Timing without a timer.

Inferred-process theories propose various internal timing mechanisms to provide discriminative stimuli for temporal control of behavior. Biobehaviorally informed computer simulations indicate that timing may emerge from the action of reinforcement on neural circuits without the need to postulate timers of any sort.     

Are generalised scalar implicatures generated by default? An on-line investigation into the role of context in generating pragmatic inferences

Recent research in semantics and pragmatics has revived the debate about whether there are two cognitively distinct categories of conversational implicatures: generalised and particularised. Generalised conversational implicatures are so-called because they seem to arise more or less independently of contextual support. Particularised implicatures are more context-bound. The Default view is that generalised implicatures are default inferences and that their computation is relatively autonomous--being computed by some default mechanism and only being open to cancellation at a second stage when contextual assumptions are taken into consideration (i.a.). It is at that second stage where contextual assumptions are considered that particularised implications are computed. By contrast, Context-Driven theorists claim that both generalised and particularised implicatures are generated by the same process and only where there is contextual support (Chierchia, 2004; Horn, 1984; Levinson, 2000 i.a.). In this paper, we present three on-line studies of the prototypical cases of generalised implicatures: the scalar implicatures 'some of the Fs' > 'not all the Fs' and 'X or Y' > 'either X or Y but not both'. These studies were designed to test the context-dependence and autonomy of the implicatures. Our results suggest that these scalar implicatures are dependent on the conversational context and that they show none of the autonomy predicted by the Default view. We conclude with a discussion of the degree to which such implicatures are purely context-driven and whether an interactionist default position may also be plausible.     

EFFECTS OF MORPHINE ON TEMPORAL DISCRIMINATION AND COLOR MATCHING: GENERAL DISRUPTION OF STIMULUS CONTROL OR SELECTIVE EFFECTS ON TIMING?

Discrepant effects of drugs on behavior maintained by temporal-discrimination procedures make conclusive statements about the neuropharmacological bases of timing difficult. The current experiment examined the possible contribution of a general, drug-induced disruption of stimulus control. Four pigeons responded on a three-component multiple schedule that included a fixed-interval 2-min, temporal discrimination, and color-matching component. Under control conditions, response rates and choice responses during the first two components showed evidence of control by time, and accuracy for color matching was high in the third component. Morphine administration flattened the distribution of fixed-interval responding and produced a general disruption of accuracy in the temporal-discrimination component, whereas accuracy in the color-matching component was relatively unaffected. Analysis of the psychophysical functions from the temporal-discrimination component indicated that morphine decreased accuracy of temporal discrimination by decreasing overall stimulus control, rather than by selectively affecting timing. These results suggest the importance of determining the neurophysiological bases of stimulus control as it relates to temporal discrimination.     

The effects of interval duration on temporal tracking and alternation learning

On cyclic-interval reinforcement schedules, animals typically show a postreinforcement pause that is a function of the immediately preceding time interval (temporal tracking). Animals, however, do not track single-alternation schedules-when two different intervals are presented in strict alternation on successive trials. In this experiment, pigeons were first trained with a cyclic schedule consisting of alternating blocks of 12 short intervals (5 s or 30 s) and 12 long intervals (180 s), followed by three different single-alternation interval schedules: (a) 30 s and 180 s, (b) 5 s and 180 s, and (c) 5 s and 30 s. Pigeons tracked both schedules with alternating blocks of 12 intervals. With the single-alternation schedules, when the short interval duration was 5 s, regardless of the duration of the longer interval, pigeons learned the alternation pattern, and their pause anticipated the upcoming interval. When the shorter interval was 30 s, even when the ratio of short to long intervals was kept at 6:1, pigeons did not initially show anticipatory pausing-a violation of the principle of timescale invariance.     

Individual differences in impulsive choice and timing in rats

Individual differences in impulsive choice behavior have been linked to a variety of behavioral problems including substance abuse, smoking, gambling, and poor financial decision-making. Given the potential importance of individual differences in impulsive choice as a predictor of behavioral problems, the present study sought to measure the extent of individual differences in a normal sample of hooded Lister rats. Three experiments utilized variations of a delay discounting task to measure the degree of variation in impulsive choice behavior across individual rats. The individual differences accounted for 22-55% of the variance in choice behavior across the three experiments. In Experiments 2 and 3, the individual differences were still apparent when behavior was measured across multiple choice points. Large individual differences in the rate of responding, and modest individual differences in timing of responding were also observed during occasional peak trials. The individual differences in timing and rate, however, did not correlate consistently with individual differences in choice behavior. This suggests that a variety of factors may affect choice behavior, response rate, and response timing.     

时间知觉的脑机制:时钟模型的困境和新导向

长期以来人们认为神经系统是通过类似于时钟的方式来实现对一段时间的知觉的,并认为多巴胺能系统(基地神经节)和时钟的快慢有关。与多巴胺信号有关的药物的动物实验的结果以及帕金森氏症(parkinson’s disease)患者的行为表现被看作是支持以上看法的证据。然而,最近的大量研究对这个理论提出了挑战,结合行为研究和脑机制研究的新成果,研究者提出了知觉信息可以通过神经活动状态或加工中的能量消耗来表达。     

Making disjunctions exclusive

This work examines how people interpret the sentential connective “or”, which can be viewed either inclusively (A or B or both) or exclusively (A or B but not both). Following up on prior work concerning quantifiers (Bott & Noveck, 2004; Noveck, 2001; Noveck & Posada, 2003), which shows that the common pragmatic interpretation of “some”, some but not all, is conveyed as part of an effortful step, we investigate how extra effort applied to disjunctive statements leads to a pragmatic interpretation of “or”, or but not both. Experiment 1 compelled participants to wait for three seconds before answering, hence giving them the opportunity to process the utterance more deeply. Experiments 2 and 3 emphasized “or”, either by visual means (“OR”) or by prosodic means (contrastive stress) as another way to encourage participants to apply more effort. Following a relevance-theoretic line of argument, we hypothesized that conditions encouraging more processing effort would give rise to more pragmatic inferences and hence to more exclusive interpretations of the disjunction. This prediction was confirmed in the three experiments.     

The relativity of time perception produced by facial emotion stimuli

Insults elicit intense emotion. This study tests the hypothesis that one's social image, which is especially salient in honour cultures, influences the way in which one reacts to an insult. Seventy-seven honour-oriented and 72 non-honour oriented participants answered questions about a recent insult episode. Participants experienced both anger and shame in reaction to the insult. However, these emotions resulted in different behaviours. Anger led to verbal attack (i.e., criticising, insulting in return) among all participants. This relationship was explained by participants’ motivation to punish the wrongdoer. Shame, on the other hand, was moderated by honour. Shame led to verbal disapproval of the wrongdoers behaviour, but only among the honour-oriented participants. This relationship was explained by these participants’ motivation to protect their social image. By contrast, shame led to withdrawal among non-honour-oriented participants.