My owner,right or wrong: the effect of familiarity on the domestic dog’s behavior in a food-choice task

Dogs are strongly influenced by human behavior, and they readily form bonds with specific humans. Yet these lines of inquiry are not often combined. The goal of this study was to investigate whether such bonds would play a role in how dogs behave in response to human signals. Using various types of signals, we compared dogs’ use of information from a familiar human (their owner) versus an unfamiliar human when choosing between two food containers. In some conditions, the owner indicated a container that gave food and a stranger indicated a container that did not; in other conditions, this was reversed. Dogs more often chose the container indicated by or nearest to their owner, even when this container never yielded a food reward. In two conditions, dogs chose at chance: a control condition in which both pointers were strangers and a condition in which the owner and stranger sat reading books and provided no social signal. This is the first study to directly compare owners to strangers in a single food-choice situation. Our results suggest that dogs make decisions by attending preferentially to social signals from humans with whom they have become familiar.     

Use of kind information for object individuation in young domestic chicks

In this paper, we studied the ability of newborn chicks to use kind information (sortal objects) provided by social and food attractors to determine the number of distinct objects present in an event (object individuation). Newly hatched chicks were reared with five imprinting objects and were fed mealworms. Chicks’ spontaneous tendency to approach the larger group of items was exploited. At test, on day 2 post-hatching, chicks observed two events in which objects, differing in kind, were each hidden behind one of two identical screens. Approaching either screen was considered a preferential choice. In Experiment 1, chicks presented with two social versus two food attractors did not exhibit any preference. In contrast, in Experiment 2, when chicks saw two different attractors (one social and one food) hidden behind a screen and one attractor hidden twice (i.e. moved back and forth two times) behind the other screen, they spontaneously approached the two different attractors rather than the single one seen twice. An explanation based on the preference for the more varied set was ruled out in Experiment 3: chicks did not preferentially choose between two different versus two identical objects when both groups were simultaneously presented. Results suggest for the first time that a non-human species uses kind information for individuating objects in a cross-basic-level contrast (i.e. food and social items) with minimal experience. As social and food stimuli differ in property as well as in kind information, the alternative explanation accounting for use of property information alone is also discussed.     

The status of consonants and vowels in phonological assembly: Testing the two-cycles model with Italian

Recent studies by Berent and Perfetti (1995) and Lee, Rayner, and Pollatsek (2001) have shown a processing priority of consonants over vowels in tasks like backward masking and reading, respectively. One possible explanation for this advantage of consonants is in terms of the specific characteristics of the English spelling (i.e., a great inconsistency in the spelling-sound relations for vowels), and therefore is not predicted for a language, like Italian, with a transparent orthography. The aim of the present experiments was to investigate the consonant advantage in Italian with the backward masking paradigm. The first two experiments, with a perceptual identification and a naming task, showed a masking reduction effect for masks sharing vowels with the target at the shortest SOAs, in addition to a pseudo-homophone advantage as compared to the control condition. In the third experiment, where a lexical decision task was used, the advantage of the mask sharing vowels disappeared. The fourth experiment was a replication of Experiment 1 with different materials. Overall, the results suggest that the advantage of consonants can only be found in English, whereas in Italian, for which the computation of phonology of vowels and consonants is similar, no effect is apparent. Thus, the processing priority for consonants seems to depend on the inconsistencies of vowel phonology in English.     

Effectiveness of child psychoanalytic psychotherapy in a clinical outpatient setting

The objective of this study was to evaluate the outcome of child psychoanalytic psychotherapy in a clinical outpatient setting in a city in southern Brazil. Three psychological tests (Rorschach, Bender and WISC III) were administered to 23 children, aged 6–11 years old, and the Child Behaviour Check List (CBCL) was completed by the parents. All testing was completed before the beginning of the individual psychoanalytic psychotherapy. The same measures were repeated after 12 months of intervention. The 23 children who received individual psychoanalytic psychotherapy were compared with a control group who did not receive any kind of intervention. In the clinical group, the results indicated a statistically significant reduction of anxiety symptoms (0.002) and school problems (0.031), improvement in interpersonal relationships (0.022), and positive change in the following CBCL scales: withdrawn (0.010), thought problems (0.022), anxiety and depression (0.017), internalising (0.008) and total (0.003). An effect size of 0.696 was calculated based on the CBCL total scale before and after the intervention. The results revealed that child psychoanalytical psychotherapy is mostly effective in the treatment of female children who present internalising disorders.     

