Idea habitats: how the prevalence of environmental cues influences the success of ideas

We investigate 1 factor that influences the success of ideas or cultural representations by proposing that they have a habitat, that is, a set of environmental cues that encourages people to recall and transmit them. We test 2 hypotheses: (a) fluctuation: the success of an idea will vary over time with fluctuations in its habitat, and (b) competition: ideas with more prevalent habitats will be more successful. Four studies use subject ratings and data from newspapers to provide correlational support for our 2 hypotheses, with a negative factoid, positive rumor, catchphrases, and variants of a proverb. Three additional experimental studies manipulate the topic of actual conversations and find empirical support for our theory, with catchphrases, proverbs, and slang. The discussion examines how habitat prevalence applies to a more extensive class of ideas and suggests how habitats may influence the process by which ideas evolve.     

Verbal cues facilitate memory retrieval during infancy

In three experiments, 18-month-olds were tested in a deferred imitation paradigm. Some infants received verbal information during the demonstration and at the time of the test (full narration), and some did not (empty narration). When tested after a 4-week delay, infants given full narration exhibited superior retention relative to infants given empty narration (Experiment 1). This retention advantage appears to be due to the effects of verbal cues at the time of memory retrieval. There was no effect of verbal cues that were presented only at the time of original encoding (Experiment 2A). Furthermore, infants who received verbal cues only at the time of retrieval exhibited superior retention relative to infants who received verbal cues only at the time of original encoding (Experiment 2B). These findings demonstrate that verbal cues can enhance memory retrieval by participants who are not yet fluent speakers themselves.     

Glucocorticoid-induced impairment of long-term memory retrieval in rats: an interaction with dopamine D2 receptors

This study investigated glucocorticoid-dopaminergic interactions in modulating retrieval of long-term memory in an inhibitory avoidance task. Young adult male rats were trained in one trial inhibitory avoidance task (0.5 mA, 3 s footshock). On the retention test given 48 h after training, the latency to re-enter the dark compartment of the apparatus was recorded. Systemically administered corticosterone (1 or 3 mg/kg) given to rats 30 min before retention testing impaired their memory retrieval, but the lower dose was more effective than the higher one. Administration of the dopamine (DA) D2 receptor antagonist sulpiride (6 or 20 mg/kg) 30 min before corticosterone attenuated the impairing effects of corticosterone (1 mg/kg) on memory retrieval. Administration of the DA D1 receptor antagonist SCH23390 (25 or 50 microg/kg) had no effect on corticosterone-induced impairment of memory retrieval. Further, applied doses of sulpiride or SCH23390 alone were ineffective in modulating memory retrieval. These findings provide evidence for the existence of an interaction between glucocorticoids and DA D2 receptor on memory retrieval process.     

Repeated priming increases memory accessibility in infants

In previous research on priming (reactivation) with 3-month-olds, two primes recovered a forgotten memory faster than one, suggesting that prior priming had increased the accessibility of the forgotten memory. Exploiting the fact that the minimum duration of a prime indexes the accessibility of the forgotten memory, we currently examined whether prior priming also reduces the minimum effective prime duration. In three experiments, 60 3-month-olds learned an operant task, forgot it, and then were exposed to successive primes either 1 day and 1 week after forgetting (Experiment 1) or 1 and 2 weeks after forgetting (Experiment 2). In both cases, prior priming reduced the minimum duration of the second prime, a result that was independent of the duration of the first prime (Experiment 3). These findings confirm that priming increases the accessibility of a latent memory and raise the possibility that repeated priming underlies the extended memorability of persons and events that infants encounter sporadically.     

Cumulative semantic inhibition in picture naming: experimental and computational studies

We report an experiment in which subjects named 120 pictures, consisting of series of five pictures drawn from each of 24 semantic categories (and intermixed with 45 fillers). The number of intervening trials (lag) between successive presentations of members of the same category varied from two to eight. Subjects' naming latencies were slowed by 30 ms for each preceding member of the category. This effect was both cumulative and linear, and unrelated to the lag elapsing since the previous presentation of a category member. These results definitively demonstrate the occurrence of cumulative interference for word retrieval by prior retrieval of other exemplars of the same semantic category-cumulative semantic inhibition. We claim that this inhibition effect could only occur if the spoken word production system possesses three specific properties (competition, priming, and sharing of semantic activation). We provide computational-modelling evidence in support of this claim. We show that no current theory of spoken word production has all of these properties. In their current form, all these theories are falsified by these results. We briefly discuss the obstacles that may be encountered by current models were they modified to account for our findings.     

