Ralph J. Roberts

Grab it! Biased attention in functional hand and tool space

This study explored whether functional properties of the hand and tools influence the allocation of spatial attention. In four experiments that used a visual-orienting paradigm with predictable lateral cues, hands or tools were placed near potential target locations. Results showed that targets appearing in the hand’s grasping space (i.e., near the palm) and the rake’s raking space (i.e., near the prongs) produced faster responses than did targets appearing to the back of the hand, to the back of the rake, or near the forearm. Validity effects were found regardless of condition in all experiments, but they did not interact with the target-in-grasping/raking-space bias. Thus, the topology of the facilitated space around the hand is, in part, defined by the hand’s grasping function and can be flexibly extended by functional experience using a tool. These findings are consistent with the operation of bimodal neurons, and this embodied component is incorporated into a neurally based model of spatial attention.

Implied body action directs spatial attention

Research confirms that the body influences perception, but little is known about the embodiment of attention. We investigated whether the implied actions of others direct spatial attention, using a lateralized covert-orienting task with nonpredictive central cues depicting static, right/left-facing bodies poised in midaction. Validity effects (decreased response times for validly compared with invalidly cued trials) indicated orienting in the direction of the implied action. In Experiment 1, we compared action (running, throwing) with nonaction (standing) cues. Only the action cues produced validity effects, suggesting that implied action directs attention. The action cues produced faster responses overall, suggesting that action cues prime motor responses. In Experiment 2, we determined whether action cues shifted attention in a specific direction rather than to a general side of space: Two cues had similar action speed and motor effort but differed in implied direction (jumping, vertical; throwing, horizontal). Validity effects were found only for the throw cues for which the implied motion direction was consistent with lateralized target locations. In Experiment 3, we compared block-like stimuli to the throwing action stimuli to examine whether lower level perceptual information could account for the attention effects alone. Validity effects were found only for the human-action stimuli. Overall, the results suggest that predictive simulations of action shift attention in action-consistent directions.

Difficult Access: The Impact of Recall Steps on Flight Management System Errors

This study examines flight management system (FMS) tasks and errors by C–130 pilots who were recently qualified on a newly introduced advanced FMS. Twenty flight tasks supported by the FMS were analyzed using a cognitive stage model (Sherry, Polson, Feary, & Palmer, 2002) to identify steps with the potential for errors. If a step was found not to have visual cues such as labels or prompts for the required action sequence it was identified as a recall step and a potential source of difficulty. If the action was supported by salient labels and prompts it was identified as a recognition step. Actual pilots using an FMS were observed and performance and errors categorized into the related task step. The greatest amount of observed difficulty was accessing the correct function, labeled as an access error. This process was found to be particularly vulnerable to recall problems. Pilots had the likelihood of .74 for committing an access error on tasks with 2 recalled access steps. This is compared to .13 for 1 recalled access step and .06 for no recalled access steps. Errors associated with formatting, inserting, or verifying entries were less common than access errors; however, these errors primarily occurred on tasks in which recall steps were required for the related step. A total of 93% of the format errors, 80% of the insert errors, and 81% of the verify errors occurred on the tasks that did not have good recognition support for each associated step. On a positive note, experience with the new FMS in the preceding 6 months was correlated with a decrease in overall errors, r(22) = –.42, p < .05, and a decrease in errors associated with inadequate knowledge to accomplish a required step, r(22) = –.61, p < . 01.

Walking Reveals Trunk Orientation Bias for Visual Attention

Our trunks influence where we perform actions in space. Thus, trunk direction may define a region of space that is accorded special treatment by the attention system. We investigated conditions under which a trunk orientation bias for attention might be relevant for healthy adults. Three experiments compared visual detection performance for participants standing and walking on a treadmill. Together, the experiments disambiguate the relative contributions of motor activity, motor load, and cognitive load on trunk orientation biases. In Experiment 1, trunk orientation biases (i.e., faster target detection for targets in front of the body midline) were observed in both forward and sideways walking conditions, but not in standing conditions. In Experiment 2, we ruled out the notion that the trunk orientation bias arose from increased motor activity; in fact, the bias was greatest when participants walked at an unusually slow pace. In Experiment 3, we directly compared motor load with cognitive load in a dual-task paradigm; cognitive load influenced overall performance speed, but only motor load produced trunk orientation bias. These results suggest that a trunk orientation bias emerges during walking and motor load conditions.

