Reciprocation of generosity and knowledge of game termination in the decomposed Prisoner's Dilemma Game

Sahlins proposed a model of reciprocity for social interaction citing three forms drawn from observations of kinship systems. The model describes an altruistic form of reciprocity, a balanced or economic form and a negative form in which individuals try to outdo each other. This model was applied to a two-person variation of the Prisoner's Dilemma Game where Ss were presented with a confederate who responded over trials entirely generously, contingently generously or non-generously. Half of the Ss were informed that there would be ten trials while the other half were uninformed. Basically, Ss tended to match the generosity level of the confederate and were less generous when trial number was known. Evidence for Sahlins' model is provided by Ss reports of reasons for their choices in the game. Those in the generous condition gave reasons for reciprocating based on a general feeling of obligation, trust and desire to cooperate. Those in the contingently generous condition gave reasons for reciprocating based on economic exchange and a desire to maintain a balance of resources. Ss in the non-generous condition gave reasons based on a desire to take what profits one could before the other got them. In addition, Ss indicated a significant tendency to exploit the other on the final trial under the informed condition for the contingently generous but not for the generous condition.     

Groups perform better than the best individuals on letters-to-numbers problems: informative equations and effective strategies

One-hundred 3-person groups and 300 individuals solved 2 letters-to-numbers problems, requiring identification of the coding of 10 letters to 10 numbers by proposing an equation in letters, receiving the answer in letters, proposing a hypothesis, and receiving feedback on the hypothesis on each trial. There were 5 instruction conditions: (a). standard, (b). use at least 3 letters on all equations, (c). use at least 4 letters on all equations, (d). number 1 known before beginning problem, and (e). number 9 known before beginning problem. The groups had fewer trials to solution, proposed more complex equations, and identified more letters per equation than the best individuals. Performance was best under instructions to use at least 4 letters and with the number 9 known.     

Evaluation of hypotheses in concept identification

The aim of this paper is to investigate the nature of hypothesis evaluation in conceptual tasks, especially in the identification of bidimensional concepts. In such tasks, hypothesis testing is seen as being composed of sampling and evaluation stages. With complex problems only one hypothesis seems likely to be sampled on each trial, and it is suggested that this hypothesis is evaluated according to a statistical decision-making process. In Experiment I, Ss were given an initial hypothesis involving one of eight rules and required to test it in an attempt to find a concept. When this given hypothesis was true (i.e., the concept), no difference was found between rules for the number of instances selected to the criterion of solution. Moreover, there was a tendency for Ss to choose instances which were predicted to be positive according to the hypothesis under test. Experiment II examined the role of memory in hypothesis testing. Immediate recall of instances selected revealed no difference between true and false hypotheses. Both primacy and recency effects were evident in recall. The number of instances correctly recalled was more than expected by models of hypothesis sampling and evaluation, and this was attributed to Ss having a low criterion for recall without intrusions. Examination of intrusions suggested that Ss may have retained some, but not all, of the features of the stimuli selected. Some differences were found between rules and between positive and netative instances on recall. These effects were suggested to be due to different amounts of information processing when classifying each type of instance for each rule; the results of Experiment III supported this suggestion.     

Processing of sequentially presented letters

The effect on the number of letters S can report of the duration of each sequentially presented letter was compared with that of processing time, defined as the time from the onset of a letter to the onset of the next letter. Four Ss were each shown 1250 common English words, from four to eight letters long, one letter at a time. Each letter acted as a visual noise field for the preceding letter. The duration of each letter and the interval between letters was varied independently. The S reported the letters he saw after each word was displayed. It was found that the processing time (onset to onset) predicted the number of letters correctly reported, regardless of the partition between on time and off time. A calculation was made of the number of milliseconds of on plus off time that are needed to ensure correct report of each letter. This time was independent of the duration of the processing time, but was positively correlated with the number of letters in the word. This correlation is probably in part artifactual, so that no claim can be made that it takes longer to process a letter of a long as compared to a short word.     

