Age and the selectivity of visual information processing.

Two experiments assessed age differences in the selectivity of visual information processing. Selectivity was measured by the amount of interference caused by nontarget letters when Ss detected a target letter in a visual display. In both experiments, young and elderly groups participated in search and nonsearch conditions; in the search condition, targets appeared anywhere in the display, whereas in the nonsearch condition targets were confined to the center position of the display. In Exp I, 20 19–27 yr olds and 20 65–90 yr olds were assigned to either condition for 2 sessions of testing. In Exp II, 16 young (mean age 19.8 yrs) and 16 elderly (mean age 71.8 yrs) Ss participated in both conditions. In both experiments, nontargets produced larger interference effects for old compared to young Ss in the search condition but not in the nonsearch condition. The obtained pattern of age effects could not be explained by age-related reductions in parafoveal acuity. Findings indicate that the magnitude of divided-attention deficit increases with age, whereas focused-attention deficits are unaffected by aging. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Locus and persistence of capacity limitations in visual information processing.

Although there is considerable evidence that stimuli such as digits and letters are extensively processed in parallel and without capacity limitations, recent data suggest that only the features of stimuli are processed in parallel. In an attempt to reconcile this discrepancy, the simultaneously/successive detection paradigm was used with stimuli from experiments indicating parallel processing and with stimuli from experiments indicating that only features can be processed in parallel. In Exp I, with 30 undergraduates, large differences between simultaneous and successive presentations were obtained with an R target among P and Q distractors and among P and B distractors, but not with digit targets among letter distractors. As predicted by the feature integration theory of attention, false-alarm rates in the simultaneous condition were much higher than in the successive condition with the R/PQ stimuli. In Exp II, with 10 Ss, the possibility that attention is required for any difficult discrimination was ruled out as an explanation of the discrepancy between the digit/letter results and the R/PQ and R/PB results. Exp III (40 Ss) replicated the R/PQ and R/PB results of Exp I and extended these findings to a new set of stimuli. Exp IV (6 Ss) found that large amounts of consistent practice did not generally eliminate capacity limitations. It is concluded that the notion of capacity-free letter perception has limited generality. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age and skill in visual search.

The effects of age and experience on visual-cognitive performance were examined by administering a domain-relevant visual search task and a standard letter search task to skilled and control Ss at 2 age levels (young and middle-aged adults). In the skilled task, Ss searched for a designated item within 3-item displays using images of bacteria morphology as targets and distractors. Each target was preceded by a word prime representative of bacteria morphology that was valid, invalid, or neutral with respect to the diagnostic characteristics of the target. Skilled Ss showed an age deficit in letter search performance, but the performance of the young and middle-aged skilled Ss was not different on the domain-relevant task. Valid primes produced benefits for the young and middle-aged skilled participants, whereas control Ss were unaffected by the prime manipulation. Results were consistent with the prediction that experience serves to attenuate age-related declines in visual-cognitive performance in the skilled domain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotic susceptibility and performance on various attention-specific cognitive tasks.

In 2 experiments, 52 undergraduates were administered the Harvard Group Scale of Hypnotic Susceptibility, Form A, and were divided into groups with high and low hypnotic susceptibility (HS). In Exp I (32 Ss), time-to-location of a target in a visual search was assessed. For this task, the letter Z was embedded within either straight- or round-form letters. Results indicate that Ss of high HS were significantly faster than those of low HS in locating the embedded letter. Exp II (20 Ss) investigated performance on single- and double-digit arithmetic problems as a function of HS level. Ss were presented with addition problems and asked to complete them within 60 sec. Ss of high HS completed a significantly greater number of double- but not single-digit problems within this time than did Ss of low HS. Results are discussed in terms of the 2 groups' differing strategies or operations in the performance of cognitive tasks. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Presenting words without interior letters: Superiority over single letters and influence of postmask boundaries.

In 5 experiments with a total of 32 Ss, exterior letter pairs from 4-letter words (e.g., d??k from dark) were presented in pattern-postmasked displays, in the positions they would occupy if the whole word were shown. In Exp 1, letter pairs (d??k) were reported more accurately than single letters (d) (the pair–letter effect). In Exps 2 and 3, performances with letter pairs dropped to those for single letters when each letter in a pair was masked individually or when masks were much wider than letter pairs. In Exps 4 and 5, the pair–letter effect and mask influence were both removed when one letter in each pair was replaced by a number sign (d??#) or when letter pairs were not the exterior letters of real words (e.g., y??f). These findings suggest that the exterior letter combinations of words are represented psychologically and access to these representations is affected by mask configuration. Implications for current word-recognition models are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Patterns of eye movements during parallel and serial visual search tasks.

