Variables underlying the recognition of random shapes

Speed of sorting decks of 32 cards with two alternative stimuli was measured. The stimuli were pairs of dots with attributes of distance between dots, angle of orientation of the pair, and position of the pair to the right or left of center. The attributes varied in relative discriminability and were used in all possible pair- and triple-correlated (redundant) combinations. Results showed an increase in speed of sorting with either an increase in discriminability or an increase in number of redundant attributes. It is argued that the increased speed with addition of redundant attributes is due both to a selective serial processing of attributes (requiring attribute separability) and to an increased discriminability with combined attributes (requiring attribute integrality).     

Immediate and delayed recognition of sequentially presented random shapes.

Two experiments tested whether short-term memory accounts for the recency effect observed with rapid sequential presentation of nonverbal stimuli. Four random shapes were presented sequentially (with no interstimulus interval) on each trial at rates of 150 msec, 250 msec, 500 msec, and 1,000 msec per stimulus. Subsequent recognition varied positively with exposure duration, ranging from 57% at 150 msec to 77% at 1,000 msec. Two serial position effects were observed: a slight decrease in recognition accuracy for the first stimulus in each sequence and a large increase in recognition for the last stimulus in each sequence. The recency effect was not altered by an intervening 30-sec delay, an intervening 30-sec copying task, or an intervening 30-sec copying and counting task. Since neither visual nor verbal distractors altered recognition accuracy, it was suggested that all shapes were processed directly into long-term memory storage. It also was hypothesized that long-term storage of a nonverbal stimulus requires identification of a distinctive feature of the stimulus and that this process may continue for a brief period after actual stimulus offset.     

The role of scanpaths in the recognition of random shapes

Eye movements of 12 Ss were examined during learning and recognition of two-dimensional random shapes to determine the nature of the memorial representation of a stimulus and the utilization of this memorial representation in pattern recognition. Specifically, the purpose of this study was to test the scanpath model of pattern perception by determining whether scanpaths exist and, if so, how they influence recognition performance. Scanpaths, defined as overlapping fixation patterns in learning and recognition tasks, were observed in over half of all eye-movement records regardless of shape complexity. Presence of scanpaths did not increase recognition performance as measured by errors in recognition and Ss’ ability to reproduce the shapes. Although scanpaths did not influence recognition performance, their occurrence implicates them as a potential factor in the recognition process.     

Odor recognition: familiarity, identifiability, and encoding consistency

The investigation examined the association between the perceived identity of odorous stimuli and the ability to recognize the previous occurrence of them. The stimuli comprised 20 relatively familiar odorous objects such as chocolate, leather, popcorn, and soy sauce. Participants rated the familiarity of the odors and sought to identify them. At various intervals up to 7 days after initial inspection, the participants sought to recognize the odors among sets of distractor odors that included such items as soap, cloves, pipe tobacco, and so on. The recognition response entailed a confidence rating as to whether or not an item had appeared in the original set. At the time of testing, the participants also sought to identify the stimuli again. The results upheld previous findings of excellent initial recognition memory for environmentally relevant odors and slow forgetting. The results also uncovered, for the first time, a strong association between recognition memory and identifiability, rated familiarity, and the ability to use an odor label consistently at inspection and subsequent testing. Encodability seems to enhance rather than to permit recognizability. Even items identified incorrectly or inconsistently were recognized at levels above chance.     

Dissociated imageability,concreteness, and familiarity in lateralized word recognition

According to Paivio’s (1971) dual-coding theory, the representational memory of words is indexed by familiarity ratings, whereas associated imagery (one type of referential memory) is indexed by imageability and concreteness ratings. The theory predicts that word recognition near threshold will be influenced only by the former and not by the latter two attributes. However, previous empirical findings are unclear on this issue. Furthermore, the report of some studies that imageability and concreteness interact with the visual field of presentation pose a potential challenge to the theory. Here, five experiments present lateralized words whose semantic attributes are dissociated by design and by correlational analysis. In support of the theory, a metaanalysis shows that only familiarity affects overall recognition and that none of the attributes interacts with visual field. Yet statistical power to find the effects was high, and a general right-field recognition advantage supports the hemispheric validity of the findings. Implications for continuous (e.g., “cascade”) models of information processing are discussed.     

