Covert visual orienting across the lifespan.

Three groups of 20 K–5th graders, 20 college students, and 20 older adults (mean age 72.8 yrs) were tested. The S's task was the speeded discrimination of "X" from "O", but of primary interest was the effect of a location cue that appeared prior to the target. Both an abrupt stimulus cue and a voluntary information cue were studied using response time measures. Eye movements were monitored to control for differences in the ability to maintain fixation. Exp 1 showed that in comparison with young adults, children were less able to sustain orienting over time, and senior adults required more time to use the cue. Exp 2 (using K–1st graders, 4th–5th graders, 20 college students, and 20 older adults) tested the relation between stimulus and information cues when they both occurred prior to a given target. All age groups were able to use information cues in the presence of conflicting stimulus cues, but young adults were better able to do so than either children or senior adults. Results are interpreted as support for the view that separate mechanisms underlie stimulus-based versus information-based spatial orienting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Marking effects in Pavlovian trace conditioning.

[Correction Notice: An erratum for this article was reported in Vol 13(3) of Journal of Experimental Psychology: Animal Behavior Processes (see record 2008-10750-001). The last sentence in the second paragraph of the Discussion on page 128 should read as follows: "A second possibility is that in the marked ITI group, the marking of irrelevant events in the middle of the intertrial interval promoted associations between those events and food, which then interfered with the learning of an association between SI and food."] In four experiments we investigated pigeons' acquisition of a successive discrimination with a trace autoshaping procedure. The conditioned stimuli were 5-s presentations of colored key lights, one of which was followed by food after a 5-s delay. In Experiment 1, which used spatially defined cues, we found that acquisition of differential responding to the reinforced cue was facilitated when a brief flash of light immediately followed both reinforced and nonreinforced cues. Experiment 2 found a similar enhancement by the added light flash in a purely visual discrimination. Experiment 3 found that the flash facilitated learning only when presented immediately after the discriminative cues, and not when it occurred immediately before the cues or at the time of reinforcement. A fourth experiment found this facilitation effect only when the flash and reinforcement occurred on the same trial. These results are interpreted in terms of marking: The flash enhanced learning because it triggered a backward scan through recent memory to search for possible predictors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus control in instrumental discrimination learning and reinforcement schedule situations.

Investigated ways in which control is exercised over responding by cues associated with reinforcement (RC) as well as nonreinforcement (NC) in discrimination tasks. In Phase 1 of Exp I, with 20 male albino Holtzman rats, either RC or NC was reinforced. In Phase 2, RC and RN were employed as the brighter stimulus (S+) and the less bright stimulus (S–) cues. Results show that differential responding developed less rapidly when the cue reinforced in Phase 1 was the S– rather than the S+ cue in Phase 2, regardless of whether that cue was RC or NC. In Exp II, using 16 male albino Holtzman rats, the S+ cue was a compound of a hedonic cue and a brightness cue, as was the S– cue. Differential responding developed less rapidly when the hedonic cue reinforced in S– was the same as that reinforced in S+, again regardless of whether the cue was RC or NC. Results show that both cues regulated responding and that neither was frustrating to Ss. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Marking effects in Pavlovian trace conditioning": Correction to Thomas, Robertson, and Lieberman.

Reports an error in "Marking effects in Pavlovian trace conditioning" by Glyn V. Thomas, Derek Robertson and David A. Lieberman (Journal of Experimental Psychology: Animal Behavior Processes, 1987[Apr], Vol 13[2], 126-135). The last sentence in the second paragraph of the Discussion on page 128 should read as follows: "A second possibility is that in the marked ITI group, the marking of irrelevant events in the middle of the intertrial interval promoted associations between those events and food, which then interfered with the learning of an association between SI and food." (The following abstract of the original article appeared in record 1987-24113-001.) In four experiments we investigated pigeons' acquisition of a successive discrimination with a trace autoshaping procedure. The conditioned stimuli were 5-s presentations of colored key lights, one of which was followed by food after a 5-s delay. In Experiment 1, which used spatially defined cues, we found that acquisition of differential responding to the reinforced cue was facilitated when a brief flash of light immediately followed both reinforced and nonreinforced cues. Experiment 2 found a similar enhancement by the added light flash in a purely visual discrimination. Experiment 3 found that the flash facilitated learning only when presented immediately after the discriminative cues, and not when it occurred immediately before the cues or at the time of reinforcement. A fourth experiment found this facilitation effect only when the flash and reinforcement occurred on the same trial. These results are interpreted in terms of marking: The flash enhanced learning because it triggered a backward scan through recent memory to search for possible predictors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inescapable shock and attention to internal versus external cues in a water discrimination escape task.

