Sunk cost: pigeons (Columba livia), too, show bias to complete a task rather than shift to another

The sunk cost effect involves the bias to stay with an alternative because one has already invested resources, even when there is a better alternative available. In a series of experiments, at various points during a 30-peck requirement, pigeons (Columba livia) could choose between completing the response requirement (at a different location in Experiment 1 or the same location in Experiments 3 and 4) and switching to a constant number of pecks. In three experiments, the pigeons showed a bias to complete the pecks already started, even when that required more pecking. We also demonstrated that the bias depended on the initial investment and was not produced merely because the pigeons preferred a variable alternative over a fixed alternative. The deviation from optimal choice suggests that pigeons show a bias similar to the sunk cost effect in humans.     

Effects on modeling sequential body movements when viewed from the front or rear

This study investigated the effect of having a model demonstration viewed from the rear and/or front on the subsequent acquisition of sequential gross-movement patterns, and further examined how participants who observed the bi-angle model directed their attention toward the rear view or the front view in mirror. The movement pattern consisted of seven pauses. A total of 36 participants was divided into three groups: the rear-angle group, which observed the rear view; the front-angle group, which observed from the front view and had to change the motions into their mirror opposites; and the bi-angle group, which observed the rear view and the front view in the mirror. The results showed that (1) all groups acquired the movement pattern, (2) the bi-angle and the rear-angle groups reproduced the demonstrated movement more accurately than the front-angle group, and (3) the bi-angle group tended to focus gaze on viewing the model from the rear. These results suggest that rear viewing was more effective than front viewing, because the participants could simply copy the motion, the bi-angle group members directed their visual attention to the view from the rear without any instruction about observational strategy, and modeling effect was the same for the rear-angle group and the bi-angle group.     

Multichannel fNIRS assessment of overt and covert confrontation naming

Confrontation naming tasks assess cognitive processes involved in the main stage of word production. However, in fMRI, the occurrence of movement artifacts necessitates the use of covert paradigms, which has limited clinical applications. Thus, we explored the feasibility of adopting multichannel functional near-infrared spectroscopy (fNIRS) to assess language function during covert and overt naming tasks. Thirty right-handed, healthy adult volunteers underwent both naming tasks and cortical hemodynamics measurement using fNIRS. The overt naming task recruited the classical left-hemisphere language areas (left inferior frontal, superior and middle temporal, precentral, and postcentral gyri) exemplified by an increase in the oxy-Hb signal. Activations were bilateral in the middle and superior temporal gyri. However, the covert naming task recruited activation only in the left-middle temporal gyrus. The activation patterns reflected a major part of the functional network for overt word production, suggesting the clinical importance of fNIRS in the diagnosis of aphasic patients.     

Pigeons can discriminate “good” and “bad” paintings by children

Humans have the unique ability to create art, but non-human animals may be able to discriminate “good” art from “bad” art. In this study, I investigated whether pigeons could be trained to discriminate between paintings that had been judged by humans as either “bad” or “good”. To do this, adult human observers first classified several children’s paintings as either “good” (beautiful) or “bad” (ugly). Using operant conditioning procedures, pigeons were then reinforced for pecking at “good” paintings. After the pigeons learned the discrimination task, they were presented with novel pictures of both “good” and “bad” children’s paintings to test whether they had successfully learned to discriminate between these two stimulus categories. The results showed that pigeons could discriminate novel “good” and “bad” paintings. Then, to determine which cues the subjects used for the discrimination, I conducted tests of the stimuli when the paintings were of reduced size or grayscale. In addition, I tested their ability to discriminate when the painting stimuli were mosaic and partial occluded. The pigeons maintained discrimination performance when the paintings were reduced in size. However, discrimination performance decreased when stimuli were presented as grayscale images or when a mosaic effect was applied to the original stimuli in order to disrupt spatial frequency. Thus, the pigeons used both color and pattern cues for their discrimination. The partial occlusion did not disrupt the discriminative behavior suggesting that the pigeons did not attend to particular parts, namely upper, lower, left or right half, of the paintings. These results suggest that the pigeons are capable of learning the concept of a stimulus class that humans name “good” pictures. The second experiment showed that pigeons learned to discriminate watercolor paintings from pastel paintings. The subjects showed generalization to novel paintings. Then, as the first experiment, size reduction test, grayscale test, mosaic processing test and partial occlusion test were carried out. The results suggest that the pigeons used both color and pattern cues for the discrimination and show that non-human animals, such as pigeons, can be trained to discriminate abstract visual stimuli, such as pictures and may also have the ability to learn the concept of “beauty” as defined by humans.     