Oxidative stress in university students during examinations

Mental stress in psychiatric disease and in daily life contributes to oxidative stress in the body. In this study we investigated a connection between possible psychological stress caused by university undergraduate examinations and oxidative stress experienced by our test subjects. Some parameters of oxidative stress (single strand breaks of DNA in lymphocytes, sensitivity to lipid oxidation and antioxidant status) were studied in medical students on the day of the examination (stress condition) and compared with the same parameters obtained from the same students during the term between two examination periods (non-stress condition). The results show that in the stress condition oxidative damage to DNA and sensitivity to lipid oxidation were significantly increased (p<0.05) when compared with the same parameters in "non-stress" conditions. A significant decrease in plasma antioxidant activity (p<0.05) in students that were under stress was observed. These results suggest that during university examinations students are under increased oxidative stress.     

Dissociating the influence of familiarity and meaningfulness from word frequency in naming and lexical decision performance

Performance in two experiments was compared on a list of words of high and low frequency in which familiarity/meaningfulness (FM) was balanced and on a list of high- and low-frequency words in which FM was confounded with frequency (i.e., high frequency--high familiarity vs. low frequency--low familiarity). Both repetition and task (lexical decision and naming) were investigated. In the lexical decision task of Experiment 1, both frequency and repetition effects were larger in the list with FM confounded than in the list with FM matched. In the naming task, frequency and repetition effects and their interaction were significant, but there was no influence of FM list context. In Experiment 2, in which the repetitions occurred across blocks, as opposed to randomly intermixed within a list, similar results were found; however, there was no interaction between list and repetition. The results suggest that an evaluation of items in terms of their meaning and familiarity explains a large part of the variance, only in lexical decision. These dimensions may be cued both by subjective feelings of familiarity and the extent to which semantic information is available and by episodic traces due to recent encounters with the item.     

Stereo motion transparency processing implements an ecological smoothness constraint

Transparent motion stimuli allow us to investigate how visual motion is processed in the presence of multiple sources of information. We used stereo random-dot kinematograms to determine how motion processing is affected by the difference in direction and depth of two overlapping motion components. Observers judged whether a noise dot display contained one or two directions of motion. For all disparity differences, performance did not change among angles greater than 60 degrees, but the ability to detect transparent motion fell dramatically as the direction difference decreased below 60 degrees. When a disparity difference was added between the two motion components, detection became easier. We compared these results to an ideal-observer model limited by stimulus uncertainty and low-level sources of internal noise. The resulting measure of efficiency--the ratio of human to model performance--reflects changes in how motion stimuli are being processed. A decrease of both the direction and disparity differences had the effect of decreasing efficiency. These results suggest that the mechanism processing transparent motion may implement a smoothness constraint that tends to combine similar motions into a single percept.     

The role of affordances in inhibition of return

Inhibition of return (IOR) is a response delay that occurs when the target is preceded by an irrelevant stimulus (cue) at the same location. IOR can be object based, as well as location based. The aim of the present study was to investigate the role of the pragmatic features of a visually presented object in causing IOR. Two experiments were carried out using different objects as stimuli, for which the graspable part (affordance) was clearly defined. The presentation of a whole object, with the part commonly used to grasp it located below, served as a cue. The presentation of either the graspable or the ungraspable part of the cued or uncued object served as the target Results showed that responses were slower when the graspable part was shown in the cued location than when the ungraspable part was shown in the same location. The effect was apparently linked to the kind of action necessary to grasp an object.     

When similarity breeds content: need for closure and the allure of homogeneous and self-resembling groups

Four studies explored the relation between members' need for cognitive closure and their feelings toward groups. It was found that high (vs. low) need for closure individuals liked in-groups and out-groups more as function of the degree to which their membership was perceived as homogeneous (Studies 1-4), provided it was also self-similar (Studies 3 and 4). These results are discussed in terms of the relation between need for closure and homogeneous (vs. heterogeneous) groups' apparent potential as "closure providers."