Do my hands prime your hands? The hand-to-response correspondence effect

Reliable affordances: A generative modeling approach for test-retest reliability of the affordances task

The affordances task serves as an important tool for the assessment of cognition and visuomotor functioning, and yet its test-retest reliability has not been established. In the affordances task, participants attend to a goal-directed task (e.g., classifying manipulable objects such as cups and pots) while suppressing their stimulus-driven, irrelevant reactions afforded by these objects (e.g., grasping their handles). This results in cognitive conflicts manifesting at the task level and the response level. In the current study, we assessed the reliability of the affordances task for the first time. While doing so, we referred to the "reliability paradox," according to which behavioral tasks that produce highly replicable group-level effects often yield low test-retest reliability due to the inadequacy of traditional correlation methods in capturing individual differences between participants. Alongside the simple test-retest correlations, we employed a Bayesian generative model that was recently demonstrated to result in a more precise estimation of test-retest reliability. Two hundred and ninety-five participants completed an online version of the affordances task twice, with a one-week gap. Performance on the online version replicated results obtained under in-lab administrations of the task. While the simple correlation method resulted in weak test-retest measures of the different effects, the generative model yielded a good reliability assessment. The current results support the utility of the affordances task as a reliable behavioral tool for the assessment of group-level and individual differences in cognitive and visuomotor functioning. The results further support the employment of generative modeling in the study of individual differences.

Emotions in motion: affective valence can influence compatibility effects with graspable objects

Previous studies showed that affective valence (positive, negative) influences Stimulus-Response Compatibility (SRC) effects elicited by both relevant and irrelevant spatial dimensions. We tested whether valence influences SRC effects when the irrelevant spatial dimension rather than being conveyed by the entire stimulus location is conveyed by the location of the stimulus' graspable part, i.e., the Handle-Response (H-R) compatibility effect. Participants saw objects with either a flower, a spider or nothing on their handle and categorized them as kitchen utensils or garage tools through button presses. In Experiment 1, a random presentation of valenced stimuli was used, whereas in Experiment 2 differently valenced stimuli were arranged in different blocks. Furthermore, participants in Experiment 2 could be spider-fearful or not. In Experiment 1, an H-R compatibility effect occurred for response latencies, regardless of whether stimuli presented a negative, positive or no element on their handle. In Experiment 2 the effect occurred only when a positive element was shown on the object's handle. In addition, spider-fearful individuals showed significantly slower responses when the element appearing on the object's handle had a negative valence. These results suggest that the SRC effect observed with pictures of graspable objects may be sensitive to the affective characteristics of stimuli and that approach/avoidance response tendencies may also depend on individual differences (being spider-fearful or not).

Effects of the social context on the neurophysiological correlates of observed error monitoring

Monitoring the motor performance of others, including the correctness of their actions, is crucial for the human behavior. However, while performance (and error) monitoring of the own actions has been studied extensively at the neurophysiological level, the corresponding studies on monitoring of others' errors are scarce, especially for ecological actions. Moreover, the role of the context of the observed action has not been sufficiently explored. To fill this gap, the present study investigated electroencephalographic (EEG) indices of error monitoring during observation of images of interrupted reach-to-grasp actions in social (an object held in another person's hand) and non-social (an object placed on a table) contexts. Analysis in time- and time-frequency domain showed that, at the level of conscious error awareness, there were no effects of the social context (observed error positivity was present for erroneous actions in both contexts). However, the effects of the context were present at the level of hand image processing: observing erroneous actions in the non-social context was related to larger occipito-temporal N1 and theta activity, while in the social context this pattern was reversed, i.e., larger N1 and theta activity were present for the correct actions. These results suggest that, in case of easily predictable ecological actions, action correctness is processed as early as at the level of hand image perception, since the hand posture conveys information about the action (e.g., motor intention). The social context of actions might make the correct actions more salient, possibly through the saliency of the correctly achieved common goal.