In 2 experiments with a total of 24 undergraduates, eye movements were monitored while Ss performed parallel and serial search tasks. In Exp 1a, Ss searched for an "O" among "X"s (parallel condition) and for a "T" among "L"s (serial condition). In the parallel condition of Exp 1b, "Q" was the target and "O"s were distractors; in the serial condition, these stimuli switched roles. Displays contained 1, 12, or 24 stimuli, with both target-present and target-absent trials. RT and eye-movement measures (number of fixations, saccadic error, and latency to move) indicated that search efficiency was greatest in the parallel conditions, followed by the serial condition of Exp 1a and, finally, by the serial condition of Exp 1b. This suggests that eye movements are correlated with the attentional processes underlying visual search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Orthographic and lexical processing of visual letter strings.

Three experiments tested whether orthographic and lexical properties of a letter string influence the time to search for a component letter. 102 Canadian undergraduates served as Ss. Orthographic redundancy, defined by single-letter position-specific frequency, facilitated the search of targets specified prior to and simultaneously with the letter string. Words were searched faster than nonwords when the target followed the letter string. Neither orthographic nor lexicality had significant effects when the position of the target within the string was certain. Results are consistent with a hierarchical-levels model of word perception in which the activation of detectors at different levels is constrained by task demands. (French abstract) (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in memory-driven selective attention.

Investigated the ability of young and elderly adults to use memory-driven selective attention in 2 visual-search experiments. In Exp I, 16 18–22 yr olds and 16 60–74 yr olds were Ss in a yes–no search paradigm. Stimulus-onset-asynchrony (SOA) was varied from 200 to 1,000 msec. In Exp II, 18 18–24 yr olds and 18 60–73 yr olds were presented 1 of 2 target letters as a cue, using the same SOA ranges. Results in both experiments show that both age groups exhibited faster RTs to a visual display on trials when advance information (a cue) correctly predicted the particular target letter that would most likely be present in the display. Variations in the SOA between the cue and the display demonstrated that both age groups were capable of developing this selective preparation for a particular target letter within 200 msec. Results indicate that age differences in performance were determined primarily by quantitative changes in the speed of information processing rather than by qualitative changes in attention. In both experiments, the 2 age groups differed in the type of relationship between speed and accuracy that they adopted, suggesting a possible age difference in performance strategy. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of information below fixation in reading and in visual search.

Two experiments examined whether or not readers obtain useful information from below the currently fixated line. In Exp 1, 15 adults read passages of text, and the availability of visual information below the line fixated was manipulated using a variant of the moving window technique. Reading was no slower when there was no letter information below the fixated line than when there was full information below the fixated line. However, a condition that made the strings of letters below the fixated line less wordlike caused reading to be slowed down by about 6%. In Exp 2, 15 adults searched for a target word through passages of text. There was no clear evidence that the availability of information below the line made search more efficient. It appears that in reading, little visual information is extracted below the line of text fixated. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positional differences in performance on members of confusable and nonconfusable letter pairs.

Previous experiments by the present author (see PA, Vols 67:6977 and 70:7125) showed that a parafoveally presented letter is more accurately identified when flanked by a letter to its foveal side than when flanked by one to its peripheral side, but only if the 2 letters are nonconfusable. The present 4 experiments, with 65 undergraduates, indicated that the basis for this confusability–asymmetry interaction is not criterion or response bias, but rather that it occurs earlier in visual processing. In Exp I, the interaction was found when only 1 pair member was reported, thus eliminating response bias requiring the report of both letters as the source of the effect. In Exp II, the data were subjected to signal detection analysis, and the interaction persisted. In Exp III, pair members were presented simultaneously or in rapid sequence, and the interaction was found only with simultaneous presentations. In Exp IV, letters were used with upper- and lowercase counterparts that were quite different in shape. Uppercase letters that were most and least confusable for each S were paired for presentation in their uppercase or in mixed-case forms. The interaction occurred only with uppercase pairs. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of search procedures in real-life spatial environments.

