Age-of-acquisition effects in delayed picture-naming tasks

We report two experiments that explored the linguistic locus of age-of-acquisition effects in picture naming by using a delayed naming task that involved only a low proportion of trials (25 %) while, for the large majority of the trials (75 %), participants performed another task—that is, the prevalent task. The prevalent tasks were semantic categorization in Experiment 1a and grammatical-gender decision in Experiments 1b and 2. In Experiment 1a, in which participants were biased to retrieve semantic information in order to perform the semantic categorization task, delayed naming times were affected by age of acquisition, reflecting a postsemantic locus of the effect. In Experiments 1b and 2, in which participants were biased to retrieve lexical information in order to perform the grammatical gender decision task, there was also an age-of-acquisition effect. These results suggest that part of the age-of-acquisition effect in picture naming occurs at the level at which the phonological properties of words are retrieved.     

Dissociations between vision for perception and vision for action depend on the relative availability of egocentric and allocentric information

In three experiments, we scrutinized the dissociation between perception and action, as reflected by the contributions of egocentric and allocentric information. In Experiment 1, participants stood at the base of a large-scale one-tailed version of a Müller-Lyer illusion (with a hoop) and either threw a beanbag to the endpoint of the shaft or verbally estimated the egocentric distance to that location. The results confirmed an effect of the illusion on verbal estimates, but not on throwing, providing evidence for a dissociation between perception and action. In Experiment 2, participants observed a two-tailed version of the Müller-Lyer illusion from a distance of 1.5 m and performed the same tasks as in Experiment 1, yet neither the typical illusion effects nor a dissociation became apparent. Experiment 3 was a replication of Experiment 1, with the difference that participants stood at a distance of 1.5 m from the base of the one-tailed illusion. The results indicated an illusion effect on both the verbal estimate task and the throwing task; hence, there was no dissociation between perception and action. The presence (Exp. 1) and absence (Exp. 3) of a dissociation between perception and action may indicate that dissociations are a function of the relative availability of egocentric and allocentric information. When distance estimates are purely egocentric, dissociations between perception and action occur. However, when egocentric distance estimates have a (complementary) exocentric component, the use of allocentric information is promoted, and dissociations between perception and action are reduced or absent.     

Prospective memory: Effects of divided attention on spontaneous retrieval

We examined the effects of divided attention on the spontaneous retrieval of a prospective memory intention. Participants performed an ongoing lexical decision task with an embedded prospective memory demand, and also performed a divided-attention task during some segments of lexical decision trials. In all experiments, monitoring was highly discouraged, and we observed no evidence that participants engaged monitoring processes. In Experiment 1, performing a moderately demanding divided-attention task (a digit detection task) did not affect prospective memory performance. In Experiment 2, performing a more challenging divided-attention task (random number generation) impaired prospective memory. Experiment 3 showed that this impairment was eliminated when the prospective memory cue was perceptually salient. Taken together, the results indicate that spontaneous retrieval is not automatic and that challenging divided-attention tasks interfere with spontaneous retrieval and not with the execution of a retrieved intention.     

Top-down constraint on recognition memory

Can recognition memory be constrained “at the front end,” such that people are more likely to retrieve information about studying a recognition-test probe from a specified target source than they are to retrieve such information about a probe from a nontarget source? We adapted a procedure developed by Jacoby, Shimizu, Daniels, and Rhodes (Psychonomic Bulletin & Review 12:852–857, 2005) to address this question. Experiment 1 yielded evidence of source-constrained retrieval, but that pattern was not significant in Experiments 2, 3, and 4 (nor in several unpublished pilot experiments). In Experiment 5, in which items from the two studied sources were perceptibly different, a pattern consistent with front-end constraint of recognition emerged, but this constraint was likely exercised via visual attention rather than memory. Experiment 6 replicated both the absence of a significant constrained-retrieval pattern when the sources did not differ perceptibly (as in Exps. 2, 3 and 4) and the presence of that pattern when they did differ perceptibly (as in Exp. 5). Our results suggest that people can easily constrain recognition when items from the to-be-recognized source differ perceptibly from items from other sources (presumably via visual attention), but that it is difficult to constrain retrieval solely on the basis of source memory.     

Escaping the recent past: Which stimulus dimensions influence proactive interference?

