Age-related changes in attentional tracking of multiple moving objects

In a multiple-object tracking (MOT) task, young and older adults attentively tracked a subset of 10 identical, randomly moving disks for several seconds, and then tried to identify those disks that had comprised the subset. Young adults who habitually played video games performed significantly better than those who did not. Compared to young subjects (mean age = 20.6 years) with whom they were matched for video game experience, older subjects (mean age = 75.3 years) showed much reduced ability to track multiple moving objects, particularly with faster movement or longer tracking times. Control measurements with stationary disks show that the age-related decline in MOT was not caused by a general change in memory per se. To generate an item-wise performance measure, we examined older subjects' proportion correct according to the serial order in which individual disks were identified. Correct identification of target disks declined with the order in which targets were reported, suggesting that attentional tracking produced graded, rather than all-or-none, outcomes.     

Effects of prenatal X-irradiation on open-field behavior in rats: application of randomized fostering technique and mapping results

Sprague-Dawley (SD) rats were given X-irradiation (150 R) on Day 17 of gestation. After birth, all male pups were pooled once and then assigned randomly to irradiated mothers and control mothers. Offspring were administered an open-field test at about 7 weeks of age. The analysis was performed on the basis of two approaches: In the per subject approach, individual subject data (aggregation across Day 2 through Day 4) were treated as the basic unit of statistical analysis. In the per litter approach, double aggregation (aggregation across Day 2 through Day 4 for each subject and aggregation across subjects within each litter) was used. The per subject approach was slightly more sensitive as to the treatment effect, but it induced a reduction in the magnitude of eta squared. A principal component analysis was performed using eta squared together with those of several reference groups. Results were plotted on a map constructed from component scores. The characteristics of behavior in X-irradiated rats were very similar to those of the earlier stage of trials in terms of the location on the map. The postnatal maternal effect on open-field behavior was not serious and was adequately negligible in practice. A new fostering procedure was proposed and its advantages discussed.     

Japanese normative set of 359 pictures

This study provides Japanese normative measures for 359 line drawings, including 260 pictures (44 redrawn) taken from Snodgrass and Vanderwart (1980). The pictures have been standardized on voice key naming times, name agreement, age of acquisition, and familiarity. The data were compared with American, Spanish, French, and Icelandic samples reported in previous studies. In general, the correlations between variables in the present study and those in the other studies were relatively high, except for name agreement. Naming times were predicted in multiple regression analyses by name agreement. The full set of the norms and the new pictures may be downloaded from www.psychonomic.org/archive/.     

Reduction of the flash-lag effect in terms of active observation

In the present study, we investigated how observers’ control of stimulus change affects temporal and spatial aspects of visual perception. We compared the illusory flash-lag effects for automatic movement of the stimulus with stimulus movement that was controlled by the observers’ active manipulation of a computer mouse (Experiments 1, 2, and 5), a keyboard (Experiment 3), or a trackball (Experiment 4). We found that the flash-lag effect was significantly reduced when the observer was familiar with the directional relationship between the mouse movement and stimulus movement on a front parallel display (Experiments 1 and 2) and that, although the unfamiliar directional relationship between the mouse movement and stimulus movement increased the flash-lag effect at the beginning of the experimental session, the repetitive observation with the same unfamiliar directional relationship reduced the flash-lag effect (Experiment 5). We found no consistent reduction of the flash-lag effect with the use of a keyboard or a trackball (Experiments 3 and 4). These results suggest that the learning of a specific directional relationship between a proprioceptive signal of hand movements and a visual signal of stimulus movements is necessary for the reduction of the flash-lag effect.     

On the relation between object and action: Response consistency and stimulus–response compatibility

A series of four experiments investigated factors influencing the selection of objects and responses associated with the objects. The experiments focused on the interaction between response consistency and the spatial compatibility of the response (involving inhibition of an irrelevant distractor) in conditions of task switching. To test for the response consistency effect, a cue indicated the dimension of the display to be selected for the participant's response. The stimulus displays were either consistent, neutral, or inconsistent (including a distractor stimulus) with the response to the stimulus. The responses were either compatible or incompatible with the location of the stimulus. Intertrial dependences were examined by switching or repeating the tasks across trials. The results suggest that links between objects and actions set up by targets can be replaced by links between a distractor and a response under certain conditions. The implications for stimulus and response selection are discussed.     

Mapping Open-Field Behavior in Rats: Applicability Across Sexes

Open-field behavior of female and male Sprague-Dawley rats was plotted on a map using scores derived from a principal-component analysis. As reference points on the map, three treatment conditions were used: electric shock, extensive stroking, and additional trials after habituation to the field. Five measures were used: ambulation, penetration into the inner square, rearing, defecation, and urination. The behaviors in each treatment condition clearly cohered with each other on the map, regardless of sex difference in raw scores. This coherence shows that the nature of the emotional behavior caused by the present treatments is similar across sexes, indicating, to some degree, the applicability of the map across the sexes. The additional experiment (concerning the estrus effect on the open-field behavior) suggests that the estrus effect is not large enough to compromise the validity of the map, which was constructed on the basis of the data without control of the estrus effect.