What is unique about the human eye? Comparative image analysis on the external eye morphology of human and nonhuman great apes

The gaze-signaling hypothesis and the related cooperative-eye hypothesis posit that humans have evolved special external eye morphology, including exposed white sclera (the white of the eye), to enhance the visibility of eye-gaze direction and thereby facilitate conspecific communication through joint-attentional interaction and ostensive communication. However, recent quantitative studies questioned these hypotheses based on new findings that humans are not necessarily unique in certain eye features compared to other great ape species. Therefore, there is currently a heated debate on whether external eye features of humans are distinguished from those of other apes and how such distinguished features contribute to the visibility of eye-gaze direction. This study leveraged updated image analysis techniques to test the uniqueness of human eye features in facial images of great apes. Although many eye features were similar between humans and other species, a key difference was that humans have uniformly white sclera which creates clear visibility of both eye outline and iris; the two essential features contributing to the visibility of eye-gaze direction. We then tested the robustness of the visibility of these features against visual noises such as darkening and distancing and found that both eye features remain detectable in the human eye, while eye outline becomes barely detectable in other species under these visually challenging conditions. Overall, we identified that humans have distinguished external eye morphology among other great apes, which ensures robustness of eye-gaze signal against various visual conditions. Our results support and also critically update the central premises of the gaze-signaling hypothesis.

Experimental evidence for the gaze-signaling hypothesis: White sclera enhances the visibility of eye gaze direction in humans and chimpanzees

Hallmark social activities of humans, such as cooperation and cultural learning, involve eye-gaze signaling through joint attentional interaction and ostensive communication. The gaze-signaling and related cooperative-eye hypotheses posit that humans evolved unique external eye morphology, including exposed white sclera (the white of the eye), to enhance the visibility of eye-gaze for conspecifics. However, experimental evidence is still lacking. This study tested the ability of human and chimpanzee participants to detect the eye-gaze directions of human and chimpanzee images in computerized tasks. We varied the level of brightness and size in the stimulus images to examine the robustness of the eye-gaze directional signal against visually challenging conditions. We found that both humans and chimpanzees detected gaze directions of the human eye better than that of the chimpanzee eye, particularly when eye stimuli were darker and smaller. Also, participants of both species detected gaze direction of the chimpanzee eye better when its color was inverted compared to when its color was normal; namely, when the chimpanzee eye has artificial white sclera. White sclera thus enhances the visibility of eye-gaze direction even across species, particularly in visually challenging conditions. Our findings supported but also critically updated the central premises of the gaze-signaling hypothesis.

Signaling Hypothesis and Size Anomaly in Indian Stock Market

The dividend signaling hypothesis means that dividend change announcements send signals to the market about its prospects. Market capitalization anomaly or size effect means small-cap stocks variances and returns are different than the large-cap stocks. The sample was tested for dividend change announcement, and the sample was divided into large, medium, and small sample sizes based on the market capitalization of the stocks to test the size effect. Event methodology market model used to calculate the abnormal returns on the dividend announcement day. We found that dividends send signals to the market, and the market reacts positively to the dividend change announcements on event day (Aharony and Swary 1980, Litzenberger and Ramaswamy 1982, Dhillon and Johnson 1994, Below and Johnson 1996), but results may vary with the size of the company. Small-cap companies' variances are higher than the large-cap and mid-cap companies, and also small-cap variances are not equal to other variances results similar to Wong (1989), Bandara and Samarakoon (2002), Sehgal and Tripathi (2006), and Switzer (2010). Finally, we concluded that the dividend signaling hypothesis and market capitalization or size effect anomaly exist in the Indian stock market

Identity signaling, identity reception and the evolution of social recognition in a Neotropical frog

Animals recognize familiar individuals to perform a variety of important social behaviors. Social recognition is often mediated by communication between signalers who produce signals that contain identity information and receivers who categorize these signals based on previous experience. We tested two hypotheses about adaptations in signalers and receivers that enable the evolution of social recognition using two species of closely related territorial poison frogs. Male golden rocket frogs (Anomaloglossus beebei) recognize the advertisement calls of conspecific territory neighbors and display a "dear enemy effect" by responding less aggressively to neighbors than strangers, while male Kai rocket frogs (A. kaiei) do not. Our results did not support the identity signaling hypothesis: both species produced advertisement calls that contain similar amounts of identity information. Our results did support the identity reception hypothesis: both species exhibited habituation of aggression to playbacks simulating the arrival of a new neighbor, but only golden rocket frogs showed renewed aggression when they subsequently heard calls from a different male. These results suggest that an ancestral mechanism of plasticity in aggression common among frogs has been modified through natural selection to be specific to calls of individual males in golden rocket frogs, enabling a social recognition system.