Task-switching and long-term priming: role of episodic stimulus-task bindings in task-shift costs

When subjects switch between two tasks, performance is slower after a task switch than after a task repetition. We report five experiments showing that a large part of these "task-shift-costs" cannot be attributed to a control operation, needed to configure the cognitive system for the upcoming task (e.g., ). In all experiments subjects switched between picture-naming and word-reading. We presented different stimuli either in just one of the two tasks, or in both of them. Shift-costs were larger for stimuli presented in both tasks than for those presented in only one task, even after more than 100 intervening trials between prime and probe events. We suggest (as proposed by ) that stimuli acquire associations with the tasks in which they occur. When the current task activation is weak, as on a switch of tasks, stimuli can trigger retrieval of the associated, competing task, provoking larger time costs.     

Differential ordering of objects and attributes

By reference to nominated attributes, a genus, being a population of objects of one specified kind, may be partitioned into species, being subpopulations of different kinds. A prototype is an object representative of its species within the genus. Using this framework, the paper describes how objects can be relatively differentiated with respect to attributes, and how attributes can be relatively differentiating with respect to objects. Methods and rationale for such differential ordering of objects and attributes are presented by example, formal development, and application.For a genus comprisingn species of object there is a subsetP ofn distinct prototypes. With respect tom nominated attributes, each object in has anm-element characterization. Together these determine ann ×m objects × attributes matrix, the rows of which are the characterizations of the prototypical objects. Over then species in , an associated relative frequency vector gives the distribution of objects (and of their characterizations). The matrix and vector associate the objects in with points in a metric space (P, ); and it is with respect to various sums of distances in this attribute space that one can differentially order objects and attributes.The definition of the distance function is generalized across kinds of difference, types of characterization, scale-types of measurement, Minkowskiindex 1, and any form of distribution of objects over species. Explanatory and taxonomic applications in psychology and other fields are discussed, with focus on classification, identification, recognition, and search. The Braille code and the identification of its characters provide illustration.An anticipation and some preliminary indications were given in Sutcliffe and Bristow (1966), Sutcliffe (1972, 1973), and Nowakowska (1975). Subsequently the ideas have been extended and their applications realized in a computer program which, in its development, has so far gone through many minor and three major revisions to its present form in Sutcliffe (1985). The foregoing provided the foundation for the empirical applications and for the presentation in this paper of the ideas in their general form. the research has been supported by funds from the University of Sydney Research Grant and from the Australian Research Grants Scheme. In the working out and exposition of the ideas I have very much benefited from constructive critical comment given by C. R. Latimer, J. B. Michell, G. Oliphant, and E. Seneta, and from the professional programming skills of Michael Wilson and David Shillito. I am grateful for the invitation and the facilities for writing extended during 1983 by Georges Noizet, Laboratoire de Psychologie Expérimentale, Université René Descartes, Paris V, and by Samuel Messick, Vice President for Research, E.T.S. Princeton, N.J. Finally, I acknowledge the improvements in presentation of this paper which have arisen from the editor's and reviewers' comments.     

Are attentional resources a mediator for sex differences in memory?

The divided attention paradigm was used to investigate sex differences in encoding and retrieval processes of memory. Participants performed a memory and reaction time (RT) task under full attention and two divided attention conditions, that is, at encoding and retrieval. Results revealed that females recalled significantly more words than males under the full attention and divided attention at encoding conditions. Results further showed that secondary task costs were larger for males than females during divided attention at retrieval. Furthermore, regardless of sex, recall was best under full attention and worst under divided attention at encoding conditions. In relation to the RT task, RTs were shorter under full attention and longer under the divided attention at retrieval condition. Overall, these results show that females recall more words than males possibly due to a more severe effect of reduced attention during encoding than retrieval for males. The current findings thus suggest that a reduction in attentional resources may mediate sex‐related decreases in word recall.     

Spaced Retrieval Enhances Memory in Older Adults with Probable Alzheimer's Disease

We used the spaced retrieval method to improve recall of everyday objects in older adults with probable Alzheimer's Disease. Three training sessions were administered on alternate days over a week. On each training trial, participants selected a designated object from an array of items at increasingly longer retention intervals. Implicit and explicit memory for the target item was assessed after each session. Results indicated that spaced-retrieval training enhanced retention of the target item within and across sessions for all participants. Implications of these findings for current views on memory interventions for cognitively impaired older adults are discussed. affiliated with the Menorah Park Center for the Aging