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It is said that "absence makes the heart grow fonder." But, when and why does an absent event become salient to the heart or to the brain? An absent event may become salient when its nonoccurrence is surprising. Van Hamme and Wasserman (1994) found that a nonpresented but expected stimulus can actually change its associative status-and in the opposite(More)
For many decades, developmental and comparative psychologists have used a variety of string tasks to assess the perceptual and cognitive capabilities of human children of different ages and different species of nonhuman animals. The most important and widely used of these problems are patterned-string tasks, in which the organism is shown two or more(More)
Previous studies showed that the anterior cingulate cortex (ACC) plays a role in selective visual attention. The current study further examined the role of the ACC in attention using a visual cuing task with task-relevant and task-irrelevant stimuli. On every trial, 2 stimuli were presented on the touchscreen; 1 was task-relevant and the other was(More)
Four pigeons discriminated whether a target spot appeared on a colored figural shape or on a differently colored background by first pecking the target and then reporting its location: on the figure or the background. We recorded three dependent variables: target detection time, choice response time, and choice accuracy. The birds were faster to detect the(More)
We explored college students' discrimination of complex visual stimuli that involvedmultiple-item displays. The items in each of the displays could be all the same, all different, or diverse mixtures of some same and some different items. The participants had to learn which of two arbitrary responses was correct for each of the displays without being told(More)
Because of the importance of the sense of sameness for psychological science and because of the tenuous support for this notion in pigeons’ matching-to-sample behavior, we experimentally explored the possibly special status of sameness for pigeons. Using photographs from three different natural categories (dogs, fish, and flowers) in a three-alternative(More)
The impairment in responding to a secondly trained association because of the prior training of another (i.e., proactive interference) is a well-established effect in human and animal research, and it has been demonstrated in many paradigms. However, learning theories have been concerned with proactive interference only when the competing stimuli have been(More)
A critical cue for figure-ground assignment in humans is area: smaller regions are more likely to be perceived as figures than are larger regions. To see if pigeons are similarly sensitive to this cue, we trained birds to report whether a target appeared on a colored figure or on a differently colored background. The initial training figure was either(More)
Recent research has shown that the acquisition of a second cue–outcome association can interfere with responding appropriate to a previously acquired association between another cue and the same outcome, even if the two cues had never received compound training (Matute & Pineño, 1998a). This is similar to other results in the paired-associate literature but(More)