Alignment effects in beer mugs: Automatic action activation or response competition?

The visual size of graspable objects is needed to induce the potentiation of grasping behaviors even with verbal stimuli

Merely perceiving objects usually grasped with a power or a precision grip (e.g., an apple vs. a cherry) potentiate power-grip and precision-grip responses, respectively. According to the size-coding account, this potentiation effect is due to the compatibility between size codes associated with both stimuli and responses, rather than to the simulation of motor information stored at a conceptual level (i.e., the embodied account). At the stimulus level, size-coding would occur, because objects associated with a power grip are usually presented in a larger visual size than objects associated with a precision grip. However, this explanation is challenged by results, showing that reading nouns of objects associated with power or precision grip also leads to potentiation effects, even though the visual size of the displayed object is no longer perceived. Therefore, we designed three experiments to better understand this word-based potentiation effect and to investigate whether it relies on size codes. Our results showed a word-based potentiation effect only when the object nouns were interleaved with pictures depicting the objects in their typical visual size. We discuss the contributions of these results for both the size-coding account and the embodied account of the potentiation effect of grasping behaviors.

The Influence of Poststudy Action Congruency on Memory Consolidation

Abstract. The actions associated with objects are thought to be automatically activated when processing object names. Recent studies, however, have failed to find evidence for a role of the motor system in long-term memory for objects. One exception is a study by van Dam et al. (2013) in which participants studied object names associated with pressing (e.g., doorbell) or twisting (e.g., jar), followed by pressing or twisting actions in a seemingly unrelated task. In the final memory test, performance for action congruent words was better than for action incongruent words. We aimed to generalize these findings. In Experiments 1 and 2, we found no effect of action congruency on repetition priming in lexical decision and man-made/natural decision. In Experiment 3, the action congruency manipulation was administered immediately after initial study or a day later, just prior to the recognition memory test. We found no effects of action congruency and timing of the action. Finally, Experiment 4 was a direct replication of Experiment 1 of van Dam et al. (2013). Again, we failed to find an effect of poststudy action congruency. Thus, we obtained no evidence for the view that motor actions play a role in long-term memory for objects.

Size coding of alternative responses is sufficient to induce a potentiation effect with manipulable objects

The mere perception of manipulable objects usually grasped with a power-grip (e.g., an apple) or a precision-grip (e.g., a cherry) potentiate power-grip- and precision-grip-responses, respectively. This effect is seen as to be driven by automatic access of the representation of manipulable objects that includes a motor representation of usually performed grasping behaviors (i.e., the embodied view). Nevertheless, a competing account argues that this effect could be due to an overlapping of size codes used to represent both manipulable objects and response options. Indeed, objects usually grasped with a power- and a precision-grip (e.g., an apple vs. a cherry) could be coded as large- and small-objects, respectively; and power- and precision-grip responses as large- and small-responses, respectively. We conducted 4 experiments to test this hypothesis. In Experiment 1, the response device usually used in studies reporting a potentiation effect is fixed horizontally (the grasping component of responses was removed). We instructed participants to press the small-switch with their index-digit and the large-switch with their palm-hand. In line with the size-coding-hypothesis, responses on the small-switch performed with the index-digit led to shorter RTs when objects usually associated with a precision-grip (e.g., a cherry) were presented compared to objects usually associated with a power-grip (e.g., an apple). A reverse pattern was obtained for responses on the large-switch performed with the palm-hand. In Experiments 2, 3 and 4, we went further by investigating which factors of Experiment 1 allow the size coding of responses: the size of switch and/or the size of the effector part used. Data confirmed the critical involvement of the size of switches and the possible involvement of the size of the effector part used. Thus, data support the possibility that the potentiation of grasping is due to a compatibility/incompatibility between size codes rather than involving motor representations of usually performed grasping behaviors as advocated in several embodied views. Moreover, data support the possibility that responses are coded thanks to a size code that extends the Theory of Event Coding.

The prominent role of perceptual salience in object discrimination: overt discrimination of graspable side does not activate grasping affordances

Responses to object stimuli are often faster when jutting handles are aligned with responding hands, than when they are not: handle-to-hand correspondence effects. According to a location coding account, locations of visually salient jutting parts determine the spatial coding of objects. This asymmetry then facilitates same-sided responses compared to responses on the opposite side. Alternatively, this effect has been attributed to grasping actions of the left or the right hand afforded by the handle orientation and independent of its salience (affordance activation account). Our experiments were designed to disentangle the effects of pure salience from those of affordance activations. We selected pictures of tools with one salient and non-graspable side, and one graspable and non-salient side (non-jutting handle). Two experiments were run. Each experiment had two groups of participants: one group discriminated the location of the salient side of the object stimuli; the other group discriminated the location of the graspable side of them. In Experiment 1, responses were left and right button presses; in Experiment 2, they were left and right button presses plus reach-and-grasp actions. When visual salience was removed from graspable sides, no correspondence effect was observed between their orientation and the responding hands in both the experiments. Conversely, when salience depended on non-graspable portions, a correspondence effect was produced between their orientation and the responding hand. Overt attention to graspable sides did not potentiate any grasping affordance even when participants executed grasping responses in addition to button presses. Results support the location coding account: performance was influenced by the spatial coding of visually salient properties of objects.