Children's abilities to search for missing objects in real-life environments were investigated in 2 studies with a total of 70 2 yr 7 mo–6 yr 2 mo old Ss. Exp I involved searches of 8 locations on a school playground; Exp II involved searches of 8 large cupboards. In each study, Ss performed a free search followed by a logical search. In free search, the S was instructed to search the 8 locations to find a missing item. In logical search a critical search area within the 8 locations was defined for the Ss on the basis of (a) where the item was last seen and (b) where it was first discovered missing. In free search, more older than younger Ss searched each location at least once and searched all locations sequentially. Detailed comparisons of search patterns under the free and logical conditions revealed that older Ss understood the critical search area. In contrast, younger Ss' searches under the logical condition depended on one salient association of a location with the missing item. The developmental trends indicated that several memory and logical processes determine search procedures. The development and integration of these processes are discussed. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Location coding with letters versus unfamiliar, familiar, and labeled letter-like forms.

Errors in reporting a post cued target in a string of several letters more often involve a letter appearing elsewhere in the string (mislocation error) than one not appearing in the string (intrusion error). However, this difference is not found with strings of relatively unfamiliar symbols or forms. Two experiments, with a total of 70 Ss, explored the reason for this difference. Exp 1 showed that the difference was not an artifact of different overall accuracy levels or exposure durations for the 2 character types. In Exp 2, relative to no experience, initial experience with the forms through familiarization or learning labels for them produced mislocation and intrusion frequencies that were more similar to those for letters. This change was related to the development of stored representations for forms that are similar to those for letters. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pictorial mnemonics for phonics.

Evaluated whether picture mnemonics help prereaders learn letter–sound associations in 2 experiments with 20 1st graders (Exp I), 30 preschoolers, and kindergartners (Exp II). Pictures integrating the associations were compared with disassociated pictures and with a no-picture control condition. Ss in the integrated-picture group learned 5 letter-sound associations (e.g., f, /f/), each represented by a picture whose shape included the letter (e.g., letter f drawn as the stem of a flower) and whose name (flower) began with the letter's sound. Ss in the disassociated-picture group learned letter–sound associations with pictures having the same names as the integrated pictures, but drawn differently—without letter shapes. Ss in the control group learned associations with picture names but no pictures. Prior to letter–sound training, all groups were taught how to segment the initial sounds of the picture names. Results reveal that Ss taught with integrated mnemonics learned more letter–sound associations and also more letter–picture associations than did the other 2 groups, which did not differ. Integrated pictures were effective because they linked 2 otherwise unconnected items in memory. It is concluded that the shape of letters included in pictures reminded learners of previously seen pictures with those shapes whose names began with the relevant letter sounds. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of misoriented words and letter strings.

In Exp I, 8 undergraduates were presented with English words transformed in any of 4 combinations of rotation and distortion of spatial relationships between letters, and recognition time was measured. Both misorientation and distortion of relationships slowed down recognition, and their effects were additive. A similar effect of transformation was also found for strings of unrelated letters (Exp II, 10 undergraduates). With the word stimuli, Ss were given different amounts of information about the transformation prior to presentation. Prior information reduced the differences between mean processing times for different transformations but did not change their ordinal relationships. Information about order of letters was more helpful than information about orientation. The time to recognize a transformed word was positively related to the number of letters in the word, and the effect of the number of letters interacted with the type of transformation. Results support the hypothesis that the process of normalizing a misoriented word or nonword operates on it as a single unit rather than on each letter separately. (French summary) (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading ability and single-letter orthographic redundancy.

Two experiments investigated the role of one form of intraword orthographic redundancy: the characteristic asymmetric spatial distributions of letters of the alphabet across serial positions within words. In Exp I, 81 college students demonstrated recognition knowledge of these distributions when given only the letter name, word length, and serial position information with no other context. Ss were correct more often for those letters which are least variable across serial positions. In Exp II, 28 5th graders who were skilled readers demonstrated a sensitivity to letter positional distributions similar to that of the adults; 20 poor readers did not. However, performance was equivalent for both good and poor readers on a subset of letters relatively unpredictable with respect to serial position. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual interactions in two-word displays: Familiarity and similarity effects.

Previous studies have demonstrated the existence of perceptual interactions in the processing of 2-word displays such as SAND LANE. Four experiments were conducted with 99 undergraduates to study the role of familiarity and similarity of the stimuli on these interactions. Exp I examined whether migration errors, and the effect of surround similarity on these errors depend on the fact that the migrating letters fit together with the surround in which they occur to form familiar higher order units. Exp II replicated the results of Exp I using a slightly different paradigm. Exp III examined the role of lexicality, independent of orthographic regularity, by comparing word stimuli to orthographically regular nonword stimuli, and Exp IV examined the role of physical, as opposed to abstract, similarity of the stimuli. Overall findings indicate that when postcued to report 1 of the 2 words, Ss often made migration errors, in that the report of the specified word included a letter of the other word (e.g., LAND or SANE instead of SAND). Migrations depended on the abstract, structural similarity of the strings, but not on the physical similarity; on whether the strings were words; and on whether the possible migration responses were words. Results reveal that migration errors could not be attributed to a guessing strategy. Findings are interpreted in terms of models in which both strings simultaneously access high-level structural knowledge about what sequences of letters fit together to form familiar wholes. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of information in iconic memory: Differences between nonretarded and retarded subjects.

