Short-term memory for flavour

The short-term memory for the flavour of a wine in frequent but nonexpert drinkers was studied in an experiment comparing memory for wine under conditions where participants imagined and remembered a target wine with memory under conditions where participants carried out subsequent imaging and image rating tasks on the wine and on competing mental images. The results show that the cognitive operation of mental image rating produced enhanced memory when the operations were performed on the image of the target wine and somewhat impaired memory when operations were performed on an image of a competing flavour or operations performed on mental images in other domains. It is concluded that sensory traces of flavour may be effectively maintained in short-term memory when supported by appropriate encoding operations.     

Short-term memory for time intervals

The effect of intertrial interval, preset interval, and retention interval on the performance of rats in a time estimation task was described. On each trial a signal was presented for a duration of 2 to 8 sec. Eighteen rats were trained to press one lever (the short response) if the signal was shorter than 4 sec, and another lever (the long response) if the signal was longer than 4 sec. When trials were massed (Experiment 1), the percentage long response was affected by the classification of the previous signal, but not by its actual duration. This suggests that the animals remembered the response made on the previous trial, but not the signal duration. If a response was not permitted on the previous trial (Experiment 2), the duration or classification of the previous signal had no effect on performance. This supports the conclusion from the first experiment and suggests that an animal can reset its internal clock in less than 2 sec. In Experiment 3, the difference limen of the psychophysical function increased with the duration of the retention interval, but the point of subjective equality did not change. This suggests that resetting of the internal clock occurs on a non-time dimension.     

Short-term memory for intonation.

Ss were presented with lists of 16 words, each word spoken in one of four intonations. The final word was a repetition of one of the first 15 words, 40 Ss having to judge whether it was spoken in the same intonation as its earlier occurrence. A control group of 40 Ss did a similar task, ignoring intonation. Retention of intonation was significantly poorer, indicating that intonation is an additional load not normally retained. This argues against acoustic or articulatory encoding in short-term memory and in favor of an abstract-verbal encoding mode. Results are also interpreted as supporting the position that verbal and motor short-term membory obey similar laws.     

Short-term haptic memory for three-dimensional objects

In 8 experiments college students felt 32 geometric objects and were tested in a signal-detection framework to same or distractor items. Retention intervals and intervening experiences were also manipulated following initial touching. In all instances performance was high, and there was no evidence of a decline in haptic sensitivity over the retention intervals employed. These surprising results were interpreted as consistent with the 1985 contention of Klatzky, Lederman, and Metzger that the haptic modality constitutes an expert system.     

Social psychological models of choice behavior and drivers' left turns

ABSTRACT. The authors reanalyzed data from a simulated left-turn experiment (P. A. Hancock, J. K. Caird, S. Shekhar, & M. Vercruyssen, 1991) to test the adequacy of the nonlinear Gray-Tallman satisfaction balance model of choice behavior (L. N. Gray & I. Tallman, 1984) in predicting left turns. Participants (Hancock et al., 1991) were 40 experienced U.S. drivers who were exposed to simulated oncoming traffic; the size of the vehicle (motorcycle, compact vehicle, full-sized vehicle, delivery truck), its speed (10-70 mph, or 16-112 kmph), and the intervehicle time gap (3-9 s) varied. Hancock et al. (1991) measured (a) the likelihood of a left turn and (b) the occurrence of a collision. The probability of a left turn was greater for larger intervehicle time gaps and for oncoming smaller vehicles traveling at higher speeds. The Gray-Tallman (1984) model explained 69% of the variation in turning versus 57% for a linear regression model. In making decisions people tend to treat the values and costs affecting choices in a multiplicative, rather than linear, fashion. The Gray-Tallman model also has the potential for incorporating, both theoretically and mathematically, an unlimited range of potential values and costs that may influence left turn decisions.     

