (say, the key-pressing response R1 or R2) and each action is consistently followed by an effect stimulus (say, sound E1 or E2). The effect stimulus is not relevant to the task and subjects are not encouraged in any way to attend to, or acquire the action–effect relationship. In the transfer phase the effect stimuli are now being presented as target stimuli, and the sound-key mapping can be either consistent (E1 → R1 and E2 → R2) or inconsistent (E1 → R2 and E2 → R1) with the key-sound mapping of the acquisition phase. In general, it is found that subjects perform better during the transfer phase when an acquisition-consistent effect–action mapping is required as compared to an inconsistent mapping (e.g., Elsner and Hommel,
The available studies on action–effect learning have used novel, arbitrary relations between action–effects, so that the amount of learning could be experimentally controlled. Moreover, as the novel action–effects are commonly task-irrelevant and subjects are often explicitly instructed to ignore them, the acquisition of action–effect associations must be considered implicit or at least non-intentional. Indeed, Elsner and Hommel (
Even though it is theoretically important to demonstrate that spontaneous action–effect learning can take place under such “unfavorable” circumstances, one may argue that these circumstances are not particularly ecologically valid. Infants, children, and adult novices facing a new task will often actively explore the appropriateness and potential of alternative actions to reach a particular goal, and thus explicitly carry out specific actions to produce specific effects. In the present study, we investigated whether these circumstances also allow for the acquisition of bidirectional action–effect associations. Apart from ecological validity considerations, this research goal was motivated by some recent observations that seem to call into doubt that intentional action–effect learning leads to bidirectional associations.
As Verschoor et al. (submitted) demonstrated, requiring subjects to verbalize the causal relation between actions and effects eliminates the consistency effects in the transfer phase of the Elsner and Hommel (
The question of this study thus was whether explicit action–effect acquisition would be sufficient to eliminate bidirectional associations, which would put rather tight constraints on ideomotor theorizing in the context of action control, or whether explicit acquisition would be comparable to implicit acquisition as measured by many other studies on action–effect learning (e.g., Elsner and Hommel,
In an additional attempt to consider more realistic situations, we were also interested to see whether pre-existing knowledge about the causal relationship between an action and its effects would alter the directionality of the respective association. To investigate that, we compared learning of a novel, unfamiliar, and arbitrary pairing of a key-pressing action with a tone, with learning of a pairing that we considered familiar to our subjects from pre-experimental experience (i.e., non-arbitrary, as defined in reference to that experience). To accomplish this contrast between non-arbitrary and arbitrary action–effects, we manipulated the actions effects so that one key would produce the sound that the respective object was known to produce (e.g., pressing the trumpet key produced a typical trumpet sound, from here on symbolized as <toot>), whereas pressing the other key produced a novel and arbitrarily chosen sound (e.g., bell key → <piew>). There are at least two possible outcomes of this familiarity manipulation (a further possibility will be discussed later). First, one may assume that pre-existing associations facilitate bidirectional learning, so that the familiar relationship produces a stronger consistency effect. Second, however, it may be that knowing about the causal relationship between trumpets and the sound they produce strengthens the association from trumpet to <toot> but works against creating a bidirectional association. This should reduce or eliminate the consistency effects on RTs and error rates in the transfer phase for the non-arbitrary action–effects.
A final purpose of the present study was to compare the learning performance of adult subjects with 4-year-old children. In previous studies we obtained evidence of action–effect acquisition in both adults and children, even though the performance profiles differed in detail (Eenshuistra et al.,
Participants were 34 4-year-old children (
The experiment was divided into an acquisition phase and a transfer phase. Trials in the acquisition phase started with the presentation of a visual stimulus, a picture of Ernie or Bert from Sesame Street. A picture of Ernie signaled a go trial, which required a freely chosen left or right key press on a specially designed two-key keyboard. One key was marked with a picture of a trumpet and the other key with a picture of a bell. Pressing one of the two keys was always followed by a sound that was plausibly related to the picture marking the key (trumpet key followed by <toot> or bell key followed by <tring>) resulting in a
The transfer phase consisted of a go/no-go two-choice reaction-time task. Again a picture of Ernie signaled a go trial and a picture of Bert a no-go trial (no-go trials were used to make the task more appealing). The picture of Ernie staid on screen until a response was made or until 2 s had passed. In a no-go trial a picture of Bert without any sound was presented for 2 s. The inter-trial interval was 1500 ms.
A go trial started with the presentation of the picture of Ernie together with one of the two sounds that in the preceding acquisition phase served as action–effects (200 ms). The action–effects now served as imperative stimuli. Participants were to respond to the stimuli as quickly and accurately as possible according to a fixed stimulus–response (S–R) mapping. They were randomly assigned to either a consistent or an inconsistent S–R mapping in the transfer phase. In the consistent mapping condition, the sound-key mapping matched the key-sound mapping of the acquisition phase (e.g., trumpet key → <toot> and bell → <piew> in the acquisition phase became <toot> → trumpet key and <piew> → bell key in the transfer phase). In the inconsistent mapping condition, the sound-key assignment was reversed (e.g., trumpet key → <toot> and bell → <piew> in the acquisition phase became <piew> → trumpet key and <toot> → bell key in the transfer phase). As in our previous study (Eenshuistra et al.,
Associatedness was coded with respect to the relation between the key label (trumpet or bell label) and the sound; e.g., responding with the trumpet key to <toot> would fall into the non-arbitrary category while responding with the bell key to <piew> would count as arbitrary.
