Age-linked declines in retrieving orthographic knowledge: empirical, practical, and theoretical implications.

This study developed and tested a Transmission Deficit hypothesis of how aging affects retrieval of orthographic knowledge. Young, older, and very old adults heard a tape-recorded series of difficult-to-spell words of high and low frequency, spoken slowly, clearly and repeatedly, and wrote down each word at their own pace. With perceptual errors and vocabulary differences factored out, misspellings increased with aging, especially for high-frequency words. In addition, data from a metamemory questionnaire indicated that the oldest adults were aware of their declining ability to spell. These findings were not due to general slowing, educational factors, hours per week spent reading, writing, or solving crossword puzzles, or age-linked declines in monitoring or detecting self-produced errors. However, the results fit Transmission Deficit predictions, and suggested an age-linked decline in retrieval of orthographic knowledge that resembles age-linked declines in spoken word retrieval observed in many other studies. Practical implications of this age-linked decline for conceptions of normal aging are noted.

Aging on the input versus output side: theoretical implications of age-linked asymmetries between detecting versus retrieving orthographic information.

This experiment tested for age-linked asymmetries predicted under Node Structure theory (NST; D. G. MacKay & D. M. Burke, 1990) between detecting versus retrieving orthographic information. Older adults detected that briefly presented words were correctly spelled (e.g., endeavor) or misspelled (e.g., endeavuor) as readily as did young adults. However, they were less able than young adults to retrieve the correctly and incorrectly spelled words that they had seen. These age-linked asymmetries were not due to educational factors, stimulus characteristics, sensory-level factors, task complexity, floor or ceiling effects, general slowing, or cohort-related activities, but they were consistent with NST predictions and with similar asymmetries in a wide range of other studies. By contrast, repetition deficits in detecting and retrieving repeated- versus unrepeated-letter misspellings (e.g., elderdly vs. elderkly) were symmetrical or equivalent in magnitude for young and older adults. Implications for a wide range of theories of cognitive aging and of repetition deficits are discussed.

Repetition blindness and aging: evidence for a binding deficit involving a single, theoretically specified connection.

This study tested 2 main hypotheses for explaining repetition blindness (RB), a difficulty in encoding and recalling rapidly presented repeated words in sentences. Under 1 hypothesis, RB reflects an inhibitory process and should be more pronounced in young than in older Ss, who typically exhibit diminished inhibitory processes. Under the second hypothesis, RB reflects a failure to bind a specific connection: The second connection from the single node for encoding a repeated word is difficult to form under time pressure. Under this binding hypothesis, young adults should exhibit less RB than older adults, who typically require more time to form new connections. Results supported a version of the binding hypothesis but contradicted the inhibition hypothesis, and did not support hypotheses whereby RB reflects either a refractory effect or perceptual fusion of the repeated words.

A tale of two paradigms or metatheoretical approaches to cognitive neuropsychology: did Schmolck, Stefanacci, and Squire (2000) show that hippocampal lesions only impair memory, whereas adjacent (extrahippocampal) lesions impair detection and explanation of sentence ambiguity?

This note discusses two fundamentally different paradigms or metatheoretical approaches that currently guide cognitive neuropsychology: the Theoretical- vs. Anatomical-paradigms. To illustrate these paradigms, we compare a Theoretical-paradigm paper (MacKay & James, 2001) with an Anatomical-paradigm paper (Schmolck, Stefanacci, & Squire, 2000): These papers report virtually identical experiments on relations between language, memory, and hippocampal systems, using the same task (the detection and explanation of ambiguities in sentences that participants know are ambiguous), virtually identical ambiguous sentences, and at least one identical participant (the amnesic HM). However, MacKay and James made strikingly different claims from Schmolck et al., and we show that the Schmolck et al. claims comport not with their data but with an unstated theory to which they are implicitly committed within the Anatomical-paradigm.

The problem of rehearsal or mental practice.

The present study examines several methodological and conceptual problems which in the past have made it difficult to accept the hypothesis that mental practice facilitates behavioral skill. An experiment on skill in speech production is then reported which overcomes the methodological problems. Subjects practice producing a sentence at maximal rate either mentally (mental practice) or overtly (physical practice) and then produced a transfer sentence which was either related or unrelated. The maximal rate of speech was faster for related than unrelated transfer sentences, and the degree of transfer for the mental and physical practice conditions was equivalent. A theory was developed to explain these results and overcome the conceptual problems outlined in the introduction. Implications of the theory for several related phenomena are discussed: rehearsal, errors in action, automatization, control processes in motor skills, speed-up as a function of practice, the relative advantages of physical vs. mental practice, and the evoked potentials accompanying mental rehearsal of an action.

The Moses, mega-Moses, and Armstrong illusions: integrating language comprehension and semantic memory.

