Discrimination Difficulty Research Articles

CLIP-DFGS: A Hard Sample Mining Method for CLIP in Generalizable Person Re-Identification

Recent advancements in pre-trained vision-language models like CLIP have shown promise in person re-identification (ReID) applications. However, their performance in generalizable person re-identification tasks remains suboptimal. The large-scale and diverse image-text pairs used in CLIP's pre-training may lead to a lack or insufficiency of certain fine-grained features. In light of these challenges, we propose a hard sample mining method called DFGS (Depth-First Graph Sampler), based on depth-first search, designed to offer sufficiently challenging samples to enhance CLIP's ability to extract fine-grained features. DFGS can be applied to both the image encoder and the text encoder in CLIP. By leveraging the powerful cross-modal learning capabilities of CLIP, we aim to apply our DFGS method to extract challenging samples and form mini-batches with high discriminative difficulty, providing the image model with more efficient and challenging samples that are difficult to distinguish, thereby enhancing the model's ability to differentiate between individuals. Our results demonstrate significant improvements over other methods, confirming the effectiveness of DFGS in providing challenging samples that enhance CLIP's performance in generalizable person re-identification.

Autistic traits are associated with differences in the perception of genuineness and approachability in emotional facial expressions, independently of alexithymia.

People with autism and higher levels of autistic traits often have difficulty interpreting facial emotion. Research has commonly investigated the association between autistic traits and expression labeling ability. Here, we investigated the association between two relatively understudied abilities, namely, judging whether expressions reflect genuine emotion, and using expressions to make social approach judgements, in a nonclinical sample of undergraduates at an Australian university (N = 149; data collected during 2018). Autistic traits were associated with more difficulty discriminating genuineness and less typical social approach judgements. Importantly, we also investigated whether these associations could be explained by the co-occurring personality trait alexithymia, which describes a difficulty interpreting one's own emotions. Alexithymia is hypothesized to be the source of many emotional difficulties experienced by autistic people and often accounts for expression labeling difficulties associated with autism and autistic traits. In contrast, the current results provided no evidence that alexithymia is associated with differences in genuineness discrimination and social approach judgements. Rather, differences varied as a function of individual differences in specific domains of autistic traits. More autistic-like social skills and communication predicted greater difficulty in genuineness discrimination, and more autistic-like social skills and attention to details and patterns predicted differences in approach judgements. These findings suggest that difficulties in these areas are likely to be better understood as features of the autism phenotype than of alexithymia. Finally, results highlight the importance of considering the authenticity of emotional expressions, with associations between differences in approach judgements being more pronounced for genuine emotional expressions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Angular Dependence of Hump‐Shape Hall Effects for Distinguishing between Karplus–Luttinger and Geometrical Origins

AbstractAmong the vast magnetic heterostructures explored in Condensed Matter Physics, two contrasting interpretations of the hump‐shaped Hall Effects remain ambiguous and debated, namely, the overlap of two opposite‐signed Karplus–Luttinger Hall loops associated with inhomogeneous collinear domains with perpendicular anisotropy, or the Geometrical/Topological Hall Effect emanated from hexagonal close‐packed lattice of Skyrmion ground state with smoothly varying non‐collinear moments. Their similarity in topology implies difficulty in discrimination via magnetic imaging. Here, this ambiguity is overcome and clarified by the divergence exponent of hump peak fields extracted from Hall measurements with magnetic field rotation on several heterostructures. Their difference in sensitivity to in‐plane fields reveals that the former mechanism involves higher uniaxial anisotropy than the latter, departing from the Skyrmion ground state regime by the Ginzburg–Landau framework of triple‐q spin‐wave superposition. Numerous material systems can be summarized into a single curve of divergence exponent versus the collinear quality factor, bridging the crossover of the two mentioned mechanisms.

