Free recall and complexity of pictorial stimuli

In order to explore variables underlying primacy and recency effects in free recall of pictorial material, norms were developed using 120 subjects who rated the vividness and complexity of slides. Two experiments were then run in which two levels of each of these variables (extreme high and low ratings) were factorially combined. In the first experiment 24 subjects were shown three mixed lists, two short and one long (consisting of materials of all four combinations of vividness and complexity), and in the second experiment 12 subjects were shown four pure lists (consisting of materials of a single type). Analysis of variance showed list length in the mixed list experiment and complexity in both experiments to be strong determinants of recall. Greatest recall was for items of low complexity in short lists. Weak, but statistically significant, serial position effects were evident, particularly for less complex items. The effects of primacy and recency seem to decrease with increasing complexity of visual materials, perhaps because of the greater difficulty in rehearsing more complex pictures either verbally or iconically.     

Encoding and memory for verbal and pictorial stimuli

Memory for visually presented verbal and pictorial material was compared using stimuli chosen to minimize non-essential differences between the two types of material. Experiment I required retention of a short list; verbal and pictorial stimuli were remembered equally well. Experiment II required recall of single items after 30 s of backwards counting; recall was much superior for pictorial stimuli. The type of task appeared to affect encoding, with verbal encoding reported to be predominant in Experiment I and visual encoding, or imagery, common in Experiment II.     

Emotional enhancement of immediate memory: Positive pictorial stimuli are better recognized than neutral or negative pictorial stimuli

We examined emotional memory enhancement (EEM) for negative and positive pictures while manipulating encoding and retrieval conditions. Two groups of 40 participants took part in this study. Both groups performed immediate implicit (categorization task) and explicit (recognition task) retrieval, but for one group the tasks were preceded by incidental encoding and for the other group by intentional encoding. As indicated by the sensitivity index (d'), after incidental encoding positive stimuli were easier to recognize than negative and neutral stimuli. Participants' response criterion was more liberal for negative stimuli than for both positive and neutral ones, independent of encoding condition. In the implicit retrieval task, participants were slower in categorizing positive than negative and neutral stimuli. However, the priming effect was larger for emotional than for neutral stimuli. These results are discussed in the context of the idea that the effect of emotion on immediate memory enhancement may depend on the intentionality to encode and retrieve information.     

Irrelevance of sample stimuli and directed forgetting in pigeons

A successive matching procedure was used to investigate which aspect of the test-omission procedure is responsible for establishing a postsample stimulus as a cue to forget in pigeons. It was found that a postsample stimulus that reliably followed a sample that was irrelevant to performance functioned as a cue to forget. This result was obtained regardless of whether termination of that postsample stimulus was followed by reinforcement or by the presentation of sample-independent discriminative stimuli. It was also found that a postsample stimulus that functioned as a cue to forget at the beginning of training lost that function when it was repeatedly presented on trials in which the sample was relevant to performance. These findings reveal that (a) neither a reduction in reinforcement rate nor the omission of the opportunity for discriminated responding is necessary to establish an effective cue to forget and (b) irrelevance of the sample to performance is a sufficient condition to establish a cue to forget. These results suggest that a postsample stimulus that is presented on trials in which remembering the sample is not reinforced differentially will come to set the occasion for not remembering the sample.     

Equivalence class formation as a function of preliminary training with pictorial stimuli

The present experiment investigated the effects of preliminary training with pictorial stimuli on the subsequent formation of three 5‐member equivalence classes (A?B?C?D?E) in 84 university students assigned to seven groups of 12. In the Abstract (ABS) group, all stimuli were abstract shapes. In the Picture (PIC) group, the C stimuli were pictures, and the remaining stimuli were the same abstract shapes as in the ABS group. For the remaining five groups, all stimuli were the same abstract shapes as in the ABS group. However, across groups, preliminary training involved either the establishment of conditional relations with simultaneous (SMTS) or delayed (DMTS) matching‐to‐sample with 0 s, 3 s, 6 s, or 9 s between the abstract C stimuli and the meaningful pictures. For the ABS and the PIC groups, 16.7% and 83.3% of participants formed classes, respectively. Preliminary training with SMTS and DMTS with 0 s, 3 s, and 6 s produced a linear increase in the likelihood of equivalence class formation, 41.7%, 50%, and 75%, respectively. Increasing the duration of delay further from 6 s to 9 s produced a substantial decline, 50%. This experiment extends knowledge about how including meaningful pictures enhances equivalence class formation.     

