The effects of preceding stimuli on the judgments of current stimuli were examined in a study using absolute judgments of loudness with feedback. It

The rate of blinking is related to certain mental activities. One common feature of states associated with low blink rates is the presence of concentrated cognitive activity. The purpose of the present study was to determine how blinking is affected by variations in mental load; it was hypothesized that, for a given nonvisual task, blinking would decrease as mental load increased. The first study reported here manipulated memory load by requiring Ss to retain a sequence of 4, 6, or 8 digits. The second study involved mental arithmetic under time pressure; half the trials contained zeros in the sequence of numbers to be summed. In both studies the rate of blinking was low when mental load was high and the rate was high when mental load was low. It is speculated that blinking may disrupt certain cognitive processes and may therefore be inhibited when these processes are active. When mental load is increased, the inhibition of blinking may be an adaptive mechanism which protects vulnerable cognitive processes from interference.

Blinking is related to certain cognitive processes. For example, individuals “punctuate” their speech by blinking between phrases and at the end of sentences. Daydreaming is associated with low rates of blinking. Blinking occurs between fixations and may be timed so as not to interfere with significant visual input. Apparently, blinking occurs at transitions between internal events and is inhibited at other times. In the experiment reported here, blinking was measured while the activity of operational memory was manipulated with mental load kept constant. The rate of blinking was significantly reduced when the cognitive operation of internal counting was being performed. It is inferred that the blink rate is low when information in memory is being operated on. To suspend blinking during certain cognitive activities would be adaptive if blinking disrupts them. Since the blackout period of the blink produces a rapid change in visual level, blinking disrupts those cognitive processes utilizing display areas accessible to visual input. Operational memory and the visual imagination may share components with the visual perceptual system. To protect these vulnerable processes from interference, blinking may be inhibited when they are active.

In an effort to understand some of the functional determinants of naming, Koehler's maluma-takete demonstration was examined in two studies, to see whether the matching of the nonsense words and nonsense figures could be accounted for on the basis of physiognomic similarity, as measured by the semantic differential. Matching was found to occur overwhelmingly in the expected direction, and the similarity of semantic differential locations of matched pairs was far greater than that of non-matched pairs. This held strikingly for “literal” scales (such as “Angular-Rounded”) but also held to a lesser extent for clearly “non-literal” scales (such as “Fresh-Stale”), indicating that physiognomic properties over and beyond simple literal description of the stimuli were involved. Study of the semantic differential locations of letters composing the nonsense words, and of ratings of the “fittingness” of the letters as names for the nonsense figures, showed that the physiognomic similarity presumably mediating the naming phenomenon may, at least in the Koehler demonstration, reside in the individual letters rather than in some emergent quality of the whole word. All in all, the study attempted to go beyond just checking whether a “fittingness” phenomenon occurs in naming, by exploring processes hypothesized to underlie the “fittingness.” In at least some cases, physiognomic similarity may be the psychological process mediating naming.

Performance of two pigeons given tasks in discriminating colors was examined on trials before and after they had occasionally received rewards for pecking when exposed to light of specific wavelengths. After a reward, the probability that the birds would respond to light svtimuli that were never rewarded was higher than before the reward was given, but paradoxically the birds showed no general decline in their ability to differentiate between stimuli at wavelengths 1 millimicron apart.

The procedure of Guttman & Kalish (1956) for obtaining generalization gradients in extinction following variable interval (VI) training to a single stimulus value has proved a valuable tool for the analysis of behavior. The length of the VI trial, however, limits the usefulness of this procedure for certain types of questions. An alternative generalization testing procedure, explored in the present study, involves short, closely spaced discrete trials, each trial terminated by a single peck, and employs a probability measure of response. The relatively brief sampling time of the discrete trial procedure permits a more detailed tracking of the behavioral change during the generalization test. The present study was designed to examine the change in extent of generalization during extinction and recovery of responding. MethodTwelve White Carneaux pigeons, maintained at 80% of their ad lib weights, were trained to peck a Plexiglas key illuminated from behind by 550 mf.L from Bausch and . LOmb monochromators. All control, timing, schedule, and analysis functions were provided by a LINC computer operating on-line. Relays controlled by the LINC activated shutters, magazines, and magazine lights. The LINC in addition sensed switch openings resulting from pecks. During the first 14 days of training percent reinforcement was reduced from 100% to 10%, and trial time was reduced from 6 to 3 sec. For the last six days of training the animals were run on 3 sec trials and 10% random reinforcement. Throughout training and testing, trials were terminated either when the 3 sec had elapsed or when a peck occurred.The 11 stimuli used for the generalization test consisted of monochromatic values from 500 to 600 mf.L, at 10 mf.L intervals. Each sequential block of 11 3 sec trials was composed of the 11 test stimuli presented in random order separated by 2 sec blackouts. Four days of generalization testing occurred, conSisting of 4000 trials. Interpolated feedings ("free" feedings) occurred at regular intervals throughout

Perceptual and Motor Skills, 1975, 41, 403-406 NOTE: This is a physiological experiment with integrative overtones. T h e concept of operational memory sharing display areas accessible to visual input and therefore being vulnerable to visual interference i$ affirmed. This would place confirmed responsibility upon the clinician to use this informationain training the LD child to cope with an unreliable operational memory. -F.M.

Generalization gradients on wavelength were obtained from pigeons using a discrete trials procedure. For a group tested with 3 sec trials, it was found that gradients produced by responses of shorter latencies showed greater extent of generalization than did gradients produced by responses of longer latencies. This relationship was also shown to hold when latencies were experimentally controlled by training different groups of animals on trials of differing lengths.In an earlier experiment (Holland &: Baker, 1967) generalization gradients on wavelength were obtained from pigeons using a brief discrete trials procedure and employing probability of peck as a response measure. The current paper examines the relationship between the latency of the responses and the extent of the generalization gradients produced at given latencies. Subjects Twenty-four White Carneaux pigeons were used, maintained at 80% of their ad lib weights. All were experimentally naive. ApparltusThe pigeons worked in four identical darkened cubical experimental chambers. The keys were springloaded plates of Plexiglas illuminated from behind by Bausch and Lomb Model 33-86-25 monochromators. Individual shutters for each box were solenoidactivated plates mounted in the path of the beam. Reinforcements were provided from grain magazines accessible through 3 in. circular holes below the keys. All control, timing, schedule, and analysis functions were provided by a UNC computer operating on-line. Responses were sensed by the UNC. The latency of the responses was timed by a clock internal to the LINC which operated in .05 sec units. Method Experiment 1. Following magazine training, 12 birds were trained by the method of approximation to peck a key illuminated by 550 mfJ.. After 100 continuously reinforced responses with the shutter open, 6 sec discrete trials were introduced. The animals were run daily on discrete trials for the next 13 days, during which certain parameters were slowly changed: percent reinforcement was reduced from 100% to 10%; trial time was reduced from 6 to 3 sec; and daily number of trials given was increased from 100 to 200. The animals were then run for six days on 3 sec trials and 10% reinforcement. Throughout training and testing, trials were terminated either when the allotted trial time had elapsed or when a peck occurred. During the last six days of training all birds were responding essentially to every trial.