Attention and information storage in visual short-term memory

Schioldborg, P. Attention and information storage in visual short-term memory. Scand. J. Psychol., 1973, 14, 1–3.- Information retrieval from STM was examined with Sperling's (1960) method. Of nine letters displayed in rows of three, the number of letters correctly reported from each row differed significantly, the mean being 2.4, 2.2, and 1.6 letters for the middle, upper, and lower row, respectively. By increasing exposure time, number of correctly reported letters increased for each row at equal rate. However, by increasing the delay period of the selection signal, number of letters decreased at different rates, the reduction being 48%, 24%, and 10% for the lower, upper, and middle row respectively. The results are assumed to reflect differences in the initial attention level for the individual item; the smaller this level, the lower the level of information processing and the faster the erasure from STM.     

Order of report and processing in tachistoscopic recognition

Two groups of 12 Ss were shown tachistoscopically 4 letters and 4 numbers. Within these alpha-numeric sequences, three variables were systematically manipulated: grouping of items, initial item, and familiarity of the letter sequences. One group of Ss reported first letters then numbers from each sequence; the other group reported numbers then letters. The results indicated that grouping, redundancy, and order of report had significant effects on letter accuracy but not on number accuracy. These effects were interpreted in terms of processing, particularly the use of spatial and identity information during recognition.     

Short-term retention of superimposed and of spatially distinct multiletter visual arrays

On each trial, Ss attempted to retain a series of five visually presented letters while concurrently “shadowing” (repeating aloud) a rapid series of aurally presented letters. If serial-position accuracy is ignored, they were able to store more than only the last letter of a typical series, even though all five letters appeared on the same screen, and that performance was superior to the retention of five auditorily presented letters. Together, these findings suggest that a form of visual storage might have been employed for the retention of visual stimuli and, specifically, one that was relatively immune to erasure as compared to “iconic” storage. In further support of that hypothesis, retention of such visual series as measured by free-recall accuracy was not inferior to that of five letters, each of which was presented on a separate screen.     

A different look at perceptual defense for taboo words

Hober has concluded from previous work that meaningfulness, frequency, and related stimulus variables directly affect the clarity of letters of words. To examine whether the letters of taboo words would be harder to see, 12 taboo words were matched in length to 12 very frequent and 12 very rare neutral words. Each word was shown an unpredictable number of times. Three groups of 8 Ss each were required, respectively, either to name the letters they saw on each flash, name the letters and then guess the word, or guess the word only. While no differences were found among the three groups, the clarity of the letters of the frequent words exceeded that for the rare words, which in tum was higher than that of the taboo words. This difference was apparent on even the first flash, supporting the interpretation of a perceptual defense effect.     

Groups perform better than the best individuals on letters-to-numbers problems: effects of group size

Individuals and groups of 2, 3, 4, or 5 people solved 2 letters-to-numbers problems that required participants, on each trial, to identify the coding of 10 letters to 10 numbers by proposing an equation in letters, receiving the answer in letters, proposing a hypothesis, and receiving feedback on the correctness of the hypothesis. Groups of 3, 4, and 5 people proposed more complex equations and had fewer trials to solution than the best of an equivalent number of individuals. Groups of 3, 4, and 5 people had fewer trials to solution than 2-person groups but did not differ from each other. These results suggest that 3-person groups are necessary and sufficient to perform better than the best individuals on highly intellective problems.     

Response set effects in recognition memory

In three experiments, Ss responded to individual digits or letters according to whether or not each was in some prememorized list. There were either two possible responses (yes-no condition) or a single response (yes-only and no-only conditions). With memory sets of one, two, or four digits, RT was a linear function of memory set size. The slope of the function was least under the yes-only condition and greatest under the yes-no condition. Nonspecific practice had little effect on any of the slopes. With memory sets of 4, 8, or 12 letters, the slopes under the yes-only and yes-no conditions did not seem to differ, and practice with specific sets flattened the function considerably in both cases. Overall, the errors under the yes-no condition were mostly false alarms, those under the no-only condition mostly misses, and those under the yes-no condition were divided about equally. The results are interpreted partially in terms of a multiple-observations model of decision time.     