Why additive utility models fail as descriptions of choice behavior

This experiment sought to determine whether previously found metric violations of additive expectancy-value models C.F. J. C. Shanteau, Journal of Experimental Psychology, 1974, 103, 680–691; J. G. Lynch and J. L. Cohen, Journal of Personality and Social Psychology, 1978, 36, 1138–1151) were attributable to the inappropriateness of these models or to nonlinearities in the relationship between numerical ratings and underlying psychological impressions. Undergraduate participants performed two tasks employing the same experimental stimuli. In the first task, they rated the subjective values of hypothetical bets, judged separately and in combination. In the second task, they made pairwise comparisons of the same bets in terms of preference. The use of the same experimental stimuli in both tasks allowed a test of alternative models of utility judgment through application of the criterion of scale convergence (M. H. Birnbaum & C. T. Veit, Perception and Psychophysics, 1974, 15, 7–15). Results suggested that the additive expectancy-value model of judgments of the utilities of combinations of outcomes should be replaced by a weighted averaging rule in which the weight given to the value of each outcome in the averaging process is greater when this value is negative and extreme than when it is neutral.     

Short-term memory for spatial and temporal information

Two experiments examined the probed recall of visually presented letter sequences in which the items appeared at different spatial locations. Three types of probe were compared: (1) spatial position; (2) temporal association; and (3) combined position and association. In the first experiment, in which the spatial locations of the items were correlated with their temporal order, spatial probes were more effective than temporal association probes. In the second experiment spatial location was uncorrelated with temporal order, and spatial probes were less effective than temporal association probes. Regardless of the probe, errors tended to be items presented close in time to correct responses: spatial proximity was far less important. The results are discussed in terms of a storage system in which items and their spatial locations are organized within a temporal format. Both experiments showed superior combined probe performance, demonstrating that short-term retrieval is not limited to the use of one type of cue at a time. Secondary aspects of the results showed additionally that subjects can “edit” their responses to avoid making obvious mistakes, and that spatial location can be partially forgotten rather than being completely lost.     

Short-term memory for repeated and non-repeated items

Digit sequences containing repeated items are retained differently in short-term memory from sequences containing no repeated items. The repeated items are remembered better or worse than items in the corresponding positions of “all-different” sequences depending on the number of times the item is repeated, the number of items repeated, the number of items intervening between the occurences of a repeated item, and the position of the repeated items in relation to the beginning and end of the sequence. In every type of repetition studied, except one, memory for the non-repeated items in sequences with repeated items is better than for the corresponding items of all-different sequences. This is true in some cases despite significant specific interference between the (non-repeated) items following the separated occurrences of repeated items. The negative effects in memory for repeated items and the positive effects in memory for non-repeated items are greater when the items are presented at the rate of five per sec. than at one per sec., contrary to the hypothesis that differential rehearsal is responsible for these effects. The results are interpreted as supporting an “associative,” as opposed to a “non-associative,” theory of short-term memory, as this distinction is defined in the paper.     

Short-term memory for Chinese characters and radicals

Short-term memory for Chinese radicals and characters, varying in orthographic complexity, frequency, and—for radicals—intercharacter frequency (the number of compound characters that contain the radical), was studied using an immediate free-recall task. When radicals or characters are relatively frequent, so that their pronunciations are well known by literate Chinese, they seem to be maintained in verbal form in short-term memory. For these stimuli, intercharacter frequency and complexity have relatively small influences on memory span. Stimuli low in frequency, with pronunciations that are not apt to be known, seem to be maintained in visual form in short-term memory. Memory span is much smaller for these stimuli and is influenced by both intercharacter frequency and complexity. Furthermore, short-term memory for relatively high-frequency characters is interfered with more by a verbal than by a visual intervening task, whereas the opposite is true for low-frequency characters.     