The role of familiarity in item recognition, associative recognition, and plurality recognition on self-paced and speeded tests

Four experiments compare the effect of familiarity on item, associative, and plurality recognition on self-paced and speeded tests. The familiarity of test items was enhanced by presenting a prime that matched the subsequent test item. On item and plurality recognition tests, participants were more likely to respond "old" to primed than to unprimed test items. In associative recognition, priming increased the proportion of old responses on a speeded test, but not on a self-paced test. This suggests that familiarity plays a larger role in item and plurality recognition than in associative recognition on self-paced tests. On speeded tests, priming has a similar effect on item, associative, and plurality recognition. Results suggest that item and associative recognition rely differentially on familiarity and recollection. They are also consistent with recent evidence suggesting that different processes underlie plurality and associative recognition.     

Testing a neurocomputational model of recollection, familiarity, and source recognition

The authors assess whether the complementary learning systems model of the medial temporal lobes (Norman & O'Reilly, 2003) is able to account for source recognition receiver operating characteristics (ROCs). The model assumes that recognition reflects the contribution of a hippocampally mediated recollection process and a cortically mediated familiarity process. The hippocampal process is found to produce threshold output functions that lead to U-shaped zROCs, whereas the cortical process produces Gaussian signal detection functions and linear zROCs. The model is consistent with several dual process theories of recognition and is capable of producing the types of zROCs observed in studies of item and source recognition. In addition, the model makes the novel prediction that as the level of feature similarity across items increases, the ability of the hippocampus to encode distinct representations for each stimulus will diminish, and the threshold nature of recollection will break down, leading source zROCs to become more linear. The authors conducted 3 new behavioral source experiments that confirmed the model's prediction. The results demonstrate that the model provides a viable account of item and source recognition performance.     

Pictorial interference with geometric shapes and achromatic shades

In two experiments, subjects were required to match printed names with subsequently displayed achromatic shades or geoinetric shapes. The presence of incongruent shades or shapes at the time of word display substantially slowed the RT for performing the match. This pictorial interference (interference due to a visual, nonlingalistic attributel was substantially attenuated, however, as the delay between the word display and shapes or shades to be matched was increased beyond 100 msec. These findings illnstrate the occurrence of a transitory automatic pathway activation from an irrelevant pictorial attribute, which may be contrasted with the verbal interference effects typically observed in Stroop-naming tasks. In both our tasks and the Stroop task, selectiwe attention fails when a stimulus must be transformed to another form of encoding in the presence of a competing stimulns which is already close to that form.     

Judging familiarity and emotion from very brief musical excerpts

In the present study, the gating paradigm was used to measure how much perceptual information that was extracted from musical excerpts needs to be heard to provide judgments of familiarity and of emotionality. Nonmusicians heard segments of increasing duration (250, 500, 1,000 msec, etc.). The stimuli were segments from familiar and unfamiliar musical excerpts in Experiment 1 and from very moving and emotionally neutral musical excerpts in Experiment 2. Participants judged how familiar (Experiment 1) or how moving (Experiment 2) the excerpt was to them. Results show that a feeling of familiarity can be triggered by 500-msec segments, and that the distinction between moving and neutral can be made for 250-msec segments. This finding extends the observation of fast-acting cognitive and emotional processes from face and voice perception to music perception.     

Increased analgesia to thermal stimuli in rats after brief exposures to complex pulsed 1 microTesla magnetic fields

Nociceptive thresholds to a 55 degrees C hot surface were measured for female Wistar rats before treatments and 30 min. and 60 min. after the treatments. After injection with either naloxone or saline following baseline measurements, the rats were exposed for 30 min. to either sham fields or to weak (about 1 microTesla) burst-firing magnetic fields composed of 230 points (4 msec. per point) presented once every 3 sec. The rats that had received the burst-firing magnetic fields exhibited elevated nociceptive thresholds that explained about 50% of the variance. A second pattern, designed after the behaviour of individual thalamic neurons during nociceptive input and called the "activity rhythm magnetic field" produced only a transient analgesic effect. These results replicated previous studies and suggest that weak, extremely low frequency, pulsed magnetic fields with biorelevant temporal structures may have utility as adjuncts for treatment of pain.     

