Many people occasionally experience confusion as to whether they have actually performed or only imagined (thought about) performing some action in the past. Five experiments are reported that investigate some of the memory and decision processes involved in distinguishing between memories of doing and memories of imagining doing, Each experiment involved an activity phase ,and a test phase. As each item, typically a line drawing, was presented, subjects traced or imagined tracing the outline of the item or simply looked at the item. Approximately 15 rain later, subjects were tested for their ability to recognize each item and to identify the activity performed on it.

No abstract

The purpose of this study is to further understanding of the function of nonlinear vocalizations in red wolves (Canis rufus) by examining the acoustic, structural, and contextual characteristics of nonlinear sounds as compared to linear sounds. Video recordings of captive wolves from a breeding facility were analyzed. The acoustic nature of sound units was consistent with that of other social canids. The sound units included high-frequency squeaks (2600-9500 Hz) and low-frequency wuhs (160-1600 Hz) occurring either as separate units or in combination as nonlinear units (squeak-wuh frequency jumps, biphonations, squeaks with sidebands) and frequency jumps within squeaks. These low-amplitude sounds occurred in trains of 1-30 units that were classified as squeak vocalizations (49%), wuh vocalizations (19%), and nonlinear vocalizations (any combination including one or more nonlinear units, 32%). Nonlinear vocalizations transitioned directionally from high-frequency units to mixed-frequency units which has implications for the study of sound production and function. Wolves squeaked most often when oriented toward others, implying a solicitation function, while wuh vocalizations were more common during social interactions. Nonlinear vocalizations occurred most often during penmate-play or when oriented toward neighbors, indicating that nonlinear sound production may signal an increase in arousal.

Do true qualitative differences exist between the processing of pictorial and linguistic materials or are the differences simply a matter of degree? The dual code hypothesis (Paivio, 1971) assumes the existence of verbal and imaginal coding systems. The former is specialized for the coding of linguistic and sequential information, while the latter is specialized for pictorial and spatial information processing; it is also most durable. Alternatively,, Anderson and Bower (1973) postulate a unitary processing system where all information enters a conceptual data base. While the unitary model appears to predict only quantitative performance differences, the dual code hypothesis predicts both qualitative and quantitative effects.Because both models predict quantitative differences, such effects are not sufficient to distinguish between the two models. Furthermore, quantitative effects, as investigated most often, are difficult to interpret, since it is virtually impossible to equate words and pictures on most psychological dimensions. That is, picture superiority effects are ambiguous simply because the level of interitem similarity across form classes has not been equated. Consideration of these difficulties led to the conclusion that direct comparisons of performance on pictures and words should not be attempted at this time. Rather, the pattern of results within form classes should be compared. If qualitative differences exist, the patterns across conditions should be different for the two types of materials; if only quantitative effects exist, the trends should be similar. Experiments using variants of this paradigm point to the potential existence of both qualitative and quantitative differences in the processing and retention of pictorial and linguistic materials.The present experiments investigate the retention of temporal and spatial structures as a function of form class. The dual code hypothesis predicts that, with words, temporal structures should be retained better than spatial structures; with pictures, the reverse should hold. The unitary model predicts similar trends for the two form classes. A series of experiments demonstrate that (a) temporal and spatial structures may be coded independently of one another, (b) linguistic materials lead to temporal superiority whereas pictorial forms give rise to temporal/spatial equality, (c) imposed encoding strategies do not influence the above patterns, and (d) imaginal processing does not necessarily lead to superior retention. These findings support the basic spirit, though not all of the particulars, of the dual code hypothesis and raise several questions concerning the nature of temporal and spatial structures.

No abstract