Proactive interference occurs when information from the past disrupts current processing and is a major source of confusion and errors in short-term memory (STM; Wickens, Born, & Allen, Journal of Verbal Learning and Verbal Behavior, 2:440–445, 1963). The present investigation examines potential boundary conditions for interference, testing the hypothesis that potential competitors must be similar along task-relevant dimensions to influence proactive interference effects. We manipulated both the type of task being completed (Experiments 1, 2, and 3) and dimensions of similarity irrelevant to the current task (Experiments 4 and 5) to determine how the recent presentation of a probe item would affect the speed with which participants could reject that item. Experiments 1, 2, and 3 contrasted STM judgments, which require temporal information, with semantic and perceptual judgments, for which temporal information is irrelevant. In Experiments 4 and 5, task-irrelevant information (perceptual similarity) was manipulated within the recent probes task. We found that interference from past items affected STM task performance but did not affect performance in semantic or perceptual judgment tasks. Conversely, similarity along a nominally irrelevant perceptual dimension did not affect the magnitude of interference in STM tasks. Results are consistent with the view that items in STM are represented by noisy codes consisting of multiple dimensions and that interference occurs when items are similar to each other and, thus, compete along the dimensions relevant to target selection.     

Investigating the speed–accuracy trade-off: Better use deadlines or response signals?

Deadlines (DLs) and response signals (RSs) are two well-established techniques for investigating speed–accuracy trade-offs (SATs). Methodological differences imply, however, that corresponding data do not necessarily reflect equivalent processes. Specifically, the DL procedure grants knowledge about trial-specific time demands and requires responses before a prespecified period has elapsed. In contrast, RS intervals often vary unpredictably between trials, and responses must be given after an explicit signal. Here, we investigated the effects of these differences in a flanker task. While all conditions yielded robust SAT functions, a right-shift of the curves pointed to reduced performance in RS conditions (Experiment 1, blocked; Experiments 2 and 3, randomized), as compared with DL conditions (Experiments 1–3, blocked), indicating that the detection of the RS imposes additional task demands. Moreover, the flanker effect vanished at long intervals in RS settings, suggesting that stimulus-related effects are absorbed in a slack when decisions are completed prior to the signal. In turn, effects of a flat (Experiment 2) versus a performance-contingent payment (Experiment 3) indicated that susceptibility to response strategies is higher in the DL than in the RS method. Finally, the RS procedure led to a broad range of slow responses and high accuracies, whereas DL conditions resulted in smaller variations in the upper data range (Experiments 1 and 2); with performance-contingent payment (Experiment 3), though, data ranges became similar. Together, the results uncover characteristic procedure-related effects and should help in selection of the appropriate technique.     

Coarse guidance by numerosity in visual search

In five experiments, we examined whether the number of items can guide visual focal attention. Observers searched for the target area with the largest (or smallest) number of dots (squares in Experiment 4 and “checkerboards” in Experiment 5) among distractor areas with a smaller (or larger) number of dots. Results of Experiments 1 and 2 show that search efficiency is determined by target to distractor dot ratios. In searches where target items contained more dots than did distractor items, ratios over 1.5:1 yielded efficient search. Searches for targets where target items contained fewer dots than distractor items were harder. Here, ratios needed to be lower than 1:2 to yield efficient search. When the areas of the dots and of the squares containing them were fixed, as they were in Experiments 1 and 2, dot density and total dot area increased as dot number increased. Experiment 3 removed the density and area cues by allowing dot size and total dot area to vary. This produced a marked decline in search performance. Efficient search now required ratios of above 3:1 or below 1:3. By using more realistic and isoluminant stimuli, Experiments 4 and 5 show that guidance by numerosity is fragile. As is found with other features that guide focal attention (e.g., color, orientation, size), the numerosity differences that are able to guide attention by bottom-up signals are much coarser than the differences that can be detected in attended stimuli.     