Short-term memory for emotional faces in dysphoria

The study aimed to determine if the memory bias for negative faces previously demonstrated in depression and dysphoria generalises from long- to short-term memory. A total of 29 dysphoric (DP) and 22 non-dysphoric (ND) participants were presented with a series of faces and asked to identify the emotion portrayed (happiness, sadness, anger, or neutral affect). Following a delay, four faces were presented (the original plus three distractors) and participants were asked to identify the target face. Half of the trials assessed memory for facial emotion, and the remaining trials examined memory for facial identity. At encoding, no group differences were apparent. At memory testing, relative to ND participants, DP participants exhibited impaired memory for all types of facial emotion and for facial identity when the faces featured happiness, anger, or neutral affect, but not sadness. DP participants exhibited impaired identity memory for happy faces relative to angry, sad, and neutral, whereas ND participants exhibited enhanced facial identity memory when faces were angry. In general, memory for faces was not related to performance at encoding. However, in DP participants only, memory for sad faces was related to sadness recognition at encoding. The results suggest that the negative memory bias for faces in dysphoria does not generalise from long- to short-term memory.     

Short-term recognition memory for serial order and timing

Recent evidence suggests that a common temporal representation underlies memory for serial order of items in a sequence, and the timing of items in a sequence. This stands in contrast to other data suggesting a reliance on only ordinal information in short-term memory tasks. An experiment is reported here in which participants were post cued to perform a comparison between a probe and study list of items irregularly spaced in time, on the basis of order or temporal information.Participants' performance on theserial recognition task was notaffected by the temporal proximity of items, although participants were able to use temporal information to perform a temporal recognition task. Application of a temporal matching model of serial and temporal recognition suggests that although participants were able to remember the timing of items, this memory for timing was unlikely to determine serial recognition performance. The results suggest a dissociation between ordinal and temporal information in short-term memory.     

Scalable choice models

Two representational criteria for probabilistic choice models are studied. These criteria, called scalability and weak scalability, are shown to be characterized by behavioral axioms designated, respectively, as pairwise dependence and weak pairwise dependence. The former is shown to be equivalent to the order independence axiom of Tversky. In addition, structural conditions on the choice alternatives are established under which all axioms are equivalent.     

Short-term memory across eye blinks

The effect of eye blinks on short-term memory was examined in two experiments. On each trial, participants viewed an initial display of coloured, oriented lines, then after a retention interval they viewed a test display that was either identical or different by one feature. Participants kept their eyes open throughout the retention interval on some blocks of trials, whereas on others they made a single eye blink. Accuracy was measured as a function of the number of items in the display to determine the capacity of short-term memory on blink and no-blink trials. In separate blocks of trials participants were instructed to remember colour only, orientation only, or both colour and orientation. Eye blinks reduced short-term memory capacity by approximately 0.6–0.8 items for both feature and conjunction stimuli. A third, control, experiment showed that a button press during the retention interval had no effect on short-term memory capacity, indicating that the effect of an eye blink was not due to general motoric dual-task interference. Eye blinks might instead reduce short-term memory capacity by interfering with attention-based rehearsal processes.     

Short-term memory and aphasia.

Short-term retention tests of verbal item information (short-term memory for items) and order information (memory for sequences) were administered to aphasic, nonaphasic brain-damaged, and normal subjects. Memory for both parameters was significantly impaired in aphasics only. One-third of errors made by aphasics resulted from a specific, separable defect in short-term memory for sequences. As information load increased, memory for sequences became critical for linguistic performance of aphasics.     

Short-term recognition memory of tones

Four Os participated in a recognition memory experiment for a period of 5 weeks. The task required O to judge whether two temporally sequenced tones (ISI = 0.5, 2.0, or 8.0 sec) were the “same” or “different ” Latencies and confidence ratings were obtained for each judgment. TSD analyses applied to individual O’s data indicated consistent and rapidly decreasing d’s as a function of ISI. ROC functions generated from the latencies and ratings produced comparable results, indicating the feasibility of using latency measures along with the type of judgments made to obtain sensitivity measures. Response bias, as indicated by the differences in the latencies between “same” and “different” judgments, did not produce consistent trends.