Harvey G. Shulman

The effects of graphemic, phonetic, and semantic relationships on access to lexical structures

The question of whether or not lexical information is accessed directly from a visual code or by a process of phonetic mediation was investigated in three lexical decision experiments. Phonetic similarity influenced decisions about visually presented words only when they were to be discriminated from orthographically regular nonwords. When consonant strings or random letter strings were used as nonwords, phonetic similarity effects were absent, and graphemic similarity exerted a powerful effect while evidence of semantic priming was found. This pattern was interpreted as evidence of direct lexical access, which is probably the normal processing mode for skilled readers. Phonetic coding, when it occurs, may be a storage strategy rather than a part of the addressing chain for lexical structures.

Control Properties of Semantic Coding in a Lexical Decision Task.

Decisions about whether pairs of letter strings are both words or not are typically faster for pairs of semantically related words than unrelated words ( Meyer & Schvaneveldt, Journal of Experimental Psychology, 1971, 90, 227–234 ). Previous studies used orthographically legal, pronounceable nonwords in this task. In two experiments it was shown that the semantic relatedness effect is greatly reduced when orthographically illegal, unpronounceable strings were used as negative items. This finding supports the conclusion that options may be exercised on which of the codes representing a letter string are used in making lexical decisions.

Semantic Confusion Errors in Short-Term Memory.

The analysis of error data in short-term memory (STM) tasks has frequently led to the conclusion that semantic information is not stored efficiently in STM. Experiment I used a probe recognition memory task requiring the recognition of either identity or synonymity. Conditions between which the opportunity for semantic confusion errors differed resulted in changes in the rate of false recognition. This evidence was viewed as supporting the hypothesis that semantic information may be stored in STM when such storage is a task demand. A second experiment explored the ability to recognize synonymity when storage in STM is not involved. The results showed less than perfect recognition, indicating that synonyms are only approximate instances of semantic identity.

MSH/ACTH 4–10 in men and women: Effects upon performance of an attention and memory task

Abstract During two test sessions, twelve males and twelve females were subcutaneously administered 30 mg doses of MSH/ACTH4–10 or the diluent control solution in a double-blind, randomized, completely crossed design. The results indicated that in comparison to the control session, reaction time scores for the Sternberg item recognition task were significantly decreased after MSH/ACTH 4–10 administration. The reaction time scores were reduced by a nearly equal amount at each of four memory set sizes; this pattern of results suggests that the peptide exerts its effects on attention as opposed to memory. The decreased reaction times after peptide treatment occurred without a concomitant change in error rate. In addition, the order of treatment interacted significantly with the peptide treatment so that performance was apparently facilitated whether MSH/ACTH 4–10 administration preceded testing by an hour or by several days. Self-reported anxiety levels were not significantly affected by the peptide treatment. Males and females did not significantly differ on reaction time scores, error scores, or anxiety levels in the present study.

Differential effects of repetition on pre- and postcategorical memory traces

The effect of list repetition on immediate recall for aurally presented nine-letter lists was studied under two conditions. In the first, a redundant stimulus item was presented as the tenth item in each list, while the suffix was not included in a control condition. As in previous research (Crowder & Morton, 1969), the stimulus suffix selectively interfered with recall at the terminal presentation serial positions, indicating the presence of precategorical acoustic storage. Repetition had a nonselective effect on performance. This result and an analysis of acoustic errors support the inference that qualitative differences in the memory code may lead to differences in other functional properties of the memory trace, such as responsiveness to repetition.