Changes in spinal reflex excitability in a countermanded timed response task

Subjects (N = 8) performed a timed response task in which they attempted to synchronize an impulsive foot-press response with the last in a series of four regularly spaced tones. In Experiment 1, the response was countermanded on one third of the trials (stop trials) by a stop signal that appeared at a predetermined delay after the third tone. No stop signal appeared on the remaining trials (go trials). All subjects showed a systematic transition from withholding the response on stop trials in which the stop signal appeared shortly after the third tone to executing the response on trials in which a single stop signal delay had been chosen so that a response would be made on about 50% of the stop trials. We elicited Hoffmann (H) reflexes from the soleus muscle on all trials to determine whether the reflexes were augmented on occasions on which a response was prepared but withheld. Mean H-reflex amplitudes on go trials and on stop trials on which the response was executed were similar and showed a marked augmentation beginning about 250 ms before response onset; mean H-reflex amplitudes on stop trials on which the response was withheld showed less pronounced augmentation. Inspection of individual H-reflex amplitudes revealed that on stop trials on which the response was withheld the reflexes could be augmented to the same extent as on trials on which the response was executed. This dissociation of H-reflex augmentation and response execution shows that H-reflex augmentation reflects a controlled response process. Ballistic response processes therefore must be limited to a brief duration.     

Integration and representation in rats' serial pattern learning in the T-maze

Rats were exposed to three-trial series consisting of reinforced (R) trials and one nonreinforced (N) trial in a fixed order, RRN and RNR (Experiments 1 and 2) or NRR and RRN (Experiment 3), on extended visually distinct runways in a T-maze. When initially presented with the same sequence on each series in a session (separate presentations) with the same runway on all trials within a series (Experiments 1 and 3), all the rats developed slower running speeds on N than on R trials. When a runway was sometimes changed between the first and next two trials during separate presentations training (Experiment 2) or both sequences were later intermixed within each session in each experiment, only rats exposed to each sequence on a specific runway maintained these serial running patterns. Rats displayed serial running patterns on a test RNN sequence similar to that on the RNR sequence (Experiment 2), as would be predicted by an intertrial association model of serial pattern learning (Capaldi & Molina, 1979), but responded on test RRR and NRN sequences (Experiment 3) as would be predicted by an ordinal-trial-tag/intratrial association model (Burns, Wiley, & Payne, 1986). Results from test series of free-choice trials in Experiments 1 and 2 failed to support a prediction of the intratrial association model that these rats would integrate RRN and RNR sequences. Rather than always selecting a baited runway on both the second and the third free-choice trials, the rats only selected a baited runway on the third trial on the basis of their choice on the second trial, as would be predicted by the intertrial association model. Only after experiencing all possible outcome sequences during forced-choice training in Experiment 3 did these rats predominantly select a baited runway on every free-choice trial.     

Rate changes after unscheduled omission and presentation of reinforcement

Changes in response rate similar to frustration effects were studied in a two-lever situation. Responding on one lever on a fixed-interval schedule produced access to water for 5 sec and an exteroceptive stimulus. In the presence of this stimulus, responding on another lever on a fixed-interval schedule produced access to water for 5 sec and terminated the stimulus. Occasional omission of a previously scheduled reinforcer after responding on the first lever resulted consistently in increases in rate on the second lever during the immediately succeeding interval. In another procedure, occasional presentation of a previously unscheduled reinforcer after responding on the first lever resulted consistently in decreases in rate on the second lever during the immediately succeeding interval. Changes occurred after the first omissions or presentations and were about the same in magnitude as the procedure continued over several sessions. Typically, an increase or decrease in rate was maintained throughout an entire 100-sec interval. Changes in rate on the second lever of approximately the same magnitude also occurred when rate on the first lever was near-zero under a schedule that differentially reinforced behavior other than lever pressing.     

Strong Attachment to Heroes: How Does It Occur and Affect People’s Self-Efficacy and Ultimately Quality of Life?

In spite of increasing evidence on the influence of heroes on the lives of ordinary people, there has been no formal study on the subject in relation to people’s attachment to a hero (or hero attachment). The current study proposed a consumer model to examine how a hero makes a positive impact on people’s lives in terms of their hero attachment, self-efficacy, and life satisfaction. Using observations from a survey, we examined both the direct and indirect effects that the contribution of a hero in people’s fundamental A-R-C (autonomy, relatedness, and competence) need fulfillment has on self-efficacy and ultimately on life satisfaction. We found that the impact of a hero in fulfilling the A-R-C needs has a direct, differential effect on self-efficacy and life satisfaction. More importantly, we found that the fulfillment of A-R-C needs by a hero significantly influences hero attachment, which in turn positively affects life satisfaction through self-efficacy. As the first empirical study on hero attachment in relation to people’s self-efficacy and life satisfaction, the study yields significant theoretical contributions and practical implications for practitioners and policy makers in the areas of public health, education, and quality of life.     