Pigeons perceive the Ebbinghaus-Titchener circles as an assimilation illusion

A target circle surrounded by larger "inducer" circles looks smaller, and one surrounded by smaller circles looks larger than they really are. This is the Ebbinghaus-Titchener illusion, which remains one of the strongest and most robust of contrast illusions. Although there have been many studies on this illusion in humans, virtually none have addressed how nonhuman animals perceive the same figures. Here the authors show that the Ebbinghaus-Titchener figures also induce a strong illusion in pigeons but, surprisingly, in the other direction; that is, all five successfully trained pigeons judged the target circle surrounded by larger circles to be larger than it really is and vice versa. Further analyses proved that neither the gaps between target and inducer circles nor the cumulative weighted surface of these figural elements could account for the birds' responses. Pigeons are known to show similarities to humans on various cognitive and perceptual tasks including concept formation, short-term memory, and some visual illusions. Our results, taken together with pigeons' previously demonstrated failure at visual completion, provide strong evidence that pigeons may actually experience a visual world too different for us to imagine.     

Neural and molecular mechanisms of microcognition in Limax

Various non-mammalian model systems are being explored in the search for mechanisms of learning and memory storage of sufficient generality to contribute to the understanding of mammalian learning mechanisms. The terrestrial mollusk Limax maximus is one such model system in which mammalian-quality learning has been documented using odors as conditioned stimuli. The Limax odor information-processing circuits incorporate several system design features also found in mammalian odor-processing circuits, such as the use of cellular and network oscillations for making odor computations and the use of nitric oxide to control network oscillations. Learning and memory formation has been localized to a particular central circuit, the procerebral lobe, in which selective gene activation occurs through odor learning. Since the isolated Limax brain can perform odor learning in vitro, the circuits and synapses causally linked to learning and memory formation are assessable for further detailed analysis.     

Behavioral speed contagion: automatic modulation of movement timing by observation of body movements

To coordinate our actions with those of others, it is crucial to not only choose an appropriate category of action but also to execute it at an appropriate timing. It is widely documented that people tend to unconsciously mimic others' behavior. The present study show that people also tend to modify their movement timing according to others' movements even when the observed and the to-be-executed movements are unrelated. Observers viewed either point-light biological motion, scrambled biological motion, or solid object motion. The stimulus sequence was presented at three different (half, normal, and double) rates. After a 300-2400-ms blank period, the observers performed a simple choice reaction-time task that was unrelated to the presented stimulus sequence. The observation of the biological motion produced a negative correlation between reaction time and stimulus speed, whereas no such trend was observed with the scrambled or solid object motion. Furthermore, speed-dependent modulation occurred only when the task was imposed within approximately 1s after the offset of the biological motion. These results suggest that behavioral tempo may be contagious; the speed of others' movements may automatically influence the timing of movement execution by the observer.     

Head-putter coordination patterns in expert and less skilled golfers

The authors examined the patterns of expert and less skilled golfers in putting on an indoor surface to 1 of 3 circular targets (1, 3, and 5 m away) in trials with a ball present (and putted) or not present (a practice stroke). As expected, the experts performed better than the less skilled golfers on a large number of outcome and kinematic measures. Displacement and velocity profiles of the head and putter revealed high positive correlations for the less skilled golfers, indicating a dominant allocentric coordination pattern, but high negative correlations for the expert golfers, indicating a dominant egocentric coordination pattern. The observed coordination patterns did not interact with the distance of the intended putt or the presence/absence of a ball. These findings offer preliminary evidence that, although contrary to traditional beliefs, fundamental differences exist in putting coordination modes between expert and less skilled golfers.     

Reduced relative frequency of knowledge of results without visual feedback in learning a golf-putting task

This study examined the effects of reduced relative frequency of knowledge of results (KR) on learning to putt in golf. Participants (19 men and 15 women) putted a golf ball, stopping the ball on a line at a distance of 3.5 m from the starting position, which included an uphill portion. After a pretest, participants were assigned as they arrived in balanced order by sex to one of two groups (100% KR, 33% KR) and practiced 60 trials. Those in the 100% KR group performed the task in its natural context, while others assigned to the 33% KR were shown the location of the putted ball after every third trial. All participants then performed a posttest and two retention tests, done 10 min. and 24 hr. after the posttest. Analysis at posttest showed each group had a constant error and an absolute constant error (/CE/) less than those at pretest. Also, in the retention test conducted the following day, the constant error of the 33% KR group was less than that of the 100% KR group. Third, in the posttest and both retention tests, the /CE/ of the 100% KR group was larger than that of the 33% KR group. These results suggest that reduced relative frequency of knowledge of results is effective in learning the accuracy of the golf putt.