Optimization of fast output from SiPM array for pulse shape discrimination techniques at high counting rates

Plastic scintillators with pulse shape discrimination (PSD) capability, when combined with silicon photo-multipliers (SiPMs), enable the development of compact neutron detectors with lower power consumption and insensitivity to magnetic fields. However, the SiPM array has a significantly large pulse width of the output signal, which leads to discrimination difficulties at high counting rates. There are two outputs of a SiPM array: a standard output for energy measurement and a fast output for timing measurement. The pulse width of the standard output signal is in the range of hundreds nanoseconds, while the pulse width of the other one is in the range of tens nanoseconds. Fast output signals have traditionally been considered suitably for fast timing, however utilizing them for PSD has been little explored. In our previous work, we successfully implemented PSD by using fast output signals from a SiPM. Despite the obvious negative overshoot in fast signals, we achieved PSD of fast signals by using longer sampling times. However, this approach was still limited at high counting rates. This study proposes a compensation network for fast output signals, which is composed of a compensation unit consisting of a resistor and a capacitor. This design effectively compensates the overshoot of the fast output and shortens the pulse width from 60 ns to 44 ns. Additionally, it highlights the frequency amplitude differences between the neutron and gamma signals from fast output in the high-frequency component, thus improving the PSD capability of the fast output.

Non-word repetition and vocabulary in Kuwaiti Arabic-speaking children with down syndrome and typically developing children

Overview Non-word repetition (NWR) is one of the most effective predictors of language impairments in children as it has been found to correlate with various language measures and the association between NWR and vocabulary is well documented in typically developing (TD) studies. However, there is a dire need for investigations of language skills in Kuwaiti Arabic individuals with Down Syndrome, and this study set out to fill a gap in this field. Method In this paper, we compare the vocabulary and NWR skills of a group of 48 individuals with DS aged 6–20 years to a group of 44 TD children aged 3–10 years matched on nonverbal IQ. Furthermore, we investigate the correlations among these language measures in the two groups and examine whether NWR can predict receptive and expressive vocabulary in these two groups. Result Results found DS participants performed significantly less than the TD group on the three language measures (receptive vocabulary t(90)= −3.17, p < .01, expressive vocabulary t(90)= −3.27, p < .01, and NWR t(90)= −8.32, p < .01). Moreover, there were strong correlations between NWR and vocabulary (receptive and expressive) in the TD group but not the DS group. Conclusion Findings supported the working memory model and the phonological processing account for the TD group. On the other hand, the poor association between NWR and vocabulary in the DS group might be due to poor phonological discrimination difficulties and speech discrimination difficulties.

Recreational music exposure and hearing health in young adults

ObjectiveThis study aimed to compare daily and total recreational music exposure levels and extended-spectrum audiogram results in young adults without pre-existing hearing problems.DesignThe study included healthy volunteers aged 18–25 with no known ear disease or hearing loss. Participants completed a questionnaire, underwent otoscopic and tympanometric examinations, and determined preferred music volumes in an audiometry booth using calibrated music samples of their preferred genres. Hearing thresholds up to 16 kiloHertz (kHz) were measured. Daily music exposure for each participant was normalized to 8 h to calculate a time-weighted average of 8 h (TWA8). Total exposure (TE) was calculated by multiplying TWA8 by the number of years of music listening.ResultsA total of 32.4% of participants had TWA8s above 65 dB. Their hearing thresholds at 125, 250, 500, and 16,000 Hz and the average of 125 Hz–8 kHz were significantly higher. Participants with TWA8s above 65 dB were also more prone to speaking loudly and experiencing communication difficulties on the phone. Those with a TE of more than 400 experienced significantly more speech discrimination difficulty in noisy environments and temporary hearing loss/tinnitus after exposure to loud music. Participants with a TE above 700 had worse thresholds at 4, 14, and 16 kHz frequencies, as well as 125–8000 Hz and 500–4000 Hz averages compared to those with a TE below 700.ConclusionsThis study provides evidence that recreational music with much lower exposure levels than the universally accepted TWA8 of 85 dB could negatively impact hearing in healthy young adults. Therefore, maintaining a maximum TWA8 of 65 dB is recommended.

Size-Specific Infrared Spectroscopy of Neutral Hydrated Clusters Based on a Vacuum Ultraviolet Free Electron Laser.

