Is time to scan visual images due to demand characteristics?

The time to scan across an object in a mental image increases with the distance scanned. Does this finding reflect the operation of underlying mechanisms or the effects of demand characteristics? Two types of demand characteristics were considered here. First, the scanning effects were shown to persist even when they conflicted with the experimenters' expectations. Experimenters were led to expect different rates of scanning and different effects of distance on scan times, but the results in all cases showed no hint of experimenter effects, instead displaying the usual increase in time with distance scanned. Second, the scanning effects were shown to persist in the absence of implicit task demands. Effects of distance were observed in an experiment in which subjects were never asked to scan the image; furthermore, such effects were observed only for items that should require spontaneous scanning even though they were randomly intermixed with items that should not, and this distinction was never mentioned nor alluded to in the instructions. Thus, experimenter effects and task demands are not sufficient explanations for the increase in the time to scan across an image as distance is increased.     

The time to name disoriented natural objects

A series of experiments revealed systematic effects of orientation on the time required to identify line drawings of natural objects. Naming time increases as patterns are rotated further from the upright. With practice, however, the effect of orientation is reduced considerably. Furthermore, the reduced orientation effect with practice on a set of objects does not transfer to a new set of objects, suggesting that the acquired ability to reduce the orientation effect is specific to particular patterns. Finally, for departures in orientation from the upright between 0° and 120°, the magnitude of the orientation effect on identification for patterns seen for the first time is equivalent to that found in a mental rotation task using the same patterns (making left/right decisions about rotated patterns). This final result suggests that novel depictions of a known class of objects may be identified by a process of mental rotation.     

Curve tracing: A possible basic operation in the perception of spatial relations

The two experiments in this study suggest that fast internal tracing of curves is employed by the visual system in the perception of certain shape properties and spatial relations. The experimental task in the first experiment was to determine, as rapidly as possible, whether two Xs lay on the same curve or on different curves in a visual display. Mean response time for “same” responses increased monotonically with increasing distance along the curve between the Xs. The task in the second experiment was to decide either that a curve joining two Xs was unbroken or that the curve had a gap. Decision times again increased as the length of the curve joining the Xs was increased. The results of both experiments suggest that people can trace curves in a visual display internally at high speed (the average rate of tracing was about 40° of visual angle per second). Curve tracing may be an important visual process used to integrate information from different parts of a visual display.     

A pitfall for the expectancy theory of human eyelid conditioning

Two simple eyeblink conditioning experiments with random intermittent reinforcement schedules were performed. In Experiment 1, subjects had to rate their expectancy for an unconditioned stimulus (US) on a seven-level scale prior to each trial. As anticipated, expectancy for US increased with a successive conditioned stimulus (CS) alone, and decreased with successive CS-US pairings. However, Experiments 1 and 2 showed that the frequency of eyeblink conditioned responses (CRs) evolved in a direction opposite to that of expectancy changes: CRs increased, whereas expectancy for US decreased, and vice versa. The possible effect of sensitization on eyeblink response was ruled out by the lack of a run effect in an unpaired control group in Experiment 2. These results tend to disconfirm the expectancy theory of conditioning. Although they were explicitly predicted by the conventional “strength” theory of conditioning, an alternative interpretation is proposed within a cognitive framework.     

Correlational analyses of explicit and implicit memory performance

Sixty-four subjects were administered two tests of explicit memory (selective recall and recognition) and four tests of implicit memory (identification in a perceptual clarification procedure, word-fragment completion, tachistoscopic identification, and anagram solution). Each test drew on a different subset of a long list of previously displayed words. Although the four implicit memory tests showed sizable priming effects, correlational and factor analyses showed striking dissociations. On the one hand, performance on the perceptual clarification procedure and word-completion tests were related to one another, as well as to recall and recognition. On the other hand, performance on tachistoscopic identification and anagram solution were related to one another, but not to the measures for the other tasks. A framework is proposed to reconcile these new results with current knowledge on the explicit/implicit memory distinction, based in particular on studies of amnesic subjects. It is argued that a small number of tasks, especially tachistoscopic identification, may serve as relatively uncontaminated and ubiquitous indicators of implicit memory. However, explicit remembering could affect performance in so-called implicit memory tasks that allow for a strategy of controlled selection of candidate responses from accumulating cues, in experimental conditions that make the explicit remembering of relevant events possible.     

