Visually guided catching and tracking skills in pigeons: A preliminary analysis

Research on reaching, tracking, and catching in the pigeon has been hampered by limitations of technology. A new system was developed in which the target was a small rectangle presented on a video display terminal and the pecking response was detected with touch technology. The target moved up and down vertically with sinusoidal velocity. A coincidence between the location of the pigeon's beak and the cursor produced reinforcement. The pigeon pecked ahead and behind the target, but most pecks occurred behind the target so the dominant tracking strategy was lagging. The pigeon was adept at “catching” the target at many locations throughout the trajectory. Transfer of motor learning was tested on probe trials during which the trajectory changed from vertical to horizontal. On transfer trials the pigeons' dominant pattern of pecking immediately shifted from vertical to horizontal. The motor skill displayed by the pigeons was flexible and adaptive, suggesting that the pigeons had learned to track the cursor.     

Functional classes and equivalence relations

Three adult subjects were taught a set of two-choice simultaneous discriminations, with three positive and three negative stimuli; all possible combinations of positive and negative stimuli yielded nine different pairs. The discriminations were repeatedly reversed and rereversed, the former positive stimuli becoming negative and the former negative stimuli becoming positive. With all subjects, a reversal of the contingencies for one pair of stimuli became sufficient to change their responses to all of the other pairs. The reversals had produced functional stimulus classes. Then, all subjects showed conditional discriminations emerging between members of a functional class; given a sample from one class and comparisons from both classes, they selected the comparison that was in the same class as the sample. Next, 2 of the subjects showed that the within-class conditional relations possessed the symmetric and transitive properties of equivalence relations; after having been taught to relate new stimuli to existing class members, the subjects then matched other class members to the new stimuli. Subsequent tests of two-choice discriminations showed that the conditional discriminations had transferred functional class membership to the new stimuli. The 3rd subject, who did not show equivalence relations among functional class members, was also found to have lost the within-class conditional relations after the equivalence tests.     

Effects of average movement velocity on reaction time and spatiotemporal accuracy in single-aiming and rapid-timing movement tasks

The effects of instructed movement speed were investigated in two experiments. First, rapid-timing and single-aiming movement tasks were compared. Unlike rapid timing, single aiming implies spatial accuracy. The aim of the first experiment was twofold: (a) to examine whether the requirement of accurate placement termination in single aiming affects the negative relationship between instructed average velocity and reaction time found in rapid timing, and (b) to test the speed-accuracy relationships predicted by the symmetric impulse variability model of these movement tasks. For this purpose, four average velocities (5, 24, 75, and 140 cm/s) were investigated in both types of movement tasks in a two-choice reaction task. The effects of average velocity on reaction time were similar in both single-aiming and rapid-timing tasks, and the predicted linear relationship between instructed average velocity and spatial accuracy was not found. The results suggest that the movement control mode, that is, open loop or closed loop, interferes with effects of instructed average velocity. The movement control mode explanation was confirmed in the second experiment with respect to the effect of paired velocities on reaction time. It is argued that the type of movement control mode must be considered in the interpretation of effects of instructed average velocity on reaction time and spatiotemporal measures.     

On task and theory specificity

One of the significant limitations of the motor control and skill acquisition domain is that the theories, models, and hypotheses are, in most cases, task specific. Many lines of theorizing fail to hold up under even small changes in task constraints, although clearly the field does have some robust phenomena. It is proposed that a broader consideration of the role of task constraints, which is grounded in the methodology of nonlinear dynamics, may help to formulate a more general action theory of coordination and control.     

Autobiographical memory in a case of multiple personality disorder

Previous research on multiple personality disorder (MPD) has been concerned with between-personalities amnesia, and little attention has been paid to within-personality memory function. This study examined the autobiographical memory of a multiple personality patient, I.C., with cueing procedures that have proven useful in previous studies of normal and abnormal memory. Results indicated that I.C. was able to retrieve autobiographical episodes from the recent past, although her performance differed in several respects from that of matched controls. The study also revealed a striking deficit in I.C.'s autobiographical memory for childhood: She was unable to recall a single episode from prior to the age of 10 in response to various retrieval cues, whereas control subjects had no difficulty recalling numerous childhood episodes. This phenomenon of extended childhood amnesia has not been reported previously in studies of MPD.     