Handle-Hand Compatibility Effects for the Right and Left Hand Using Reach-to-Touch Movements

In stimulus-response compatibility tasks, performance is better when the handle of an object is oriented on the same side of the response than when the handle is oriented on the opposite side. Two major alternative accounts, the motor affordance and spatial accounts, have been proposed to explain this handle-hand compatibility effect. In two experiments, we tested between these two accounts by administering a go/no-go task to right-handed participants. Handled objects presented on a touchscreen were used as stimuli. Half of the participants had to reach-to-touch the stimuli by using their dominant hand, the other half by using their nondominant hand. Liftoff times (LTs), movement times (MTs) and spatial coordinates of the movement endpoints were recorded. Results from the LTs and MTs analyses showed no evidence of handle-hand compatibility effects. In contrast, the analyses of the spatial coordinates revealed that participants' touches were shifted more laterally towards the handle when the handles were oriented on the same side of the responding hand (Experiments 1 and 2). Furthermore, the right-hand touches landed higher (towards the handle) than the left-hand touches, especially when the vertical object dimension was particularly salient (Experiment 1). Overall, these results are in line with the activation of hand motor programs to reach and grasp the object as predicted by the motor account, at least for the right/dominant hand.

Affordance Compatibility Effect for Word Learning in Virtual Reality

Rich sensorimotor interaction facilitates language learning and is presumed to ground conceptual representations. Yet empirical support for early stages of embodied word learning is currently lacking. Finding evidence that sensorimotor interaction shapes learned linguistic representations would provide crucial support for embodied language theories. We developed a gamified word learning experiment in virtual reality in which participants learned the names of six novel objects by grasping and manipulating objects with either their left or right hand. Participants then completed a word-color match task in which they were tested on the same six words and objects. Participants were faster to respond to stimuli in the match task when the response hand was compatible with the hand used to interact with the named object, an effect we refer to as affordance compatibility. In two follow up experiments, we found that merely observing virtual hands interact with the objects was sufficient to acquire a smaller affordance compatibility effect, and we found that the compatibility effect was driven primarily by responses with a compatible hand and not by responses in a compatible spatial location. Our results support theoretical views of language which ground word representations in sensorimotor experiences, and they suggest promising future routes to explore the sensorimotor foundations of higher cognition through immersive virtual experiments.

Boundaries to grounding abstract concepts

Grounded theories of cognition claim that concept representation relies on the systems for perception and action. The sensory-motor grounding of abstract concepts presents a challenge for these theories. Some accounts propose that abstract concepts are indirectly grounded via image schemas or situations. Recent research, however, indicates that the role of sensory-motor processing for concrete concepts may be limited, providing evidence against the idea that abstract concepts are grounded via concrete concepts. Hybrid models that combine language and sensory-motor experience may provide a more viable account of abstract and concrete representations. We propose that sensory-motor grounding is important during acquisition and provides structure to concepts. Later activation of concepts relies on this structure but does not necessarily involve sensory-motor processing. Language is needed to create coherent concepts from diverse sensory-motor experiences.This article is part of the theme issue 'Varieties of abstract concepts: development, use and representation in the brain'.

The effect of grasp compatibility in go/no-go and two-choice tasks

The grasp compatibility effect has been put forward as evidence for the automatic involvement of the motor system during mental object representation. In three experiments, participants responded to object pictures or names by grasping cylinders using a precision or power grasp. In a two-choice task in which both grasps were used, we obtained grasp compatibility effects, but in a go/no-go task, in which only one grasp was used, there was no effect. These results indicate that the effect depends on the availability of response choice, in the present case, different size grasps. This suggests that grasp compatibility effects are better explained by coding of the stimulus and response on the same dimension, size, rather than automatic activation of a motor action towards the object.

Effects of grasp compatibility on long-term memory for objects

Previous studies have shown action potentiation during conceptual processing of manipulable objects. In four experiments, we investigated whether these motor actions also play a role in long-term memory. Participants categorized objects that afforded either a power grasp or a precision grasp as natural or artifact by grasping cylinders with either a power grasp or a precision grasp. In all experiments, responses were faster when the affordance of the object was compatible with the type of grasp response. However, subsequent free recall and recognition memory tasks revealed no better memory for object pictures and object names for which the grasp affordance was compatible with the grasp response. The present results therefore do not support the hypothesis that motor actions play a role in long-term memory.

Curb Your Embodiment

To explain how abstract concepts are grounded in sensory-motor experiences, several theories have been proposed. I will discuss two of these proposals, Conceptual Metaphor Theory and Situated Cognition, and argue why they do not fully explain grounding. A central idea in Conceptual Metaphor Theory is that image schemas ground abstract concepts in concrete experiences. Image schemas might themselves be abstractions, however, and therefore do not solve the grounding problem. Moreover, image schemas are too simple to explain the full richness of abstract concepts. Situated cognition might provide such richness. Research in our laboratory, however, has shown that even for concrete concepts, sensory-motor grounding is task dependent. Therefore, it is questionable whether abstract concepts can be significantly grounded in sensory-motor processing.

Creating Affording Situations: Coaching through Animate Objects

We explore the ways in which animate objects can be used to cue actions as part of coaching in Activities of Daily Living (ADL). In this case, changing the appearance or behavior of a physical object is intended to cue actions which are appropriate for a given context. The context is defined by the intention of the users, the state of the objects and the tasks for which these objects can be used. We present initial design prototypes and simple user trials which explore the impact of different cues on activity. It is shown that raising the handle of a jug, for example, not only cues the act of picking up the jug but also encourages use of the hand adjacent to the handle; that combinations of lights (on the objects) and auditory cues influence activity through reducing uncertainty; and that cueing can challenge pre-learned action sequences. We interpret these results in terms of the idea that the animate objects can be used to create affording situations, and discuss implications of this work to support relearning of ADL following brain damage or injury, such as might arise following a stroke.