Confusability and interference between members of parafoveal letter pairs

In each of three experiments, confusability between members of a parafoveally exposed pair of letters affected accuracy of identifying the peripheral, but not the central, letter. Confusability was determined from a confusion matrix developed for each subject. In Experiment 1, only one letter in each pair was identified on each exposure, and the position of pair members was varied over trials while the absolute position of the pair was held at a constant distance from fixation. In Experiment 2, both letters were identified on each exposure. In Experiment 3, the criterion letter was presented at a constant distance from fixation, and both letters were identified on each exposure. Since results in Experiment 3 were the same as in Experiments 1 and 2, the effect cannot be explained with reference to an interaction between confusability and acuity. The implications of the findings for various models of visual information processing are discussed.     

Recognition memory for distractor faces depends on attentional load at exposure

Incidental recognition memory for faces previously exposed as task-irrelevant distractors was assessed as a function of the attentional load of an unrelated task performed on superimposed letter strings at exposure. In Experiment 1, subjects were told to ignore the faces and either to judge the color of the letters (low load) or to search for an angular target letter among other angular letters (high load). A surprise recognition memory test revealed that despite the irrelevance of all faces at exposure, those exposed under low-load conditions were later recognized, but those exposed under high-load conditions were not. Experiment 2 found a similar pattern when both the high- and low-load tasks required shape judgments for the letters but made differing attentional demands. Finally, Experiment 3 showed that high load in a nonface task can significantly reduce even immediate recognition of a fixated face from the preceding trial. These results demonstrate that load in a nonface domain (e.g., letter shape) can reduce face recognition, in accord with Lavie’s load theory. In addition to their theoretical impact, these results may have practical implications for eyewitness testimony.     

Free sorting with stimuli clustered in a multidlmensional attribute space

An experiment was conducted to determine whether Ss leam, without knowledge of results or prior familiarization with the prototypes, to sort histoform stimuli generated by three probablistic rules into categories consistent with these mies. Seven Ss were asked to sort 30 stimuli (10 from each schema population) on each trial. No constraints were placed on the number of categories to be used. A statistic was developed to measure consistency between schema-defined categories and subjeet-defined categories. Four of the seven Ss met the leaming criterion, and demonstrated increasing consistency with the schema-defined categories across trials. In general, more categories than necessary were used to classify the stimuli correctly. The results raise several questions about classification strategies used by Ss in perceptual learning tasks with stimuli generated by probabilistic rules, and indicate the need for further research conceming the variables that influence perceptual category formation.     

Vocal and manual response latencies to bilateral and unilateral tachistoscopic letter displays

Bilateral rows of eight letters and unilateral rows of four letters were presented in randomized sequences for 100 ms. Subjects were required to recall all letters in a trial (Experiment I); recall letters from one hemifield cued at exposure (Experiment II); recognize a single letter, making a vocal response (Experiment III); recognize a single letter, making a manual response (Experiment IV). In Experiments I, II and III, identification errors were fewer and vocal response latencies were faster for RVF stimuli, except in the bilateral condition on Experiment I; in Experiment IV manual response latencies were the same, for left and right, bilateral and unilateral conditions. Collectively, the results could not be satisfactorily accounted for by any one hypothesis: report-order, trace-scanning, or cerebral dominance. The relative contribution of each process to the laterality effect was discussed.     