This study develops a new theory of the Moses illusion, observed in responses to general knowledge questions such as, "How many animals of each kind did Moses take on the Ark?" People often respond "two" rather than "zero" despite knowing that Noah, not Moses, launched the Ark. Our theory predicted two additional types of conceptual error demonstrated here: the Armstrong and mega-Moses illusions. The Armstrong illusion involved questions resembling, "What was the famous line uttered by Louis Armstrong when he first set foot on the moon?" People usually comprehend such questions as valid, despite knowing that Louis Armstrong was a jazz musician who never visited the moon. This Armstrong illusion was not due to misperceiving the critical words (Louis Armstrong), and occurred as frequently as the Moses illusion (with critical words embedded in identical sentential contexts), but less frequently than the mega-Moses illusion caused when Moses and Armstrong factors were combined.

Memory, language, and ageing.

This overview provides both theoretical and empirical reasons for emphasizing practice and familiar skills as a practical strategy for enhancing cognitive functioning in old age. Our review of empirical research on age-related changes in memory and language reveals a consistent pattern of spared and impaired abilities in normal old age. Relatively preserved in old age is memory performance involving highly practised skills and familiar information, including factual, semantic and autobiographical information. Relatively impaired in old age is memory performance that requires the formation of new connections, for example, recall of recent autobiographical experiences, new facts or the source of newly acquired facts. This pattern of impaired new learning versus preserved old learning cuts across distinctions between semantic memory, episodic memory, explicit memory and perhaps also implicit memory. However, familiar verbal information is not completely preserved when accessed on the output side rather than the input side: aspects of language production, namely word finding and spelling, exhibit significant age-related declines. This emerging pattern of preserved and impaired abilities presents a fundamental challenge for theories of cognitive ageing, which must explain why some aspects of language and memory are more vulnerable to the effects of ageing than others. Information-universal theories, involving mechanisms such as general slowing that are independent of the type or structure of the information being processed, require additional mechanisms to account for this pattern of cognitive aging. Information-specific theories, where the type or structure of the postulated memory units can influence the effects of cognitive ageing, are able to account for this emerging pattern, but in some cases require further development to account for comprehensive cognitive changes such as general slowing.

H.M., word knowledge, and aging: support for a new theory of long-term retrograde amnesia.

This study develops a new theory of long-term retrograde amnesia that encompasses episodic and semantic memory, including word knowledge. Under the theory, retrograde amnesia in both normal individuals and hippocampal amnesics reflects transmission deficits caused by aging, nonrecent use of connections, and infrequent use of connections over the life span. However, transmission deficits cause severe and irreversible retrograde amnesia only in amnesics who (unlike normal persons) cannot readily form new connections to replace nonfunctioning ones. The results of this study are consistent with this theory: For low-frequency but not high-frequency words, a famous "hippocampal amnesic" (H.M.) at age 71 performed worse than memory-normal control participants in a lexical decision experiment and a meaning-definition task (e.g., What does squander mean?). Also as predicted, H.M.'s lexical decision performance declined dramatically between ages 57 and 71 for low-frequency words, but was age-invariant for high-frequency words.

H.M. revisited: relations between language comprehension, memory, and the hippocampal system.

Three studies tested the claim that H.M. exhibits a "pure memory deficit" that has left his ability to comprehend language unimpaired relative to memory-normal controls. In Study 1, H.M. and memory-normal controls of comparable intelligence, education, and age indicated whether sentences were ambiguous or unambiguous, and H. M. detected ambiguities significantly less often than controls. In Study 2, participants identified the two meanings of visually presented sentences that they knew were ambiguous, and relative to controls, H.M. rarely discovered the ambiguities without help and had difficulty understanding the first meanings, experimenter requests, and his own output. Study 3 replicated these results and showed that they were not due to brain damage per se or to cohort effects: Unlike H.M., a patient with bilateral frontal lobe damage detected the ambiguities as readily as young and same-cohort older controls. These results bear on two general classes of theories in use within a wide range of neurosciences and cognitive sciences: The data favor "distributed-memory theories" that ascribe H.M.'s deficit to semantic-level binding processes that are inherent to both language comprehension and memory, over "stages-of-processing theories," where H.M.'s defective storage processes have no effect on language comprehension.

Cross-language facilitation, semantic blindness, and the relation between language and memory: a reply to Altarriba and Soltano.

This comment corrects some inaccuracies, points to some methodological problems, and makes three substantive observations regarding the Altarriba and Soltano (1996) article. First, token individuation theory does not explain what is new and interesting in the Altarriba and Soltano data, namely cross-language semantic facilitation in lists and a list-sentence effect, that is, a large difference in the effect of semantic repetition when identical translation equivalents occurred in sentences versus lists. Second, Altarriba and Soltano's small and nonsignificant semantic blindness effect for translation equivalents in split-language sentences is attributable to the peculiar nature of their materials, procedures, analyses, and experimental design. These problems nullify their conclusion that semantic blindness does not occur, and we discuss several clear cases where semantic blindness has been demonstrated. Finally, we suggest an explanation for Altarriba and Soltano's unexplained effects (cross-language facilitation and the list-sentence effect) and show why these effects are important for the general issue of relations between language and memory.