Self-control in male and female rats

Eight male and 8 female Wistar rats were exposed to a discrete-trial procedure in which they chose between the presentation of a small (one pellet) or a large (three pellets) reinforcer. The delay to the small and large reinforcer was 6.0 s in the first condition of Experiment 1. Subjects consistently chose the large reinforcer. When the delay to the small reinforcer was decreased to 0.1 s in the next experimental condition, all subjects continued to choose the large 6.0-s delayed reinforcer. When the contingencies correlated with the two levers were reversed in the next experimental condition, the majority of subjects (5 males and 6 females) still chose the large delayed reinforcer over the small immediately presented reinforcer. The delay to the small reinforcer was maintained at 6.0 s, but the delay to the large reinforcer was varied among 9.0, 15.0, 24.0, and 36.0 s in Experiment 2, in which 4 males and 4 females participated. Most subjects consistently chose the large increasingly delayed reinforcer, although choice for the small 6.0-s delayed reinforcer developed in some females when the large reinforcer was delayed for 24.0 or 36.0 s. These choice patterns were not predicted from a literal application of a model that says choice should favor the alternative correlated with the higher (amount/delay) ratio.     

Imagery limitations in totally congenitally blind subjects

Research on totally blind subjects performing tasks that involve visual imagery has often shown that they do not behave differently from matched sighted subjects, even when their blindness is congenital. If visual imagery is based on visual perception, such tasks may not required visual imagery. In the present article visual images are considered as representations maintaining some properties of visible objects and constructed on the basis of information from various sources. Owing to the absence of visual experience, the limitations of such representations are explored in a series of experiments requiring memorization of single nouns, pairs of nouns, or triplets of nouns associated with a cue noun. Recall by blind subjects was impaired when multiple interactive images (with noun pairs and triplets) are formed. The poorer recall of blind subjects reflected also loss of order information. Recall was better for both groups with locative noun cues and high-imagery targets.     

Mecamylamine prevents the enhancement of retention induced by lysine vasopressin in mice

Lysine vasopressin (0.03 microgram/kg, sc) enhanced retention of a one-trial, step-through inhibitory avoidance task when injected into male Swiss mice immediately post-training, as indicated by retention performance 48 h later. A low dose of the vasopressin antagonist, AAVP (0.01 microgram/kg, sc), did not significantly affect retention, whereas a higher dose (0.03 microgram/kg, sc) impaired retention. Neither lysine vasopressin nor AAVP modified latencies to step-through of mice that had not received a footshock during training. The simultaneous injection of AAVP (0.01 microgram/kg, sc) prevented the enhancement of retention induced by lysine vasopressin. The influence of lysine vasopressin on retention was antagonized by the simultaneous administration of mecamylamine (5 mg/kg, sc) but not by hexamethonium (5 mg/kg, sc), atropine (0.5 mg/kg, sc), or methylatropine (0.5 mg/kg, sc). A modulatory role of vasopressin on the activity of central cholinergic nicotinic mechanisms which participate in memory formation is suggested.     

Life-span ontogeny of the parallel-lines illusion

The magnitude of two assimilative and one contrastive version of the parallel-lines illusion was measured using 72 observers whose ages ranged in years from the teens to the seventies. Only the overestimated assimilative illusion varied significantly with age, producing smaller misestimations in both youth and old age and a maximal distortion in the 50s. This quadratic trend duplicated the adult-age course of the overestimated Müller-Lyer illusion thereby reinforcing the belief that the two are kindred visual anomalies. As with the Müller-Lyer, the ontogeny of the parallel-lines illusion is best explained by age-induced changes in the vigor of contour interactions.     

The effects of self-management of school attendance by problem adolescents.

Self-management of attendance by problem adolescents was shown to improve attendance in an alternative school. The use of biased measures to investigate change is discussed as well as the utility of frequent measures. The effect of improved attendance on academics is presented and future research in this area is suggested.     

Hemispheric equality in reaction times to emotional and non-emotional nouns

Twenty presentations of 6 emotional and 6 non-emotional words in mixed random orders were monaurally presented to the right or left ear. Using the left hand, subjects pushed one of two response buttons indicating type of word heard. Performance improved in later trials and emotional words were recognized more quickly regardless of ear presentation. No differences were associated with the separate ear presentations. Equivalent hemispheric performance indicates equal processing sensitivity to four-letter emotional and non-emotional nouns and substantiates the right hemisphere's verbal processing capability for simple nouns.     

Training the disturbed enuretic

Twenty-two disturbed enuretic children were treated for their bedwetting with training procedures. Eighteen of 22 (81.8%) reached the initial success criterion in an average of 57.5 days. Ten of the 18 (55.6%) met the retraining criteria of relapse, and 9 of the relapses were successfully retrained, while I stopped wetting spontaneously. As compared to non-relapsed children, relapsed children had a significantly higher number of initial symptoms checked. The results indicate that a training approach is effective for the treatment of enuresis in disturbed children, but the more disturbed have a greater likelihood of relapse.     

Increased susceptibility of aphasics to a distractor task in the recall of verbal commands

The ability of 15 control, 15 nonaphasic brain-damaged, and 15 aphasic patients to carry out three-word commands on the Token Test was studied under three conditions: no delay, 20-sec unfilled delay, and 20-sec delay filled with a counting task. Only aphasics with mild to moderate comprehension deficit participated in the experiment and their scores in the no-delay condition were not inferior to those of the other two groups. The 20-sec unfilled delay did not bring about a decrement of the performance in any group, while all of them were impaired with 20-sec filled delay. The rate of forgetting was, however, significantly greater in aphasics than in patients without language disorders, even when the scores of the no-delay condition were introduced as covariates in the analysis of the filled-delay condition. The same result was obtained when, in a second experiment, 4 sec elapsed between the end of the command and the beginning of the counting activity. The increased susceptibility of aphasics to the disruptive effect of the distractor task is viewed as following a failure in organizing verbal information, a deficit that may contribute to lowering their comprehension level.