Are forward and backward recall the same? A dual-task study of digit recall

There is some debate surrounding the cognitive resources underlying backward digit recall. Some researchers consider it to differ from forward digit recall due to the involvement of executive control, while others suggest that backward recall involves visuospatial resources. Five experiments therefore investigated the role of executive-attentional and visuospatial resources in both forward and backward digit recall. In the first, participants completed visuospatial 0-back and 2-back tasks during the encoding of information to be remembered. The concurrent tasks did not differentially disrupt performance on backward digit recall, relative to forward digit recall. Experiment 2 shifted concurrent load to the recall phase instead and, in this case, revealed a larger effect of both tasks on backward recall, relative to forwards recall, suggesting that backward recall may draw on additional resources during the recall phase and that these resources are visuospatial in nature. Experiments 3 and 4 then further investigated the role of visual processes in forward and backward recall using dynamic visual noise (DVN). In Experiment 3, DVN was presented during encoding of information to be remembered and had no effect upon performance. However, in Experiment 4, it was presented during the recall phase, and the results provided evidence of a role for visual imagery in backward digit recall. These results were replicated in Experiment 5, in which the same list length was used for forward and backward recall tasks. The findings are discussed in terms of both theoretical and practical implications.     

Exploiting illusory effects to disclose similarities in numerical and luminance processing

Recent studies have suggested that numerical and physical magnitudes are similarly processed by a generalized magnitude system. The present study investigates the number?Cluminance interaction, taking advantage of illusory effects in a cued line bisection task with numerical or nonnumerical flankers and varying levels of luminance. The results showed that both dimensions influenced bisection performance. Whereas numbers (Experiment 1) induced a systematic shift of the subjective midpoint toward the larger digit, luminance (Experiment 2) modulated the bisection performance toward the darker flanker. By combining these two illusions (Experiments 3 and 4), the two dimensions interfered with each other. This pattern of results suggests overlapping representations for physical and numerical magnitudes and highlights the value of illusory effects in cognitive research.     

A comparison of visual and auditory representational momentum in spatial tasks

Similarities have been observed in the localization of the final position of moving visual and moving auditory stimuli: Perceived endpoints that are judged to be farther in the direction of motion in both modalities likely reflect extrapolation of the trajectory, mediated by predictive mechanisms at higher cognitive levels. However, actual comparisons of the magnitudes of displacement between visual tasks and auditory tasks using the same experimental setup are rare. As such, the purpose of the present free-field study was to investigate the influences of the spatial location of motion offset, stimulus velocity, and motion direction on the localization of the final positions of moving auditory stimuli (Experiment 1 and 2) and moving visual stimuli (Experiment 3). To assess whether auditory performance is affected by dynamically changing binaural cues that are used for the localization of moving auditory stimuli (interaural time differences for low-frequency sounds and interaural intensity differences for high-frequency sounds), two distinct noise bands were employed in Experiments 1 and 2. In all three experiments, less precise encoding of spatial coordinates in paralateral space resulted in larger forward displacements, but this effect was drowned out by the underestimation of target eccentricity in the extreme periphery. Furthermore, our results revealed clear differences between visual and auditory tasks. Displacements in the visual task were dependent on velocity and the spatial location of the final position, but an additional influence of motion direction was observed in the auditory tasks. Together, these findings indicate that the modality-specific processing of motion parameters affects the extrapolation of the trajectory.     

Focused attention improves working memory: implications for flexible-resource and discrete-capacity models

Performance in working memory (WM) tasks depends on the capacity for storing objects and on the allocation of attention to these objects. Here, we explored how capacity models need to be augmented to account for the benefit of focusing attention on the target of recall. Participants encoded six colored disks (Experiment 1) or a set of one to eight colored disks (Experiment 2) and were cued to recall the color of a target on a color wheel. In the no-delay condition, the recall-cue was presented after a 1,000-ms retention interval, and participants could report the retrieved color immediately. In the delay condition, the recall-cue was presented at the same time as in the no-delay condition, but the opportunity to report the color was delayed. During this delay, participants could focus attention exclusively on the target. Responses deviated less from the target’s color in the delay than in the no-delay condition. Mixture modeling assigned this benefit to a reduction in guessing (Experiments 1 and 2) and transposition errors (Experiment 2). We tested several computational models implementing flexible or discrete capacity allocation, aiming to explain both the effect of set size, reflecting the limited capacity of WM, and the effect of delay, reflecting the role of attention to WM representations. Both models fit the data better when a spatially graded source of transposition error is added to its assumptions. The benefits of focusing attention could be explained by allocating to this object a higher proportion of the capacity to represent color.     

