David R. Thomson

A switch in task affects priming of pop-out: evidence for the role of episodes

Maljkovic and Nakayama (Memory & Cognition, 22(6), 655–678, 1994) demonstrated that response times decrease in a pop-out search task when target-defining features repeat from one trial to the next. This priming of pop-out (PoP) effect has been explained by some researchers as reflecting low-level modulations in attentional control settings Lee, Mozer, and Vecera (Attention, Perception, & Psychophysics, 71(5), 1059–1071, 2009). The present experiments tested whether a shift in higher order task requirements from trial n − 1 to trial n alters PoP effects. The results of Experiments 1 and 2 demonstrated that a switch in task significantly modulated PoP effects when shape was the relevant pop-out dimension. Experiment 3 failed to show significant modulation of PoP as a function of task switch when the pop-out dimension was color, but the findings of Experiment 4 did show modulation of PoP for color when the relative salience of target and distractors was high. Together, the results strongly support the view that PoP effects can be sensitive to a switch in task, a result consistent with the view that PoP effects are modulated by trial-to-trial episodic integration processes.

Perceptual distinctiveness produces long-lasting priming of pop-out

Maljkovic and Nakayama (1994) demonstrated memory influences in singleton search from one trial to the next, an effect they termed priming of pop-out (PoP). This effect was described as resulting from the persistence of an implicit memory trace, the influence of which could be observed for around five to eight subsequent trials. The seemingly short-lived nature of this priming effect has been attributed to decay of the underlying memory representation that occurs when attention is directed to intervening search items, even when such items are perceptually dissimilar from the search trials upon which PoP is measured (Maljkovic & Nakayama, 2000). The present study reexamines the role of perceptual similarity as a mechanism of interference by examining the influence on PoP of rare search trials that were perceptually distinct with respect to the other, common trials. Long-lasting (n − 16) PoP was observed for rare trials that were composed of distinct target/distractor colors, suggesting that PoP can be observed across at least twice as many trials as has previously been reported. Thus, the time span across which PoP can be measured depends heavily on the nature of the intervening search displays, a result that must be accommodated by current theoretical accounts of PoP.

An Information-Based Approach to Labeling Biotechnology Consumer Products

Using an economic framework this paper explores the need for labeling of biotechnological consumer products. In particular, we assess the impact of labeling on information problems faced by consumers and regulators. Using information analysis, we propose an approach to labeling biotechnology products that attempts to respect both the real nature of consumer information-processing capacities and approaches and the environment of uncertainty in which any regulatory policy for biotechnology will operate. We conclude that the fact of uncertainty on the scientific front and the nature of consumer concerns in this area gives rise to a need for some type of labeling. Using labels to convey substantive information, however, is likely to be of limited value to consumers. A comprehensive approach to information policy for consumers in this field should aim instead to use labeling requirements to harness the incentives of producers and other private entities to effectively convey to consumers what they want and need to know. We therefore recommend that governments require a simple alert label on biotechnology consumer goods that will prompt consumers to assess their information needs and producers or others to supply those needs. Government regulation in this scheme would consist of basic health and safety regulation and direct or indirect monitoring and regulation of the content of the information ultimately conveyed to consumers by producers and others.

Negative priming 1985 to 2015: a measure of inhibition, the emergence of alternative accounts, and the multiple process challenge

In this article, three generations of authors describe the background to the original article; the subsequent emergence of vigorous debates concerning what negative priming actually reflects, where radically different accounts based on memory retrieval were proposed; and a re-casting of the conceptual issues underlying studies of negative priming. What started as a simple observation (slowed reaction times) and mechanism (distractor inhibition) appears now to be best explained by a multiple mechanism account involving both episodic binding and retrieval processes as well as an inhibitory process. Emerging evidence from converging techniques such as functional magnetic resonance imaging (fMRI), and especially electroencephalography (EEG), is beginning to identify these different processes. The past 30 years of negative priming experiments has revealed the dynamic and complex cognitive processes that mediate what appear to be apparently simple behavioural effects.

Context-specific control and the Stroop negative priming effect

The present study highlights the utility of context-specific learning for different probe types in accounting for the commonly observed dependence of negative priming on probe selection. Using a Stroop priming procedure, Experiments 1a and 1b offered a demonstration that Stroop priming effects can differ qualitatively for selection and no-selection probes when probe selection is manipulated between subjects, but not when it is manipulated randomly from trial to trial within subject (see also Moore, 1994). In Experiments 2 and 3, selection and no-selection probes served as two contexts that varied randomly from trial to trial, but for which proportion repeated was manipulated separately. A context-specific proportion repeated effect was observed in Experiment 2, characterized by modest quantitative shifts in the repetition effects as a function of the context-specific proportion repeated manipulation. However, with a longer intertrial interval in Experiment 3, a context-specific proportion repeated manipulation that focused on the no-selection probes changed the repetition effect qualitatively, from negative priming when the proportion repeated was .25 to positive priming when the proportion repeated was .75. The results are discussed with reference to the role of rapid, context-specific learning processes in the integration of prior experiences with current perception and action.

