A comparison of blindpulling and blindwalking as measures of perceived absolute distance

Blindwalking has become a common measure of perceived absolute distance and location, but it requires a relatively large testing space and cannot be used with people for whom walking is difficult or impossible. In the present article, we describe an alternative response type that is closely matched to blindwalking in several important respects but is less resource intensive. In the blindpulling technique, participants view a target, then close their eyes and pull a length of tape or rope between the hands to indicate the remembered target distance. As with blindwalking, this response requires integration of cyclical, bilateral limb movements over time. Blind-pulling and blindwalking responses are tightly linked across a range of viewing conditions, and blind-pulling is accurate when prior exposure to visually guided pulling is provided. Thus, blindpulling shows promise as a measure of perceived distance that may be used in nonambulatory populations and when the space available for testing is limited.     

Competition between color salience and perceptual load during visual selection can be biased by top-down set

Visual salience and perceptual load may both influence the efficiency of visual selection. Recently, Gibson and Bryant (2008) showed that perceptual load can dominate color salience in a distractor interference paradigm. The purpose of the present study was to investigate the possibility that knowledge (of color or load) may modulate the relative operation of these two mechanisms. Consistent with previous findings, perceptual load dominated color salience, but only in certain contexts in which display load was mixed and high-load displays preceded other high-load displays. More important, color salience dominated perceptual load in other contexts in which display load was mixed and low-load displays preceded high-load displays. In addition, color salience also dominated perceptual load in contexts in which display load was fixed and advance knowledge of load was available. Altogether, the present findings suggest that the competition between color salience and perceptual load can vary as a function of task context, thereby supporting top-down accounts, although the precise aspect of task context remains to be identified.     

Automatic imitation of biomechanically possible and impossible actions: effects of priming movements versus goals

Recent behavioral, neuroimaging, and neurophysiological research suggests a common representational code mediating the observation and execution of actions; yet, the nature of this representational code is not well understood. The authors address this question by investigating (a) whether this observation-execution matching system (or mirror system) codes both the constituent movements of an action as well as its goal and (b) how such sensitivity is influenced by top-down effects of instructions. The authors tested the automatic imitation of observed finger actions while manipulating whether the movements were biomechanically possible or impossible, but holding the goal constant. When no mention was made of this difference (Experiment 1), comparable automatic imitation was elicited from possible and impossible actions, suggesting that the actions had been coded at the level of the goal. When attention was drawn to this difference (Experiment 2), however, only possible movements elicited automatic imitation. This sensitivity was specific to imitation, not affecting spatial stimulus-response compatibility (Experiment 3). These results suggest that automatic imitation is modulated by top-down influences, coding actions in terms of both movements and goals depending on the focus of attention.     

A unified framework for addiction: vulnerabilities in the decision process

The understanding of decision-making systems has come together in recent years to form a unified theory of decision-making in the mammalian brain as arising from multiple, interacting systems (a planning system, a habit system, and a situation-recognition system). This unified decision-making system has multiple potential access points through which it can be driven to make maladaptive choices, particularly choices that entail seeking of certain drugs or behaviors. We identify 10 key vulnerabilities in the system: (1) moving away from homeostasis, (2) changing allostatic set points, (3) euphorigenic "reward-like" signals, (4) overvaluation in the planning system, (5) incorrect search of situation-action-outcome relationships, (6) misclassification of situations, (7) overvaluation in the habit system, (8) a mismatch in the balance of the two decision systems, (9) over-fast discounting processes, and (10) changed learning rates. These vulnerabilities provide a taxonomy of potential problems with decision-making systems. Although each vulnerability can drive an agent to return to the addictive choice, each vulnerability also implies a characteristic symptomology. Different drugs, different behaviors, and different individuals are likely to access different vulnerabilities. This has implications for an individual's susceptibility to addiction and the transition to addiction, for the potential for relapse, and for the potential for treatment.     

What is the impact of the explicit knowledge of sequence regularities on both deterministic and probabilistic serial reaction time task performance?

The aim of this study was to explore the role of prior explicit sequence knowledge by comparing its influence on serial reaction time (SRT) performance with either a deterministic or a probabilistic sequence. The results confirm that, with a deterministic sequence, preliminary explicit learning improves SRT performance. On the other hand, with a probabilistic sequence, the results show no advantage for SRT performance in explicit-learning conditions. In addition, by using the process dissociation procedure (Jacoby, 1991), we show that performance on a subsequent generation task was more sustained by controlled processes for participants in the explicit-learning conditions than for those in the incidental condition. On the whole, these results, showing that the influence of explicit knowledge can be suppressed in certain specific conditions, are consistent with the intervention of both implicit and explicit mechanisms in SRT tasks, and the results also show that their relative influence can be modulated by the particular demands of the task.     

