Waiting in pigeons: the effects of daily intercalation on temporal discrimination.

Pigeons trained on cyclic-interval schedules adjust their postfood pause from interval to interval within each experimental session. But on regular fixed-interval schedules, many sessions at a given parameter value are usually necessary before the typical fixed-interval "scallop" appears. In the first case, temporal control appears to act from one interfood interval to the next; in the second, it appears to act over hundreds of interfood intervals. The present experiments look at the intermediate case: daily variation in schedule parameters. In Experiments 1 and 2 we show that pauses proportional to interfood interval develop on short-valued response-initiated-delay schedules when parameters are changed daily, that additional experience under this regimen leads to little further improvement, and that pauses usually change as soon as the schedule parameter is changed. Experiment 3 demonstrates identical waiting behavior on fixed-interval and response-initiated-delay schedules when the food delays are short (less than 20 s) and conditions are changed daily. In Experiment 4 we show that daily intercalation prevents temporal control when interfood intervals are longer (25 to 60 s). The results of Experiment 5 suggest that downshifts in interfood interval produce more rapid waiting-time adjustments than upshifts. These and other results suggest that the effects of short interfood intervals seem to be more persistent than those of long intervals.     

THE EFFECT OF MEANING FREQUENCY ON PROCESSING LEXICALLY AMBIGUOUS WORDS: Evidence From Eye Fixations

Abstract —Subjects read sentences containing lexically ambiguous words while their eye movements were monitored Biased ambiguous words (those that have one highly dominant sense) were used m sentences containing a prior context that instantiated their subordinate sense Control words were matched m frequency both to the dominant and to the subordinate meaning of the ambiguous word (high- and low-frequency controls) Subjects fixated longer on both the ambiguous word and the low-frequence control than on the high-frequency control When the target was ambiguous, however, the duration of posttarget fixations was longer and the likelihood of making a regression to the target was greater than when the target was an unambiguous control The results are discussed m relation to current models of lexical ambiguity resolution     

Part—whole information is useful in visual search for size × size but not orientation × orientation conjunctions

In visual search tasks, subjects look for a target among a variable number of distractor items. If the target is defined by a conjunction of two different features (e.g., color × orientation), efficient search is possible when parallel processing of information about color and about orientation is used to “guid” the deployment of attention to the target. Another type of conjunction search has targets defined by two instances of one type of feature (e.g., a conjunction of two colors). In this case, search is inefficient when the target is an item defined by parts of two different colors but much more efficient if the target can be described as a whole item of one color with a part of another color (Wolfe, Friedman-Hill, & Bilsky, 1994). In this paper, we show that the same distinction holds for size. “Part— whole” size × size conjunction searches are efficient; “part-part” searches are not (Experiments 1–3). In contrast, all orientation × orientation searches are inefficient (Experiments 4–6). This difference between preattentive processing of color and size, on the one hand, and orientation, on the other, may reflect structural relationships between features in real-world objects.     

On the brightness of short and long flashes

The equation proposed by S. S. Stevens to describe the relations among brightness, intensity, and duration involves assumptions that are here made explicit. The equation is shown to apply to earlier studies designed to measure critical duration.     

Methylphenidate and cognitive therapy: A comparison of treatment approaches with hyperactive boys

This study of hyperactive boys evaluated the effects of three modes of treatment in relation to an untreated group. The treatments were administered over a 3-month period and included cognitive training, stimulant drug therapy (methylphenidate), and the two treatments combined. A follow-up assessment was conducted approximately 3 months after contact between the training staff and the child had ceased. Analyses of attentional deployment and cognitive style measures, tests of academic achievement, and behavioral ratings showed that only those children in the two medication treatment conditions demonstrated improvement in attentional deployment and behavioral ratings. In the cognitive therapy condition, there were changes only on measures of attentional deployment. The data did not provide evidence indicating that the combined medication and cognitive therapy condition was any more effective than that condition involving medication alone. Discussion provides future guidelines for evaluation of the relative effectiveness of stimulant drug therapy and other psychological treatment modalities.     

SENSATIONS, SWATCHES, AND SPECKLED HENS

Abstract: We argue that there is a interesting connection between the old problem of the Speckled Hen and an argument that can be traced from Russell to Armstrong to Putnam that we call the “gradation argument.” Both arguments have been used to show that there is no “Highest Common Factor” between appearances we judge the same – no such thing as “real” sensations. But, we argue, both only impugn the assumption of epistemic certainty regarding introspective reports.