In these experiments we examined discrimination learning in a water escape task following exposure to escapable, yoked inescapable, or no electric shock. Inescapable shock did not have an effect on swim speeds in any of the experiments. Inescapable shock interfered with the acquisition of a position (left–right) discrimination when an irrelevant brightness cue (black and white stimuli) was present. However, inescapable shock did not affect the acquisition of the position discrimination when the irrelevant brightness cue was removed. Inescapably shocked Subjects showed facilitated learning relative to escapably shocked and nonshocked subjects when the brightness cue was included as a relevant cue. These data may resolve discrepancies between studies that did, and did not, find inescapable shock to interfere with the acquisition of discriminations. Moreover, they point to attentional processes as one locus of the cognitive changes produced by inescapable shock and suggest the exposure to inescapable shock biases attention away from "internal" response-related cues toward "external" cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of visual and body movement information in infant search.

Three experiments investigated the use of visual input and body movement input arising from movement through the world on spatial orientation. Infants between 9.5 and 18 months participated in a search task in which they searched for a toy hidden in 1 of 2 containers. Prior to beginning search, either the infants or the containers were rotated 180*; these rotations occurred in a lit or dark environment. These experiments were distinguished by the environmental cues for object location; Experiment 1 used a position cue, Experiment 2 a color cue, and Experiment 3 both position and color cues. Accuracy was better in Experiments 2 and 3 than in Experiment 1. All studies found that search was best after infant movement in the light; all other conditions led to equivalently worse performance. These results are discussed relative to a theoretical characterization of spatial coding focusing on the uses of spatial information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Simon effect occurs relative to the direction of an attention shift.

We investigated whether the Simon effect depends on the orienting of attention. In Experiment 1, participants were required to execute left-right discriminative responses to 2 patterns that were presented to the left or right of fixation. The 2 patterns were similar, and the discrimination was difficult. A letter at fixation signaled whether the current trial was a catch trial. The results showed a reversal of the Simon effect. That is, spatially noncorresponding responses were faster than spatially corresponding responses. In Experiment 2, the discrimination of the relevant stimulus attribute was easy. In Experiment 3, the discrimination of the relevant stimulus attribute was difficult, but the stimulus exposure time was long. In either experiment, the regular Simon effect was reinstated. In Experiment 4, the letter that signaled a catch trial appeared to the left or right of the imperative stimulus. The Simon effect occurred relative to the position of the letter. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contrasting predictions of extended comparator hypothesis and acquisition-focused models of learning concerning retrospective revaluation.

Three conditioned suppression experiments with rats investigated contrasting predictions made by the extended comparator hypothesis and acquisition-focused models of learning, specifically, modified SOP and the revised Rescorla–Wagner model, concerning retrospective revaluation. Two target cues (X and Y) were partially reinforced using a stimulus relative validity design (i.e., AX–Outcome; BX–No outcome; CY–Outcome; DY–No outcome), and subsequently one of the companion cues for each target was extinguished in compound (BC–No outcome). In Experiment 1, which used spaced trials for relative validity training, greater suppression was observed to target cue Y for which the excitatory companion cue had been extinguished in relation to target cue X for which the nonexcitatory companion cue had been extinguished. Experiment 2 replicated these results in a sensory preconditioning preparation. Experiment 3 massed the trials during relative validity training, and the opposite pattern of data was observed. The results are consistent with the predictions of the extended comparator hypothesis. Furthermore, this set of experiments is unique in being able to differentiate between these models without invoking higher-order comparator processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in cue perception in a visual scene: Investigation of cue type.

Sex differences in spatial navigation indicate that women may focus on positional, landmark cues whereas men favor Euclidean, directional cues. Some studies have investigated sex differences in proximal and distal cue use; however, sex differences in gradient (i.e., graded features) and pinpoint (i.e., single, defined) cue perception remain unexamined. In the current experiments, paired photographs were presented in which the 2nd photograph showed the same scene with cues removed (Experiment 1) or isolated (Experiment 2) from the 1st photograph. In Experiment 1, women showed less disruption of task performance than men showed following cue removal but were slowest after proximal pinpoint cue removal. Male performance was slowed by distal gradient and proximal pinpoint cue removal. In Experiment 2, women were faster than men at identifying isolated proximal and distal pinpoint cues and were more accurate at identifying isolated distal gradient and distal pinpoint cues. Better pinpoint cue perception and memory in women indicates one possible mechanism underlying female preference for landmark-based navigation strategies. Findings also show that whereas men may preferentially rely on distal gradient cues they are not better at perceiving those cues than are women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A developmental study of hypothesis testing and cue selection strategies.