Spectroscopic study of neutral hydrated clusters provides microscopic insights into the local structures and dynamics of complex systems but is very challenging because of the difficulty in size discrimination. Recently, we developed infrared (IR) spectroscopy based on threshold ionization using a tunable vacuum ultraviolet free electron laser (VUV-FEL). This experimental method allows for size-specific IR spectroscopic measurement of numerous neutral clusters without confinement, such as messenger tags, ultraviolet chromophores, and host matrix. This Perspective aims to highlight the latest advances in VUV-FEL-based IR spectroscopic studies on the confinement-free neutral amine-water, sulfur dioxide-water, and metal-water clusters. Fruitful collaborations with high-level quantum chemical calculations are reviewed. Future research directions with relevance to the atmosphere, biology, and catalysis are proposed.

Lexical effects on talker discrimination in adult cochlear implant usersa).

The lexical and phonological content of an utterance impacts the processing of talker-specific details in normal-hearing (NH) listeners. Adult cochlear implant (CI) users demonstrate difficulties in talker discrimination, particularly for same-gender talker pairs, which may alter the reliance on lexical information in talker discrimination. The current study examined the effect of lexical content on talker discrimination in 24 adult CI users. In a remote AX talker discrimination task, word pairs-produced either by the same talker (ST) or different talkers with the same (DT-SG) or mixed genders (DT-MG)-were either lexically easy (high frequency, low neighborhood density) or lexically hard (low frequency, high neighborhood density). The task was completed in quiet and multi-talker babble (MTB). Results showed an effect of lexical difficulty on talker discrimination, for same-gender talker pairs in both quiet and MTB. CI users showed greater sensitivity in quiet as well as less response bias in both quiet and MTB for lexically easy words compared to lexically hard words. These results suggest that CI users make use of lexical content in same-gender talker discrimination, providing evidence for the contribution of linguistic information to the processing of degraded talker information by adult CI users.

성취평가제 확대 적용에 따른 대입전형 평가의 방향

Objectives The purpose of this study is to explore the problems of the standard-based assessment, which is ex-panded in the high school credit system and the 2022 revised curriculum, and the direction of desirable college admission operation.&#x0D; Methods To this end, a survey was conducted on high school teachers and university admissions officers, and the questionnaire was composed of a background variable and a total of 14 questions in 4 areas and was prepared on a 5-point Likert scale. For the collected data, descriptive statistics, t-test, cross-analysis, and one-way var-iance analysis were conducted. In-depth interviews with experts (two high school teachers and admissions offi-cers each) were conducted to secure the validity and reliability of the survey results.&#x0D; Results First, the expansion of the standard-based assessment will reduce the student sub-curricular screening and expand the comprehensive student sub-curricular screening. Second, when the standard-based assess-ment is expanded, the boundary between the student sub-curricular screening and the student sub-curricular screening is blurred, and it is necessary to introduce qualitative evaluation in the student sub-curricular screening. Third, admissions officers were more negatively aware of the operation of subject selection and grade inflation according to student wishes than teachers, and teachers preferred to introduce or strengthen interview evaluation and admissions officers preferred to introduce or strengthen the minimum academic standards for the CSAT as a way to compensate for the difficulty of discrimination in student sub-curricular evaluation.&#x0D; Conclusions When applying the standard-based assessment requires additional factors, specific methods, spe-cific methods should be applied depending on the characteristics of the universities of universities should be ap-plied according to the characteristics of universities. In order to Evaluation of Desirable University Admissions high school life records, and universities need to strengthen the competitiveness of the evaluation of the evaluation.

Unilateral tactile agnosia as an onset symptom of corticobasal syndrome.