Further studies of the McCollough effect

Following prolonged viewing of black and white striped pattems in colored light, red and green aftereffects that lasted as long as 3 days were seen on the patterns, illuminated with white light. Altemate exposures of a vertical pattern of stripes in green light and a horizontal in white light (or a vertical in white light and a horizontal in red light) produced a red aftereffect on the vertical pattern and a green on the horizontal. The red and green aftereffects were also produced with a single vertical pattern. Adaptation colors that were at all greenish produced a red aftereffect on a vertical pattern and a green on a horizontal, whereas colors that were at all reddish produced a green aftereffect on a vertical pattern and a red on a horizontal. Colors near pure blue and pure yellow, which had little red or green content, produced weak aftereffects. The saturation of the aftereffects on the vertical grating varied in proportion to the red or green content of the adaptation color. Vivid red and green aftereffects were frequently obtained with the vertical and horizontal adaptation patterns paired with colors that closely bracketed pure yellow or pure blue. In all cases, the aftereffects gradually desaturated as the head was gradually tilted down to the side; the colors on each test pattern, vertical and horizontal, vanished at 45-deghead tilt and reversed beyond 45 deg.     

Peak shift in concurrent schedules

Pigeons were exposed to two keys, a main key and a changeover key. Initially non-differential training was given in which pecking the main key was reinforced on a variable-interval 2-min schedule when the key displayed the first stimulus, a black line on a blue background, and was reinforced on an identical but independent variable-interval 2-min schedule when the key displayed a plain blue stimulus. Later, differential training was given in which pecking the main key was reinforced on a variable-interval 2-min schedule when the first stimulus was displayed; and was reinforced on a variable-interval 10-min schedule when a second stimulus, a black line of another orientation on a blue background, was displayed. During non-differential and differential training, each peck on the changeover key changed the stimulus on the main key. Generalization tests were given before and after the differential training. These consisted of presentations on the main key of seven orientations of the black line on the blue background, including the first and second stimuli, with no reinforcements being given. Changeover-key pecks changed the stimuli on the main key. Generalization gradients were obtained using three measures: time spent, responses, and response rate in the presence of each test stimulus. Typically, maximum values on these measures occurred to stimuli away from the first in a direction opposite the second stimulus, and minimum values occurred to stimuli away from the second in a direction opposite the first.     

Orthography influences the perception and production of speech

One intriguing question in language research concerns the extent to which orthographic information impacts on spoken word processing. Previous research has faced a number of methodological difficulties and has not reached a definitive conclusion. Our research addresses these difficulties by capitalizing on recent developments in the area of word learning. Participants were trained to criterion on a set of associations between novel pictures and novel spoken words. Spelling-sound consistent or spelling-sound inconsistent spellings were introduced on the 2nd day, and the influence of these spellings on speech processing was assessed on the 3rd day. Results showed significant orthographic effects on speech perception and speech production in a situation in which spelling-sound consistency was manipulated with perfect experimental control. Results are discussed in terms of a highly interactive language system in which there is a rapid and automatic flow of activation in both directions between orthographic and phonological representations.     

Mood state,task demand,and effort-related cardiovascular response

Drawing on the mood-behaviour model (Gendolla, 2000), two studies investigated informational effects of mood on effort-related cardiovascular response. Experiment 1 manipulated mood state (positive, negative) and task difficulty (easy, difficult, extremely difficult). Effects on cardiovascular reactivity were as expected: On the easy level, reactivity was weak in a positive mood, but strong in a negative mood; on the difficult level, reactivity was strong in a positive mood, but weak in a negative mood; on the extremely difficulty level mood had no effect. Experiment 2 manipulated mood only. As predicted, subjective demand and cardiovascular response were both higher in a negative mood than in a positive mood and the mood effect on cardiovascular response diminished after statistically controlling for the demand appraisals. Neither study revealed any mood effects on cardiovascular response during the mood inductions.     

The impact of the American War on Terror on Malaysian Islam

This essay provides an introductory discussion of the impact of the American war on terrorism on Malaysia, a Muslim country with a long record of parliamentary democracy and one of the most developed in the Muslim world. With a discussion of a possible decades-long US military and political engagement with the Muslim world as a background, the essay presents a detailed account of the impact of the US wars in Afghanistan, the Philippines and Iraq on Malaysian national politics, particularly on its political Islam. It is argued that the war on terrorism has benefited Mahathir Mohamad, helping to reverse his declining political fortunes following his sacking of Anwar Ibrahim as his deputy, which influenced his retirement from politics. The essay explains the reasons, external and domestic, for Malaysia's participation in the global war on terrorism and the extent of its involvement, including its leadership role in anti-terrorism in the Muslim world. It also discusses the views of Mahathir and Anwar on the roots of Muslim terrorism and what it will take to overcome this problem. Both believe the resolution of the Israeli–Palestinian conflict is crucial to the defeat of terrorism in the Muslim world. The essay concludes with an examination of the possibility of Malaysia entering a new phase in its war on terrorism as Abdullah Badawi, Mahathir's successor, and Anwar appear to have convergent views on political Islam and on the importance of democracy as a tool to fight terrorism.     

