Extracting parity and magnitude from Arabic numerals: developmental changes in number processing and mental representation.

Children from Grades 2, 3, 4, 6, and 8 (7.8, 9.2, 9.8, 11.7, and 13. 6 years old, respectively) made speeded, bimanual parity (odd/even) judgments of the Arabic numerals 0-9. Analysis of response times indicated that from fourth grade on, parity information is retrieved directly from memory rather than being extracted by means of a mental calculation strategy. As early as Grade 3, children exhibited the SNARC (Spatial-Numerical Association of Response Codes) effect, where small numbers were responded to faster with the left hand than with the right hand, while the converse held true for large numbers. This finding, previously demonstrated only in adults, confirms that (a) children represent magnitude information in the form of a left-to-right oriented mental number line, and (b) this information is accessed obligatorily even when irrelevant. Finally, although the SNARC effect remained strong at Grade 4, it was attenuated at Grades 6 and 8 by a linguistic effect based on associations between the unmarked adjectives "even" and "right" and between the marked adjectives "odd" and "left." Copyright 1999 Academic Press.     

Morally Relevant Features

This article summarizes the account of morality presented in Morality: Its Nature and Justification (Oxford, 1998), with emphasis on that aspect of morality that deals with justifying violations of the moral rules. Such justification requires a two-step procedure; the first is describing the situation using only morally relevant features. I list these features, noting how diverse they are, and describe their characteristics. The second step is estimating the consequences of publicly allowing a violation with the same morally relevant features, that is, allowing a violation when everyone knows that it is allowed to violate the rule in the same circumstances, and comparing this to the estimated consequences of not publicly allowing that kind of violation. I then explain why fully informed, impartial rational persons can sometimes disagree about whether a violation should be publicly allowed and note that such weakly justified violations are the controversial cases.     

The relation of gender-role orientation to sexual experience among college students

This study examined the relations of gender and three aspects of gender roles — self concept, behavior, and sexual attitudes — to three aspects of sexual behavior — sexual experience, reasons for intercourse, and contraceptive use. Gender was strongly related to all three aspects of sexual behavior. For both men and women, sex role behaviors were related to sexual experience and to reasons for intercourse, but not to contraceptive use, and sex role self-concept was unrelated to any of the aspects of sexual behavior. The results indicate that sexual behavior is influenced both by societal gender role norms and by individual differences in the acceptance of those norms.     

Inhibition and working memory: effect of acute sleep deprivation on a random letter generation task]

The literature contains inconsistent data on the effects of acute sleep deprivation on the superior cognitive functions. The primary purpose of this study is to determine the effectiveness of inhibition, one of the functions of the working memory executive centre (EC), over an extended, 36-hour waking period. Inhibition is a cognitive mechanism whereby individuals ignore non-relevant information recorded in their working memory. We also tested the effects of a 36-hour period of acute sleep deprivation on simple reaction time. Twelve young, healthy volunteers (M = 21.5 years, sigma = 2.3) performed a random generation task involving letters and a simple reaction time psychomotor test over four sessions held at 10-hour intervals. Each participant was assigned a "constant routine." Participants were kept awake in a prone position within a room whose environment was held strictly constant (light, noise, temperature, meals, etc.). This control procedure provided assurance that any variation in participant performance was solely caused by sleep deprivation. The random generation task, nearly two minutes in length, consisted in verbally producing a sequence of 100 letters in a random fashion (i.e. by inhibiting, for example, alphabetical order) and by keeping to a set rhythm. Our assumption was that capacity for inhibition diminished as the number of hours of sleep deprivation increased. The simple reaction test, 10 minutes in length, involved pressing a button as swiftly as possible to cause a black square to disappear from a screen. In this case our assumption was that acute sleep deprivation alters simple reaction time. Analysis of variance (ANOVA) through repeated measures using the "sessions" factor as an intra-subject variable showed no significant changes in randomization indices of the random generation task, contrary to analysis of average simple reaction times. Participants' reaction times deteriorated over the first two minutes of the test during the night they were deprived of sleep. It would seem that the contradictory results of previous studies of the effects of acute sleep deprivation on the inhibition function would be due to errors in factor identification. In conclusion, the inhibition function, as measured during the performance of a brief task, seems to remain intact during an extended, 36-hour waking period. Simple reaction time assessed by means of a brief psychomotor test is affected during a night of sleep deprivation. The working-memory inhibition executive function shows greater resistance to acute sleep deprivation than does psychomotor reaction time for the performance of short tasks.     

The future of the American Group Psychotherapy Association: whither we goest?