Revisiting the time course of inter-trial feature priming in singleton search

Current theories of the locus of inter-trial priming effects in efficient visual search posit an early perceptual component that reflects the short-term influence of a memory trace for low-level stimulus attributes. Despite the fact that this memory trace is hypothesized to be short term, and should therefore have a diminishing influence on performance over time, there has been relatively little study of the effect of time alone on singleton priming effects. The present series of experiments addresses this issue by systematically examining the effect of time on the priming of pop-out (PoP) effect. In Experiment 1, we show that the PoP effect does indeed diminish with increases in the RSI between trials, and does so in accord with a power-law function. In Experiment 2, we show that temporal discriminability of trial nxa0−xa01 from the trial that precedes it does not contribute to PoP effects. The results of Experiment 3 revealed two key results: (1) the PoP effect survives an equivalent number of intervening trials across very different RSI conditions; and (2) the cumulative target repetition benefit does depend on the RSI between trials. Together, the results favor neither a simple passive decay nor a strong episodic retrieval account of the PoP effect.

Learning what to expect: context-specific control over intertrial priming effects in singleton search

The present study explored the degree to which repetition effects in color pop-out search from trial n − 1 to trial n are subject to the attentional control settings of the observer. Intertrial priming effects were compared between two contexts that differed in terms of the utility of immediate prior experience for current performance; in one context, the target was likely to repeat, and in the other context, the target was likely to alternate from one trial to the next. Across two experiments, priming of pop-out (PoP) effects (Malkjovic & Nakayama; Memory & Cognition 22:657-672, 1994) were modulated in accord with the probability of target color repetition in a given trial context. Importantly, this modulation persisted when trial history preceding trial n − 1 was controlled for. Furthermore, this control over PoP seems not to derive from explicit strategies and is not an artifact of randomly occurring strings of same-target trials. We argue that priming effects in singleton search from trial n − 1 to trial n are subject to a form of implicit top-down control.

Long-Term Conceptual Implicit Memory: A Decade of Evidence

Demonstrations of long-term implicit memory are numerous, but to date they have been reported in what might be thought of as perceptually driven tasks. In the present experiment, a low-frequency U.S. state name was presented verbally to participants within the context of a memory-course lecture, and the influence of that experience was measured indirectly 4 to 8 weeks later using a state-name-generation task. Participants were significantly more likely to generate the critical state name when it had been presented in an earlier lecture than when it had not been presented in an earlier lecture, a novel demonstration of long-term, conceptually driven priming after a single stimulus exposure.

On the preservation of vigilant attention to semantic information in healthy aging

Despite decades of research on younger adults, little is known about the way in which vigilant attention is affected by healthy aging, and the small body of work that does exist has yielded mixed findings. Prior examinations of aging and vigilant attention have focused almost exclusively on sensory/perceptual tasks despite the fact that many real-world vigilance tasks are semantic in nature and it has been shown that older adults exhibit memory and attention deficits in semantic tasks in other domains. Here, we present the first empirical investigation of vigilant attention to verbal stimuli in healthy normal aging. In Experiment 1 we find that older adults are just as able as younger adults to identify critical targets defined by category membership (both overall and over time). In Experiment 2, we increase the difficulty of the task by changing the target category from one block to the next, but again find no age-group effects in accuracy. Response time data, however, show that older adults respond more slowly and subjective ratings indicate that older adults experience higher workload and arousal compared to their younger counterparts. The practical as well as theoretical implications of these findings are discussed.

An imagery-induced reversal of intertrial priming in visual search.

Maljkovic and Nakayama (1994) found that pop-out search performance is more efficient when a singleton target feature repeats rather than switches from 1 trial to the next—an effect known as priming of pop-out (PoP). They also reported findings indicating that the PoP effect is strongly automatic, as it was unaffected by knowledge of the upcoming target color. In the present study, we examined the impact of visual imagery on the PoP effect. Participants were instructed to imagine a target color that was opposite that of the preceding trial (e.g., if the prior target was red, then imagine green). Under these conditions, responses were faster for targets that matched the imagined color than for targets that matched the previous target color, reversing the typical PoP effect. There was no such reversal of the PoP effect for participants asked to verbalize rather than imagine an upcoming target color. In Experiment 3, we explored whether the PoP effect was indeed eliminated in the prior experiments, or instead obscured by the opposing visual imagery effect. Two conditions were compared, 1 in which a PoP effect could oppose the visual imagery effect, and another in which no such effect was possible, allowing inferences about whether a PoP effect was present. The results indicated that the PoP effect was present, but obscured by the larger visual imagery strategy effect that pushed performance in the opposite direction. Overall, the results suggest that the PoP effect is sensitive to top-down strategies that involve visual representations.