Tactile agnosia is the inability to recognize objects via haptic exploration, in the absence of an elementary sensory deficit. Traditionally, it has been described as a disturbance in extracting information about the physical properties of objects ("apperceptive agnosia") or in associating object representation with its semantic meaning ("associative agnosia"). However, tactile agnosia is a rare and difficult-to-diagnose condition, due to the frequent co-occurrence of sensorimotor symptoms and the lack of consensus on the terminology and assessment methods. Among tactile agnosia classifications, hyloagnosia (i.e., difficulty in quality discrimination of objects) and morphoagnosia (i.e., difficulty in shape and size recognition) have been proposed to account for the apperceptive level. However, a dissociation between the two has been reported in two cases only. Indeed, very few cases of pure tactile agnosia have been described, mostly associated with vascular damages in somatosensory areas, in pre- and postcentral gyrus, intraparietal sulcus, supramarginal gyrus, and insular cortex. An open question is whether degenerative conditions affecting the same areas could lead to similar impairments. Here, we present a single case of unilateral right-hand tactile agnosia, in the context of corticobasal syndrome (CBS), a rare neurodegenerative disease. The patient, a 55-year-old woman, initially presented with difficulties in tactile object recognition, apraxia for the right hand, and an otherwise intact cognitive profile. At the neuroimaging level, she showed a lesion outcome of a right parietal oligodendroglioma removal and a left frontoparietal atrophy. We performed an experimental evaluation of tactile agnosia, targeting every level of tactile processing, from elementary to higher order tactile recognition processes. We also tested 18 healthy participants as a matched control sample. The patient showed intact tactile sensitivity and mostly intact hylognosis functions. Conversely, she was impaired with the right hand in exploring geometrical and meaningless shapes. The patient's clinical evolution in the following 3 years became consistent with the diagnosis of CBS and unilateral tactile apperceptive agnosia as the primary symptom onset in the absence of a cognitive decline. This is the third case described in the literature manifesting morphoagnosia with almost completely preserved hylognosis abilities and the first description of such dissociation in a case with CBS.

노인 혐오범죄 및 인권침해에 대한 형사정책적 개선방안에 관한 연구

Due to industrialization, urbanization, and nuclear familyization, the meaning of the Eastern country and the idea of the elderly filial piety are gradually fading, and the lack of a stable source of income, poverty, economic difficulties, job vulnerability, physical and mental health vulnerability, and social isolation and disconnection have caused elder hatred and discrimination. In particular, COVID-19 has increased the difficulty of social relations, elder hatred and discrimination have led to various crimes against the elderly, and various policies are being implemented to resolve the violation of the human rights of the elderly and protect the human rights of the elderly. In particular, in order to harmonize with the rapidly changing times and act as a rights subject, social systems must be established and operated to ensure access to various information, and systems that support the elderly to have the ability to utilize them must also be prepared, but the search for these legal and institutional measures around the world is being overlooked, and the vulnerability of elderly human rights is intensifying. Therefore, from a criminal policy perspective, this paper proposed five policies: first, the enactment of the “Act on the Prohibition of Elder Hate,” second, the enactment of the “Protection of Senior Human Rights” by local governments, third, the development and activation of education programs for the elderly at crime victim support centers, and fourth, the establishment of a council for “prevention and protection of human rights against elder hate crimes” by local governments, and fifth, the establishment of a “Hate Crime Prevention Instructor” certificate.

Comprehensive Comparative Analyses of Aspidistra Chloroplast Genomes: Insights into Interspecific Plastid Diversity and Phylogeny.

Limestone karsts are renowned for extremely high species richness and endemism. Aspidistra (Asparagaceae) is among the highly diversified genera distributed in karst areas, making it an ideal group for studying the evolutionary mechanisms of karst plants. The taxonomy and identification of Aspidistra species are mainly based on their specialized and diverse floral structures. Aspidistra plants have inconspicuous flowers, and the similarity in vegetative morphology often leads to difficulties in species discrimination. Chloroplast genomes possess variable genetic information and offer the potential for interspecies identification. However, as yet there is little information about the interspecific diversity and evolution of the plastid genomes of Aspidistra. In this study, we reported chloroplast (cp) genomes of seven Aspidistra species (A. crassifila, A. dolichanthera, A. erecta, A. longgangensis, A. minutiflora, A. nankunshanensis, and A. retusa). These seven highly-conserved plastid genomes all have a typical quartile structure and include a total of 113 unique genes, comprising 79 protein-coding genes, 4 rRNA genes and 30 tRNA genes. Additionally, we conducted a comprehensive comparative analysis of Aspidistra cp genomes. We identified eight divergent hotspot regions (trnC-GCA-petN, trnE-UUC-psbD, accD-psaI, petA-psbJ, rpl20-rps12, rpl36-rps8, ccsA-ndhD and rps15-ycf1) that serve as potential molecular markers. Our newly generated Aspidistra plastomes enrich the resources of plastid genomes of karst plants, and an investigation into the plastome diversity offers novel perspectives on the taxonomy, phylogeny and evolution of Aspidistra species.