Previous investigators who have evaluated M. Levine's hypothesis testing model of learning have employed blank-trial probes in order to determine which hypothesis was sampled on specific trials. A method of determining which hypothesis was sampled that did not require blank trials was administered to children in Grades 1, 3, and 5, undergraduates, and old adults (mean age = 75 years). A 2-choice, multidimensional discrimination task was presented in which the Ss first chose the stimulus thought to be correct and then pointed to a single cue in a complete set of decomposed cues from the learning task. Results are in accord with other studies of hypothesis testing in that developmental differences were observed. Younger and older children differed in the cue selection strategies used during learning. Undergraduates used very efficient strategies that often led to learning, while the old adults were quite inconsistent and often failed to recognize when they had selected the correct reinforced cue. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rhesus monkeys (Macaca mulatta) rapidly learn to select dominant individuals in videos of artificial social interactions between unfamiliar conspecifics.

Social animals, such as primates, must behave appropriately in complex social situations such as dominance interactions. Learning dominance information through trial and error would be dangerous; therefore, cognitive mechanisms for rapid learning of dominance information by observation would be adaptive. We used a set of digitally edited artificial social interactions to examine whether rhesus monkeys (Macaca mulatta) can learn dominance relationships between unfamiliar conspecifics through observation. Our method allowed random assignment of stimulus monkeys to ranks in an artificial hierarchy, controlling for nonbehavioral cues that could indicate dominance. Subject monkeys watched videos depicting 1 stimulus monkey behaving dominantly toward another and were rewarded for selecting the dominant individual. Monkeys rapidly learned this discrimination across 5 behavior types in Experiment 1 and transferred performance to novel videos of new individuals in Experiment 2. In addition, subjects selected the dominant individual more often than expected by chance in probe videos containing no behavioral dominance information, indicating some retention of the relative dominance status of stimulus monkeys from training. Together, our results suggest that monkeys can learn dominance hierarchies through observation of third-party social interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of the dorsomedial striatum in behavioral flexibility for response and visual cue discrimination learning.

These experiments examined the effects of dorsomedial striatal inactivation on the acquisition of a response and visual cue discrimination task, as well as a shift from a response to a visual cue discrimination, and vice versa. In Experiment 1, rats were tested on the response discrimination task followed by the visual cue discrimination task. In Experiment 2, the testing order was reversed. Infusions of 2% tetracaine did not impair acquisition of the response or visual cue discrimination but impaired performance when shifting from a response to a visual cue discrimination, and vice versa. Analysis of the errors revealed that the deficit was not due to perseveration of the previously learned strategy, but to an inability to maintain the new strategy. These results contrast with findings indicating that prelimbic inactivation impairs behavioral flexibility due to perseveration of a previously learned strategy. Thus, specific circuits in the prefrontal cortex and striatum may interact to enable behavioral flexibility, but each region may contribute to distinct processes that facilitate strategy switching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When cues collide: Use of stress and statistical cues to word boundaries by 7- to 9-month-old infants.

Prior research suggests that stress cues are particularly important for English-hearing infants' detection of word boundaries. It is unclear, though, how infants learn to attend to stress as a cue to word segmentation. This series of experiments was designed to explore infants' attention to conflicting cues at different ages. Experiment 1 replicated previous findings: When stress and statistical cues indicated different word boundaries, 9-month-old infants used syllable stress as a cue to segmentation while ignoring statistical cues. However, in Experiment 2, 7-month-old infants attended more to statistical cues than to stress cues. These results raise the possibility that infants use their statistical learning abilities to locate words in speech and use those words to discover the regular pattern of stress cues in English. Infants at different ages may deploy different segmentation strategies as a function of their current linguistic experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of return and visuospatial attention in healthy older adults and individuals with dementia of the Alzheimer type.

Covert orienting of visuospatial attention in response to peripherally presented cues was assessed in healthy younger and older adults and those with dementia of the Alzheimer type (DAT) during a simple detection task. The results yield both an age-related increase (Experiments 1 and 2) and a DAT-related increase (Experiment 2) in the facilitatory effect of a single peripheral cue on detection. By contrast, equivalent inhibition of return (i.e., a slowing of target detection at previously cued locations) was observed for all 3 groups when a 2nd cue was presented at central fixation. Results suggest that both healthy older adults and individuals with DAT experience changes in the posterior attention system thought to subserve visuospatial attention. Results also suggest limitations on the generality of inhibitory deficits in healthy aging and DAT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cue and response-choice acquisition and reversal after exposure to uncontrollable shock: Induction of response perseveration.

Evaluated the effects of inescapable shock in shock-motivated cue, response-choice (RC), and RC/positional Y-maze discrimination tasks. Ss were 253 male CD-1 mice. In the RC paradigm, Ss were required to turn in a predetermined direction to escape, whereas in the RC/positional task, Ss were required to enter the arm to the right of the start arm on any given trial. Although inescapable shock retarded escape performance, this was dependent on task difficulty and on the compatibility between response tendencies and the response requirement of the task. Irrespective of the task, exposure to inescapable shock did not influence accuracy of discrimination responding (acquisition or performance of a previously established discrimination). Likewise, discrimination reversal performance was unaffected by inescapable shock in either the cue or the RC paradigm. In contrast, acquisition of the RC/positional reversal was retarded by inescapable but not escapable shock. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The temporal dynamics of a visual discrimination: The role of stimulus comparison and opponent processes.

