In Experiments 1 and 2, after studying a list containing connotatively neutral words that were presented once or were presented at various spacing intervals, subjects either attempted free recall or made affective judgments of the study-list targets along a pleasant/unpleasant dimension. Spacing effects occurred in recall, and massed items were judged to be more unpleasant than once-presented and spaced words. In the third experiment, subjects studied homogeneous lists composed of either connotatively good words or connotatively bad ones. Spacing effects were absent in the recall of both types of words because massed-practice words were recalled at a high level, one that was about the same as that for spaced-practice words. Affective judgments were unrelated to presentation condition, and both good and bad massed words were judged to be positive in affect. Although the data suggest that different study conditions can lead to different affective reactions, the results are moot with regard to the relationship between affect and the magnitude of spacing effects.Long-term recall of repeated verbal items increases as the temporal spacing between presentations increases. Theoretical accounts of this pervasive spacing effect (for reviews, see Glenberg, 1979;Hintzman, 1974;Melton, 1970) have focused on various cognitive activities such as encoding, storage, and retrieval. According to these theoretical efforts, processes underlying the spacing effect result from what social psychologists (e.g., Zajonc, 1980) call "cold cognitions." Cold cognitions represent analytic activities and their outcomes, such as feature analysis, rehearsal, and other typical mnemonic activities and internal representations. The general picture derived from research on the spacing effect seems to be that some sort of trace elaboration process and inattention to the second presentation of a massed item are among the most important factors leading to spacing effects (Crowder, 1976;Hintzman, 1976). Exactly why cold cognitions lead to trace multiplexing and failures to attend to massed repetitions has not been well specified. One reason for the failure to determine the causes of the spacing effect may be due to the fact that theories and research have tended to ignore "hot cognitions," which in contrast to cold cognitions include those associated with the affective domain of experience. Boredom, preference, positive arousal, and other affective states and processes have not received much emphasis as factors determining the spacing effect. The present paper reports several experiments designed to test the idea that affective processes play an important role in the spacing effect.

Three experiments were conducted in which positive and negative contrast on visual display terminals were directly compared. Operator tasks included visual search and reading, with accuracy and timeliness of response measured. In all cases where significant differences exist, better performance was obtained with negative contrast (dark characters or symbols on a lighter background). The increases in performance range from a low of 2.0 percent to a high of 31.6 percent. Based on the above results, we believe that there are significant advantages in visual task performance obtained from the selection of negative contrast displays.Current standards that require negative contrast appear to be justified, while future revisions of ANSVHFS 100-1 988 and other standards should seriously consider incorporating negative contrast as a recommendation or requirement.

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This study was conducted to investigate the effects of display failures and rotation of dot-matrix symbols on visual search performance. The type of display failure (cell, horizontal line, vertical line), failure mode (ON, failures matched the symbols; OFF, failures matched the background), percentage of failures (0, 1, 2, 3, 4%), and rotation angle (0, 70, 105 degrees) were the variables examined. Results showed that displays which exhibit ON cell failures greater than 1% significantly affect search time performance. Cell failures degrade performance more than line failures. Search time and accuracy were best when symbols were oriented upright. The effects of display failures and rotation angle were found to be independent. Implications for display design and suggestions for quantifying the distortion due to rotation are discussed.