Joseph B. Sala

Dissociation of the neural systems for working memory maintenance of verbal and nonspatial visual information

Working memory for names and faces was investigated to ascertain whether verbal and nonspatial visual information is maintained in working memory by separate neural systems. The subjects performed a delayed match-to-sample task for famous or unfamous faces and names and a sensorimotor control task. Several occipital, temporal, parietal, and prefrontal areas were activated during all memory delays, in comparison with the control delays. Greater delay activity for unfamous faces than for names was obtained in the right fusiform gyrus, right inferior frontal gyrus (IFG), right IFG/ precentral gyrus, and right medial superior frontal gyrus, whereas greater delay activity for unfamous names than for faces was observed in the precuneus, left insula/postcentral gyrus, and left IFG/ precentral gyrus. There was no significant difference in the prefrontal activity in the comparison between famous faces and names. Greater delay activity for famous names than for faces was obtained in visual association and parietal areas. The results indicate that there is a functional dissociation based on information type within the neural system that is responsible for working memory maintenance of verbal and nonspatial visual information.

Flexible Working Memory Representation of the Relationship between an Object and Its Location as Revealed by Interactions with Attention

Working memory (WM) selectively maintains a limited amount of currently relevant information in an active state to influence future perceptual processing, thought, and behavior. The representation of the information held in WM is unknown, particularly the degree of separation between the representation of an object’s identity and its location. The present experiments examined the flexibility of object and location WM representations by measuring reaction times on a visual discrimination task during the delay period of a WM recognition task for object identities, locations, or both. The results demonstrate that during WM delay periods, attention is biased toward information that matches the current contents of WM. Attention is not biased toward information that was present in the encoded memory sample but not relevant for the memory recognition test. This specificity of the interaction between WM and attention applies to both the identity and the location of the remembered stimulus and to the relationship between an object and its location. The results suggest that when this relationship is necessary for task performance, WM represents an object and its identity in an integrated manner. However, if this relationship is not task relevant, the object and location information are represented in WM separately.

Effects of Mobile Technology Use on Walking

Objective: The goal of this study was to evaluate the efficacy of combining cognitive and kinematic measurements to study the effects of mobile technology use on walking. Background: It has previously been shown that being distracted by a cell phone, or other mobile technology, can have a negative impact on activities such as crossing a street and may also alter gait patterns. While the negative effects of cell phone use on driving have been extensively studied, research into the distracted pedestrian is lacking. Method: Twelve adults walked down an office corridor without using a cell phone (BASELINE) and while performing a secondary cognitive task under two conditions. The secondary task involved answering simple multiplication problems through either text messaging (TEXT) or while talking on the phone (VOICE). Participants’ gait patterns were measured using a GAITRite gait pad LEGSys wearable wireless sensors. Results: In the TEXT condition, participants walked more slowly and had shorter strides. There was no significant difference between the VOICE and BASELINE condition. Participants answered more multiplication problems per trial in the VOICE condition as compared to the TEXT condition. Excluding typos, error rates for the multiplication problems were not significantly different between the TEXT and VOICE conditions. Conclusion: This study demonstrated that the effect of reading and responding to text messages on gait was able to be detected utilizing methods that do not require strictly sterile laboratory settings. This serves as a proof of concept for researchers to bring the study and evaluation of distracted walking into the naturalistic environments in which it actually occurs. Application: This proof of concept will serve as a roadmap towards moving the study of gait and distraction from simple observational studies in naturalistic environments to specific quantitative analysis of people performing real world tasks in real world settings.

Product warnings and the involuntary capture of attention

In both published papers and in guidelines of regulatory agencies and voluntary standards, examples can be found where the assumption is made that what will capture attention is that which is salient or conspicuous, and that these qualities are both necessary and sufficient to capture attention. A review of the published, peer-reviewed literature on attention capture, however, invites the conclusion that there are very few features of an object that will draw attention to themselves without or against the observer’s intentions. The ability of warnings to draw attention to themselves involuntarily is discussed within the context of the extant attention capture literature.

Trends in Consumer Product Warnings Found in Voluntary Standards

Consumer products available today in the United States often have safety information on and accompanying them. This practice is far more common now than earlier in the 20th century. In this paper, the evolution of the use of warnings with consumer products is examined as they appeared in voluntary standards provided by one national standard making body, the American Society for Testing and Materials (ASTM). ASTM had been developing consensus voluntary standards since 1898, but it was not until the 1970s that it first focused on consumer products. Over the next three decades there were increases in the number and type of consumer products included. Further, for any given product, the amount of safety information frequently increased with subsequent revisions of a standard. These trends in warnings generally parallel the patterns observed with federally mandated warnings for consumer products.

