Effects of surface texture on weight perception when lifting objects with a precision grip

In this paper, we show that, when lifting an object using a precision grip with the distal pads of the thumb and index finger at its sides, the perceived weight depends on the object’s surface texture. The smoother the surface texture, the greater the perceived weight. We suggest that a smoother object is judged to be heavier because the grip force, normal to the surface, required to prevent it from slipping is greater. The possibility of there being an influence of surface texture per se is excluded by a second experiment that employed a variant of the precision grip in which the thumb supports the weight of the object from underneath. With the grip oriented in this way, there is no need to match grip force to surface texture and, under these conditions, there is no effect of surface texture on weight perception. In the first two experiments, the test and comparison weights were lifted successively by the same hand. In a third experiment, the effect of surface texture was replicated for sequential lifts made with separate hands. Thus, the effect is not restricted to comparisons made with the same hand.     

The Fire Chief microworld generating program: An illustration of computer-simulated microworlds as an experimental paradigm for studying complex decision-making behavior

Computer-simulated microworlds bridge the gap between the complexity of field investigations and the rigor of laboratory studies. The purpose of this paper is to draw attention to the major methodological issues involved in developing and using computer-simulated microworlds for the psychological study of complex decision-making behavior. These issues comprise flexibility and generality in the microworlds that can be created, adequate psychological validity, automatic trial administration and data logging, capacity to interface simulations of psychological processes, and adequate testing and documentation. Each of these issues is illustrated by indicating how it has been addressed in Fire Chief, a microworld generating program specifically designed for creating realistic, yet controllable, decision-making task environments in the psychology laboratory. Fire Chief (Omodei & Wearing, 1993a) is introduced as both fully portable to other research teams and suitable for use in many different contexts requiring a complex task situation.     

Individual differences in preschoolers' physiological and verbal responses to videotaped angry interactions

Individual differences in selection of intensity of angry interactions and physiological and self-reported responses to interadult anger were examined in preschoolers (N=34). Children watched two videotaped angry interactions between adults, while their heart rates and skin conductance responses and levels were monitored; then they were interviewed. Before the second argument, children were given the perceived choice of watching an intense or mild angry exchange. Individual differences in responding to the angry interactions were found. Both (a) children with relatively higher externalizing behavior problems and (b) boys who chose to watch intense anger had lower tonic heart rates; 80% of boys with externalizing problems chose to watch intense anger. Further, children who chose to watch intense anger (a) exhibited lower declines in heart rates upon the presentation of the argument, (b) perceived the actors as more angry, and (c) reported lower amounts of distress during the argument than those who chose mild anger.     

On the naming of color words and color patches

Subjects can name color words faster than they can name color patches. To account for that effect, a generic model of naming is described which assumes that words access the mental lexicon directly, whereas color patches do so only indirectly via an initial imaginal or semantic representation. However, Lund (1927) reported that the naming advantage for words disappeared when all the items to be named on a page were the same (i.e., they were blocked). In the present study, three experiments are reported that were designed to provide a clearer empirical definition of Lund’s blocking effect and to ascertain the extent to which it requires a modification of the generic model. The blocked lists had 50 items arranged into 10 blocks, with each block homogeneous with respect to color. The block lengths were either all a predictable length of 5 items or they varied randomly from 1 to 9 items. The data indicated the following: (1) The blocking effect occurred even when the task required a full identification of each item, and (2) the blocking effect was confined to within-block transitions. Blocking seemed to eliminate the word advantage by allowing the subject to re-use the lexical entry used for the immediately prior item, which is consistent with the generic model.     

An observation of gender-specific teacher behavior in the ESL classroom

For the most part, gender-differentiated teacher behavior in English as a Second Language classrooms in the United States has not been examined. Does the preference for male students demonstrated by both male and female teachers in American classrooms (Sadker et. al., 1992) also occur in ESL classrooms? If so, are ESL teachers aware they show such bias? To find out, the author observed and evaluated, both quantitatively and qualitatively, classroom interactions of four ESL teachers. The teachers, two males and two females, were white, American-born, and had finished graduate studies. All but one of the ESL teachers observed showed remarkable equality in their classroom interactions with the genders. The results are discussed, and future research directions proposed.     

Heterosexual Therapists Leading Lesbian and Gay Therapy Groups: Therapeutic and Political Realities

The authors describe the thought processes, plans, and reflections of two heterosexual therapists who decided to lead gay and lesbian therapy groups in a university counseling center. The debate regarding the viability of the heterosexual counselor and the gay and lesbian client pair is discussed, as are the practical issues informing and maintaining thegroups. Campus political issues regarding the groups and counselor homophobia are explored.     

Object recognition contributions to figure-ground organization: Operations on outlines and subjective contours

In previous research, replicated here, we found that some object recognition processes influence figure-ground organization. We have proposed that these object recognition processes operate on edges (or contours)detected early in visual processing, rather than on regions. Consistent with this proposal, influences from object recognition on figure-ground organization were previously observed in both pictures and stereograms depicting regions of different luminance, but not in randomdot stereograms, where edges arise late in processing (Peterson & Gibson, 1993). In the present experiments, we examined whether or not two other types of contours—outlines and subjective contours—enable object recognition influences on figure-ground organization. For both types of contours we observed a pattern of effects similar to that originally obtained with luminance edges. The results of these experiments are valuable for distinguishing between alternative views of the mechanisms mediating object recognition influences on figure-ground organization. In addition, in both Experiments 1 and 2, fixated regions were seen as figure longer than nonfixated regions, suggesting that fixation location must be included among the variables relevant to figure-ground organization.     

Measuring and predicting the effects of alcohol consumption on contrast sensitivity for stationary and moving gratings

Contrast sensitivity was measured for 12 healthy young males while sober, after ingestion of an alcohol placebo, and after ingestion of alcohol (95% grain alcohol; mean estimated blood alcohol level = .088%). Observations were made for both stationary gratings and gratings that traveled through a circular path and required pursuit eye movements. The significant alcohol-related reduction in contrast sensitivity was 2.6 times greater for moving (.29-log-unit reduction) than for stationary gratings (.11-log-unit reduction). The loss in contrast sensitivity for the moving gratings of high spatial frequency (12 cpd) was particularly severe (.37 log unit). Estimated blood alcohol level was correlated with the loss in contrast sensitivity for moving gratings (r = .61), but not with the loss for stationary gratings. Estimated blood alcohol level was strongly correlated with the difference between the loss in contrast sensitivity to moving and stationary gratings (r = .75). These results are consistent with reports that alcohol consumption degrades the ability to make pursuit eye movements. Subjects’ perceived intoxication level was not a reliable predictor of any index of visual performance.