Safety behaviour: a reconsideration

There is ample evidence that the use of safety behaviour can interfere with the progress of therapy, particularly if exposure is involved. As a result, it is widely asserted that safety behaviour is anti-therapeutic. However, an unqualified rejection of safety behaviour should be reconsidered because we now have theoretical justification, experimental evidence and clinical observations showing that the judicious use of safety behaviour, especially in the early stages of treatment, can be facilitative. Experiments in which escape behaviour facilitated fear reduction, and others in which the use of safety gear facilitated fear reduction, are reviewed. It also appears that safety behaviour does not necessarily prevent disconfirmatory experiences. We propose that additional investigations of the judicious use of safety behaviour will help to elucidate therapeutic uses of safety behaviour in the treatment of anxious and related types of psychopathology.     

Starting with the "right" foot minimizes sprint start time

Although asymmetries in hand and foot performance have been examined using a variety of movement tasks that require the fine control of the timing and amplitude of force generation, foot asymmetries in a functional gross motor movement task, such as the track and field sprint start, have yet to be examined. Twenty individuals (10 experienced, 10 inexperienced) were assessed for pedal asymmetries using the track and field sprint start. Each participant performed 48 starts (24 right foot starts and 24 left foot starts). The pattern of pedal asymmetries was consistent with that of manual asymmetries in that a left foot (i.e., left foot in rear position) reaction time advantage was found while there was a right foot (i.e., right foot in rear position) advantage for movement time and total response time (time from stimulus presentation until the end of the movement). These results are consistent with a right hemisphere specialization for spatio-temporal and attentional processes, and a left hemisphere specialization for movement execution.     

Multicultural experience enhances creativity: the when and how

Many practices aimed at cultivating multicultural competence in educational and organizational settings (e.g., exchange programs, diversity education in college, diversity management at work) assume that multicultural experience fosters creativity. In line with this assumption, the research reported in this article is the first to empirically demonstrate that exposure to multiple cultures in and of itself can enhance creativity. Overall, the authors found that extensiveness of multicultural experiences was positively related to both creative performance (insight learning, remote association, and idea generation) and creativity-supporting cognitive processes (retrieval of unconventional knowledge, recruitment of ideas from unfamiliar cultures for creative idea expansion). Furthermore, their studies showed that the serendipitous creative benefits resulting from multicultural experiences may depend on the extent to which individuals open themselves to foreign cultures, and that creativity is facilitated in contexts that deemphasize the need for firm answers or existential concerns. The authors discuss the implications of their findings for promoting creativity in increasingly global learning and work environments.     

Heuristic and algorithmic processing in English, mathematics, and science education

Many college students experience difficulties in basic academic skills. Recent research suggests that much of this difficulty may lie in heuristic competency--the ability to use and successfully manage general cognitive strategies. In the present study, the authors evaluated this possibility. They compared participants' performance on a practice California Basic Educational Skills Test and on a series of questions in the natural sciences with heuristic and algorithmic performance on a series of mathematics and reading comprehension exercises. Heuristic competency in mathematics was associated with better scores in science and mathematics. Verbal and algorithmic skills were associated with better reading comprehension. These results indicate the importance of including heuristic training in educational contexts and highlight the importance of a relatively domain-specific approach to questions of cognition in higher education.     

What 50 years of research tell us about pausing under ratio schedules of reinforcement

Textbooks in learning and behavior commonly describe performance on fixed-ratio schedules as “break and run,” indicating that after reinforcement subjects typically pause and then respond quickly to the next reinforcement. Performance on variable-ratio schedules, on the other hand, is described as steady and fast, with few long pauses. Beginning with Ferster and Skinner''s magnum opus, Schedules of Reinforcement (1957), the literature on pausing under ratio schedules has identified the influences on pausing of numerous important variables, in particular ratio size and reinforcement magnitude. As a result, some previously held assumptions have been called into question. For example, research has shown that the length of the pause is controlled not only by the preceding ratio, as Ferster and Skinner and others had assumed (and as implied by the phrase postreinforcement pause), but by the upcoming ratio as well. Similarly, despite the commonly held belief that ratio pausing is unique to the fixed-ratio schedule, there is evidence that pausing also occurs under variable-ratio schedules. If such widely held beliefs are incorrect, then what about other assumptions? This article selectively examines the literature on pausing under ratio schedules over the past 50 years and concludes that although there may indeed be some common patterns, there are also inconsistencies that await future resolution. Several accounts of pausing under ratio schedules are discussed along with the implications of the literature for human performances, most notably the behaviors termed procrastination.