The author describes his perspective about what the future holds for the American Group Psychotherapy Association (AGPA). Utilizing Nitsun's (1996) construct of the "anti-group" as an organizing metaphor, he delineates the destructive forces both within and outside the organization that are currently affecting it, and then describes how they can be transformed into instruments for positive development. He suggests that the AGPA can and must continue to provide a "holding environment" (Winnicott, 1960) for professionals interested in working with people in groups. In addition, he asserts that the organization will build upon its remarkable response to the September 11, 2001 debacle in the United States to expand its services to those who have been traumatized. Beyond this, he underscores the importance of the AGPA consolidating and expanding its various educational offerings into a coherent package that will meet the needs of any and all who are interested in learning about how to work effectively with groups. In these and other ways, he contends that the AGPA will thereby confirm Nitsun's assertion that anti-group forces can be transformed, and that organizations that confront these forces constructively can not only survive but thrive.     

Recognising facial expression from spatially and temporally modified movements

We examined how the recognition of facial emotion was influenced by manipulation of both spatial and temporal properties of 3-D point-light displays of facial motion. We started with the measurement of 3-D position of multiple locations on the face during posed expressions of anger, happiness, sadness, and surprise, and then manipulated the spatial and temporal properties of the measurements to obtain new versions of the movements. In two experiments, we examined recognition of these original and modified facial expressions: in experiment 1, we manipulated the spatial properties of the facial movement, and in experiment 2 we manipulated the temporal properties. The results of experiment 1 showed that exaggeration of facial expressions relative to a fixed neutral expression resulted in enhanced ratings of the intensity of that emotion. The results of experiment 2 showed that changing the duration of an expression had a small effect on ratings of emotional intensity, with a trend for expressions with shorter durations to have lower ratings of intensity. The results are discussed within the context of theories of encoding as related to caricature and emotion.     

Heading and path information from retinal flow in naturalistic environments

In four experiments, we explored the heading and path information available to observers as we simulated their locomotion through a cluttered environment while they fixated an object off to the side. Previously, we presented a theory about the information available and used in such situations. For such a theory to be valid, one must be sure of eye position, but we had been unable to monitor gaze systematically; in Experiment 1, we monitored eye position and found performance best when observers fixated the designated object at the center of the display. In Experiment 2, when we masked portions of the display, we found that performance generally matched the amount of display visible when scaled to retinal sensitivity. In Experiments 3 and 4, we then explored the metric of information about heading (nominal vs. absolute) available and found good nominal information but increasingly poor and biased absolute information as observers looked farther from the aimpoint. Part of the cause for this appears to be that some observers perceive that they have traversed a curved path even when taking a linear one. In all cases, we compared our results with those in the literature.     

How conscious experience and working memory interact

Active components of classical working memory are conscious, but traditional theory does not account for this fact. Global Workspace theory suggests that consciousness is needed to recruit unconscious specialized networks that carry out detailed working memory functions. The IDA model provides a fine-grained analysis of this process, specifically of two classical working-memory tasks, verbal rehearsal and the utilization of a visual image. In the process, new light is shed on the interactions between conscious and unconscious aspects of working memory.     

Signalling and incentive processes in instrumental reinforcer devaluation

We have previously reported that conditioning an aversion to the reinforcer using an isotonic lithium chloride (LiCl) solution following instrumental training reduces performance in a subsequent extinction test only if animals are re-exposed to the reinforcer prior to the test. Rescorla (1992), in contrast, reported an immediate devaluation effect using a hypertonic LiCl solution that did not depend upon re-exposure. In two experiments we examined the effect of using a hypertonic LiCl solution to condition the aversion to the reinforcer on subsequent instrumental performance in extinction, with and without re-exposure. In Experiment 1 thirsty rats were trained to press a lever for a sucrose solution before being injected with 0.6 M LiCl either immediately or after a delay. Half of the immediate and delay groups were then re-exposed to the sucrose in the absence of the lever, with the remainder being exposed to water. Contrary to the previously reported effects of isotonic LiCl, a hypertonic solution induced a reinforcer devaluation effect in all the immediately poisoned animals, which did not depend upon re-exposure to the reinforcer. In Experiment 2 the possibility that this devaluation effect was induced by the discomfort associated with the hypertonicity of the solution was assessed by replicating Experiment 1 but, in addition, using two immediately poisoned groups given the LiCl injection under anaesthesia. In the absence of anaesthesia, the devaluation effect observed without re-exposure to the reinforcer in Experiment 1 was replicated. When the injection was given under anaesthesia, however, a reinforcer devaluation effect was observed only in animals that were re-exposed to the reinforcer prior to the extinction test. These results were interpreted as evidence that a reinforcer devaluation effect induced by pairing the reinforcer with illness depends upon a process of incentive learning, whereas a devaluation effect mediated by learning a signalling relationship between the reinforcer and somatic discomfort does not.