Redundant Messages Research Articles

Verbal Reasoning and Working Memory

A series of experiments was carried out to explore the hypothesis that a central working memory (WM) system is utilized during verbal reasoning. WM was provisionally defined in terms of two major features of short-term memory (STM): its limited storage capacity and its use of speech-coded information. The reasoning task required subjects to match (verify) as rapidly as possible a sentence of varying grammatical form with a symbolic referent. Experiments I and II studied the effect of storing an additional STM load on sentence verification latencies. As many as six items could be correctly recalled with no slowing of verification speed. Experiment III used a different procedure in which the STM items had to be articulated aloud during verification. In this case six-item STM loads slowed verification speed considerably, and did so more for the more difficult sentences. Only a small non-significant slowing of verification speed was obtained when redundant messages were articulated. Experiment IV showed that latencies were also increased by introducing phonemic similarity into the verification task. Generally the results were not fully consistent with the hypothesis of WM as a limited capacity store called upon by the verification task. Instead they supported the view that the WM is a general executive system with a limited capacity for information processing. It was proposed that the articulatory system, used in rehearsal and concerned with speech-coding, is a “peripheral” of the more central WM executive and plays a relatively minor role in verbal reasoning.

Selective Attention and Secondary Message Analysis: A Reconsideration of Broadbent's Filter Model of Selective Attention

If the type of channel sharing which Broadbent (1958) hypothesized for low information messages also occurs with high information verbal messages, then his filter model is an adequate model of the selective attention process. Analysis which proceeds by a hierarchy of tests and the fluctuating redundancy of primary prose messages can together account for the characteristics of secondary message detection. This hypothesis was tested using four levels of redundancy in the primary message, and two types of secondary message targets, requiring analysis to two different levels in the hierarchy of tests for detection. It was predicted that there should be more target detection as redundancy increased, and more detection of the targets requiring the lower level of analysis than of those requiring the higher. The predictions were confirmed with the exception that the higher level targets were detected with equal frequency at all levels of redundancy. A possible reason for this is suggested.

Biomedical gerontology. Current theories of biological aging.

Several lines of evidence have led to the notion that biological aging occurs as a result of changes in information-containing molecules either at the genetic or epigenetic level. The error theory, the redundant message theory, the codon restriction theory, and the transcriptional event theory represent the major current conceptualizations of biological aging as held by most gerontologists. The finding that cultured normal human and animal cells undergo a finite number of population doublings in vitro has provided new insights into age changes at the cellular level. The number of mitotic events that cultured normal animal cells can undergo appears to be inversely related to the age of the donor. A direct proportionality exists, however, between the mean maximum life-span of a species and the number of population doublings that their cultured embryonic cells will undergo. The several biochemical decrements known to occur prior to the cessation of mitotic activity in vitro are thought to herald those manifestations of senescence seen in the whole animal. Yet to be explained is how those cell classes such as the germ plasm and continuously propagable cancer cells escape from the inevitability of biological aging.—Hayflick, L. Current theories of biological aging. Federation Proc. 34: 9–13, 1975.

The Effect of Reducing the Redundancy of Written Messages by Deletion of Function Words

(1972). The Effect of Reducing the Redundancy of Written Messages by Deletion of Function Words. The Journal of Psychology: Vol. 82, No. 2, pp. 299-306.

Logical structure of adaptive systems: I. Microevolution, conditioning and their decision problems