Compatibility effects with destination and origin of motion

Previous studies highlighted spatial compatibility effects other than those strictly arising from stimulus-response locations. In particular, the so-called Destination Compatibility (DC) effect refers to faster responses for dynamic (i.e., moving) stimuli the end point of which is spatially compatible with the response key. Four experiments examined whether the DC effect also occurs with static visual stimuli symbolically representing either motion destination alone (Experiment 1a), or both motion origin and destination (Experiments 1b, 2a, and 2b). Overall, our results are consistent in showing a DC effect; most importantly, the present findings reveal a predominance of the effect of destination of motion over that of origin, even when both the starting and ending positions of the stimulus are symbolically represented and participants are instructed to respond according to motion origin. This finding suggests that the DC effect is independent from other stimulus-response compatibility (SRC) effects.

Does a look of fear prompt to act? The effects of gaze and face emotional expression on manipulable objects

Gaze direction is an important social cue for understanding the intentions of other people. Indeed, interacting with others requires the ability to encode their current focus of attention in order to predict their future actions. Previous studies have showed that when asked to detect or identify a target, people are faster if shown a gaze oriented toward rather than away from that target. Most importantly, there is evidence that the emotion conveyed by the face with the averted gaze matters. We further tested the interplay between gaze and face emotion in the context of manipulable objects to understand whether and to what extent other people's gaze influences our own actions toward objects. Participants judged whether a target graspable object was upright or inverted after viewing a face cue with a central or averted gaze. Importantly, the target's handle could be oriented toward the gazed-at location or the opposite side such that gaze and handle were corresponding or non-corresponding in space. Furthermore, we manipulated the expression of the cue by using neutral and fearful faces. Results showed a handle-response (H-R) compatibility effect (i.e., a facilitation when the response key is on the same side as the object's handle) only with fearful cues with a central gaze.

Practice and transfer with mappings of spoon tip and handle to keypress responses

When orientation of a horizontal spoon image varies to the left or right, instructions can map left and right keypresses to the tip or handle location. We conducted Experiment 1 to determine whether practice with an incompatible mapping of the salient tip transfers to a test session in which the relevant part and/or mapping are changed. Participants performed 80 practice trials with tip-incompatible mapping, followed by 80 test trials with tip-compatible, tip-incompatible, handle-compatible, or handle-incompatible mapping. Performance improved across 20-trial blocks in the practice session. In the test session, responses were 65 ms faster with tip-compatible than tip-incompatible mapping but 31 ms faster with handle-incompatible than handle-compatible mapping. This latter result, and verbal reports, indicate that some participants adopted a strategy of responding compatibly to the salient tip even though instructed to respond to the handle. Experiment 2 focused on whether participants with handle-incompatible mapping instructions would adopt the tip-compatible strategy spontaneously or after receiving a hint: 77% of participants reported adopting the tip-compatible strategy in Session 1, showing that prior experience responding to the tip is not necessary and 9% of participants did not report using that strategy in Session 1 but reported changing to it in Session 2 after receiving the hint. Their responses in Session 2 were slower than those who used the strategy throughout, but this difference was minimal in the last two trial blocks. Compatible mapping of the salient spoon tip to keypresses dominated performance over prior practice with incompatible tip mapping and instructions with incompatible handle mapping.

Exploring the Role of Action Consequences in the Handle-Response Compatibility Effect

Previous research investigating handle-response compatibility effects with graspable objects used different categories of objects as stimuli, regardless of their specific, intrinsic characteristics. The current study explores whether different types of objects' characteristics may elicit different types of spatial compatibility, that is, handle-response and response-effect compatibility as well as their potential interaction. In Experiment 1, objects having a graspable handle opposite to either a visible functional component (i.e., handle-function objects: a teapot) or a latent functional component (handle-only objects: a pitcher lacking the spout) were presented separately in different blocks. Both the handle and the goal-directed functional components of these objects were located on the horizontal axis. In Experiment 2, handle-only objects had a handle located on the horizontal axis and a latent functional component located on the vertical axis (e.g., a cup). In both experiments, participants were required to judge the material (plastic and metal) the object was made of. Results showed that the handle-response compatibility effect was sensitive to whether the actions consequences of object manipulation took place on the horizontal rather than on the vertical axis.