Banks’ liquidity management dynamics: evidence from Indonesia

PurposeThis study aims to cover an important yet largely under-explored topic: the dynamic process of bank liquidity management in a vast developing economy by considering pool of funds hypothesis, signaling hypothesis and risk management hypothesis.Design/methodology/approachThe authors apply the dynamic common correlated effect (DCCE) method with an error correction model format to a long panel datasets of 84 Indonesian banks from January 2003 to August 2019, resulting in 16,800 observations.FindingsThe authors obtain convincing evidence of dynamic liquidity management with an error correction mechanism. The time needed to adjust to a liquidity shock ranges from 2.5 to 3.5 months. The empirical results strongly support the pool of funds and signaling hypotheses, whereas risk management motive appears to have secondary importance.Practical implicationsThe regulator should also encourage banks to diversify liquidity management to include interbank money market and off-balance-sheet instruments. The current condition shows that bank liquidity management is strongly correlated with intermediation dynamics and thus is contracyclical. Banks could end up with tight liquidity in a booming economy, which would pose a severe risk to their financial standing.Originality/valueTo authors’ knowledge, this study is the first to analyze bank liquidity management behavior empirically using a panel error correction mechanism. Here, the authors also try to combine a practitioner perspective with a scientific one.

Musical bonds are orthogonal to symbolic language and norms

Both Mehr et al.'s credible signaling hypothesis and Savage et al.'s music and social bonding hypothesis emphasize the role of multilevel social structures in the evolution of music. Although empirical evidence preferentially supports the social bonding hypothesis, rhythmic music may enable bonding in a way uniquely fitted to the normative and language-based character of multilevel human societies.

The dividend signaling hypothesis and the corporate life cycle

PurposeThis paper aims to examine the relationship between the dividend signaling hypothesis and a firm's life cycle.Design/methodology/approachThe authors use Dickinson's (2011) methodology to develop a proxy for the firm's stages in its life cycle and to examine the relationship between dividends and future earnings following a nonlinear setting.FindingsUsing a sample of US firms during the 2000–2014 period, the authors find that the signaling hypothesis can be dependent on firm-specific characteristics, such as life cycle stages. The authors report that the relationship between dividend changes and subsequent earnings changes is different for different life stages. They also find that changes in the amount of the dividend provide some information about future earnings, especially during the early (introductory and growth) stages. These results are consistent with the use of earnings or return on assets as the dependent variables in models of earnings expectations.Originality/valueThe authors believe that this is the first time that the dividend signaling hypothesis has been linked to the life cycle of the firm.

Do Payout Policies and Channel Preferences of Banking Industries Shift during the Tranquil Periods? Evidence from Emerging Market

This study investigates whether the dividend policy (the decision to distribute funds,and the distribution channel preferences) of the bankingsector of Pakistan isaffectedduring any periods of domesticand globalfinancialcrisis. Using a sample of publically listed commercial banks,betweenthe periods of2002 till 2015, this research document that, unlike other countries, the banks in Pakistan fail toindicate adecline in the level of fundsthat are distributedto the investors. Even though the importance of the other means of distribution has increased over time, a major portion ofthe total payoutis still covered bythecash dividends. Moreover, the results of the multinomial logit model,demonstrate that thepayout policy of the commercial bankslisted on the PSX,is not influencedby the global financial crisis. Furthermore, the analysis reveals that more liquid, profitable,and growthoriented bankshave a higher tendencyto pay dividends,thantheotherbanks that do not fall in this category. The empirical results alsoindicate that the signaling hypothesis is a relevant economic phenomenon. These findings provide insights to different stakeholders in developing the relevant policiesneededto cope up with crisis situations,such as the current ongoing Coronavirus pandemic

Does earnings transparency affect corporate payout decisions?

PurposeThe paper examines how earnings transparency affects dividend payouts for Indian firms. The authors also explore the channels through which earnings transparency affects dividend payouts.Design/methodology/approachThe authors employ panel data estimation with fixed effects to examine the role of earnings transparency on dividend payouts. The authors also use path analysis to explore causation. The paper uses a sample of more than 2000 Indian listed firms, over the period 2001–2016.FindingsThe authors report that firms showing grater earning transparency pay more cash dividend. Their results do not support the signaling hypothesis about the dividend. However, these results provide explicit support to the theory that corporate dividend policy is an outcome of information asymmetry. Moreover, the path analysis reveals the effect of earnings transparency on corporate payout through the financial constraint channel. The results are robust to idiosyncratic controls; alternate measures of payout; alternate models; endogeneity concerns; and the alternate channel of returning money to stockholders.Practical implicationsManagers should also examine earnings transparency while formulating an adequate dividend policy for their firms. This study also helps investors to identify dividend-paying stocks.Originality/valueThis study particularly contributes to the literature examining the effect of earnings quality on dividend payouts through its effect on financial constraints. We, therefore, connect two streams of research that contemplate the relation between accounting-based information variables and dividend payouts and the relationship between financial constraints and dividend payouts. Moreover, using path analysis uniquely, the authors provide evidence on the relative importance of both the direct and the indirect link.