Sequential planning in rhesus monkeys (<Emphasis Type="Italic">Macaca mulatta</Emphasis>)

In the current study, we examined the planning abilities of rhesus monkeys (Macaca mulatta) by training them on a five-item list composed of coloured photographs and then testing them on switch and mask trials. In contrast to previous studies where monkeys made responses using a joystick, in the current study, monkeys made responses directly to a touch screen. On switch trials, after a response to the first list item, the on-screen positions of two list items were exchanged. Performance on trials in which the second and third list items were exchanged was poorer compared to normal (non-switch) trials for all subjects. When the third and fourth items were exchanged, however, only one subject continued to show performance deficits. On mask trials, following a response to the first item, the remaining items were covered by opaque white squares. When two items were masked, all four subjects responded to each masked item at a level significantly above chance. When three items were masked, however, only one subjected was able to respond to all three masked items at a level significantly above chance. The results of the present study indicate that three of our four monkeys planned one response ahead while a single monkey planned two responses ahead. The significance of these findings is discussed in relation to previous studies on planning in chimpanzees and monkeys.     

Active heading control in simulated flight based on vertically extended contours

In two experiments, we manipulated the properties of 3-D objects and terrain texture in order to investigate their effects on active heading control during simulated flight. Simulated crosswinds were used to introduce a rotational component into the retinal flow field that presumably provided the visual cues used for heading control An active control task was used so that the results could be generalized to real-world applications such as flight simulation. In Experiment 1, we examined the effects of three types of terrain, each of which was presented with and without 3-D objects (trees), and found that the presence of 3-D objects was more important than terrain texture for precise heading control In Experiment 2, we investigated the effects of varying the height and density of 3-D objects and found that increasing 3-D object density improved heading control, but that 3-D object height had only a small effect. On the basis of these results, we conclude that the vertical contours improved active heading control by enhancing the motion parallax information contained in the retinal flow.     

A Time for Silence? Its Possibilities for Dialogue and for Reflective Learning

From the beginning of history sounds have played a fundamentally important role in humanity’s development as ways of expression and of communication. However in contemporary western society, and indeed globally, we are experiencing an excess of speech and a relentless encouragement to expression. Such excess indicates a misunderstanding about what expression and dialogue should be. This condition encourages us to think about silence, solitude and contemplation and the role they might play in restoring the realm of personal understanding of the Self and of one’s authentic experience of the Other. The purpose of this article is to explore the potency of a silence that arises from our participation in the world. We present first some ideas about silence as a human phenomenon. This is followed by an examination of silence and language, an investigation of silence in dialogue, and of its educational implications. The article concludes by emphasising the value of silence as potency in itself, assisting in recovering the expressive powers of language. We argue that it is important to understand the positive status of silence in order to recognise and avoid repressive speech and to introduce its potential for reflective learning.     

Coherent plaids are preattentively more than the sum of their parts

We investigated whether plaids activate preattentive mechanisms that are distinct from those activated by their component gratings. Observers searched for a target plaid, the sum of two perpendicular components in a circular window (radius = 0.65°). The target was present on half the trials. On all trials, half of the distractors had the same frequency and orientation as one component of the plaid, and the rest were the same as the other component. The target and the distractors were arrayed evenly on a circle (radius = 2.36°) around fixation. Target and distractor contrasts were randomly perturbed up to ±30%. The following results held for each of the 6 participants tested. (1) When F1 = 2 c/deg and F2 = 5.25 c/deg, response times (RTs) increased significantly when set size (number of distractors plus target, if present) was increased from four to eight. (2) When the spatial frequencies of both plaid components were the same (i.e., both 2 c/deg or both 5.25 c/deg), RTs increased very slightly, if at all, when set size was increased from four to eight. These results suggest the existence of a preattentive, plaid-sensitive mechanism with band-limited input that does not respond to individual grating components.     

Tuomela on deductive explanation

Almost every formal model of explanation thus far proposed has been demonstrated to be faulty. In this paper, a new model, proposed by Raimo Tuomela, is also demonstrated to be faulty. In particular, one condition of the model is shown to be too restrictive, and another condition of the model is shown to be too permissive.This research was supported by a grant from the Killam Foundation, administered by the Canada Council.     

The relationship between miscellaneous symptoms and major symptom factors in obsessive-compulsive disorder

The diverse symptomatology of obsessive-compulsive disorder (OCD) is being increasingly regarded as reducible to a few symptom dimensions. However, prevailing factor-analytically derived models of symptom structure omit a number of the well-recognized “miscellaneous” symptoms of OCD. This study sought to determine whether miscellaneous OCD symptoms, ascertained by the Yale-Brown Obsessive-Compulsive Scale symptom checklist, could be differentially and reliably predicted by four symptom factors (obsessions and checking, symmetry and ordering, contamination and cleaning, and hoarding) in two independent groups of individuals with OCD (n = 381 and n = 107). Logistic regression analyses were used to determine the association of each of the miscellaneous symptoms with the symptom factors; then a single confirmatory factor analysis was conducted to test the model of associations in the smaller sample. Sixteen (89%) of the 18 symptoms examined were reliably predicted by one (11 items) or two (5 items) of the factors, with obsessions and checking and symmetry and ordering emerging as foremost predictors. The expanded four-factor model showed good fit with data from the second sample. Results are conceptually meaningful, but suggest the inadequacy of groupings based solely upon overt behaviors. These findings may aid clinical understanding of OCD and be of value to studies using symptom factors to guide investigation of its causes and correlates.     

Reducing emotional reasoning: An experimental manipulation in individuals with fear of spiders

We investigated the effects of smiling on perceptions of positive, neutral and negative verbal statements. Participants viewed computer-generated movies of female characters who made angry, disgusted, happy or neutral statements and then showed either one of two temporal forms of smile (slow vs. fast onset) or a neutral expression. Smiles significantly increased the perceived positivity of the message by making negative statements appear less negative and neutral statements appear more positive. However, these smiles led the character to be seen as less genuine than when she showed a neutral expression. Disgust + smile messages led to higher judged happiness than did anger + smile messages, suggesting that smiles were seen as reflecting humour when combined with disgust statements, but as masking negative affect when combined with anger statements. These findings provide insights into the ways that smiles moderate the impact of verbal statements.     

When ideology matters: Moral conviction and the association between ideology and policy preferences in the Israeli–Palestinian conflict

Do people's policy preferences toward outgroups in intractable conflict consistently correspond with political ideology? To what extent are policy‐related cleavages between the political right and left in such contexts fueled by moral conviction and emotions? Analyses of a survey of Jewish‐Israelis (N = 119) conducted immediately after a war between Israelis and Palestinians revealed little to no ideological differences in acceptance of “collateral damage,” support for retribution, or support for compromise when positions about the Israeli–Palestinian conflict were devoid of moral fervor. Those on the left and right endorsed polarized policy preferences only when their positions about the conflict were held with moral conviction. Presence or absence of guilt about harm to Palestinians mediated the effects of moral conviction on policy preferences in this context. Copyright © 2013 John Wiley & Sons, Ltd.