照明环境与LCD显示界面背景饱和度的交互效应对视觉绩效的影响

摘 要 采用E-prime编排认知实验研究照明环境与TFT-LCD视觉显示终端界面背景饱和度的交互效应对视觉绩效的影响。依据字母视力表设计原理制作认知材料,以认知速度与准确率为视觉绩效评价指标。结果发现,照度与饱和度的交互效应对视觉绩效存在显著影响,色温与饱和度的交互效应仅对准确率存在显著影响,三因素交互作用对准确率存在显著影响。结果表明,不同照度、色温下,通过调节显示终端界面背景饱和度可改善视觉绩效。     

Visual detection in relation to display size and redundancy of critical elements I

Visual detection was studied in relation to displays of discrete elements, randomly selected consonant letters, distributed in random subsets of cells of a matrix, the S being required on each trial to indicate only which member of a predesignated pair of critical elements was present in a given display. Experimental variables were number of elements per display and number of redundant critical elements per display. Estimates of the number of elements effectively processed by a S during a 50 ms. exposure increased with display size, but not in the manner that would be expected if the S sampled a fixed proportion of the elements present in a display of given area. Test-retest data indicated substantial correlations over long intervals of time in the particular elements sampled by a S from a particular display. Efficiencies of detection with redundant critical elements were very close to those expected on the hypothesis of constant sample size over trials for any given display size and were relatively invariant with respect to distance between critical elements.     

Bilateral Reminiscence in Inverted-Reversed Printing

Reported is a study of bilateral reminiscence in printing inverted-reversed alphabetic letters. Independent variables were the printing-Hand Sequence (left-to-right vs. right-to-left), and the Interpolated Activity (control vs. upright reading vs. inverted reading). These variables were factorially combined in a 2 × 3 design with 30 Ss per cell. On second-hand performance, the upright groups were found to be superior to the combined inverted and control groups under both sequence conditions. However, the inverted group was superior to the control group only in the left-to-right condition and not in the right-to-left condition. This latter result was discussed as possibly being due to the specialization of the cerebral hemispheres for certain types of processing activities. Implications of this hypothesis were pointed out for further research, and for possible mechanisms producing reactive inhibition in the central nervous system.     

Sequential letter and word recognition in deaf and hearing subjects

To examine the processing of sequentially presented letters of familiar and nonsense words, especially among Ss of vastly differing experience on sequential tasks, three groups of Ss were tested on letters of words spelled sequentially on an alphanumeric display and on letters of words fingerspelled. These were a deaf group (N=33) with little or no hearing and who varied in their fingerspelling ability; a staff group (N=12) who taught fingerspelling and were highly proficient; and a hearing group (N=19). Of principal interest was the finding that the hearing Ss did better on nonsense letter recognition, while the deaf group did better on word recognition. Word length was important except to the staff Ss on fingerspelled words, which also suggests that concentration on fingerspelling proficiency forces attention to the whole word and not its component letters. Hearing Ss, who are the group faced with an unfamiliar task, seemed to attend to each letter and hence had more difficulty with recognition of the longer unit.     

Practiced card sorting for multiple targets

Ss were given extended practice in card sorting. Each card was inscribed with nine letters; on half the cards one letter was a “target.” With practice, the Ss could sort as fast for eight targets at once as for a single difficult target, while maintaining the same overall error rates. However, they did miss the difficult target itself more often when it occurred in the multiple-target condition than when they were searching for it alone.     

Stereopsis with opposite contrast contours

The effects of incidental stimuli, defined as visual stimuli not under verbal control, upon a selection task were observed as a function of feedback contingency. Ss judged letter pairs to be valid or invalid completions of preceding letter parts. During the presentation of the letter parts, the response pair or an alternative pair of letters was intermittently presented at a threshold value individually determined for each S. One group of Ss received a light feedback of performance contingent upon responding to the incidental stimuli; whereas a second group received a random noncontingent feedback. The results indicated: (a) both groups responded to the incidental stimuli; (b) feedback contingency had no effect on frequency of responding to the incidental stimuli; (c) frequency of responding to the incidental stimuli remained constant over 32 trials.