Picture–object recognition in the tortoise Chelonoidis carbonaria

To recognize that a picture is a representation of a real-life object is a cognitively demanding task. It requires an organism to mentally represent the concrete object (the picture) and abstract its relation to the item that it represents. This form of representational insight has been shown in a small number of mammal and bird species. However, it has not previously been studied in reptiles. This study examined picture–object recognition in the red-footed tortoise (Chelonoidis carbonaria). In Experiment 1, five red-footed tortoises were trained to distinguish between food and non-food objects using a two-alternative forced choice procedure. After reaching criterion, they were presented with test trials in which the real objects were replaced with color photographs of those objects. There was no difference in performance between training and test trials, suggesting that the tortoises did see some correspondence between the real object and its photographic representation. Experiment 2 examined the nature of this correspondence by presenting the tortoises with a choice between the real food object and a photograph of it. The findings revealed that the tortoises confused the photograph with the real-life object. This suggests that they process real items and photographic representations of these items in the same way and, in this context, do not exhibit representational insight.     

Adolescents' conception of knowledge

Since few investigations have addressed adolescents' conception of knowledge, a rationale is provided as to why it may be useful to more adequately explore how adolescents view knowledge. The few investigations which have explored these conceptions are reviewed, and three general approaches to the study of the subject are developed and briefly discussed.     

Response-stimulus interval in choice serial reaction time: Interaction with sleep deprivation, choice, and practice

In choice serial reaction time (RT), Response-to-next-Stimulus Interval (RSI) was varied from 0 to 600 msec in 40-msec steps. In three experiments, RT fell and errors rose as RSI was increased to 480 msec; they remained unchanged thereafter. The effect of RSI on RT was not linear, was reduced by 6- as compared with 4- or 3-choice responding, and was unaffected by sleep deprivation, despite loss of sleep reducing RT overall. The effect of penultimate RSI on RT was similar to that current RSI, but smaller. Two explanations of RSI—response-generated kinaesthetic feedback blocking a “central processor” and a preparatory interval as in warned simple RT—are rejected. Instead, the idea of “relative refractory state” is revived but now, because of the RSI/error finding, biased more towards responding than stimulus reception and encoding. In all three experiments the influence of RSI on RT was reduced with practice. If practice encourages automatic rather than controlled processing (Shiffrin & Schneider, 1977), the prediction is that the former will show less refractoriness.     

Counterfactual Reasoning for Regretted Situations Involving Controllable Versus Uncontrollable Events: The Modulating Role of Contingent Self-Esteem

We report a study that examined the modulating impact of contingent self-esteem on regret intensity for regretted outcomes associated with controllable versus uncontrollable events. The Contingent Self-Esteem Scale (e.g., Kernis & Goldman, 2006) was used to assess the extent to which a person’s sense of self-worth is based on self and others’ expectations. We found that there was an influence of self-esteem contingency for controllable but not for uncontrollable regret types. For controllable regret types individuals with a high contingent (i.e., unstable) self-esteem reported greater regret intensity than those with a low contingent (i.e., stable) self-esteem. We interpret this finding as reflecting a functional and adaptive role of high contingent self-esteem in terms of mobilizing the application of counterfactual reasoning and planning mechanisms that can enable personal expectations to be achieved in the future.     

Micro-mechanical measurements of fracture toughness of bismuth embrittled copper grain boundaries

Measuring the fracture properties of single grain boundaries has until now required macroscopic bi-crystals which are expensive and not always available. We describe a method for fracture testing using micro-cantilevers, manufactured using focussed ion beam machining and tested using a nanoindenter. We have used the method to measure the fracture toughness of selected grain boundaries in bismuth-embrittled copper. This technique is applicable to grain boundaries in other brittle polycrystalline samples for which large bi-crystals cannot be produced for conventional testing.     

Effects of retrieval practice and presentation modality on verbal learning: testing the limits of the testing effect

ABSTRACT

The testing effect refers to improved memory after retrieval practice and has been researched primarily with visual stimuli. In two experiments, we investigated whether the testing effect can be replicated when the to-be-learned information is presented auditorily, or visually?+?auditorily. Participants learned Swahili-English word pairs in one of three presentation modalities – visual, auditory, or visual?+?auditory. This was manipulated between-participants in Experiment 1 and within-participants in Experiment2. All participants studied the word pairs during three study trials. Half of participants practiced recalling the English translations in response to the Swahili cue word twice before the final test whereas the other half simply studied the word pairs twice more. Results indicated an improvement in final test performance in the repeated test condition, but only in the visual presentation modality (Experiments 1 and 2) and in the visual?+?auditory presentation modality (Experiment 2). This suggests that the benefits of practiced retrieval may be limited to information presented in a visual modality.     

Predicting Safer Sex Practices: The Interactive Role of Partner Cooperation and Cognitive Factors

This study integrates aspects of cognitive and social contextual approaches to understanding the practice of safer sex. Study participants were 398 unmarried college students attending one of two institutions of higher education in Texas. As predicted, individuals who perceived more cooperation from their sexual partner to practice safer sex were significantly more likely to do so than those who saw their partners as uncooperative. Especially important, as predicted, partner cooperation also moderated the relationship between cognitive and behavioral predictors and safer sex. These moderation findings demonstrate that partner cooperation limits the range of operation of psychological factors that have been shown in previous research to play a significant role in deciding to practice safer sex.     

Clark’s nutcrackers (<Emphasis Type="Italic">Nucifraga columbiana</Emphasis>) use gestures to identify the location of hidden food

Heterospecific cues, such as gaze direction and body position, may be an important source of information that an animal can use to infer the location of resources like food. The use of heterospecific cues has been largely investigated using primates, dogs, and other mammals; less is known about whether birds can also use heterospecific gestures. We tested six Clark’s nutcrackers in a two-way object-choice task using touch, point, and gaze cues to investigate whether these birds can use human gestures to find food. Most of the birds were able to use a touch gesture during the first trial of testing and were able to learn to use point and gaze (eyes and head alternation) cues after a limited number of trials. This study is the first to test a non-social corvid on the object-choice task. The performance of non-social nutcrackers is similar to that of more social and related corvids, suggesting that species with different evolutionary histories can utilize gestural information.