Rotating objects to determine orientation, not identity: evidence from a backward-masking/dual-task procedure

The effects of picture-plane rotations on times taken to name familiar objects (RTs) may reflect a process of mental rotation to stored viewpoint-specific representations: the rotate-to-recognize hypothesis. Alternatively, mental rotation might be used after stored object representations are activated by a misoriented stimulus in order to verify a weak or distorted shape percept: the double-checking hypothesis. We tested these two accounts of rotation effects in object recognition by having subjects verify the orientations (to within 90 degrees) and basic-level names of 14-msec, backward-masked depictions of common objects. The stimulus-mask interval (SOA) varied from 14 to 41 msec, permitting interpolation of the SOA required for 75% accuracy (SOAc). Whereas the SOAc to verify orientation increased with rotation up to 180 degrees, the SOAc to verify identity was briefer and asymptoted at approximately 60 degrees. We therefore reject the rotate-to-recognize hypothesis, which implies that SOAc should increase steadily with rotation in both tasks. Instead, we suggest that upright and near-upright stimuli are matched by a fast direct process and that misoriented stimuli are matched at a featural level by a slightly slower view-independent process. We also suggest that rotation effects on RTs reflect a postrecognition stage of orientation verification: the rotate-to-orient hypothesis, a version of double-checking that also explains the well-known reduction in orientation effects on RTs when naming repeated objects.     

Stress grouping improves performance on an immediate serial list recall task

Five experiments investigated whether perceptual patterning afforded by imposing a recurrent stress pattern on auditorially presented lists has a positive effect on list recall. The experiments also addressed whether the recall advantage reflected the salience that the stress pattern created for certain items or whether the recall advantage arose from the distinct grouping configurations that were produced by the stress pattern. The authors explored these issues by examining immediate serial-recall performance for spoken lists that either did or did not have a stress pattern imposed on them. Lists had an anapest or dactylic stress pattern or were monotone and consisted of two stimulus types, either digit names or common English nouns. Results showed that stress patterns enhanced serial-recall performance and that the recall benefit derived primarily from the perceptual grouping afforded by the stress patterns. Results also showed that the grouping benefit derived from stress patterning generalizes to monotone lists. In contrast, salience effects are attached to the stimulus per se and do not transfer.     

The intervention selection bias: an underrecognized confound in intervention research

Selection bias can be the most important threat to internal validity in intervention research, but is often insufficiently recognized and controlled. The bias is illustrated in research on parental interventions (punishment, homework assistance); medical interventions (hospitalization); and psychological interventions for suicide risk, sex offending, and juvenile delinquency. The intervention selection bias is most adequately controlled in randomized studies or strong quasi-experimental designs, although recent statistical innovations can enhance weaker designs. The most important points are to increase awareness of the intervention selection bias and to systematically evaluate plausible alternative explanations of data before making causal conclusions.     

The role of dopamine in reinforcement: changes in reinforcement sensitivity induced by D1-type, D2-type, and nonselective dopamine receptor agonists

Dose-dependent changes in sensitivity to reinforcement were found when rats were treated with low, moderate, and high doses of the partial dopamine D1-type receptor agonist SKF38393 and with the nonselective dopamine agonist apomorphine, but did not change when rats were treated with similar doses of the selective dopamine D2-type receptor agonist quinpirole. Estimates of bias did not differ significantly across exposure to SKF38393 or quinpirole, but did change significantly at the high dose of apomorphine. Estimates of goodness of fit (r2) did not change significantly during quinpirole exposure. Poor goodness of fit was obtained for the high doses of SKF38393 and apomorphine. Decrements in absolute rates of responding were observed at the high dose of quinpirole and at the moderate and high doses of SKF38393 and apomorphine. Changes in r2 and absolute responding may be due to increases in stereotyped behavior during SKF38393 and apomorphine exposure that, in contrast to quinpirole, were distant from the response lever. The present data provide evidence that sensitivity to reward is affected more strongly by dopamine D1-like receptors rather than D2-like receptors, consistent with evidence from other studies investigating consummatory dopamine behavior and the tonic/phasic dopamine hypothesis.     

Preintervention analysis and improvement of customer greeting in a restaurant

We examined customer greeting by employees at one location of a sandwich restaurant chain. First, a preintervention analysis was conducted to determine the conditions under which greeting a customer within 3 s of his or her entry into the restaurant did and did not occur. Results suggested that an appropriate customer greeting was most likely to occur when a door chime was used to indicate that a customer had entered the store and when the store manager was present behind the service counter. Next, a performance improvement intervention, which consisted of the combination of the use of a door chime and manager presence, was evaluated. Results showed that during baseline, a mean of 6% of customers were greeted; during intervention a mean of 63% of customers were greeted. The addition of manager-delivered verbal and graphic group feedback resulted in 100% of customers being greeted across two consecutive sessions.     

Stimulus-reinforcer and response-reinforcer relations in the control of conditioned appetitive headpoking (“goal tracking”) in rats

Experiment 1 studied the effect of several Pavlovian appetitive conditioning procedures on rats' headpoking into a food tray (goal tracking). The procedures included forward delay conditioning, CS-alone extinction, differential conditioning, and simultaneous compound conditioned inhibition training. In general, the headpoke behaved in all of these treatments much like a Pavlovian CR; however, one could also say that the headpoke behaved like an adventitiously reinforced operant for which the CS was an S^D. Experiment 2, therefore, used the differential-nondifferential technique (E. Gamzu & D. R. Williams, Science, 1971, 171, 923–925), and Experiment 3 used an omission technique (F. D. Sheffield, in W. F. Prokasy, Ed., Classical conditioning, New York: Appleton-Century-Crofts, 1965; D. R. Williams & H. Williams, Journal of the Experimental Analysis of Behavior, 1969, 12, 511–520), to try to separate the role of stimulus-reinforcer and response-reinforcer relations in controlling the headpoke. These techniques proved inadequate. The results of Experiment 2 could be given either operant or Pavlovian interpretations. Those of Experiment 3 showed that headpoking is dominated by response-reinforcer, rather than by stimulus-reinforcer, relations when the two compete but forced no conclusion about which dominates when the two act together as in acquisition. Implications for pigeon autoshaping are discussed.     

Neuropsychological significance of variations in patterns of academic performance: Verbal and visual-spatial abilities

Forty-five 9- to 14-year-old children with learning disabilities whose WISC Full Scale IQs fell within the range of 86–114 were divided into three groups on the basis of their patterns of reading, spelling, and arithmetic achievement. Group 1 was composed of children who were uniformly deficient in reading, spelling, and arithmetic; children in Group 2 were relatively adept at arithmetic as compared to their performance in reading and spelling; Group 3 was composed of children whose reading and spelling performances were average or above, but whose arithmetic performance was relatively deficient. The performances of these children on 16 dependent measures were compared. The performances of Groups 1 and 2 were superior to that of Group 3 on measures of visual-perceptual and visual-spatial abilities; Group 3 performed at a superior level to that of Groups 1 and 2 on measures of verbal and auditory-perceptual abilities. The results are discussed in terms of the relationships between varying patterns of academic abilities and patterns of brain-related behaviors, and the nature of the neuropsychological abilities that may limit performance on arithmetic calculation tasks.The research reported herein was supported, in part, under Grant #195 of the Ontario Mental Health Foundation. Funds were also supplied by Windsor Western Hospital Centre.