Probability of relapse after recovery from an episode of depression

Examined relapse rates in those individuals who have experienced an episode of unipolar depression as a function of the number of previous episodes, gender, age at onset of the episode (less than 40 vs. greater than 40), time since a previous episode, and depression level at time of interview. From of 6,742 participants, 2,046 were interviewed; of these, 1,130 had at least one, 513 reported a second and 173 reported a third episode. The probability for relapse was positively related to number of previous episodes, being female, depression level at time of interview, but not to age at onset (less than 40 vs. greater than 40). Women were also more likely to have more severe episodes. Participants with elevated depression symptoms reported a greater number of previous episodes. Following the first episode, there was a decline in hazard rate for men but not women; following the second episode, there was no change in vulnerability for men; for women, the results were ambiguous.     

Depression: A Discussion of Jung''s Ideas

Depression is differentiated into normal and pathological. Pathological depression is further divided into simple and melancholic. The characteristics of each disordered form are described. Jung's ideas on depression are described in terms of this theoretical standpoint. The concepts used by Jung to explain depression are derived from his libido theory. Through introversion unconscious contents necessary to compensate a one-sided attitude of the ego are made conscious. Introversion depletes the ego of its energy. Depression is the depleted ego's experience of itself. Jung's theory is useful to explain normal depression associated to the process of transformation. It has also been extended to explain disorders of depression via the concept of involuntary or forced introversion in the service of compensation. His therapeutic approach consisted of rectifying the imbalance of psychic energy by helping the ego to integrate unconscious contents. The subsequent accrual of psychic energy redresses the problem of the ego's depletion and depression eases. In the discussion, Jung's contributions to the understanding of depression are recognised, especially his insight into the relationship between normal depression and the process of transformation. The explanatory limitations of Jung's ideas for depressive disorder are also recognised and discussed in relation to aetiology, introversion-extraversion, aggression and psychotherapy. Current clinical information suggests that a theory of depression needs to integrate and also to reformulate some of Jung's ideas.     

A Test of Bipolar and Androgyny Perspectives of Masculinity and Femininity: The Effect of Participation in an Outward Bound Program

ABSTRACT The purposes of the present investigation are to examine theoretical issues in androgyny theory by testing the effect of participation in the Outward Bound program on measures of masculinity (M) and femininity (F) Bipolar conceptualizations of MF posit that an increase in either M or F must lead to a decrease in the other, whereas androgyny theory posits M and F to be independent constructs Consistent with a priori predictions based on the nature of the Outward Bound program, participation substantially enhanced M and had a small positive effect on F The results were reasonably consistent for male and female participants, for single-sex and mixed-sex groups, and across responses to three different MF measures Results support the androgyny interpretation of MF and demonstrate the effectiveness of the Outward Bound program in changing MF The results contradict the bipolar perspective that an increase in M must be accompanied by a decrease in F     

Agreeable fancy or disagreeable truth? Reconciling self-enhancement and self-verification

Three studies asked why people sometimes seek positive feedback (self-enhance) and sometimes seek subjectively accurate feedback (self-verify). Consistent with self-enhancement theory, people with low self-esteem as well as those with high self-esteem indicated that they preferred feedback pertaining to their positive rather than negative self-views. Consistent with self-verification theory, the very people who sought favorable feedback pertaining to their positive self-conceptions sought unfavorable feedback pertaining to their negative self-views, regardless of their level of global self-esteem. Apparently, although all people prefer to seek feedback regarding their positive self-views, when they seek feedback regarding their negative self-views, they seek unfavorable feedback. Whether people self-enhance or self-verify thus seems to be determined by the positivity of the relevant self-conceptions rather than their level of self-esteem or the type of person they are.