Infants’ discrimination of crossed and uncrossed horizontal disparity

In a series of preferential-looking experiments, infants 5 to 6 months of age were tested for their responsiveness to crossed and uncrossed horizontal disparity. In Experiments 1 and 2, infants were presented with dynamic random dot stereograms displaying a square target defined by either a 0.5° crossed or a 0.5° uncrossed horizontal disparity and a square control target defined by a 0.5° vertical disparity. In Experiment 3, infants were presented with the crossed and the uncrossed horizontal disparity targets used in Experiments 1 and 2. According to the results, the participants looked more often at the crossed (Experiment 1), as well as the uncrossed (Experiment 2), horizontal disparity targets than at the vertical disparity target. These results suggest that the infants were sensitive to both crossed and uncrossed horizontal disparity information. Moreover, the participants exhibited a natural visual preference for the crossed over the uncrossed horizontal disparity (Experiment 3). Since prior research established natural looking and reaching preferences for the (apparently) nearer of two objects, this finding is consistent with the hypothesis that the infants were able to extract the depth relations specified by crossed (near) and uncrossed (far) horizontal disparity.     

Response retrieval in a go/no-go priming-of-popout task

Priming of popout is the finding that singleton search is faster when features of a target and of nontargets are repeated across trials than when the features switch. Theoretical accounts suggest that intertrial repetition influences perceptual and attentional selection processes, episodic retrieval processes, or both. The present study combined a popout search task with a go/no-go task. In Experiment 1, the nontarget distractors in each display carried the go/no-go feature, and in Experiment 2, the texture of all items carried the go/no-go feature. Results showed that the go/no-go task moderated the intertrial repetition effects. In Experiment 1, the target color elicited retrieval of the preceding distractor color and associated no-go response, resulting in larger interference effects. In Experiment 2, the target color elicited retrieval of the preceding target color and no-go response, resulting in reduced facilitation effects. Additional results from both experiments showed that the colors in a search display also influenced target selection on the following trial. Taken together, the results of both experiments suggest that intertrial repetition influences both early selection and postselection retrieval processes.     

The mental wormhole: Internal attention shifts without regard for distance

Attention operates perceptually on items in the environment, and internally on objects in visuospatial working memory. In the present study, we investigated whether spatial and temporal constraints affecting endogenous perceptual attention extend to internal attention. A retro-cue paradigm in which a cue is presented beyond the range of iconic memory and after stimulus encoding was used to manipulate shifts of internal attention. Participants?? memories were tested for colored circles (Experiments 1, 2, 3a, 4) or for novel shapes (Experiment 3b) and their locations within an array. In these experiments, the time to shift internal attention (Experiments 1 and 3) and the eccentricity of encoded objects (Experiments 2?C4) were manipulated. Our data showed that, unlike endogenous perceptual attention, internal shifts of attention are not modulated by stimulus eccentricity. Across several timing parameters and stimuli, we found that shifts of internal attention require a minimum quantal amount of time regardless of the object eccentricity at encoding. Our findings are consistent with the view that internal attention operates on objects whose spatial information is represented in relative terms. Although endogenous perceptual attention abides by the laws of space and time, internal attention can shift across spatial representations without regard for physical distance.     

The production effect in paired-associate learning: Benefits for item and associative information

In five experiments, we extended the production effect—better memory for items said aloud than for items read silently—to paired-associate learning, the goal being to explore whether production enhances associative information in addition to enhancing item information. In Experiments 1 and 2, we used a semantic-relatedness task in addition to the production manipulation and found no evidence of a production effect, whether the measure was cued recall or item recognition. Experiment 3 showed that the semantic-relatedness task had overshadowed the production effect; the effect was present when the semantic-relatedness task was removed, again whether cued recall or item recognition was the measure. Experiments 4 and 5 provided further evidence that production can enhance recall for word pairs and, using an associate recognition test with intact versus rearranged pairs, indicated that production may also enhance associative information. That production boosts memory for both types of information is considered in terms of distinctive encoding.     