Seeing is Believing

Big data sets can be cumbersome and difficult to understand. User-centered and interactive graphical displays help communicate messages from large and complex data as well as provide a new method to identify data trends outside of tabular or statistical analysis. Human factors researchers can utilize data visuals to not only develop but also answer questions that previously proved difficult through visual exploration. This approach is especially relevant to the field of surface transportation research where complex plots can incorporate both temporal and geospatial data in an easy-to-digest format. As a proof of concept, this paper demonstrates how bike-sharing and historical bicycle collision incidents can meaningfully merge to produce graphical displays that readily identify and communicate potential infrastructure problems for safety. Through the use of Bayesian modeling and geospatial mapping, our analysis identifies two primary trends worth further consideration and research to consider for cyclist safety in Chicago.

Seeing is Believing: The Use of Data Visualization to Identify Trends for Cycling Safety

Big data sets can be cumbersome and difficult to understand. User-centered and interactive graphical displays help communicate messages from large and complex data as well as provide a new method to identify data trends outside of tabular or statistical analysis. Human factors researchers can utilize data visuals to not only develop but also answer questions that previously proved difficult through visual exploration. This approach is especially relevant to the field of surface transportation research where complex plots can incorporate both temporal and geospatial data in an easy-to-digest format. As a proof of concept, this paper demonstrates how bike-sharing and historical bicycle collision incidents can meaningfully merge to produce graphical displays that readily identify and communicate potential infrastructure problems for safety. Through the use of Bayesian modeling and geospatial mapping, our analysis identifies two primary trends worth further consideration and research to consider for cyclist safety in Chicago.

Biomechanical, Perceptual, and Cognitive Factors Involved in Maintaining Postural Control While Standing or Walking on Non-Moving and Moving Surfaces: A Literature Review

Postural control has been defined as “regulating the body’s position in space for the dual purposes of stability and orientation.” How the body achieves postural control depends, in part, on the environment. A person navigating a non-moving surface (e.g. hallway, stairway, or step ladder) will process information and will employ different strategies to maintain postural control than someone who is standing or walking on a moving surface (e.g., forklifts, personal transportation systems, escalators, and moving walkways). In both environments, sensory, cognitive, and motor control systems contribute to postural control. The musculoskeletal system uses muscle activation and joint positioning to control the body’s alignment and muscle tone. The biomechanics of postural control rely on information that the musculoskeletal system receives from sensory systems including the vestibular system, which is generally implicated in behaviors requiring balance control, as well as the somatosensory and visual systems. Furthermore, sensory information from these and other systems can be enhanced by cognitive processes, such as attention. The ability to maintain postural control while standing or walking is critical in preventing falls on both non-moving and moving surfaces. This review focuses on moving surfaces and includes a discussion of the biomechanical, perceptual, and cognitive factors responsible for postural control.Copyright

Biomechanical, Perceptual, and Cognitive Factors Involved in Balance Recovery Following Unexpected Perturbations: A Literature Review

For an individual standing or walking on a moving or non-moving surface, perturbations can result in postural instability and sudden loss of balance. When unexpected perturbations occur, specific mechanisms involving the sensory, cognitive, and motor systems activate in order to regain postural control. For example, specific muscle synergies can result in compensatory limb movements (e.g. stepping or reaching towards a fixed object) that are prevalent mechanical responses to sudden loss of balance and play a crucial role in preventing falls. These movements require the interaction of multiple sensory systems including the visual, somatosensory, and vestibular systems. If sensory information is unavailable or incomplete, there may be a greater reliance on cognitive processes such as memory and attention in order to execute a balance-recovering mechanical response; however, if cognitive processes are tasked, compensatory responses may be negatively affected. The ability to recover from sudden loss of balance is critical in preventing falls on both non-moving and moving surfaces. This review includes a discussion of the biomechanical, perceptual, and cognitive factors responsible for the control of balance recovery on moving surfaces.Copyright

Diffuse electrical injury: Questioning the scientific basis

Published reports postulate the existence of an electrical injury syndrome or pattern whereby clinical and physical manifestations of a shock injury occur remote to the actual current pathway, and may present in the absence of related acute findings. It is suggested that the extent of such injury is unrelated to the magnitude of shock current and that the timing of the ldquodiffuse electrical injuryrdquo may be indefinitely delayed with respect to the time of the sustained shock. Other reports refer to possible shock injury mechanisms that manifest solely with neuropsychological symptoms. A critical examination of this literature reveals no mechanistic basis for the association of the proposed physical symptoms of diffuse electrical injury with remote injury. Additionally, serious errors in the stated methodology of the publications citing the existence of diffuse electrical injury cast doubt upon the scientific basis for the stated conclusions.