Pupil dilation as a function of pitch discrimination difficulty: A replication of Kahneman and Beatty, 1967.

In the present paper, we carry out a replication of a seminal paper by Kahneman, D. & Beatty, J. (1967). Perception & Psychophysics, 2(3),101-105 for using pupillometry as an implicit measure of auditory processing load, specifically, non-verbal auditory processing. While numerous papers since have supported the notion that pupillometry is a fairly reliable index of processing load in general (Zekveld, A. A., Koelewijn, T., and Kramer, S. E. (2018). Trends in Hearing, 22,1-25; Winn, M. B., Wendt, D., Koelewijn, T., and Kuchinsky, S. E. (2018). Trends in Hearing, 22,1-32), they typically have relied on memory recall, and/or more sophisticated cognitive tasks such as language comprehension or split attention. Kahneman and Beatty's paper, despite that it was published more than 50 years ago, continues to be the primary citation to support the claim that pupillometry is a reliable index of task difficulty for a simple non-verbal pitch discrimination task therefore giving us an implicit measure for listening effort (e.g.,Kramer, S. E., Lorens, A., Coninx, F., Zekveld, A. A., Piotrowska, A., & Skarzynski, H. (2013). Language and Cognitive Processes, 28(4),426-442; Schlemmer, K. B., Kulke, F., Kuchinke, L., & Van Der Meer, E. (2005). Psychophysiology, 42(4),465-472; Lisi, M., Bonato, M., and Zorzi, M. (2015). Biological Psychology, 112,39-45). This type of task takes very little explicit memory, is non-verbal, and relies heavily on more low-level, automatic perceptual processing. Using two different replication studies, one exact, and one modified, we only replicated the main result in the modified replication. The true replication failed to replicate on all nine statistical tests. Overall, our findings suggest that pupil dilation can be used as an implicit measure of task difficulty for a simple, non-semantic, auditory task, however, the robustness of the effect appears relatively weak in comparison with the original study, and the amount of variation across participants much greater.

Using mixture modeling to examine differences in perceptual decision-making as a function of the time and method of participant recruitment

We examine whether perceptual decision-making differs as a function of the time in the academic term and whether the participant is an undergraduate participating for course credit, a paid in-person participant, or a paid online participant recruited via Amazon Mechanical Turk. We use a mixture modeling approach within an evidence accumulation framework that separates stimulus-driven responses from contaminant responses, allowing us to distinguish between performance when a participant is engaged in the task and the consistency in this task focus. We first report a survey showing cognitive psychologists expect performance and response caution to be lower among undergraduate participants recruited at the end of the academic term compared to those recruited near the start, and highest among paid in-person participants. The findings from two experiments using common paradigms revealed very little evidence of time-of-semester effects among course credit participants on accuracy, response time, efficiency of information processing (when engaged in the task), caution, and non-decision time, or consistency in task focus. However, paid in-person participants did tend to be more accurate than the other two groups. Groups showed similar effects of speed/accuracy emphasis on response caution and of discrimination difficulty on information processing efficiency, but the effect of speed/accuracy emphasis on information processing efficiency was less consistent among groups. We conclude that online crowdsourcing platforms can provide quality perceptual decision-making data, but recommend that mixture modeling be used to adequately account for data generated by processes other than the psychological phenomena under investigation.