Spatial organization in the free recall of pictorial stimuli

Thirty-one young adults were presented with a series of visual arrays each containing drawings of objects. Free recall of the objects on each visual array could be organized by the spatial location of the objects or by another type of organization. The other type of organization was different on each array and comprised semantic, shape, colour, size, orientation or phonetic categories. The results showed that free recall could be organized by spatial location or by semantic, shape, colour or size categories. However, only semantic and colour category organization were found to correlate significantly with recall. To account for the correlation results, two distinct general forms of organization are hypothesized.     

Directed forgetting of emotional stimuli in borderline personality disorder

On the basis of clinical literature, the authors hypothesized that individuals with borderline personality disorder (BPD) would show biased information processing when they were exposed to negative affective stimuli of a particular type. Individuals with BPD and controls were tested using a directed forgetting paradigm. Study participants were exposed to 3 types of words (borderline, neutral, positive) and were cued to either remember or forget each word as it was presented. There were no group differences on a free recall task for words in the remember condition. However, participants with BPD recalled significantly more of the borderline words from the forget condition than did controls. In other words, borderline participants remembered borderline words that they were instructed to forget. These results may be consistent with enhanced encoding of salient words and perhaps related themes in BPD individuals.     

Relation of mobility-fixity to the interpretation of pictorial stimuli

A group of 61 students who had previously (in 1986) been classified by Hansson, Rydén, and Johnsson in terms of perceptual fixity-mobility using a "free" Rod-and-Frame Test, were investigated regarding their interpretations of a nonfigurative stimulus shown repetitively at short exposure-times, and their characterization of two pictures each portraying two soldiers in intensive interaction--one man apparently attacking the other in the first picture and apparently rescuing or taking care of the other man in the second. Mobile subjects on the free Rod-and-Frame Test reported a larger number of different interpretations of the nonfigurative stimulus and construed it more frequently in terms of human themes than did the fixed subjects; in rating the pictures of soldiers, they used more extreme and complex characteristics. It appeared that, when confronted with ambiguous stimuli, the mobile individual moves both "horizontally", as it were, along the surface of objective reality, and "vertically", from present to past realities, thus conjoining subjective-emotional and objective-analytic aspects of perception. This interpretation agrees with Werner's model of mobility-fixity which implies that the mobile individual operates on different developmental levels of perceptual functioning.     

Recall of common and distinctive features of verbal and pictorial stimuli

Subjects first rated similarity of verbal and of pictorial stimuli. The same pairs of stimuli were presented again, without one common component and one distinctive component. Subjects were asked to recall the missing components and identify them as common or distinctive. The results show that components encoded as common are recalled relatively better than components encoded as distinctive, and the difference in recall is significantly greater in verbal than in pictorial stimuli.     

Effect of task demands on dual coding of pictorial stimuli

Recent studies have suggested that verbal labeling of a picture does not occur automatically. Although several experiments using paired-associate tasks produced little evidence indicating the use of a verbal code with picture stimuli, the tasks were probably not sensitive to whether the codes were activated initially. It is possible that verbal labels were activated at input, but not used later in performing the tasks. The present experiment used a color-naming interference task in order to assess, with a more sensitive measure, the amount of verbal coding occurring in response to word or picture input. Subjects named the color of ink in which words were printed following either word or picture input. If verbal labeling of the input occurs, then latency of color naming should increase when the input item and color-naming word are related. The results provided substantial evidence of such verbal activation when the input items were words. However, the presence of verbal activation with picture input was a function of task demands. Activation occurred when a recall memory test was used, but not when a recognition memory test was used. The results support the conclusion that name information (labels) need not be activated during presentation of visual stimuli.     

Nonaware classical conditioning to pictorial facial stimuli in a between-groups paradigm

The present experiment investigated the effects of aware and nonaware modes of extinction in classical conditioning to facial emotional stimuli. The subjects participated in three different experimental phases. In the first (habituation) phase they were presented with a 500 ms angry face. In the second (acquisition) phase, for half of the subjects the 500 ms face was paired with an aversive noise (experimental group) while for the other half of the subjects the face and the noise presentations were separated by 6–10 s intervals (sensitization control group). In the third (extinction) phase, these two groups were further divided into two subgroups. One subgroup of both the experimental and control group had the face stimulus presented for 30 ms, and immediately masked with a neutral picture. The other two subgroups had the face presented for 500 ms with no mask. The results showed that conditioning only occurred in the experimental subgroups which was indicated by a significant difference between skin conductance responses during habituation and corresponding responses during extinction. Secondly, comparing the experimental and control groups during the extinction phase, a significant conditioning effect was observed for both the aware and nonaware masked modes of extinction for the experimental group. The results suggest that conditioned autonomic responses may be elicited in a nonaware mode.     

