Woodpecker drum evolution: An analysis of covariation in elements of a multicomponent acoustic display among and within species

Multicomponent signals are found throughout the animal kingdom, but how these elaborate displays evolve and diversify is still unclear. Here, we explore the evolution of the woodpecker drum display. Two components of this territorial sexually selected signal, drum speed and drum length, are used by territory holders to assess the threat level of an intruding drummer. We explore the coevolution of these display components both among and within species. Among species, we find evidence for strong coevolution of drum speed and length. Within species, we find that drum speed and length vary largely independent of each other. However, in some species, there is evidence of covariation in certain portions of the drum length distribution. The observed differences in component covariation at the macro- and microevolutionary scales highlight the importance of studying signal structure both among and within species. In all cases of covariation at both evolutionary scales, the relationship between drum speed and length is positive, indicating mutual elaboration of display components and not a performance trade-off.

A Common Endocrine Signature Marks the Convergent Evolution of an Elaborate Dance Display in Frogs

AbstractUnrelated species often evolve similar phenotypic solutions to the same environmental problem, a phenomenon known as convergent evolution. But how do these common traits arise? We address this question from a physiological perspective by assessing how convergence of an elaborate gestural display in frogs (foot-flagging) is linked to changes in the androgenic hormone systems that underlie it. We show that the emergence of this rare display in unrelated anuran taxa is marked by a robust increase in the expression of androgen receptor (AR) messenger RNA in the musculature that actuates leg and foot movements, but we find no evidence of changes in the abundance of AR expression in these frogs' central nervous systems. Meanwhile, the magnitude of the evolutionary change in muscular AR and its association with the origin of foot-flagging differ among clades, suggesting that these variables evolve together in a mosaic fashion. Finally, while gestural displays do differ between species, variation in the complexity of a foot-flagging routine does not predict differences in muscular AR. Altogether, these findings suggest that androgen-muscle interactions provide a conduit for convergence in sexual display behavior, potentially providing a path of least resistance for the evolution of motor performance.

Speech-Language pathologists' decisions when designing an aided AAC display for a compilation case study of a beginning communicator

PURPOSE

The current study sought to identify decisions speech-language pathologists (SLPs) make and their rationale for those decisions when designing an AAC display for a hypothetical school-aged child who was a beginning communicator. Augmentative and alternative communication (AAC) displays support communicative interactions for children who are unable to use spoken language to meet their communication needs. Children who are at the early stages of learning language, often termed beginning or emerging communicators, may rely heavily on the AAC display to support comprehension and expression. Thus, it is important for speech-language pathologists (SLPs) to design a display that facilitates beginning communicators' communication development.

METHODS

This paper reports on the answers related to a specific case study presented in an online survey completed by 77 SLPs with experience in AAC.

RESULTS

Data illustrated design decisions driven by child-specific characteristics and informed by research regarding type of layout, representation, and the importance of various design features.

CONCLUSIONS

Suggestions for future research are provided, including identifying goals and communicative functions best supported by different types of displays, clinicians' challenges/successes growing a system with the child, and determining the importance of symbol arrangement and organisation in communicative tasks by AAC users.Implications for RehabilitationIdentification of current practices reported by speech-language pathologists given a case study to develop and implement future research.A gap between research and practice suggests the need for better dissemination and application of research supporting the inclusion of people engaged in the event depicted in a visual scene display.Foundations for future research to provide guidance regarding best design of and communication goals supported by visual scene displays and grid-based displays.

Ecological Interface Design for Computer Network Defense

OBJECTIVE

A prototype ecological interface for computer network defense (CND) was developed.

BACKGROUND

Concerns about CND run high. Although there is a vast literature on CND, there is some indication that this research is not being translated into operational contexts. Part of the reason may be that CND has historically been treated as a strictly technical problem, rather than as a socio-technical problem.

METHODS

The cognitive systems engineering (CSE)/ecological interface design (EID) framework was used in the analysis and design of the prototype interface. A brief overview of CSE/EID is provided. EID principles of design (i.e., direct perception, direct manipulation and visual momentum) are described and illustrated through concrete examples from the ecological interface.

RESULTS

Key features of the ecological interface include (a) a wide variety of alternative visual displays, (b) controls that allow easy, dynamic reconfiguration of these displays, (c) visual highlighting of functionally related information across displays, (d) control mechanisms to selectively filter massive data sets, and (e) the capability for easy expansion. Cyber attacks from a well-known data set are illustrated through screen shots.

CONCLUSION

CND support needs to be developed with a triadic focus (i.e., humans interacting with technology to accomplish work) if it is to be effective. Iterative design and formal evaluation is also required. The discipline of human factors has a long tradition of success on both counts; it is time that HF became fully involved in CND.

APPLICATION

Direct application in supporting cyber analysts.

Clutter in electronic medical records: examining its performance and attentional costs using eye tracking

OBJECTIVE

The objective was to use eye tracking to trace the underlying changes in attention allocation associated with the performance effects of clutter, stress, and task difficulty in visual search and noticing tasks.

BACKGROUND

Clutter can degrade performance in complex domains, yet more needs to be known about the associated changes in attention allocation, particularly in the presence of stress and for different tasks. Frequently used and relatively simple eye tracking metrics do not effectively capture the various effects of clutter, which is critical for comprehensively analyzing clutter and developing targeted, real-time countermeasures.

METHOD

Electronic medical records (EMRs) were chosen as the application domain for this research. Clutter, stress, and task difficulty were manipulated, and physicians' performance on search and noticing tasks was recorded. Several eye tracking metrics were used to trace attention allocation throughout those tasks, and subjective data were gathered via a debriefing questionnaire.

RESULTS

Clutter degraded performance in terms of response time and noticing accuracy. These decrements were largely accentuated by high stress and task difficulty. Eye tracking revealed the underlying attentional mechanisms, and several display-independent metrics were shown to be significant indicators of the effects of clutter.

CONCLUSION

Eye tracking provides a promising means to understand in detail (offline) and prevent (in real time) major performance breakdowns due to clutter.

APPLICATION

Display designers need to be aware of the risks of clutter in EMRs and other complex displays and can use the identified eye tracking metrics to evaluate and/or adjust their display.

Smaller pupil size and better proofreading performance with positive than with negative polarity displays

The 'positive polarity advantage' describes the fact that reading performance is better for dark text on light background (positive polarity) than for light text on dark background (negative polarity). We investigated the underlying mechanism by assessing pupil size and proofreading performance when reading positive and negative polarity texts. In particular, we tested the display luminance hypothesis which postulates that the typically greater brightness of positive compared to negative polarity displays leads to smaller pupil sizes and, hence, a sharper retinal image and better perception of detail. Indeed, pupil sizes were smaller and proofreading performance was better with positive than with negative polarity displays. The results are compatible with the hypothesis that the positive polarity advantage is an effect of display luminance. Limitations of the study are being discussed.