Background
The article under review investigates the concept of grasp actions. Bub et al. (2018) state that they are directed by an individual’s stored manipulation knowledge, which retains how one typically uses objects, and vary depending on the objective to either lift or use an object. It is assumed that lift actions are produced faster and can be accomplished even without prior experience of manipulating the object (Bub et al., 2018). Additionally, if the objective requires a different posture for lift and use grasp actions, production of the latter interferes with the former. It is supposed that use actions impose cognitive bias, affecting the subsequent production of lift actions. Bub et al. (2018) theorize that lift actions also rely on manipulation knowledge, and subsequent ones see interference from prior experience. The authors aim to investigate the switch costs, which emerge when use and lift actions are produced.
Method 1-2
The empirical part included four connected experiments, although each had a new set of participants. The first two involved 32 English-speaking subjects, and the sample size reflected the effect size obtained from analyzing the previous studies. The used materials included a cellphone, a pencil, and a spray. The first experiment employed cues for actions, demonstrated in Figure 1. The second one was more true-to-life and replaced them with short imperative sentences.
Method 3-4
The third experiment was expanded to include 48 subjects with the same characteristics. The overall number of the materials was six, with three new additions (a calculator, a lotion bottler, and a stapler). The goal necessitated the participants to switch between the two trial blocks without training, which was performed to observe the presumed use-on-lift interference. The fourth experiment had 31 participants interacting with the materials under the same conditions. It attempted to test how one’s intention impacts action interference and challenge the idea of faster lift actions.
Results
Each experiment yielded promising evidence for the hypothesis, which supposed that lift actions also needed prior experience. During the experiments, no differences between lift/use action speed were observed. Continuously repeating actions are generally performed quickly regardless of the action. Switch costs occurred from Experiment 2 but also showed no discrepancies between the two types. The third one revealed that distal goals of lifting could be sustained over time, and such cues were followed quickly due to the subject’s predisposition to do so after using an item. In the fourth experiment, Bub et al. (2018) concluded that “the intention to use an object facilitates the prior action of lifting it because the motor sequence – lift then use – is habitually conscripted” (p. 35). Figure 2 depicts mean response time and percent error throughout the study’s course.
Discussion
The observations imply that use actions correlate with the stored motor knowledge, whereas sudden lift actions can depend solely on the perceived shape and structure of an item. Simultaneously, Bob et al. (2018) discuss that “lift-to-use” sequences are well-defined in the motor system, whereas the opposite cue leads to higher switch costs. However, the primary limitations of the study comprise the participants’ preparedness to perform either task. While some cue sequences were presented in a random order, the subjects were aware of experiment’s nature.
Implications
As far as grasp actions are concerned, objects can be conflict and non-conflict. The conflict’s main drivers are that lift responds to the perceived structure, while use is a slow generation from the stored knowledge. Visual complexity produces different effects on performance, and visually unique and complex objects may improve it. To summarize everything, a person will lift an unknown object first and use a known one without lifting. The phenomenon influences how people interact with everyday tools: they do not apply extra actions, employing them efficiently.
Reference
Bub, D. N., Masson, M. E. J., & van Mook, H. (2018). Switching between lift and use grasp actions. Cognition, 174, 28–36. Web.