Two-key concurrent paced variable-interval paced variable-interval schedules of reinforcement

Nine pigeons were used in two experiments in which a response was reinforced if a variable-interval schedule had assigned a reinforcement and if the response terminated an interresponse time within a certain interval, or class, of interresponse times. One such class was scheduled on one key, and a second class was scheduled on a second key. The procedure was, therefore, a two-key concurrent paced variable-interval paced variable-interval schedule. In Exp. I, the lengths of the two reinforced interresponse times were varied. The relative frequency of responding on a key approximately equalled the relative reciprocal of the length of the interresponse time reinforced on that key. In Exp. II, the relative frequency and relative magnitude of reinforcement were varied. The relative frequency of responding on the key for which the shorter interresponse time was reinforced was a monotonically increasing, negatively accelerated function of the relative frequency of reinforcement on that key. The relative frequency of responding depended on the relative magnitude of reinforcement in approximately the same way as it depended on the relative frequency of reinforcement. The relative frequency of responding on the key for which the shorter interresponse time was reinforced depended on the lengths of the two reinforced interresponse times and on the relative frequency and relative magnitude of reinforcement in the same way as the relative frequency of the shorter interresponse time depended on these variables in previous one-key concurrent schedules of reinforcement for two interresponse times.     

Effect of electronic device use while driving on cardiovascular reactivity

Motor vehicle collisions are the leading cause of death in people ages 5–34 in the US, and secondary task engagement, such as talking on a cell phone, is a leading contributor to motor vehicle collisions. The negative effects of secondary task engagement on driving performance has become a prominent recent topic of study given the increasing amount of time drivers engage in distracted driving. However, few studies have examined the effects of secondary task engagement while driving on health related outcomes such as cardiovascular reactivity. Cardiovascular reactivity, as measured by heart rate and blood pressure, has been used in previous studies as a means of measuring effort in task engagement as well as a means to predict cardiovascular disease and stroke. This study investigates the effect of secondary task (talking on a cell phone, texting, and driving with no task) while driving in a simulator on cardiovascular reactivity. Using difference scores between baseline (a period of inactivity) and stimulus (driving with no task and driving with secondary tasks), a repeated measures analysis of variance using a mixed model approach was used to determine the effect of secondary task on cardiovascular reactivity. Findings indicated that talking on a cell phone while driving significantly increased cardiovascular reactivity via heart rate and blood pressure compared to driving with no task. Texting while driving did not differ significantly from driving with no task. This study demonstrates the need for more research on the long term effects of secondary tasks while driving on cardiovascular reactivity and for assessing the risks associated with secondary task use while driving on developing cardiovascular disease or stroke.     

Positive conditioned suppression: Transfer of performance between contingent and noncontingent reinforcement situations

Five homing pigeons were trained on concurrent variable-interval schedules. A fixed-duration stimulus was occasionally presented on one key; and, in various conditions, this stimulus terminated (a) without reinforcement, (b) in noncontingent reinforcement, (c) with reinforcement contingent on a response on the key on which the stimulus was presented, and (d) with reinforcement contingent on a response on the key on which the stimulus was not presented. Initially, a stimulus terminating in noncontingent reinforcement generally produced decreased response rates on both keys during the stimulus. Contingencies, however, reliably produced increased rates during the stimulus on the key on which the contingency was arranged, relative to the rate on the concurrently available key. Contingency conditions were followed by noncontingency conditions in which the separation of rates caused by contingencies was maintained. When rates during the stimulus were compared with response rates on the same keys in the absence of the stimulus, contingency-caused rate increases and decreases were again found, but only the rate decreases were maintained in subsequent noncontingency conditions. Further data suggested that the contingency-caused rate changes were not maintained when the stimulus terminated without reinforcement, and that they were unaffected by a threefold decrease in the reinforcement rate provided by the baseline schedules. The results support the suggestion that performance in the positive conditioned suppression procedure results from concurrent and multiple schedule interactions. They further suggest that the production of either acceleration or suppression is dependent on adventitious and historical contingencies.     

Perceptual reactance and task performance.

57 female subjects participated in a study in which perceptual reactance was assessed by the kinesthetic figural aftereffects test. Subjects identified as augmenters were quicker than reducers on a disjunctive reaction time task and a significant interactive effect was found on a paired-associate task. Augmenters performed better on a similar list while reducers were more effective on a dissimilar list.     

