Visual Predictions Operate on Different Timescales

Humans live in a volatile environment, subject to changes occurring at different timescales. The ability to adjust internal predictions accordingly is critical for perception and action. We studied this ability with two EEG experiments in which participants were presented with sequences of four Gabor patches, simulating a rotation, and instructed to respond to the last stimulus (target) to indicate whether or not it continued the direction of the first three stimuli. Each experiment included a short-term learning phase in which the probabilities of these two options were very different (p = .2 vs. p = .8, Rules A and B, respectively), followed by a neutral test phase in which both probabilities were equal. In addition, in one of the experiments, prior to the short-term phase, participants performed a much longer long-term learning phase where the relative probabilities of the rules predicting targets were opposite to those of the short-term phase. Analyses of the RTs and P3 amplitudes showed that, in the neutral test phase, participants initially predicted targets according to the probabilities learned in the short-term phase. However, whereas participants not pre-exposed to the long-term learning phase gradually adjusted their predictions to the neutral probabilities, for those who performed the long-term phase, the short-term associations were spontaneously replaced by those learned in that phase. This indicates that the long-term associations remained intact whereas the short-term associations were learned, transiently used, and abandoned when the context changed. The spontaneous recovery suggests independent storage and control of long-term and short-term associations.

You see what you look for: perceptual biases induced by targets and distractors in visual search

Visual perception is, at any given moment, strongly influenced by its temporal context – what stimuli have recently been perceived and in what surroundings. We have previously shown that to-be-ignored items produce a bias upon subsequent perception that acts in parallel with other biases induced by attended items. However, our previous investigations were confined to biases upon a visual search target's perceived orientation, and it is unclear whether these biases influence perception in a more general sense. Canonical paradigms investigating so-called serial dependence have revealed biases in the perception of items not associated with any particular task. Therefore, we test here whether the biases from visual search targets and distractors affect the perceived orientation of a neutral test line, which is neither a target nor a distractor. To do so, we asked participants to search for an oddly oriented line among distractors and report its location for a few trials and then presented a task-irrelevant test line. Next, participants were asked to report the orientation of the test line. Our results indicate that in tasks involving visual search, targets induce a positive bias upon a neutral test line if their orientations are similar, and distractors also produce a repulsive bias if the test line's orientations and the distractors' average orientation are far apart in feature space. Additionally, our results show that proximity in feature space between previous and current stimuli plays a large role in determining the direction of the perceptual biases.

Use of Stroop Test for Sports Psychology Study: Cross-Over Design Research

Background: In sports psychology research, the Stroop test and its derivations are commonly used to investigate the benefits of exercise on cognitive function. The measures of the Stroop test and the computed interference often have different interclass correlation coefficients (ICC). However, the ICC is never reported in cross-over designs involving multiple variances associated with individual differences.Objective: We investigated the ICC of the Stroop neutral and incongruent tests and interference (neutral test—incongruent test), and reverse Stroop task using the linear mixed model.Methods: Forty-eight young adults participated in a cross-over design experiment composed of 2 factors: exercise mode (walking, resistance exercise, badminton, and seated rest as control) and time (pre- and post-tests). Before and after each intervention, participants completed the Stroop neutral and incongruent, and the reverse-Stroop neutral and incongruent tests. We analyzed for each test performance and interference and calculated ICC using the linear mixed model.Results: The linear mixed model found a significant interaction of exercise mode and time for both the Stroop and reverse-Stroop tasks, suggesting that exercise mode influences the effect of acute exercise on inhibitory function. On the other hand, there was no significant effect of exercise mode for both the Stroop and reverse-Stroop interference. The results also revealed that calculating both the Stroop and reverse-Stroop interference resulted in smaller ICCs than the ICCs of the neutral and incongruent tests for both the Stroop and reverse-Stroop tasks.Conclusion: The Stroop and reverse-Stroop interferences are known as valid measures of the inhibitory function for cross-sectional research design. However, to understand the benefits of acute exercise on inhibitory function comprehensively by cross-over design, comparing the incongruent test with the neutral test also seems superior because these tests have high reliability and statistical power.

The Politics of Legal Empirics: Do Political Attitudes Predict the Results of Empirical Legal Scholarship?

Empirical legal scholarship has emerged as a dominant trend in legal scholarship. At its best, empirical scholarship subjects assertions about the effect of legal rules to a neutral test. But is empirical inquiry truly neutral? The validity of an empirical study should rest on the reliability of the methods used, rather than the political implications of its conclusions. Scholars might choose targets of inquiry, sources of data, or methods of analysis that support their political allegiances. This paper tests this thesis by matching the political beliefs of authors of empirical legal scholarship with the results of their research. The political allegiances of authors mildly correlate with the results of empirical inquiry in legal scholarship.

Investigating typographic differentiation: Italics are more subtle than bold for emphasis

Text designers are likely to benefit from guidance on how to use typographic differentiation for emphasis. Three experiments use purposely-designed fonts to explore the size and nature of differences in the stylistic characteristics of fonts (weight, width, contrast, italic) which affect letter identification. Results indicate that words set in bold and expanded fonts, when alternated with words set in a Neutral test font, may impair performance, whereas changing to italic does not. Possible explanations are explored through measuring the physical and perceptual similarities of the test fonts.

The entropy principle, and the influence of sociological pressures on SETI

We begin with the premise that the law of entropy could prove to be fundamental for the evolution of intelligent life and the advent of technological civilization. Building on recent theoretical results, we combine a modern approach to evolutionary theory with Monte Carlo realization techniques. A numerical test for a proposed significance of the law of entropy within the evolution of intelligent species is performed and results are compared with a neutral test hypothesis. Some clarifying aspects on the emergence of intelligent species arise and are discussed in the framework of contemporary astrobiology.