Compared iconic memory processes of 17 undergraduates and 18 retarded Ss (primarily aged 18–28 yrs; IQ 56–77) in 4 experiments. In Exp I, a partial report paradigm was used in which 6 retarded and 6 undergraduate Ss were presented 6 pictures under 4 intervals (0–500 msec). In Exp II, using 5 Ss in each group the same procedure as in Exp I was used but letters as well as pictures were included. Results show that although overall performance for retarded Ss was poor, they did better with letters than with pictures—a reverse of the finding with undergraduate Ss. In Exp III, 2 retarded Ss were given extended practice and incentive to perform well. Asymptote was reached in 10 days but never equaled performance of unpracticed undergraduates. In Exp IV, using 5 Ss in each group, information load was varied from 1 to 4 items, and a masking stimulus was used to interrupt processing following 6 intervals that lasted up to 250 msec. Results show that (1) there are quantitative differences between intelligence groups in iconic capacity; (2) retarded Ss process information more slowly, a difference that increases with increasing information load; and (3) there are substantive structural differences in iconic memory of retarded and nonretarded Ss. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance of process schizophrenics on tasks involving visual search.

Compared the response times of 32 process schizophrenics and 16 nonhospitalized matched controls on 3 visual search tasks. Exp I involved the location of a target letter within an array of different background letters. Other experiments required a same–different response. Exp II involved the identification of a single different letter set within the uniform context of a square display formed by up to 40 replicates of another letter. Exp III presented 2 3–6 letter clusters in a single horizontal line. The 2 clusters were identical or had 1 different letter. Word and nonword clusters were used. Paranoid and nonparanoid groups did not differ on any measure. Schizophrenic response times were about 1 sec longer, but measures of rate of increase in response time with number of letters displayed did not generally differ significantly between groups. Schizophrenics tended to make more errors. Experimental manipulations affected the response times and error rates of schizophrenics and controls alike, and to much the same degree. Results suggest that process schizophrenics are not abnormally slow when extracting information from visual displays, and they appear to perform operations and strategies similar to those of normals when doing so. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Order of processing in visual perception.

Three experiments tested predictions derived from 3 cognitive scanning hypotheses proposing respectively a left-to-right, ends-first, and peripheral-foveal order of scanning. In Exps I and II configurations of letters and/or digits were presented to 11 Ss around a central fixation point, and the stimulus was followed by a 1-sec presentation of a patterned mask or a blank white field. Backward masking selectively impaired the identification of stimuli in foveal positions whether or not these stimuli occupied middle-of-row positions. In Exp III 4 Ss made a manual same-different response to the presence or absence of a critical letter presented 3Deg. to the left or right of fixation. Noise letters appeared on either side or both sides of the critical letter. Identification response times were faster when the critical letter appeared in the left-most position in left field arrays and the right-most position in right field arrays. Principal conclusions drawn from the 3 experiments were: (a) Alphanumeric stimuli are scanned from the peripheral visual field inward towards fixation. (b) Any left-to-right scanning occurs relatively late in iconic processing. (c) An ends-first scanning strategy is a particular case of a more general peripheral-foveal strategy. (French summary) (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical access during eye fixations in reading: Effects of word-initial letter sequence.

Tested the constraint hypothesis, which states that lexical access in reading is initiated on the basis of word-initial letter information obtainable in the parafoveal region, in 2 experiments. Ss were 36 college students with normal vision. Eye movements were monitored while Ss read sentences containing target words whose initial trigram (Exp I) or bigram (Exp II) imposed either a high or a low degree of constraint in the lexicon. In contradiction to the hypothesis, high-constraint words (e.g., dwarf) received longer fixations than did low-constraint words (e.g., clown), despite the fact that high-constraint words have an initial letter sequence shared by few other words in the lexicon. A comparison of fixation times in viewing conditions with and without parafoveal letter information showed that the amount of decrease in target fixation time due to prior parafoveal availability was the same for high- and low-constraint targets. It is concluded that increased familiarity of word-initial letter sequence is beneficial to lexical access and that familiarity affects the efficiency of foveal but not parafoveal processing. A list of the sentences used in the 2 experiments is appended. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)