Immunocytochemical Mapping of an RDL-Like GABA Receptor Subunit and of GABA in Brain Structures Related to Learning and Memory in the Cricket Acheta domesticus

The distribution of putative RDL-like GABA receptors and of γ-aminobutyric acid (GABA) in the brain of the adult house cricket Acheta domesticus was studied using specific antisera. Special attention was given to brain structures known to be related to learning and memory. The main immunostaining for the RDL-like GABA receptor was observed in mushroom bodies, in particular the upper part of mushroom body peduncle and the two arms of the posterior calyx. Weaker immunostaining was detected in the distal part of the peduncle and in the α and β lobes. The dorso- and ventrolateral protocerebrum neuropils appeared rich in RDL-like GABA receptors. Staining was also detected in the glomeruli of the antennal lobe, as well as in the ellipsoid body of the central complex. Many neurons clustered in groups exhibit GABA-like immunoreactivity. Tracts that were strongly immunostained innervated both the calyces and the lobes of mushroom bodies. The glomeruli of the antennal lobe, the ellipsoid body, as well as neuropils of the dorso- and ventrolateral protocerebrum were also rich in GABA-like immuno- reactivity. The data demonstrated a good correlation between the distribution of the GABA-like and of the RDL-like GABA receptor immunoreactivity. The prominent distribution of RDL-like GABA receptor subunits, in particular areas of mushroom bodies and antennal lobes, underlines the importance of inhibitory signals in information processing in these major integrative centers of the insect brain.     

Heidegger and the source(s) of intelligibility

Wittgensteinian readings of Being and Time, and of the source of the intelligibility of Dasein's world, in terms of language and the average everyday public practices of das Man are partly right and partly wrong. They are right in correcting overly individualist and existentialist readings of Heidegger. But they are wrong in making Heidegger into a proponent of language or everydayness as the final word on intelligibility and the way the world is disclosed to us. The everydayness of das Man and language are partial sources of intelligibility but only insofar as they are comprehended within the greater unitary structure of care and temporality. Care and temporality constitute the foundational underpinnings for disclosure and the intelligibility ofthat wherein Dasein dwells.     

Computer simulations of the Rescorla-Wagner and Pearce-Hall models in conditioning and contingency judgment

A Visual BASIC program, running under Windows 3.1, simulated the predictions of the Rescorla—Wagner (Rescorla & Wagner, 1972) and the Pearce-Hall (Pearce & Hall, 1980) models and compared them to the normative contingency coefficient ΔP (Jenkins & Ward, 1965). The simulations can be applied to a variety of phenomena in human contingency judgment as well as learning and conditioning. Possible simulations include acquisition and extinction of excitatory and inhibitory conditioning, latent inhibition, blocking and overshadowing, or any other associative learning involving two single predictors, their compound, a contextual stimulus, and an outcome. The Pearce-Hall model has never been computerized before. In addition, unique features of this software include extensive use of the graphic user interface, context-sensitive help, verification of trial combinations, toggling of the contextual stimulus from ever-present to mutually exclusive with the discrete predictors, data entry via contingency tables or specifications trial by trial, single or batch randomizations of trial order, and specification of initial values. The associative simulator is both a powerful scientific instrument and a user-friendly teaching aid.     

The production and recognition of typological argumentative text markers

A series of experiments on children and adults were conducted to define the features and workings of argumentative discourse. Oral and written arguments were analyzed for the complexity of the argument support structure and the presence of typological argumentation markers (certainty modals, value judgments, etc.). Subjects were asked to assess the argumentativity of texts that did or did not contain typical argumentation markers. At about age ten, children can produce and recognize a ‘minimal argumentative structure,’ in which the speaker takes a stance and supports it with text that derives its argumentativity from the presence of this stance). However, full mastery of the negotiation process, that involves acknowledgment of the opponent's stance (generally through the use of counterarguments) is not present before the ages of 15 to 16. The minimal argumentative structure continues to develop with age and gain complexity. Certain situations are more conductive to the production of elaborate argumentative discourse, such as a genuinely controversial topic with an unfamiliar adult addressee whose stance is not known and whose reaction is thus unpredictable. Here speakers produce complex arguments while still leaving room for negotiation. Overall, certain argumentation markers can be identified in all argumentative text. these markers can be used to characterize stages of development of argumentative discourse. A number of issues remain unexplored, including: What other (implicit...) devices do speakers use to convince their audience? Why is the capacity to put argumentation in writing acquired at such a late stage of development?     

Conservation of weight in infants

Conversation of weight can be defined as the ability to affirm that the weight of an object remains invariant during the transformations of the form of the object. It is known to be achieved at a conceptual level at about 9 years of age. The behavior of infants seems to indicate that between 6 and 18 months of age they develop a sensorimotor form of conversation.