Interpreting the effects of image manipulation on picture perception in pigeons (Columba livia) and humans (Homo sapiens)

The effects of picture manipulations on humans' and pigeons' performance were examined in a go/no-go discrimination of two perceptually similar categories, cat and dog faces. Four types of manipulation were used to modify the images. Mosaicization and scrambling were used to produce degraded versions of the training stimuli, while morphing and cell exchange were used to manipulate the relative contribution of positive and negative training stimuli to test stimuli. Mosaicization mainly removes information at high spatial frequencies, whereas scrambling removes information at low spatial frequencies to a greater degree. Morphing leads to complex transformations of the stimuli that are not concentrated at any particular spatial frequency band. Cell exchange preserves high spatial frequency details, but sometimes moves them into the "wrong" stimulus. The four manipulations also introduce high-frequency noise to differing degrees. Responses to test stimuli indicated that high and low spatial frequency information were both sufficient but not necessary to maintain discrimination performance in both species, but there were also species differences in relative sensitivity to higher and lower spatial frequency information.     

Effect of arousal increase in predictable and random task switching: evidence for the involvement of the anterior attentional network in random but not in predictable task switching

Switch cost does not disappear as more preparation time for the next task is allowed. Tornay and Milán showed that the residual cost is smaller when tasks switch randomly than when they alternate in predictable sequences. They proposed that the difference was due to control mechanisms (anterior attentional network) being activated in the random condition because of its overall difficulty. Besides, it has been shown that increasing arousal levels inhibits the anterior attentional network. Therefore, Tornay and Milán's account predicts that high arousal should result in switch cost for the random condition increasing to the levels of predictable switching. In this work, this prediction was tested by assessing the interaction between increased arousal and switch cost with both predictable and random-task switching. The results may help to solve the ongoing controversy about the causes of switch cost.     

Teaching Religious Doubt with Toulmin's Model of Reasoning

Abstract. Teaching students to doubt, that is, to “test,” theological arguments as one might test any other kind of knowledge is challenging in that the warrant for such testing is not immediately clear. Stephen Toulmin, Richard Rieke, and Allan Janik's model of reasoning provides a conceptual framework that demonstrates the logical relationships between a claim, its grounds, warrants, and backing for warrants. Against such a model, the instructor and students may study religious claims, both biblical and theological, with the aim of analyzing the ways such claims find support or a lack of support depending upon the particular ways that claims and evidence have competing warrants. Several pedagogical benefits ensue. First, students see that the validity for theological claims rests as much upon warrants as it does upon grounding. Second, searching for ancient warrants privileges historical‐critical investigation. Third, competing warrants for contradictory theological claims summon pedagogical metaphors of process and development.     

Feedback of Information About the Values and Attitudes of Self and Others as Determinants of Long-Term Cognitive and Behavioral Change1

Previous experiments designed to modify persons' values and subsequent attitudes and behavior have used direct self-confrontation procedures to arouse self-dissatisfaction in subjects. The present study compared the effects on values and behavior of the previously used self-confrontation procedure with a modified value-change procedure which did not confront subjects with information about their own values. Both procedures resulted in college students significantly increasing their ranking of the values equality and freedom. These changes were evident 4 weeks after the experimental procedures. Four months after the experimental treatments subjects were solicited to behaviorally support various activities of the Committee to End Racism, and subjects in both experimental groups showed a significantly greater behavioral effect than did control subjects. Thus, significant long-term value and behavioral change may be experimentally induced even when subjects are not provided objective information about their own value-attitude system.     

Fusion frequency as a function of number and phase of binocular stimuli

The relation of fusion hertz to the number of pulses in a train was explored under three conditions: monoptically, dichoptically inphase, and dichoptically antiphase. All three conditions show an increase in fusion hertz as the number of pulses in the stimulating train increases. Over the range of pulse numbers investigated, fusion hertz varies principally with the number of pulses delivered to one eye regardless of the stimulating condition of the other eye.     

Effects of altering outcome expectancies on pigeons' delayed conditional discrimination performance

An outcome-expectancy mediation theory of learning was tested in a series of transfer experiments with pigeons. The principal technique employed was a delayed two-choice conditional discrimination in which the subject's correct choice yielded a food reward on one kind of trial and a feedback tone on the other. According to the theory, this task engenders two-link mediational chains in that each conditional cue controls a particular outcome expectancy (S-E link) and the expectancy, in turn, cues a specific choice response (E-R link). Relative to the hypothetical mediators established by preceding training, transfer problems required either the same mediational chains, the alteration of one link in each chain, or the alteration of both links in both chains for optimal performance. The results of four separate transfer experiments confirmed detailed theoretical predictions, including that of an unusual nonmonotonic transfer effect. The relation of the present theory to earlier mediation theories is discussed.