A severe capacity limit in the consolidation of orientation information into visual short-term memory

Previous research has suggested that two color patches can be consolidated into visual short-term memory (VSTM) via an unlimited parallel process. Here we examined whether the same unlimited-capacity parallel process occurs for two oriented grating patches. Participants viewed two gratings that were presented briefly and masked. In blocks of trials, the gratings were presented either simultaneously or sequentially. In Experiments 1 and 2, the presentation of the stimuli was followed by a location cue that indicated the grating on which to base one’s response. In Experiment 1, participants responded whether the target grating was oriented clockwise or counterclockwise with respect to vertical. In Experiment 2, participants indicated whether the target grating was oriented along one of the cardinal directions (vertical or horizontal) or was obliquely oriented. Finally, in Experiment 3, the location cue was replaced with a third grating that appeared at fixation, and participants indicated whether either of the two test gratings matched this probe. Despite the fact that these responses required fairly coarse coding of the orientation information, across all methods of responding we found superior performance for sequential over simultaneous presentations. These findings suggest that the consolidation of oriented gratings into VSTM is severely limited in capacity and differs from the consolidation of color information.     

Relational and item-specific influences on generate–recognize processes in recall

The generate–recognize model and the relational–item-specific distinction are two approaches to explaining recall. In this study, we consider the two approaches in concert. Following Jacoby and Hollingshead (Journal of Memory and Language 29:433–454, 1990), we implemented a production task and a recognition task following production (1) to evaluate whether generation and recognition components were evident in cued recall and (2) to gauge the effects of relational and item-specific processing on these components. An encoding task designed to augment item-specific processing (anagram-transposition) produced a benefit on the recognition component (Experiments 1–3) but no significant benefit on the generation component (Experiments 1–3), in the context of a significant benefit to cued recall. By contrast, an encoding task designed to augment relational processing (category-sorting) did produce a benefit on the generation component (Experiment 3). These results converge on the idea that in recall, item-specific processing impacts a recognition component, whereas relational processing impacts a generation component.     

Saccade latency reveals episodic representation of object color

While previous studies suggest that identity, but not color, plays a role in episodic object representation, such studies have typically used tasks in which only identity is relevant, raising the possibility that the results reflect task demands, rather than the general principles that underlie object representation. In the present study, participants viewed a preview display containing one (Experiments 1 and 2) or two (Experiment 3) letters, then viewed a target display containing a single letter, in either the same or a different location. Participants executed an immediate saccade to fixate the target; saccade latency served as the dependent variable. In all experiments, saccade latencies were longer to fixate a target appearing in its previewed location, consistent with a bias to attend to new objects rather than to objects for which episodic representations are being maintained in visual working memory. The results of Experiment 3 further demonstrate, however, that changing target color eliminates these latency differences. The results suggest that color and identity are part of episodic representation even when not task relevant and that examining biases in saccade execution may be a useful approach to studying episodic representation.     

Boundaries of semantic distraction: Dominance and lexicality act at retrieval

Three experiments investigated memory for semantic information with the goal of determining boundary conditions for the manifestation of semantic auditory distraction. Irrelevant speech disrupted the free recall of semantic category- exemplars to an equal degree regardless of whether the speech coincided with presentation or test phases of the task (Experiment 1), and this occurred regardless of whether it comprised random words or coherent sentences (Experiment 2). The effects of background speech were greater when the irrelevant speech was semantically related to the to-be-remembered material, but only when the irrelevant words were high in output dominance (Experiment 3). The implications of these findings in relation to the processing of task material and the processing of background speech are discussed.     

The effects of interleaving versus blocking on foreign language pronunciation learning

Many studies have shown that students learn better when they are given repeated exposures to different concepts in a way that is shuffled or interleaved, rather than blocked (e.g., Rohrer Educational Psychology Review, 24, 355–367, 2012). The present study explored the effects of interleaving versus blocking on learning French pronunciations. Native English speakers learned several French words that conformed to specific pronunciation rules (e.g., the long “o” sound formed by the letter combination “eau,” as in bateau), and these rules were presented either in blocked fashion (bateau, carreau, fardeau . . . mouton, genou, verrou . . . tandis, verglas, admis) or in interleaved fashion (bateau, mouton, tandis, carreau, genou, verglas . . .). Blocking versus interleaving was manipulated within subjects (Experiments 1–3) or between subjects (Experiment 4), and participants’ pronunciation proficiency was later tested through multiple-choice tests (Experiments 1, 2, and 4) or a recall test (Experiment 3). In all experiments, blocking benefited the learning of pronunciations more than did interleaving, and this was true whether participants learned only 4 words per rule (Experiments 1–3) or 15 words per rule (Experiment 4). Theoretical implications of these findings are discussed.