Midsession reversals with pigeons: visual versus spatial discriminations and the intertrial interval

Discrimination reversal learning has been used as a measure of species flexibility in dealing with changes in reinforcement contingency. In the simultaneous-discrimination, midsession-reversal task, one stimulus (S1) is correct for the first half of the session, and the other stimulus (S2) is correct for the second half. After training, pigeons show a curious pattern of choices: They begin to respond to S2 well before the reversal point (i.e., they make anticipatory errors), and they continue to respond to S1 well after the reversal (i.e., they make perseverative errors). That is, pigeons appear to be using the passage of time or the number of trials into the session as a cue to reverse, and are less sensitive to the feedback at the point of reversal. To determine whether the nature of the discrimination or a failure of memory for the stimulus chosen on the preceding trial contributed to the pigeons’ less-than-optimal performance, we manipulated the nature of the discrimination (spatial or visual) and the duration of the intertrial interval (5.0 or 1.5 s), in order to determine the conditions under which pigeons would show efficient reversal learning. The major finding was that only when the discrimination was spatial and the intertrial interval was short did the pigeons perform optimally.     

Journal author rights and self‐archiving: the case of Spanish journals

Open access (OA) literature is digital, online, free of charge, and free of most copyright and licensing restrictions. The lack of clarity of publisher permissions for archiving in OA repositories affects the adoption of the green OA route. This paper explores editorial policies and self‐archiving conditions in 1,615 Spanish scholarly journals. 48% are published by university and research institutions, 25% by associations/societies, and 17% by commercial publishers; social sciences and humanities (SSH) accounted for 67% of the journals (44.5% and 22.5%, respectively) followed by health sciences (20%); 71% offered gratis access immediately after publication, and 11% after an embargo; 31% provided some mention of author rights. Self‐archiving was specifically allowed by 65% of the journals; 52% were classified as ROMEO‐blue, 12% as green and 15% as white, and 21% could not be classified; 21%, mostly in SSH, used some type of Creative Commons license.     

Refutational texts and the change process

The purposes of this chapter are to examine the persuasive qualities of refutational text and explore the role of refutational text in educational settings that have competing agendas. As educators, we should understand the competing agendas existing in education and find ways to meet those agendas effectively. The use of refutation to aid learning fits into one agenda. The teaching of refutation as a persuasive rhetorical device fits into another.     

Design of minimum sensitivity multiple loop feedback bandpass active filters

A method is described for determining multiple loop feedback topologies which yield minimum sensitivities for symmetrical, all-pole bandpass filters. The procedure begins with a follow-the-leader feedback (FLF) topology and additional feedback loops are constructed until minimum sensitivity is achieved. Filters comprised of identical second-order sections and non-identical sections, respectively, are considered.