The development of voicing categories: A quantitative review of over 40 years of infant speech perception research

Most research on infant speech categories has relied on measures of discrimination. Such work often employs categorical perception as a linking hypothesis to enable inferences about categorization on the basis of discrimination measures. However, a large number of studies with adults challenge the utility of categorical perception in describing adult speech perception, and this in turn calls into question how to interpret measures of infant speech discrimination. We propose here a parallel channels model of discrimination (built on Pisoni and Tash Perception & Psychophysics, 15(2), 285–290, 1974), which posits that both a noncategorical or veridical encoding of speech cues and category representations can simultaneously contribute to discrimination. This can thus produce categorical perception effects without positing any warping of the acoustic signal, but it also reframes how we think about infant discrimination and development. We test this model by conducting a quantitative review of 20 studies examining infants’ discrimination of voice onset time contrasts. This review suggests that within-category discrimination is surprisingly prevalent even in classic studies and that, averaging across studies, discrimination is related to continuous acoustic distance. It also identifies several methodological factors that may mask our ability to see this. Finally, it suggests that infant discrimination may improve over development, contrary to commonly held notion of perceptual narrowing. These results are discussed in terms of theories of speech development that may require such continuous sensitivity.     

Time-varying decision boundaries: insights from optimality analysis

The most widely used account of decision-making proposes that people choose between alternatives by accumulating evidence in favor of each alternative until this evidence reaches a decision boundary. It is frequently assumed that this decision boundary stays constant during a decision, depending on the evidence collected but not on time. Recent experimental and theoretical work has challenged this assumption, showing that constant decision boundaries are, in some circumstances, sub-optimal. We introduce a theoretical model that facilitates identification of the optimal decision boundaries under a wide range of conditions. Time-varying optimal decision boundaries for our model are a result only of uncertainty over the difficulty of each trial and do not require decision deadlines or costs associated with collecting evidence, as assumed by previous authors. Furthermore, the shape of optimal decision boundaries depends on the difficulties of different decisions. When some trials are very difficult, optimal boundaries decrease with time, but for tasks that only include a mixture of easy and medium difficulty trials, the optimal boundaries increase or stay constant. We also show how this simple model can be extended to more complex decision-making tasks such as when people have unequal priors or when they can choose to opt out of decisions. The theoretical model presented here provides an important framework to understand how, why, and whether decision boundaries should change over time in experiments on decision-making.     

Traumatic stress, dissociation, and limbic irritability in patients with unipolar depression being treated with SSRIs

Recent evidence suggests that stressful experiences may be related to deficits in inhibitory functions and temporo-limbic epileptic-like activity. The latter may produce psychosensory seizure-like symptoms that may also appear in nonepileptic conditions. This study assesses whether the increased presence of the seizure-like symptoms in 113 unipolar depressive patients treated with SSRIs is associated with significantly more severe symptoms of depression, traumatic stress, and dissociation in comparison with 86 healthy controls. Results indicate that seizure-like symptoms in depressive patients have significant association with depression, symptoms of dissociation, and traumatic stress. This association suggests that processess generating seizure-like symptoms may be related to symptoms of depression, traumatic stress, and dissociation.     

The emotional feeling as a combination of two qualia: A neurophilosophical-based emotion theory

It is argued that the emotional feeling comprises the following two emotional qualia. (1) A nucleus feeling or primary emotional quale, which is the phenomenological counterpart of the end product of appraisal by the central nervous system. (2) The experience of being urged to emotion-related reflection or secondary emotional quale, which is the phenomenological counterpart of the brain's decision to inhibit pre-programmed emotional behaviour, and to initiate emotion-related reflections. Different brain modules regulate these two qualia, and thus each can be experienced independently of the other. The primary emotional quale is related to activation of the amygdala, it is emotion specific, and neutral with respect to affect. The secondary emotional quale is related to activation of the orbito-prefrontal cortex (O-PFC), and includes affective aspects.

It is argued that emotional behaviour is regulated by the following three neural mechanisms, two of which two are directly related to the two qualia. (1) An evolutionary ancient system (amygdala-system), which comprises the amygdalae and subcortical nuclei, and which activates pre-programmed emotional behaviour. (2) An evolutionary recent system (PFC-system), comprising the prefrontal cortex, which inhibits pre-programmed emotional behaviour, activates emotional reflection, generates and evaluates behavioural alternatives. In contrast to the pre-programmed behaviour, the behavioural alternatives are more likely to serve long-term goals. (3) A default mechanism, which gives rise to default (i.e., “just do something”) behaviour. The first two systems are mutually competitive, while the third mechanism takes over if either the competition between the first two mechanisms, or the decision process of the PFC-system, takes too long. This default mechanism involves the function of the medial-prefrontal cortex (M-PFC).     

Busting a Myth about Leśniewski and Definitions

A theory of definitions which places the eliminability and conservativeness requirements on definitions is usually called the standard theory. We examine a persistent myth which credits this theory to Le?niewski, a Polish logician. After a brief survey of its origins, we show that the myth is highly dubious. First, no place in Le?niewski's published or unpublished work is known where the standard conditions are discussed. Second, Le?niewski's own logical theories allow for creative definitions. Third, Le?niewski's celebrated ‘rules of definition’ lay merely syntactical restrictions on the form of definitions: they do not provide definitions with such meta-theoretical requirements as eliminability or conservativeness. On the positive side, we point out that among the Polish logicians, in the 1920s and 1930s, a study of these meta-theoretical conditions is more readily found in the works of ?ukasiewicz and Ajdukiewicz.     

Negative valence can evoke a liberal response bias in syllogistic reasoning

Recently, studies have demonstrated that negative valence reduces the magnitude of the belief-bias effect in syllogistic reasoning. This effect has been localized in the reasoning stage, in the form of increased deliberation on trials where validity and conclusion believability are incongruent. Here, using signal detection theory, we show that the attenuation of belief bias observed when valence was negative can also be evoked by a liberal response bias at the decision stage. Indeed, when valence was negative participants adopted a more liberal criterion for judging syllogisms as “valid,” and were overconfident in their judgments. They also displayed less sensitivity in distinguishing between valid and invalid syllogisms. Our findings dovetail with recent evidence from memory research suggesting that negative valence can evoke a liberal response bias without improving performance. Our novel contribution is the demonstration that the attenuating effect of negative valence on belief bias can take multiples routes—by influencing the decision stage as was the case here, the reasoning stage as has been demonstrated elsewhere, and potentially both stages.     

A Comparison of Academic Dishonesty Among Business Students in a Public and Private Catholic University

A questionnaire on academic dishonesty was administered to junior and senior business administration majors at a public and a private Catholic university. Students were asked their extent of participation in 16 dishonest academic practices; their ratings of the ethical levels of the practices; their ratings of the likelihood of reasons for participation in the practices; and their sex, grade point average (GPA), and class rank. Though the catalog of the Catholic university indicated a greater emphasis on ethics and values education than did the catalog of the public school, the two groups of students reported very similar levels of academic dishonesty. Possible reasons for the disconnect between the emphasis on values and morals at the Catholic university and the students' academic behavior are discussed.