Preference of dissonance reduction modes as a function of their order,familiarity and reversibility

Two central hypotheses of the original version of the theory of cognitive dissonance (Festinger, 1957) (1) that dissonance is to be conceived of as a primary drive and (2) that in order to reduce dissonance less resistant cognitions will be changed more than highly resistant ones led to hypotheses which were confirmed by two experiments. In Experiment I, a 2 × 3 factorial design, order and familiarity of dissonance reduction modes were manipulated. After receiving a dissonant information the subjects were offered a relatively low and a relatively high resistant cognition for dissonance reduction, each being placed first (series I, high-low resistance) or last (series II, low-high resistance) respectively. Subjects did (known) or did not (unknown) read these modes before reacting to them. Under the unknown condition dissonance will be reduced more with a specific mode if it is placed first than last. With known reduction modes the order of presentation does not have an effect. Under series I condition the first-placed, higher-resistant cognition will be changed more in the unknown condition than in the known condition. Under the series II condition the first-placed, lower-resistant cognition will be changed equally in the known and unknown condition. In short, the higher-resistant cognition will be changed more, only when it is placed first and when the following modes are not known. Two explanations for these results are possible: (1) The more dissonance is reduced by changing a more or a less resistant congnition, the less further reduction is necessary; (2) dissonance will be reduced in an internally consistent way. Experiment II excluded the first explanation. Subjects were allowed to revise their original way of reducing dissonance. First, subjects in one condition received series I unknown and subjects in the other condition received series II unknown. Reacting to the dissonance reduction modes the second time, there was more revision when the high-resistant congition was placed first (series 1 revision) than when placed last (series II revision). These results support the hypothesis that dissonance reduction by changing a less-resistant congnition more and changing a high-resistant one less is preferred. Implications of the results of the two experments for the stability of dissonance reduction, the method and interpretation of dissonance experiments are discussed.     

Orthography,phonology, and meaning: Word features that give rise to feelings of familiarity in recognition

In the present study, it is shown that participants can recognize test cues as resembling studied words even when these cues cannot be used to recall the words that they resemble. After studying a list of words, participants were given a cued recall test for which half of the cues resembled studied words on one particular feature dimension and half resembled nonstudied words on that dimension. In addition to trying to use each cue to recall a study list item, participants rated the degree to which the cue resembled a studied word. For those cues whose targets could not be identified, the mean rating was higher when the cues corresponded to studied items than when they corresponded to nonstudied items. Various types of features can give rise to this phenomenon, which was found when orthographic, phonemic, and semantic cued recall tasks were used. In all of these cases of recognition without recall, analysis of receiver operating characteristics revealed a pattern consistent with that of an equal-variance signal detection process.     

Novelty effects on recollection and familiarity in recognition memory

Recognition memory is better for novel or distinctive items than for non-novel items. However, it is not known whether these effects reflect changes in recollection or in familiarity-based recognition judgments. Some previous results have indicated that recollection should be more sensitive to novelty than to familiarity, whereas other results have suggested the opposite. We used avon Restorff paradigm in which a small proportion of studied items were made novel by presenting them in a color different from that of the majority of the study items. Memory was tested using a remember-know procedure. Across two experiments, stimulus novelty was found to benefit both recollection and familiarity. The effects on familiarity were observed under intentional and incidental encoding conditions, whereas the effects on recollection were significantly reduced, and no longer significant, under incidental as compared with intentional encoding conditions. Thus, both processes benefit from stimulus novelty, but the extent to which recollection benefits from novelty depends on the encoding condition.     

Effects of familiarity level and repetition on recognition accuracy

Theories of recognition memory based on signal detection theory posit that a recognition decision is similar to a psychophysical judgment. Like a judgment of stimulus brightness or loudness, a recognition judgment is based on the value of a unidimensional signal computed for the test item. This signal has been called the strength or familiarity value. One prediction of these models is that the ability to discriminate between a studied and nonstudied test item depends on the ability to detect the difference in their familiarities. This ability in turn is influenced by the items' familiarity levels; discrimination should become more difficult as the familiarity of both items increases. This prediction was supported in 3 experiments using a forced-choice procedure. Also, accuracy was higher when the list contained repeated items rather than a comparable number of distinct items.