Short-term Implicit Memory Research Articles

The role of short-term implicit memory in probability coding and associative learning

The role of short-term implicit memory in probability coding and associative learning

Capacity of short term implicit memory is larger than visuospatial working memory in visual search

Capacity of short term implicit memory is larger than visuospatial working memory in visual search

Where perception meets memory: A review of repetition priming in visual search tasks

What we have recently seen and attended to strongly influences how we subsequently allocate visual attention. A clear example is how repeated presentation of an object's features or location in visual search tasks facilitates subsequent detection or identification of that item, a phenomenon known as priming. Here, we review a large body of results from priming studies that suggest that a short-term implicit memory system guides our attention to recently viewed items. The nature of this memory system and the processing level at which visual priming occurs are still debated. Priming might be due to activity modulations of low-level areas coding simple stimulus characteristics or to higher level episodic memory representations of whole objects or visual scenes. Indeed, recent evidence indicates that only minor changes to the stimuli used in priming studies may alter the processing level at which priming occurs. We also review recent behavioral, neuropsychological, and neurophysiological evidence that indicates that the priming patterns are reflected in activity modulations at multiple sites along the visual pathways. We furthermore suggest that studies of priming in visual search may potentially shed important light on the nature of cortical visual representations. Our conclusion is that priming occurs at many different levels of the perceptual hierarchy, reflecting activity modulations ranging from lower to higher levels, depending on the stimulus, task, and context-in fact, the neural loci that are involved in the analysis of the stimuli for which priming effects are seen.

Capacity limits in continuous old-new recognition and in short-term implicit memory

Using explicit memory measures, Cowan predicts a new circumstance in which the central capacity limit of 4 chunks should obtain. Supporting results for such an experiment, using continuous old-new recognition, are described. With implicit memory measures, Cowan assumes that short-term repetition priming reflects the central capacity limit. I argue that this phenomenon instead reflects limits within individual perceptual processing modules.

Priming of popout: III. A short-term implicit memory system beneficial for rapid target selection

The priming of popout (PoP) (Maljkovic & Nakayama, 1994, 1996) increases the speed of attentional deployment to subsequent targets having the same feature characteristic and relative position, it lasts for approximately 5-8 trials, and is cumulative. Here we establish PoP as an example of short-term implicit memory by showing that it is qualitatively different from explicit memory. Using a post-cued recall procedure embedded in the stream of search task trials, we show that explicit memory is not selective as is PoP and is of much shorter duration. As such we argue that explicit memory is unlikely to account for the properties of PoP. In examining the decay of PoP, we find that: PoP is not evident after a 90sec delay, it does not show passive decay over much shorter intervals (1-3sec), and it gets decremented by attentional deployments to visually dissimilar stimuli, the size of the decrement being related to task difficulty. The results, taken together, suggest that PoP reflects a functionally beneficial memory system, specialized for the rapid and automatic selection of items for focal attention and saccadic eye movements.

Short-term implicit memory: visual, auditory, and cross-modality priming.

Short-term implicit memory was examined for mixed auditory (A) and visual (V) stimuli. In lexical decision, words and nonwords were repeated at lags of 0, 1, 3, and 6 intervening trials, in four prime-target combinations (VV, VA, AV, AA). Same-modality repetition priming showed a lag x lexicality interaction for visual stimuli (nonwords decayed faster), but not for auditory stimuli (longer lasting smooth decay for both words and nonwords). These modality differences suggest that short-term priming has a perceptual locus, with the phonological lexicon maintaining stimuli active longer than the orthographic lexicon and treating pseudowords as potential words. We interpret these differences in terms of the different memory needs of speech recognition and text reading. Weak cross-modality short-term priming was present for words and nonwords, indicating recoding between perceptual forms.

Acquisition of novel traces in short-term implicit memory: priming for nonwords and new associations.

McKone (1995) reported a short-lived repetition priming effect (up to 8 sec and three intervening items), superimposed on long-term priming. In lexical decision and naming, decay of this short-term implicit memory was faster for pseudowords than for words, suggesting an explanation in terms of transient activation of preexisting lexical representations. Here, we present two cases where, in contrast, preexperimental familiarity did not affect short-term priming, indicating acquisition of novel traces. Experiment 1 determined repetition priming in same-different judgments to lowercase-uppercase pairs for words, and for nonwords with three levels of wordlikeness. Across lags of 0, 1, and 6 intervening items (2-14 sec), short-term priming was the same for all stimuli, even random letter strings. Experiments 2 and 3 assessed priming in a double lexical decision task for old associations (orange-apple) and new associations (cigar-errand). Short-term priming for the association was equal in both cases.

The decay of short-term implicit memory: unpacking lag.

McKone (1995) reported a short-lived repetition priming effect, superimposed on long-lived priming. This short-term implicit memory survived a few intervening items and several seconds for words but decayed precipitously for nonwords, producing a lag x lexicality interaction. Here, mechanisms of decay are studied by disconfounding the time delay and interference components of lag. In Experiment 1, time delay was varied while number of intervening items was held constant, and vice versa. In Experiment 2, priming was plotted as a function of time delay, with and without intervening items. Using a lexical decision task, both experiments found independent contributions of time and interference to the decay of short-term priming. Further, Experiment 2 attributed the lag x lexicality interaction to a particular sensitivity of nonword traces to interference. An illustration of how these effects might arise in the word recognition system is provided.

Short-term implicit memory for words and nonwords.

A short-term implicit memory effect is reported and interpreted as arising within the word recognition system. In Experiment 1, repetition priming in lexical decision was determined for low-frequency words and pseudowords at lags of 0, 1, 2, 3, 4, 5, 9, and 23 intervening items. For words, a large short-term priming component decayed rapidly but smoothly over the first 3 items (8 s) to a stable long-term value. For nonwords, priming dropped to the long-term value with a single intervening item. This Lag x Lexicality interaction was replicated with a naming task in Experiment 2 and with high-frequency words in Experiment 3. Word frequency affected long-term priming but not the size or decay rate of short-term priming, dissociating the two repetition effects. In Experiment 4, an old-new decision task was used to test explicit memory. Parallel word and nonword decay patterns were found, dissociating short-term priming from explicit working memory.

Short-term implicit memory for words and nonwords.

Short-term implicit memory for words and nonwords.