A signal detection theory analysis of an unconscious perception effect.

The independent observation model (Macmillan & Creelman, 1991) is fitted to detection-identification data collected under conditions of heavy masking. The model accurately predicts a quantitative relationship between stimulus detection and stimulus identification over a wide range of detection performance. This model can also be used to offer a signal detection interpretation of the common finding of above-chance identification following a missed signal. While our finding is not a new one, the stimuli used in this experiment (redundant three-letter strings) differ slightly from those used in traditional signal detection work. Also, the stimuli were presented very briefly and heavily masked, conditions typical in the study of unconscious perception effects.

The time it takes elderly and young individuals to draw pictures and write words.

Twenty elderly and 20 young Ss drew pictures or wrote words for picture or word stimuli. Elderly Ss had slower response initiation than young Ss, especially when drawing. Beyond this, both age groups processed picture and word stimuli similarly. Elderly and young Ss exhibited equivalent latency increases for cross-modality trials (e.g., draw a picture given a word) over within-modality trials (e.g., draw a picture given a picture), regardless of stimulus or task modality. Strong support was found for a mathematical model of these results, which assumes age-related additive slowing for input and output subprocesses but age invariance for a cross-modality transfer subprocess. However, regressing elderly on young whole-condition latencies indicated general, multiplicative slowing: a discrepancy that questions the utility of the global Brinley plot procedure in revealing the nature of age-related slowing.

Priming outside of awareness and subsequent stimulus identification.

The influence of priming outside of awareness on performance of a color-recognition task was investigated. Using a tachistoscope, a color word that matched ("congruent prime") or did not match ("incongruent prime") the target color or a blank prime was followed by a pattern mask and the target color. Identification performance was superior on the blank prime trials to the congruent prime trials, with performance on the incongruent prime trials being the lowest. A subsequent study included a meaningless (XXX) prime condition, and it was found that meaningless primes interfered with target-color identification more than the congruent and blank prime conditions, but less than the incongruent prime condition, suggesting that primes, in addition to producing semantic activation, impose demands on information-processing capacity of the perceptual system.

Theoretical analysis of the cognitive processing of lexical and pictorial stimuli: reading, naming, and visual and conceptual comparisons.

This article reviews the research literature on the differences between word reading and picture naming. A theory for the visual and cognitive processing of pictures and words is then introduced. The theory accounts for slower naming of pictures than reading of words. Reading aloud involves a fast, grapheme-to-phoneme transformation process, whereas picture naming involves two additional processes: (a) determining the meaning of the pictorial stimulus and (b) finding a name for the pictorial stimulus. We conducted a reading-naming experiment, and the time to achieve (a) and (b) was determined to be approximately 160 ms. On the basis of data from a second experiment, we demonstrated that there is no significant difference in time to visually compare two pictures or two words when size of the stimuli is equated. There is no difference in time to make the two types of cross-modality conceptual comparisons (picture first, then word, or word first, then picture). The symmetry of the visual and conceptual comparison results supports the hypothesis that the coding of the mind is neither intrinsically linguistic nor imagistic, but rather it is abstract. There is a potent stimulus size effect, equal for both pictorial and lexical stimuli. Small stimuli take longer to be visually processed than do larger stimuli. For optimal processing, stimuli should not only be equated for size, but should subtend a visual angle of at least 3 degrees. The article ends with the presentation of a mathematical theory that jointly accounts for the data from word-reading, picture-naming visual comparison, and conceptual-comparison experiments.