Top-down influences mediate hand bias in spatial attention

Spatial attention can be biased to locations near the hand. Some studies have found facilitated processing of targets appearing within hand-grasping space. In this study, we investigated how changing top-down task priorities alters hand bias during visual processing. In Experiment 1, we used a covert orienting paradigm with nonpredictive cues and emphasized the location of the hand relative to the target. Hands or visual anchors (boards) were placed next to potential target locations, and responses were made with the contralateral hand. Results indicated a hand-specific processing bias: Hand location, but not board location, speeded responses to targets near the hand. This pattern of results replicated previous studies using covert orienting paradigms with highly predictive cues. In Experiment 2, we used the same basic paradigm but emphasized the location of the response hand. Results now showed speeded responses to targets near response locations. Together these experiments demonstrated that top-down instructional sets (i.e., what is considered to be most relevant to task performance) can change the processing priority of hand location by influencing the strength of top-down, as compared with bottom-up, inputs competing for attention resources.

The Influence of the Body and Action on Spatial Attention

Research on spatial attention traditionally focuses on how it is influenced by the location of objects within the visual environment. However, a primary function of spatial attention is to plan physical actions. When events occur in the world, visual information needs to be integrated with current body position to help prepare effective responses to these events. Further, current actions can subsequently influence further deployments of attention. Thus, spatial attention must be considered within the context of the body. Here we present research demonstrating that ones own body and the actions of others can influence spatial attention mechanisms, influencing the prioritization of functional space near the body and the direction of attention. This work emphasizes a need for an embodied theory of spatial attention and a more dynamic neural model of attention that adjusts to meet the demands of the current environment and the perceivers goals.

Simultaneous electronic recording of video and digital information on the video channel of a VTR or VCR

A technique is described that permits precise synchronization of video recorded behavior with discrete stimuli and responses. These discrete events are recorded as digital data on the video channel of a video recorder on a horizontal line that lies above the visible video information. These data may be observed in single-frame playback mode by underscanning the playback monitor. A circuit is described for computerized decoding of the digital data. Because each video field is uniquely coded, an updating of the data is possible 60 times each second. The described technique has several advantages over current approaches for synchronizing discrete stimulus and response events with video recorded behavior.

A computer-automated laboratory for studying complex perception-action skills

In this paper, we describe a computer-based laboratory for collecting and analyzing real-time performance and eye-movement data by using video game-like tasks. These tasks assess skills that require the integration of varying numbers of perception and action components. Customized hardware and software are described for configuring tasks, collecting data, reconstructing performance, and organizing, editing, and reducing data. General design considerations are emphasized for solving several of the problems encountered in constructing a real-time data collection system. The paper concludes with examples of data that illustrate the system’s usefulness for studying complex perception-action skills.

Attention orienting near the hand following performed and imagined actions

Recent studies have documented that the hand’s ability to perform actions affects the visual processing and attention for objects near the hand, suggesting that actions may have specific effects on visual orienting. However, most research on the relation between spatial attention and action focuses on actions as responses to visual attention manipulations. The current study examines visual attention immediately following an executed or imagined action. A modified spatial cuing paradigm tested whether a brief, lateralized hand-pinch performed by a visually hidden hand near the target location, facilitated or inhibited subsequent visual target detection. Conditions in which hand-pinches were fully executed (action) were compared to ones with no hand-pinch (inaction) in Experiment 1 and imagined pinches (imagine) in Experiment 2. Results from Experiment 1 indicated that performed hand pinches facilitated rather than inhibited subsequent detection responses to targets appearing near the pinch, but target detection was not affected by inaction. In Experiment 2, both action and imagined action conditions cued attention and facilitated responses, but along differing time courses. These results highlight the ongoing nature of visual attention and demonstrate how it is deployed to locations even following actions.