Nice or smart? Task relevance of self-characteristics moderates interpersonal projection

Two studies investigated the impact of trait relevance to a specific task on people's projection of their characteristics onto a cooperative partner. We either measured (Study 1) or manipulated (Study 2) the relevance of a trait to a specific cooperative task. In both studies, participants first rated themselves on a list of traits. Then they imagined completing a cooperative task with an unknown partner. Finally, they rated the partner on the same list of traits. In Study 1, we found partner ratings to be positively influenced by self ratings and the idiosyncratic measure of trait relevance. In Study 2, participants rated the self and the partner on competence and warmth traits while completing an intellectual or a social task. We found partner ratings to be positively influenced by self ratings more on competence than on warmth in the intellectual task, but more on warmth than on competence in the social task. These results suggest that people project onto others in a way that maximizes their chances to succeed in cooperation.     

Choice and segmented interreinforcement intervals

Pigeons were trained on a two-key concurrent schedule, where food reinforcers on one key were arranged by a simple variable-interval schedule and on the other key by a chain variable-interval variable-interval schedule. When the initial link of the chain was in effect, the pigeons tended to respond more on the simple variable-interval schedule, and hence less on the chain, than would be expected from a comparison of both the local and overall rates of reinforcement of the two schedules. When the terminal link of the chain was in effect, the pigeons responded more on the chain than would be expected from a comparison of the rates of reinforcement of the schedules then in effect. Overall responding on the chain was not proportional to overall reinforcement on the chain but rather was a by-product of responding during initial- and terminal-link phases.     

Social comparison on two dimensions

In this experiment social comparison on two task dimensions has been studied. The subjects received bogus feedback on their performance on two tests, one allegedly measuring creativity, the other alertness. By means of this feedback four relative position conditions were induced: scoring high on both tests, scoring low on both tests, scoring high on creativity and low on alertness, and vice versa. Anticipating either a co-operative or a competitive game, the subjects indicated their preference for one or the other task dimension and also expressed their preference for a comparison person. It was found that, as predicted, the subjects preferred and valued comparison dimensions on which they occupied a favourable position. With respect to preference for a comparison person, compensatory choices were obtained: on the dimension on which the subject performed well, they preferred an inferior other. On the dimension on which they performed poorly, they preferred a superior other. This pattern of choices was found in co-operation as well as in competition. Finally, upward preference was stronger in co-operative than in competitive conditions, particularly on the dimension on which the subject's own score was low. These and other results were discussed in relation to theoretical social comparison notions.     

The effect of failure and frustration on reflective and impulsive children

Failure was hypothesized to be an antecedent of a reflective style of responding and frustration an antecedent of an impulsive style. Failure and frustration were manipulated with an anagrams task and their effect on latency and errors on the Matching Familiar Figures Test (MFF) was assessed. The Failure group increased its latency on the MFF, replicating Messer's (1970) research, while the Frustration group showed a nonsignificant decrease in latency. There was a relation between an increase in latency and a decrease in errors on the MFF. The findings were related to research on the “frustration effect” in children and were interpreted as suggesting the need for research on the effects of the amount and patterning of failure on reflection-impulsivity.     

Abdominal exercise intensities on firm and compliant surfaces

Muscle activities at 15 sites were compared within a group of healthy young adults to evaluate their relative intensities during six abdominal exercises: partial and full sit-ups on a firm surface (floor) and on an exercise ball that was either stabilized or unstabilized. The most strenuous abdominal exercise overall (i.e., whole body workout) was the full sit-up on a firm surface which included significant muscle activities in the lower extremities. Exercise intensity was also high in the full and partial sit-ups when performed on a ball. The partial sit-up on the floor was the least strenuous of the six exercises. The greatest effect on the abdominal muscles was observed in the partial sit-up on a ball (stabilized and unstabilized). Results suggest that, although abdominal exercises on a ball may be gentler on the hip and lower back, overall exercise intensity is not necessarily lower than that on the floor. Moreover, partial sit-ups, both on the floor and on a ball, also required greater neck muscle activities than full sit-ups. In deciding what type of sit-up to do, exercise surface and different muscular activities between the partial and full sit-ups should be considered.     

The effect of target specification on objects fixated during visual search

When a person searches for a target in a cluttered visual field his eye fixations typically fall on objects. The effect of target specification on the probability of fixating different classes of objects was studied. For fields containing objects differing Widely in size, color, and shape: a high proportion of searchers’ fixations were on objects of a specified color, a moderate proportion of their fixations were on objects of a specified size, and a slight proportion of their fixations were on objects of a specified shape. When two or more target characteristics were specified, fixations were generally based on a single characteristic. It is proposed that the specification of a target creates a perceptual structure which the searcher explores. The study of visual fixations, in effect, is the study of the perceptual structure.