The influence of trial spacing on simple conditioning is well established: When successive reinforced conditioned stimulus, CS+, trials are separated by a short interval (massed training), conditioned responding emerges less rapidly than when such trials are separated by longer intervals (spaced training). This study examined the influence of trial spacing on the acquisition of an appetitive visual discrimination in rats. Experiments 1 and 2 established that massed training facilitates the acquisition of such discriminations. The results of subsequent experiments demonstrated that this trial-spacing effect reflects the proximity of nonreinforced, CS-, trials to preceding (Experiment 3) and signaled (Experiment 4) presentations of the reinforcer. Experiment 5 showed that the facilitation of discrimination learning with massed training reflected an effect on learning rather than performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recovery from blocking between outcomes.

Contemporary associative learning research largely focuses on cue competition phenomena that occur when 2 cues are paired with a common outcome. Little research has been conducted to investigate similar phenomena occurring when a single cue is trained with 2 outcomes. Three conditioned lick suppression experiments with rats assessed whether treatments known to alleviate blocking between cues would also attenuate blocking between outcomes. In Experiment 1, conditioned responding recovered from blocking between outcomes when a long retention interval was interposed between training and testing. Experiment 2 obtained recovery from blocking between outcomes when the blocking outcome was extinguished after the blocking treatment. In Experiment 3, a recovery from blocking between outcomes occurred when a reminder stimulus was presented in a novel context prior to testing. Collectively, these studies demonstrate that blocking of outcomes, like blocking of cues, appears to be caused by a deficit in the expression of an acquired association. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An inhibitory within-compound association attenuates overshadowing.

According to the comparator hypothesis (Miller & Matzel, 1988), cue competition depends on the association between a target stimulus (X) and a competing cue (e.g., an overshadowing cue [A]). Thus, it was expected that overshadowing would be reduced by establishing an inhibitory-like relationship between X and A before compound conditioning. In three lever press suppression experiments with rats, this expectation was supported. Experiment 1 showed that establishing an inhibitory X-A relationship reduced overshadowing. In Experiment 2, degrading the inhibitory-like relationship before conditioning allowed reinforced AX compound trials to result in overshadowing. Experiment 3 replicated the results of Experiment 2 when the inhibitory relationship was degraded after compound conditioning. The results support the view that within-compound associations are necessary not only for retrospective revaluation, but also for conventional cue competition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intertrial interval as a contextual stimulus: Further analysis of a novel asymmetry in temporal discrimination learning.

Four experiments investigated discrimination learning when the duration of the intertrial interval (ITI) signaled whether or not the next conditional stimulus (CS) would be paired with food pellets. Rats received presentations of a 10-s CS separated half the time by long ITIs and half the time by short ITIs. When the long ITI signaled that the CS would be reinforced and the short interval signaled that it would not be (Long+/Short?), rats learned the discrimination readily. However, when the short ITI signaled that the CS would be reinforced and the long interval signaled that it would not (Short+/Long?), discrimination learning was much slower. Experiment 1 compared Long+/Short? and Short+/Long? discrimination learning with 16-min/4-min or 4-min/1-min ITI combinations. Experiment 2 found no evidence that Short+/Long? learning is inferior because the temporal cue corresponding to the short interval is ambiguous. Experiment 3 found no evidence that Short+/Long? learning is poor because the end of a long ITI signals a substantial reduction in delay to the next reinforcer. Long+/Short? learning may be faster than Short+/Long?because elapsing time involves exposure to a sequence of hypothetical stimulus elements (e.g., A then B), and feature-positive discriminations (AB+/A?) are learned quicker than feature-negative discriminations (A+/AB?). Consistent with this view, Experiment 4 found a robust feature-positive effect when sequentially presented CSs played the role of elements A and B. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of Position and Feature Cues in Discrimination Learning by the Whiptail Lizard (Cnemidophorus inornatus).

Animals use a variety of cue types to locate and discriminate objects. The ease with which particular cue types are learned varies across species and context. An enormous literature contains comparisons of spatial cue use to use of other cue types, but few experiments examine the ease with which various nonspatial cues are learned. In addition, few studies have examined cue use in reptiles. Thus, the authors compared whiptail lizards' (Cnemidophorus inornatus) ability to learn and reverse a discrimination using either position (left or right) or visual feature cues. Lizards learned and reversed the task using position cues faster and with greater accuracy than using feature cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)