Recognition memory for pictorial stimuli: biasing effects of stimulus emotionality

The possibility that stimulus emotionality might influence recognition bias in a long-term memory task was studied with respect to both the valence and arousal dimensions of emotion. For this purpose, we used 108 International Affective Picture System pictures that were representative of all regions of this two-dimensional space. Signal detection theory analysis was applied using A'and B' D as discrimination and bias measures, respectively. In general, the results showed that greater discrimination was accompanied by a response bias that was more conservative for pleasant and for unarousing pictures than for unpleasant and for arousing ones. These results provide new evidence in connection with the emotion-induced recognition bias in long-term memory performance.     

Retrieval-induced forgetting of negative stimuli: The role of emotional intensity

Repeatedly retrieving a subset of previously studied items can cause forgetting of related non-retrieved material. We examined whether such retrieval-induced forgetting holds also for negative material. Participants studied neutral and negative stimuli and then repeatedly retrieved a subset of the neutral material. Later, a recall test was conducted in which participants were asked to recall all previously studied items. On average, retrieval practice on the neutral items caused the same amount of forgetting for neutral and negative items, indicating that the emotionality of material does not affect retrieval-induced forgetting. More detailed analysis, however, revealed that the forgetting of negative items decreased with both the emotional intensity of a negative item and the dispositional negative affectivity of a participant. The decreases in retrieval-induced forgetting may have been driven by item-specific processing of material, which is known to be enhanced for highly negative stimuli and participants high in dispositional negative affectivity and to reduce or even eliminate retrieval-induced forgetting.     

Nonaware classical conditioning to pictorial facial stimuli in a between-groups paradigm.

The present experiment investigated the effects of aware and nonaware modes of extinction in classical conditioning to facial emotional stimuli. The subjects participated in three different experimental phases. In the first (habituation) phase they were presented with a 500 ms angry face. In the second (acquisition) phase, for half of the subjects the 500 ms face was paired with an aversive noise (experimental group) while for the other half of the subjects the face and the noise presentations were separated by 6-10 s intervals (sensitization control group). In the third (extinction) phase, these two groups were further divided into two subgroups. One subgroup of both the experimental and control group had the face stimulus presented for 30 ms, and immediately masked with a neutral picture. The other two subgroups had the face presented for 500 ms with no mask. The results showed that conditioning only occurred in the experimental subgroups which was indicated by a significant difference between skin conductance responses during habituation and corresponding responses during extinction. Secondly, comparing the experimental and control groups during the extinction phase, a significant conditioning effect was observed for both the aware and nonaware masked modes of extinction for the experimental group. The results suggest that conditioned autonomic responses may be elicited in a nonaware mode.     

Intent to remember briefly presented human faces and other pictorial stimuli enhances recognition memory

Since the early days of psychology, researchers have investigated whether or not intending to remember information affects subsequent memory performance. The literature contains methodological issues and empirical contradictions, with ambiguous effects. In five experiments, a total of 576 participants viewed a rapid series of pictorial stimuli under either incidental- or intentional-memory conditions. Although the methodology was stringent, intent to remember consistently enhanced recognition memory. Recognition was enhanced even when participants viewed a picture of a human face, of an ape face, or of a bird for as little as 0.5-1.0 sec, with no interstimulus interval between it and the next picture. Rehearsal, depth of processing, and attentional allocation are discussed to explain how people might intentionally encode pictorial information to enhance their subsequent recognition memory performance.     

An inverse base rate effect with continuously valued stimuli

It is well known that people do not always make normative use of information about relative frequencies of categories when making categorical judgments. The "inverse base rate" effect (Medin & Edelson, 1988) is a typical example of this: Subjects violate normative reasoning principles by assigning certain ambiguous stimuli as belonging to the less frequent of two categories, rather than to the more common category. This effect has been explained as being due to the shifting of attention from shared stimulus features to distinctive features during learning. When stimuli are defined by values along continuous dimensions, rather than by the presence and absence of features, then attention could shift between dimensions or between values, or both. In three experiments, base rate differences were used to determine the way in which attention is shifted during learning about stimuli with continuously valued dimensions. Simulation modeling shows that the results are consistent with the movement of attention both between and within stimulus dimensions.