First, the scope of the project and its motivation are presented. Arguments are offered in support of the contention that the theoretical description presented in the body of the paper is a non-trivial one which possibly characterizes the phenomena described. Second, microevolution and conditioning are described as analogous adaptive processes that construct symbolic models of the environment by assembling classes of messages. Potential class members originating as statistically determinate memory unit variability, are tested by a two-part membership criterion. Those potential class members which satisfy formal (i.e. syntactic) criteria specified by a machine-like part of the adaptive system are messages. Messages which survive an environmentally-specified test of function are efficacious messages. Genes-in-a-population and the engrams of conditional stimuli, discriminative stimuli, and operant responses are classes of efficacious messages. Each of these classes has a size parameter (a gene's frequency; an engram's strength) whose material basis is the number of message-instances comprising the class. As a result of natural selection and reinforcement, the amount of this “message redundancy” reflects the efficacy of the messages constituting the class. Third, by reference to experimental results, it is demonstrated that decisions within adaptive systems which appear to be based upon an evaluation of the efficacy of individual message-instances are in actuality based upon message redundancy in one way or another. A scheme for a learning machine is presented which illustrates how secondary reinforcement and chaining may be simulated by measuring message redundancy. Fourth, having established as an empirical generalization that efficacy is evaluated within an adaptive system in terms of message redundancy, the logic underlying microevolution and conditioning is examined. It is demonstrated that, because of the two-part membership criterion, the efficacy of individual message-instances is undecidable within an adaptive system and, therefore, that indirect evaluation of efficacy is unavoidable. Four theorems which delineate the decision problems of microevolution and conditioning are demonstrated, and their scopes illustrated by application to the learning machine. Analogies are drawn between the decision problems of microevolution and conditioning and those of two deductive systems. Fifth, a natural extension of the theoretical description to more complex processes than microevolution and conditioning is considered. A hypothetical mechanism is suggested to account for the ability of adaptive systems to build upon the environmentally specified information they accumulate. In terms of the mechanism partial copies (complements) of efficacious messages are used as autonomous names in the construction of messages about messages. The freezing of coding structures, hierarchy formation, and self reference are briefly discussed in the light of this. An interpretation is suggested for the phyletic and intragenome polynucleotide sequence redundancies observed in genetic systems. Finally, conclusions are drawn.

The effect of speaker identity, voice inflection, vocabulary, and message redundancy on infants' selection of vocal reinforcement

Three normal infant boys aged 11–15 months played in their standard playpens at home in more than 300 test sessions with an automated behavior analysis toy that allowed them to select between pairs of voice and other audio reinforcements offered via endless loops of pre-recorded stereo audio tape. Among the salient findings were: significant preference for mother's voice feedback over simple music feedback; discriminative selection between stranger's voice and mother's voice; shifting preference related to variations of inflection, vocabulary, and speaker's identity; shifting preferences related to high and low values of feedback redundancy. Findings are discussed in a context of cognitive development and aspects of the growth of expressive speech.

On the Redundancy of Speech and Articulation and Perception

Highly redundant messages were recorded at normal and fast rates of talking. Certain words were gated out of these messages and listening tests were performed on these words. Nonredundant messages were then recorded using these same words in similar phonetic environments. The same words were again gated out and listening tests were again performed. Quite apart from these listening teats, two operational measures of redundancy were derived. One measure was based on a finite-state model of perception and readers were asked to guess what word n would be after they had read all the words through word n − 1 in a sentence. The second measure was based on the hypothesis that people reserve their final decision on the recognition of each word until they perceive an entire sentence. Readers read an entire sentence in the midst of which a word was represented by a dash. They were then asked to guess what the missing word was. Our index of redundancy was the percent of correct guesses. The results of our listening tests show that the intelligibility of the gated words is inversely proportional to the redundancy index obtained by the second measure of redundancy.

Human memory and the storage of information

The amount of selective information in a message can be increased either by increasing the variety of the symbols from which it is composed or by increasing the length of the message. Psychological experiments indicate that the variety of the symbols is far less important than the length of the message in controlling what human subjects are able to remember. Two messages equal in length but differing in the amount of information per symbol are equally easy to memorize. This fact provides an opportunity for the effective use of recoding procedures and reveals the mental economy involved in organizing the materials we want to remember. An apparent exception to the rule that length, not variety, is the limiting factor in human memory occurs in the case of redundant messages. If two messages of the same length differ because one contains redundancy familiar to the learner and the other does not, the redundant message will usually be easier to learn and remember. In terms of the theory of information, redundancy can be viewed equally well as a reduction in the information per symbol or as a reduction in the effective length of the message. Psychologically, however, these two alternatives are not equivalent; redundancy permits a reorganization into familiar sequences in a way that effectively shortens the length of the message and so makes it easier to memorize, but this is not psychologically equivalent to reducing the amount of information per symbol. It is as if each storage register could accept any one of a tremendous variety of alternative symbols, but the number of registers available was quite limited. If we use these registers to store binary symbols, the storage is inefficient. If we group the binary symbols into sequences, give each sequence a different name, and store the recoded names, we can make much more efficient use of the registers. Familiar redundancy is helpful because it enables us to recode more efficiently. These results for human memory are all the more striking in view of the fact that the amount of information per symbol is a critically important variable controlling the accuracy of our perceptions.