5,890 research outputs found
Context-dependent motor skill and the role of practice
Research has shown that retrieval of learned information is better when the original learning context is reinstated during testing than when this context is changed. Recently, such contextual dependencies have also been found for perceptual-motor behavior. The current study investigated the nature of context-dependent learning in the discrete sequence production task, and in addition examined whether the amount of practice affects the extent to which sequences are sensitive to contextual alterations. It was found that changing contextual cues—but not the removal of such cues—had a detrimental effect on performance. Moreover, this effect was observed only after limited practice, but not after extensive practice. Our findings support the notion of a novel type of context-dependent learning during initial motor skill acquisition and demonstrate that this context-dependence reduces with practice. It is proposed that a gradual development with practice from stimulus-driven to representation-driven sequence execution underlies this practice effect
Absolute identification by relative judgment
In unidimensional absolute identification tasks, participants identify stimuli that vary along a single dimension. Performance is surprisingly poor compared with discrimination of the same stimuli. Existing models assume that identification is achieved using long-term representations of absolute magnitudes. The authors propose an alternative relative judgment model (RJM) in which the elemental perceptual units are representations of the differences between current and previous stimuli. These differences are used, together with the previous feedback, to respond. Without using long-term representations of absolute magnitudes, the RJM accounts for (a) information transmission limits, (b) bowed serial position effects, and (c) sequential effects, where responses are biased toward immediately preceding stimuli but away from more distant stimuli (assimilation and contrast)
Psychoacoustic Test to Determine Sound Quality Metric Indicators of Rotorcraft Noise Annoyance
Noise certification metrics such as Effective Perceived Noise Level and Sound Exposure Level are used to ensure that helicopters meet regulations, but these metrics may not be good indicators of annoyance since noise complaints against helicopters persist. Sound quality (SQ) metrics, specifically fluctuation strength, tonality, impulsiveness, roughness, and sharpness, are explored to determine their relationship with annoyance. A psychoacoustic test was conducted at the NASA Langley Research Center Exterior Effects Room to assess annoyance to helicopter-like sounds over a range of SQ metric values. The amplitude, phase, and frequency of the AS350 helicopter main and tail rotor blade passage signal harmonics were manipulated to produce 105 unique helicopter-like sounds with prescribed values of SQ metrics. All sounds were set to roughly the same loudness level. These sounds were played to 40 subjects who rated each sound for annoyance. Analyses given in this paper point to which SQ metrics are important to the helicopter noise annoyance response
Non-adjacent dependency learning: development, domain differences, and memory
Children learn their first language simply by listening to the linguistic utterances
provided by their caregivers and other speakers around them. In order to
extract meaning and grammatical rules from these utterances, children must track
regularities in the input, which are omnipresent in language. The ability to discover
and adapt to these statistical regularities in the input is termed statistical
learning and has been suggested to be one of the key mechanisms underlying language
acquisition. In this thesis, I investigated a special case of statistical learning,
non-adjacent dependency (NAD) learning. NADs are grammatical dependencies
between distant elements in an utterance, such as is and -ing in the sentence Mary is
walking. I examined which factors play a role in the development of NAD learning
by illuminating this process from different stand points: the first study compares
NAD learning in the linguistic and the non-linguistic domain during the earliest
stages of development, at 4 months of age. This study suggests that at this age,
NAD learning seems to be domain-specific to language. The second study puts a
spotlight on the development of NAD learning in the linguistic domain and proposes
that there may be a sensitive period for linguistic NAD learning during early
childhood. Finally, the third study shows that children can not only recall newly
learned NADs in a test immediately following familiarization, but also recall them
after a retention period, which is critical to show more long-term learning. Overall,
the findings in this thesis further illuminate how NADs, as a spotlight into
language acquisition, are learned, stored in memory, and recalled
Structure from noise: Mental errors yield abstract representations of events
Humans are adept at uncovering abstract associations in the world around
them, yet the underlying mechanisms remain poorly understood. Intuitively,
learning the higher-order structure of statistical relationships should involve
complex mental processes. Here we propose an alternative perspective: that
higher-order associations instead arise from natural errors in learning and
memory. Combining ideas from information theory and reinforcement learning, we
derive a maximum entropy (or minimum complexity) model of people's internal
representations of the transitions between stimuli. Importantly, our model (i)
affords a concise analytic form, (ii) qualitatively explains the effects of
transition network structure on human expectations, and (iii) quantitatively
predicts human reaction times in probabilistic sequential motor tasks.
Together, these results suggest that mental errors influence our abstract
representations of the world in significant and predictable ways, with direct
implications for the study and design of optimally learnable information
sources.Comment: 62 pages, 7 figures, 10 table
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Serial dependence in a simulated clinical visual search task.
In everyday life, we continuously search for and classify objects in the environment around us. This kind of visual search is extremely important when performed by radiologists in cancer image interpretation and officers in airport security screening. During these tasks, observers often examine large numbers of uncorrelated images (tumor x-rays, checkpoint x-rays, etc.) one after another. An underlying assumption of such tasks is that search and recognition are independent of our past experience. Here, we simulated a visual search task reminiscent of medical image search and found that shape classification performance was strongly impaired by recent visual experience, biasing classification errors 7% more towards the previous image content. This perceptual attraction exhibited the three main tuning characteristics of Continuity Fields: serial dependence extended over 12 seconds back in time (temporal tuning), it occurred only between similar tumor-like shapes (feature tuning), and only within a limited spatial region (spatial tuning). Taken together, these results demonstrate that serial dependence influences shape perception and occurs in visual search tasks. They also raise the possibility of a detrimental impact of serial dependence in clinical and practically relevant settings, such as medical image perception
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