Fluorescent Nanomaterials for Detection and Discrimination of Amino Acids

The incessant surge and urge for amino acids (AAs) detection and discrimination has led scientists devoting extensive research efforts toward realizing an efficiently more robust methods/techniques for AAs recognition using different materials considering their crucial health impacts in the body system metabolism. Notably, fluorescent probes (FPs), as obviously known currently, are powerful noninvasive detection tools which are suitable and highly effective for biomolecules recognition displaying high‐resolution images. The last decade has witnessed exciting achievements in AAs sensing via the use of FPs and integrated probes with colorimetric sensors reviewed in 2012. However, the conducted study discovers that more advance and effective sensing along with innovative segregation methods for AAs are yet to be vastly unveiled owing to discrimination difficulties among various AAs. As a result, herein, the strategic study accounts for some recent progressive achievements made from 2013 to date for AAs recognition and discrimination via the use of fluorescent nanomaterials (FNMs) of nanoparticles, nanoclusters, and nanodots along with quantum dots (QDs) in different ways. The study concludes by outlining the sensitivity and selectivity extent of AAs, the FNMs, and QDs supramolecular chemistry studies for cancer cells, and finally their status quo based on the views and assumed perspectives.

先秦兩漢 서술·명령·금지 부정사의 동의성 연구

The purpose of this study is to examine the consiliency of ‘勿’, ‘毋’, ‘無’, ‘莫’ which combine descriptive negation, command and forbidden negation among the negative meanings of ancient Chinese.&#x0D; It is to provide the easyness of discrimination by providing the semantics of the word to the learners who complain of the discrimination of ‘勿’, ‘毋’, ‘無’, ‘莫’ having the meaning of the descriptive denial, command and forbidden denial.&#x0D; There are many previous studies on ‘勿’, ‘毋’, ‘無’, ‘莫’ and ‘勿’, ‘毋’, ‘無’, ‘莫’ still are being studied. As a diachronic consideration, there is a study on the prohibition markers of the period of Chinese in the period of Chinese in the modern times - focusing on ‘勿’, ‘毋’, ‘無’, ‘莫’. This study investigated the classification by the two-minute method of exemption and prohibition in the sense of the negative form of the 'lecture duty' aspect. The public consideration is “the” law.,This study analyzed the grammar function of negative adverbs '' specifically by using the literature statistical survey of ‘勿’, ‘毋’, ‘無’, ‘莫’.&#x0D; This study also analyzed the literary examples of the public disclosures and compared the discriminatory qualities of ‘勿’, ‘毋’, ‘無’, ‘莫’ and ‘勿’, ‘毋’, ‘無’, ‘莫’ based on the public disclosure.,Furthermore, the semantics of narrative denial, command or forbidden denial were analyzed and the differences in syntactic thoughts were analyzed.,This is to solve the discrimination difficulties of ancient Chinese learners and to analyze the grammar function of ‘勿’, ‘毋’, ‘無’, ‘莫’.

Executive Function Predicts Older Adults' Lure Discrimination Difficulties on the Mnemonic Similarity Task.

Older adults often have difficulty remembering the details of recently encountered objects. We previously found this with the Mnemonic Similarity Task (MST). Surprisingly, the older adults' MST Lure Discrimination Index (LDI) was significantly correlated with visual acuity but not with memory or executive function. Here we ran a replication with new, larger samples of young (N = 45) and older adults (N = 70). We then combined the original and replication older adult samples (N = 108) to critically examine the relative contributions of visual acuity, memory, and executive function composite scores to LDI performance using dominance analysis. This provided, to our knowledge, the first direct statistical comparison of all 3 of these factors and their interactions on LDI. Participants completed the MST and a battery assessing visual acuity, memory, and executive function. We examined age group differences on MST performance in the new (i.e., replication) young and older adult samples and performed multiple regression and dominance analysis on the combined older adult sample. Consistent with previous findings, the older adults showed significantly poorer LDI but preserved item recognition. LDI was significantly correlated with both memory and executive function but not with visual acuity. In the combined older adult sample, all 3 composites predicted LDI, but dominance analysis indicated that executive function was the most important predictor. Older adults' MST LDI difficulty may be predicted by their executive function and visual acuity. These factors should be considered when interpreting older adults' MST performance.