The acquisition phase consisted of 18 practice trials (12 go trials, 6 no-go trials) and 144 test trials (96 go trials and 48 no-go trials). Subjects were instructed that Ernie “likes music” and that they could “make music” for Ernie. They were told that they could choose freely which sound to make for Ernie by pressing the trumpet key or the bell key. The causal relation between pushing one of the keys and the resulting auditory effect was made explicit by instructing participants that “If you want the trumpet to make a sound you should push the trumpet key” and giving them the opportunity to explore the corresponding contingency by pressing the key. The same instruction followed for the bell key. Additionally, subjects were instructed that they could freely choose how often they pressed a key but that in total they had to press both keys about equally often. When participants persevered in pushing only one button during acquisition (predominantly children were prone to this), the experimenter reminded them to change keys now and then. Furthermore, they were told that Bert “does not like music” and that no response should be given when a picture of Bert appeared. To motivate subjects – especially the children – to complete the acquisition phase, they were told that Ernie was allowed to play until lunchtime. A picture of a clock that was colored for one third and two third was presented after 48 and 96 trials, respectively. After 144 trials the clock was completely colored, indicating that lunch time had reached and with that the end of the acquisition phase.
In the transfer phase participants were told that Ernie was making music and wanted them to participate. When a picture of Ernie appeared together with one of the two effect sounds, they should press the trumpet key and when they perceived Ernie together with the other effect sound they should press the bell key, thus motivating the (consistent or inconsistent) S–R mapping required for the transfer phase. Again, subjects were instructed to withhold their response when Bert appeared, because “Bert hates music and likes the silence.” As in the acquisition phase, subjects were informed about their progress in the transfer phase. However, now they were instructed that Ernie was allowed to make music until bedtime and the same clock procedure was used to indicate when bedtime had reached and the transfer phase had finished. The transfer phase consisted of 18 practice trials (12 go trials, 6 no-go trials) and 90 test trials (72 go trials and 18 no-go trials).
Left and right hand responses were equally distributed [49.8 vs. 50.2%,
Mean RTs of the transfer phase were analyzed as a function of age group, associatedness (arbitrary versus non-arbitrary), and mapping (consistency versus inconsistent), with mean overall RT of the acquisition phase as covariate. Unsurprisingly, the adults were faster than the 4-year-old children (630 vs. 1120 ms for adults and children),
Figure
The aim of the present study was threefold. First, we were interested to see whether action–effect relations that are explicitly described as causal, and in a context where the effect is willfully produced by carrying out the respective action, are acquired in the same way as implicit action–effect relations. In particular, we asked whether explicit, intentional acquisition would lead to the creation of unidirectional associations between the representations of the action and the effect. If that would have been the case, no consistency effects would have been expected in the transfer phase. Given that such effects were obtained, and that the size of these effects is almost identical to what has been observed under implicit-learning conditions (Elsner and Hommel,
The second aim of the present study was to compare the learning of novel, arbitrary relations between actions and effects, as often used in ideomotor studies, with the learning (or, better, strengthening) of action–effect relations that fit with pre-experimental knowledge. Although the effects of pre-experimental knowledge on RT’s and errors were small, they were coherent and reliable. Non-arbitrary, familiar relations affected performance and allowed for faster responding in both the acquisition and the transfer phase and more accurate responding in the transfer. However, there was no evidence that the type of relationship interacted with any other variable, including consistency. On the one hand, this means that our manipulation was successful in contrasting familiar and unfamiliar relations. On the other hand, however, the familiarity of a relation does not seem to modulate the format of the emerging or strengthened association. In particular, greater familiarity with the relationship between an action and its consequences does not seem to induce a unidirectional action → effect association
Our third aim was to compare transfer effects in young children and adults. Mapping consistency affected performance to the same degree in either group as far as reaction times are concerned. The error rates were also sensitive to consistency but more so in the 4-year-olds than in adults. This profile amounts to a perfect replication of previous observations (Eenshuistra et al.,
To summarize, the present study shows that experiencing sequences of actions and effects induces the creation of bidirectional associations between action and effect representations, no matter what the degree of familiarity with related action–effect contingencies and irrespective of whether the sequence is picked up implicitly or the action is explicitly carried out to produce the effect. This corroborates predictions from ideomotor approaches to action control (James,
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
This research was funded by the Deutsche Forschungsgemeinschaft (SPP 1107) through grants to Jutta Kray (KR 1884/3-3) and Bernhard Hommel (HO 1430/8-3). Correspondence and requests for materials should be send to Bernhard Hommel, Leiden University, Department of Psychology, Cognitive Psychology Unit, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands;