Psychophysiological evidence for continuous information transmission between visual search and response processes.

This study was designed to test whether information transmission between the perceptual and motor levels occurs continuously or in discrete steps. Ss performed visual search across nontargets that shared visual features with one of two possible targets, each assigned to a different response. In addition to reaction time, psychophysiological measures were used to assess the duration of target search and the onset of central and peripheral motor activity. Nontargets sharing features with a target selectively activated the response associated with that target, even when it was not present in the display. This suggests that information transmission to the motor level can consist of fine-grained visual information and that visual search and response selection occur in parallel.     

Task dynamics and resource dynamics in the assembly of a coordinated rhythmic activity.

Task dynamics corresponding to rhythmic movements emerge from interactions among dynamical resources composed of the musculature, the link segments, and the nervous and circulatory systems. This article investigated whether perturbations of interlimb coordination might be effect over circulatory and nervous elements. Stiffness of wrist-pendulums oscillated at a common tempo and at 180 degrees relative phase was perturbed through the use of tonic activity about an ankle. Left and right stiffnesses, the common period, and the phase relation all changed. Stiffnesses increased with ankle torque in proportion to the wrist's inertial load. Despite different changes in stiffness at the two wrists, isochrony was preserved. The stability was shown to be consistent with the proportionality of changes in stiffness to the inertial loads. The phase departed from antiphase in proportion to the asymmetry of inertial loads. The size of departures decreased with increasing ankle torque. An account was developed in terms of muscular, circulatory, and nervous functions.     

Perceptual degradation due to signal alteration: implications for auditory pattern processing.

When a passage is alternately presented to the right and left ears over headphones, perceptual processing is disrupted under certain conditions: When the signal alternation rate is approximately 3-4 cps, intelligibility is greatly reduced. Experiment 1 demonstrated that contrary to previous theorizing, the effect is not mediated by the disruption of syllabic units. Experiment 2 explored the generality of the perceptual degradation by testing perception of simple piano melodies. The basic effect holds for these complex auditory patterns. The final experiment tested a source-effect explanation of the phenomenon by using 3 signal locations (right, middle, and left) rather than 2. The degree of disruption depends on the likelihood that sounds are assigned to different sources. Together, the experiments help to account for the strikingly selective breakdown in perceptual processing and speak to the issues of perceptual units, domain specificity, and auditory source assignment.     

Phonological access of the lexicon: evidence from associative priming with pseudohomophones.

Pseudohomophones were used in a primed naming task. In Experiments 1 and 2, target pseudowords that sounded like real words (e.g., CHARE) were preceded either by context words that related associatively to the word with which the target was homophonic (TABLE-CHARE) or by context words that were not associatively related (NOVEL-CHARE). Control pairs were TABLE-THARE and NOVEL-THARE (Experiment 1) and TABLE-CHARK and NOVEL-CHARK (Experiment 2). In relation to NOVEL, TABLE benefited the naming of CHARE but not the naming of THARE or CHARK. TAYBLE-CHAIR pairs were used in Experiment 3. If the prime TAYBLE activated/table/,then/chair/would be activated associatively and the target CHAIR would be named faster than if TARBLE was the prime. Experiment 4 extended the design of Experiment 3 to include TABLE-CHAIR pairs and a comparison of a short (280 ms) and a long (500 ms) delay between context and target onsets. The priming due to associated pseudohomophones was unaffected by onset asynchrony and equal in magnitude to that due to associated words. Results suggest that lexical representations are coded and accessed phonologically.     

Immediate and delayed transfer of training effects in statistical reasoning

Ss were trained on the law of large numbers in a given domain through the use of example problems. They were then tested either on that domain or on another domain either immediately or after a 2-week delay. Strong domain independence was found when testing was immediate. This transfer of training was not due simply to Ss' ability to draw direct analogies between problems in the trained domain and in the untrained domain. After the 2-week delay, it was found that (a) there was no decline in performance in the trained domain and (b) although there was a significant decline in performance in the untrained domain, performance was still better than for control Ss. Memory measures suggest that the retention of training effects is due to memory for the rule system rather than to memory for the specific details of the example problems, contrary to what would be expected if Ss were using direct analogies to solve the test problems.     

The enhancement of retention induced by vasopressin in mice may be mediated by an activation of central nicotinic cholinergic mechanisms.

Immediate post-training subcutaneous administration of lysine vasopressin (LVP, 0.003-1.00 microgram/kg) enhanced retention, whereas the vasopressin antagonist AAVP (0.01-0.30 microgram/kg) impaired it, in male Swiss mice tested 48 h after training in an inhibitory avoidance task. Both effects were dose-dependent. Neither LVP nor AAVP affected response latencies in mice not given the footshock on the training trial. The simultaneous administration of AAVP at a dose (0.01 microgram/kg) which had no effect on retention shifted the dose-response curve of LVP to the right. Nicotine (1.0-30.0 micrograms/kg, sc), a central nicotinic cholinergic agonist, also facilitated retention in a dose-related manner without affecting the retention performance of unshocked mice. The effect of nicotine was prevented by the central acting nicotinic cholinergic receptor antagonist mecamylamine (5 mg/kg, sc.). In contrast, neither hexamethonium (5 mg/kg, sc), a peripheral acting nicotinic receptor blocker, nor atropine (0.5 mg/kg, sc) or methylatropine (0.5 mg/kg, sc), two anticholinergic drugs which are known to act on muscarinic cholinergic receptors, prevented the effect of post-training nicotine. The effects of LVP and nicotine were time-dependent, suggesting that both treatments enhanced retention by influencing post-training processes involved in memory storage. Low doses of nicotine (1.50 microgram/kg, sc) or the central anticholinesterase physostigmine (35 micrograms/kg, sc) and LVP (0.003 microgram/kg, sc), which had no effect on retention when administered alone, produced a synergistic interaction when given together following training. The influence of LVP (0.03 microgram/kg, sc) on retention was prevented not only by AAVP (0.01 microgram/kg, sc) but also by mecamylamine (5 mg/kg, sc), whereas the effects of nicotine (10.0 micrograms/kg, sc) were prevented only by mecamylamine. These results suggest that the enhancement of retention induced by vasopressin is probably due to an activation of central nicotinic cholinergic mechanisms which are critical for memory formation.     

Scratching as a behavioral index of anxiety in macaque mothers.

The aim of this study was to assess the validity of the notion that anxiety influences maternal style in monkeys. To this end, we investigated the correlations between measures of the quality of mother-infant relationship and scratching, a behavior pattern that reflects a state of anxiety. The subjects were seven group-living macaque mothers and their infants observed during the first 12 weeks postpartum. Postpartum scratching by the mothers was positively correlated with both maternal possessiveness and maternal warmth, two composite measures of the quality of mother-infant relationship that reflect a possessive and attentive maternal style. Evaluation of the correlations between maternal rank and scratching before and after parturition indicated that interactions with their infants, not those with other group companions, were the main source of anxiety for the mothers. These results support the notion that anxiety influences maternal style in monkeys and suggest that studies aimed at investigating physiological and social correlates of maternal emotionality in nonhuman primates could use scratching as a useful and simple behavioral measure.     

Effects of verbal labeling and exposure duration on implicit memory for visual patterns.

The present study investigated the role of verbal labeling and exposure duration in implicit memory for novel visual patterns. Encoding condition was varied in Experiment 1. Two encoding conditions discouraged verbal labeling and a third required it. In Experiment 2, exposure duration was manipulated to determine whether a new memory representation could be formed after a single 1-s exposure. The results suggest that verbal labeling is not necessary to support priming. Type of encoding did not affect implicit memory, but had a pronounced effect on explicit memory. Furthermore, a single 1-s exposure was sufficient to support priming, and priming was not further enhanced by longer stimulus exposures. In contrast, recognition performance was enhanced by a longer stimulus duration. Thus, priming effects with these novel figures are likely to be supported by newly acquired representations rather than by preexisting memory representations.     

Perceived benefits of marathon running in males and females

The differences in both perceived benefits and attitudes toward running between male and female runners, and between runners who classified themselves as competitive runners (CR) or recreational runners (RR), was the focus of this study. Four-hundred and two runners completed the Ten-Minute Survey for Runners within two weeks of completing a marathon. RR, more so than CR, perceived greater benefits from running. However, CR expressed a more positive attitude toward running and its role in their lives than did RR. Men perceived running to be more beneficial to them than women. However, women, more so than men, felt running had a positive effect on self-image and their lives were richer because of running. Future research concerns on the effects of competition on the lives of women are explored.