The Satogawa Index: A landscape-based indicator for freshwater biodiversity in Japan

Nationwide biodiversity indicators based on landscape heterogeneity have been developed primarily for terrestrial ecosystems, but not well for freshwater ecosystems worldwide. A plausible reason for this limitation is the difficulty in the fine discrimination of freshwater environments by remote sensing. However, in recent years, Geographic Information System (GIS) vector data of freshwater land cover are classified in detail (i.e. rice paddy fields, other marshy wetlands, rivers, ponds and lakes) in Japan. Using these GIS data, we developed an index for freshwater landscape heterogeneity with 1 km square as the spatial unit, which was named the ‘Satogawa’ Index (SGI). The SGI formula consisted of two-component terms, one reflecting the diversity of freshwater land covers, and the other representing their spatial shapes. We calculated the SGI at a central region in Japan and found significant relationships with the species richness of Odonata (dragonflies and damselflies) and freshwater fish. The amounts and spatial patterns of freshwater landscape elements by which the SGI was estimated were different among regions in Japan; however, the SGI may be adapted to other regions as a surrogate of aquatic species richness, a typical measure of freshwater biodiversity. Although several modifications are underway that may have negative consequences for freshwater biodiversity, land use has been changed to prevent flood damage and improve the freshwater environment. The SGI may reveal the influences of the changes in land use on freshwater biodiversity and may identify the type and amount of lotic and lentic environment that should be supplemented to improve freshwater biodiversity at a certain location.

Learning from Freja the harbor porpoise to appreciate movements as an important behavioral readout to understand echolocation-based target discrimination

Toothed whales routinely discriminate and select prey via echolocation. Over a decade, the harbor porpoise Freja in Fjord and Bælt, Kerteminde, Denmark participated in a series of target discrimination experiments involving metal objects. Different from experiments in which the subjects were constrained to be stationary, Freja’s free and voluntary movements offered insights into the tightly coupled nature of acoustic sampling and movements in echolocation-based target discrimination. Compared with observations from wild animals with unknown prey, the controlled experimental task and stimuli made it possible to interpret her behavior based on predictable target echo features. Here, we test the hypothesis that an echolocating animal plans its movement based on prior echo returns to gather better target discrimination information. We trained Freja to approach and select a sphere against a spheroid in a two-alternative forced-choice discrimination task, and show that her performance and movement trajectory varied depending on the aspect ratio and presentation angle of the spheroid. Consistent with our hypothesis, we further show that Freja’s movement patterns were likely driven by echo information received earlier during the approach that is correlated with the discrimination difficulty. These results highlight movements as an important behavioral readout of the dynamic, closed-loop sensorimotor feedback in echolocation. [Work supported by ONR.]

Understanding others' distal goals from proximal communicative actions.

Many social interactions require individuals to coordinate their actions and to inform each other about their goals. Often these goals concern an immediate (i.e., proximal) action, as when people give each other a brief handshake, but they sometimes also refer to a future (i.e. distal) action, as when football players perform a passing sequence. The present study investigates whether observers can derive information about such distal goals by relying on kinematic modulations of an actor's instrumental actions. In Experiment 1 participants were presented with animations of a box being moved at different velocities towards an apparent endpoint. The distal goal, however, was for the object to be moved past this endpoint, to one of two occluded target locations. Participants then selected the location which they considered the likely distal goal of the action. As predicted, participants were able to detect differences in movement velocity and, based on these differences, systematically mapped the movements to the two distal goal locations. Adding a distal goal led to more variation in the way participants mapped the observed movements onto different target locations. The results of Experiments 2 and 3 indicated that this cannot be explained by difficulties in perceptual discrimination. Rather, the increased variability likely reflects differences in interpreting the underlying connection between proximal communicative actions and distal goals. The present findings extend previous research on sensorimotor communication by demonstrating that communicative action modulations are not restricted to predicting proximal goals but can also be used to infer more distal goals.