The Persistent Interlocutor

A Persistent Interlocutor (PI) is someone who, in argumentative contexts, does not cease to question her opponent’s premises. The epistemic relevance of the PI has been debated throughout the history of philosophy. Pyrrhonians famously claim that our inability to dialectically vindicate our claims against a PI implies scepticism. Adam Leite disagrees (2005). Michael Resorla argues that the debate is based on a false premise (2009). In this paper, I argue that these views all fail to accurately account for the epistemic relevance of the PI. I then briefly present an account that aims to do better in this regard, based on the modal notion of safety. On the account proposed, the PI does not violate epistemic or dialectical norms. Rather, her behaviour tends to be epistemically perverse in the sense that it wastes cognitive resources. Perhaps surprisingly, this defect turns out not to be unique to the PI.

     

Insights into computational thinking from think-aloud interviews: A systematic review

This systematic review examines 35 empirical studies featuring the use of think-aloud interviews in computational thinking (CT) research. Findings show that think-aloud interviews (1) are typically conducted in Computer Science classrooms and with K-12 students; (2) are usually combined with other exploratory CT assessment tools; (3) have the potential to benefit learners with special needs and identify the competency gaps through involving diverse participants; (4) are conducted in the absence of cognitive models and standard procedures; and (5) display insufficient definitional and methodological rigor. Theoretically, this review presents a systematic assessment about the application of think-aloud interviews in CT studies and identifies the limitations in existing CT-related think-aloud studies. Practically, this review serves as a reference for studying the cognitive processes during CT problem-solving and provides suggestions for CT researchers who intend to incorporate think-aloud interviews in their studies.     

Early judgments of semantic and syntactic acceptability by children

Judgments of the acceptability of correct, word order reversed, and semantically anomalous sentences were elicited from 2- and 3-year-old children in a game played with hand puppets. All of the sentences used were simple imperatives and each child was asked to correct those he called wrong. Performance on the judgment task was correlated with each child's mean length of utterance and with his comprehension of reversible active and passive sentences. Only the linguistically most advanced children were able to make a significant number of appropriate judgments and corrections of reversed word order imperatives. Less developed children could appropriately judge and correct semantically anomalous but not incorrect word order imperatives. The importance of semantic as opposed to syntactic factors in children's judgments of the acceptability of sentences is stressed.This research was supported in part by PHS Grant HD-02908 from the National Institute of Child Health and Development. Roger Brown is the principal investigator.     

A new approach to the generation of visual stimuli for eye-movement research

An interactive, computer-controlled, visual stimulus generator is described, suitable for both psychophysical and neurophysiological experimentation on human subjects. The system core is a wide-screen electrostatic cathode-ray tube, which can be used both as a television monitor, to display standard video pictures, and as anx-y oscilloscope, so that a bright dot can be moved around the display by electrical signals. In addition, a third working mode is provided, according to which a time-compressed video picture of limited size (fast picture) plays the role that is typical of the spot in a standard oscilloscope. Through computer-assisted time compression, the frame period of the video signal is reduced to about one tenth of its standard value. The fast picture can accordingly be driven by even the fastest eye movements, and it can be displayed as a stabilized image, or, more generally, in the altered retinal feedback condition. Moreover, as compared with a standard video picture, the fast image can be “flashed” over much shorter time periods. Since a standard input video signal is used for both standard and fast video pictures, all the image processing facilities of commercial videographic systems can be fully exploited by the proposed device.     

Shape from stereo: A systematic approach using quadratic surfaces

We used quadratic shapes in several psychophysical shape-from-stereo tasks. The shapes were elegantly represented in a 2-D parameter space by the scale-independentshape index and the scale-dependentcurvedness. Using random-dot stereograms to depict the surfaces, we found that the shape of hyperbolic surfaces is slightly more difficult to recognize than the shape of elliptic surfaces. We found that curvedness (and indirectly, scale) has little or no influence on shape recognition.     

Ethnicity of Defendants and Jurors as Influences on Jury Decisions1

To assess the influence of ethnicity on jury decisions, 480 subjects viewed a videotaped trial of an Anglo or Hispanic defendant. Anglo or Hispanic majority 6-person juries deliberated until a unanimous verdict was reached. The juries that convicted the defendant were asked to determine sentence length and to provide a probation/ parole recommendation. Anglo majority juries convicted the defendant significantly more (M= 79%) than did the Hispanic majority juries (M= 52%), x²= 5.45, p < 0.02. No main effect of defendant ethnicity was obtained, but there was an interaction between the defendant and the jury's ethnicity, x²= 5.41, p < 0.02. Anglo majority juries were more lenient with the Anglo defendant, but the Hispanic majority juries did not differ in their conviction rates. No significant effects were obtained for sentence length. Differences in probation/parole recommendations were a function of jury ethnicity, F(l, 15) = 4.74, p < 0.05. Anglos were more likely to recommend that the defendant serve the full term of the sentence. These results are interpreted in terms of stereotyping and are discussed regarding their implications for a defendant's constitutional right to a fair trial.     

Mental image reversal and verbal recoding: When ducks become rabbits

A recent debate has concerned whether classical bistable configurations (e.g., duck/rabbit) can be reinterpreted using mental imagery. Research in this field indicates that image reversal is possible only when subjects change their specification of orientation. In a series of four experiments, we demonstrate that mental reversal of classical bistable configurations( CBCs) is impeded by verbally recoding the visual pattern at the time of input. When subjects were prevented from verbally recoding visual stimuli in short-term memory, they fared systematically better in mentally reversing the CBC, even when they received no instructions to change their reference frame or specification of orientation. On this basis, we suggest a model of image reversal that takes into account the interaction between memory codes and provides a new perspective on verbal recoding, verbal overshadowing, and mental discoveries.